// ----------------------------------------------------------------------------------------------------------------------------
//
// Version 2.03
//
// ----------------------------------------------------------------------------------------------------------------------------

#include <windows.h>

#ifndef WM_MOUSWHEEL
    #define WM_MOUSWHEEL 0x020A
#endif

#include "glmath.h"
#include "string.h"

#include <gl/glew.h> // http://glew.sourceforge.net/
#include <gl/wglew.h>

#include <FreeImage.h> // http://freeimage.sourceforge.net/

// ----------------------------------------------------------------------------------------------------------------------------

#pragma comment(lib, "opengl32.lib")
#pragma comment(lib, "glu32.lib")
#pragma comment(lib, "glew32.lib")
#pragma comment(lib, "FreeImage.lib")

// ----------------------------------------------------------------------------------------------------------------------------

extern CString ModuleDirectory, ErrorLog;

// ----------------------------------------------------------------------------------------------------------------------------

#define BUFFER_SIZE_INCREMENT 1048576

// ----------------------------------------------------------------------------------------------------------------------------

class CBuffer
{
private:
    BYTE *Buffer;
    int BufferSize;

private:
    int Position;

public:
    CBuffer();
    ~CBuffer();

private:
    void SetDefaults();

public:
    void AddData(void *Data, int DataSize);
    void Empty();
    void *GetData();
    int GetDataSize();
};

// ----------------------------------------------------------------------------------------------------------------------------

extern int gl_max_texture_size, gl_max_texture_max_anisotropy_ext;

// ----------------------------------------------------------------------------------------------------------------------------

class CTexture
{
private:
    GLuint Texture;

private:
    int Width, Height;

public:
    CTexture();
    ~CTexture();

private:
    void SetDefaults();

public:
    operator GLuint ();

private:
    FIBITMAP *GetBitmap(char *FileName, int &Width, int &Height, int &BPP);

public:
    bool LoadTexture2D(char *FileName);
    bool LoadTextureCubeMap(char **FileNames);
    void Destroy();

public:
    int GetWidth();
    int GetHeight();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CShaderProgram
{
private:
    GLuint VertexShader, FragmentShader;

private:
    GLuint Program;

public:
    GLuint *UniformLocations, *AttribLocations;

public:
    CShaderProgram();
    ~CShaderProgram();

private:
    void SetDefaults();

public:
    operator GLuint ();

private:
    GLuint LoadShader(char *FileName, GLenum Type);

public:
    bool Load(char *VertexShaderFileName, char *FragmentShaderFileName);
    void Destroy();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CPlane
{
private:
    vec3 N;
    float ND;
    int O;

public:
    CPlane();
    ~CPlane();

public:
    void Set(const vec3 &A, const vec3 &B, const vec3 &C);
    bool AABBBehind(const vec3 *AABBVertices);
    float AABBDistance(const vec3 *AABBVertices);
};

// ----------------------------------------------------------------------------------------------------------------------------

class CFrustum
{
private:
    vec3 Vertices[8];

private:
    CPlane Planes[6];

public:
    CFrustum();
    ~CFrustum();

public:
    void Set(const mat4x4 &ViewProjectionMatrixInverse);
    bool AABBVisible(const vec3 *AABBVertices);
    float AABBDistance(const vec3 *AABBVertices);
    void Render();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CCamera
{
public:
    vec3 X, Y, Z, Position, Reference;

public:
    mat4x4 ViewMatrix, ViewMatrixInverse, ProjectionMatrix, ProjectionMatrixInverse, ViewProjectionMatrix, ViewProjectionMatrixInverse;

public:
    CFrustum Frustum;

public:
    CCamera();
    ~CCamera();

public:
    void Look(const vec3 &Position, const vec3 &Reference, bool RotateAroundReference = false);
    void Move(const vec3 &Movement);
    vec3 OnKeys(BYTE Keys, float FrameTime);
    void OnMouseMove(int dx, int dy);
    void OnMouseWheel(float zDelta);
    void SetPerspective(float fovy, float aspect, float n, float f);

private:
    void CalculateViewMatrix();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CVertex
{
public:
    vec3 Position;
    vec3 Normal;
};

// ----------------------------------------------------------------------------------------------------------------------------

class CAABB
{
private:
    vec3 Vertices[8];

public:
    CAABB();
    ~CAABB();

public:
    void Set(const vec3 &Min, const vec3 &Max);
    bool PointInside(const vec3 &Point);
    bool Visible(CFrustum &Frustum);
    float Distance(CFrustum &Frustum);
    void Render();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CBSPTreeNode
{
private:
    vec3 Min, Max;

private:
    int Depth;

private:
    CAABB AABB;

private:
    bool Visible;
    float Distance;

private:
    int *Indices;

private:
    int IndicesCount;

private:
    GLuint IndexBufferObject;

private:
    CBSPTreeNode *Children[2];

public:
    CBSPTreeNode();
    ~CBSPTreeNode();

private:
    void SetDefaults();

public:
    void InitAABB(const vec3 &Min, const vec3 &Max, int Depth, float MinAABBSize);
    bool CheckTriangle(CVertex *Vertices, int *Indices, int A, int B, int C);
    void AllocateMemory();
    bool AddTriangle(CVertex *Vertices, int *Indices, int A, int B, int C);
    void ResetAABB(CVertex *Vertices);
    int InitIndexBufferObject();
    int CheckVisibility(CFrustum &Frustum, CBSPTreeNode **VisibleGeometryNodes, int &VisibleGeometryNodesCount);
    float GetDistance();
    void Render();
    void RenderAABB(int Depth);
    void Destroy();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CBSPTree
{
private:
    CBSPTreeNode *Root;

private:
    CBSPTreeNode **VisibleGeometryNodes;
    int VisibleGeometryNodesCount;

public:
    CBSPTree();
    ~CBSPTree();

private:
    void SetDefaults();

public:
    void Init(CVertex *Vertices, int *Indices, int IndicesCount, const vec3 &Min, const vec3 &Max, float MinAABBSize = 16.0f);
    void QuickSortVisibleGeometryNodes(int Left, int Right);
    int CheckVisibility(CFrustum &Frustum, bool SortVisibleGeometryNodes);
    void Render(bool VisualizeRenderingOrder);
    void RenderAABB(int Depth);
    void Destroy();
};

// ----------------------------------------------------------------------------------------------------------------------------

class CTerrain
{
private:
    int Size, SizeP1;
    float SizeD2;

private:
    vec3 Min, Max;

private:
    float *Heights;

private:
    int VerticesCount;

private:
    GLuint VertexBufferObject;

public:
    CBSPTree BSPTree;

public:
    CTerrain();
    ~CTerrain();

private:
    void SetDefaults();

public:
    bool LoadTexture2D(char *FileName, float Scale = 256.0f, float Offset = -128.0f);
    bool LoadBinary(char *FileName);
    bool SaveBinary(char *FileName);
    int CheckVisibility(CFrustum &Frustum, bool SortVisibleGeometryNodes = true);
    void Render(bool VisualizeRenderingOrder = false);
    void RenderAABB(int Depth = -1);
    void Destroy();

public:
    vec3 GetMin();
    vec3 GetMax();

private:
    int GetIndex(int X, int Z);
    float GetHeight(int X, int Z);

public:
    float GetHeight(float X, float Z);

private:
    float GetHeight(float *Heights, int Size, float X, float Z);
};

// ----------------------------------------------------------------------------------------------------------------------------

class COpenGLRenderer
{
private:
    int LastX, LastY, LastClickedX, LastClickedY;

private:
    int Width, Height;

private:
    mat4x4 ViewMatrix, ProjectionMatrix;

private:
    CCamera Camera;

private:
    CShaderProgram Shader;

private:
    CTerrain Terrain;

private:
    bool Wireframe, RenderAABB, RenderTree2D, VisualizeRenderingOrder, SortVisibleGeometryNodes, VisibilityCheckingPerformanceTest;
    int Depth;

public:
    CString Text;

public:
    COpenGLRenderer();
    ~COpenGLRenderer();

public:
    bool Init();
    void Render();
    void Animate(float FrameTime);
    void Resize(int Width, int Height);
    void Destroy();

private:
    void CalculateProjectionMatrix();
    void CheckCameraTerrainPosition(vec3 &Movement);

public:
    void CheckCameraKeys(float FrameTime);

public:
    void OnKeyDown(UINT Key);
    void OnLButtonDown(int X, int Y);
    void OnLButtonUp(int X, int Y);
    void OnMouseMove(int X, int Y);
    void OnMouseWheel(short zDelta);
    void OnRButtonDown(int X, int Y);
    void OnRButtonUp(int X, int Y);
};

// ----------------------------------------------------------------------------------------------------------------------------

class COpenGLView
{
private:
    char *Title;
    int Width, Height, Samples;
    HWND hWnd;
    HGLRC hGLRC;

private:
    COpenGLRenderer OpenGLRenderer;

public:
    COpenGLView();
    ~COpenGLView();

public:
    bool Init(HINSTANCE hInstance, char *Title, int Width, int Height, int Samples);
    void Show(bool Maximized = false);
    void MessageLoop();
    void Destroy();

public:
    void OnKeyDown(UINT Key);
    void OnLButtonDown(int X, int Y);
    void OnLButtonUp(int X, int Y);
    void OnMouseMove(int X, int Y);
    void OnMouseWheel(short zDelta);
    void OnPaint();
    void OnRButtonDown(int X, int Y);
    void OnRButtonUp(int X, int Y);
    void OnSize(int Width, int Height);
};

// ----------------------------------------------------------------------------------------------------------------------------

LRESULT CALLBACK WndProc(HWND hWnd, UINT uiMsg, WPARAM wParam, LPARAM lParam);

// ----------------------------------------------------------------------------------------------------------------------------

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR sCmdLine, int iShow);

#include "opengl_21_tutorials_win32_framework.h"

// ----------------------------------------------------------------------------------------------------------------------------

CBuffer::CBuffer()
{
    SetDefaults();
}

CBuffer::~CBuffer()
{
    Empty();
}

void CBuffer::SetDefaults()
{
    Buffer = NULL;
    BufferSize = 0;

    Position = 0;
}

void CBuffer::AddData(void *Data, int DataSize)
{
    int Remaining = BufferSize - Position;

    if(DataSize > Remaining)
    {
        BYTE *OldBuffer = Buffer;
        int OldBufferSize = BufferSize;

        int Needed = DataSize - Remaining;

        BufferSize += Needed > BUFFER_SIZE_INCREMENT ? Needed : BUFFER_SIZE_INCREMENT;

        Buffer = new BYTE[BufferSize];

        memcpy(Buffer, OldBuffer, OldBufferSize);

        delete [] OldBuffer;
    }

    memcpy(Buffer + Position, Data, DataSize);

    Position += DataSize;
}

void CBuffer::Empty()
{
    if(Buffer != NULL)
    {
        delete [] Buffer;
    }

    SetDefaults();
}

void *CBuffer::GetData()
{
    return Buffer;
}

int CBuffer::GetDataSize()
{
    return Position;
}

// ----------------------------------------------------------------------------------------------------------------------------

int gl_max_texture_size = 0, gl_max_texture_max_anisotropy_ext = 0;

// ----------------------------------------------------------------------------------------------------------------------------

CTexture::CTexture()
{
    SetDefaults();
}

CTexture::~CTexture()
{
}

void CTexture::SetDefaults()
{
    Texture = 0;

    Width = 0;
    Height = 0;
}

CTexture::operator GLuint ()
{
    return Texture;
}

FIBITMAP *CTexture::GetBitmap(char *FileName, int &Width, int &Height, int &BPP)
{
    FREE_IMAGE_FORMAT fif = FreeImage_GetFileType(FileName);

    if(fif == FIF_UNKNOWN)
    {
        fif = FreeImage_GetFIFFromFilename(FileName);
    }

    if(fif == FIF_UNKNOWN)
    {
        return NULL;
    }

    FIBITMAP *dib = NULL;

    if(FreeImage_FIFSupportsReading(fif))
    {
        dib = FreeImage_Load(fif, FileName);
    }

    if(dib != NULL)
    {
        int OriginalWidth = FreeImage_GetWidth(dib);
        int OriginalHeight = FreeImage_GetHeight(dib);

        Width = OriginalWidth;
        Height = OriginalHeight;

        if(Width == 0 || Height == 0)
        {
            FreeImage_Unload(dib);
            return NULL;
        }

        BPP = FreeImage_GetBPP(dib);

        if(Width > gl_max_texture_size) Width = gl_max_texture_size;
        if(Height > gl_max_texture_size) Height = gl_max_texture_size;

        if(!GLEW_ARB_texture_non_power_of_two)
        {
            Width = 1 << (int)floor((log((float)Width) / log(2.0f)) + 0.5f); 
            Height = 1 << (int)floor((log((float)Height) / log(2.0f)) + 0.5f);
        }

        if(Width != OriginalWidth || Height != OriginalHeight)
        {
            FIBITMAP *rdib = FreeImage_Rescale(dib, Width, Height, FILTER_BICUBIC);
            FreeImage_Unload(dib);
            dib = rdib;
        }
    }

    return dib;
}

bool CTexture::LoadTexture2D(char *FileName)
{
    CString DirectoryFileName = ModuleDirectory + FileName;

    int Width, Height, BPP;

    FIBITMAP *dib = GetBitmap(DirectoryFileName, Width, Height, BPP);

    if(dib == NULL)
    {
        ErrorLog.Append("Error loading texture " + DirectoryFileName + "!\r\n");
        return false;
    }

    GLenum Format = 0;

    if(BPP == 32) Format = GL_BGRA;
    if(BPP == 24) Format = GL_BGR;

    if(Format == 0)
    {
        ErrorLog.Append("Unsupported texture format (%s)!\r\n", FileName);
        FreeImage_Unload(dib);
        return false;
    }

    Destroy();

    glGenTextures(1, &Texture);

    this->Width = Width;
    this->Height = Height;

    glBindTexture(GL_TEXTURE_2D, Texture);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    if(GLEW_EXT_texture_filter_anisotropic)
    {
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, gl_max_texture_max_anisotropy_ext);
    }

    glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, Width, Height, 0, Format, GL_UNSIGNED_BYTE, FreeImage_GetBits(dib));

    glBindTexture(GL_TEXTURE_2D, 0);

    FreeImage_Unload(dib);

    return true;
}

bool CTexture::LoadTextureCubeMap(char **FileNames)
{
    int Width, Height, BPP;

    FIBITMAP *dib[6];

    bool Error = false;

    for(int i = 0; i < 6; i++)
    {
        CString DirectoryFileName = ModuleDirectory + FileNames[i];

        dib[i] = GetBitmap(DirectoryFileName, Width, Height, BPP);

        if(dib[i] == NULL)
        {
            ErrorLog.Append("Error loading texture " + DirectoryFileName + "!\r\n");
            Error = true;
        }
    }

    if(Error)
    {
        for(int i = 0; i < 6; i++)
        {
            FreeImage_Unload(dib[i]);
        }

        return false;
    }

    GLenum Format = 0;

    if(BPP == 32) Format = GL_BGRA;
    if(BPP == 24) Format = GL_BGR;

    if(Format == 0)
    {
        ErrorLog.Append("Unsupported texture format (%s)!\r\n", FileNames[5]);

        for(int i = 0; i < 6; i++)
        {
            FreeImage_Unload(dib[i]);
        }

        return false;
    }

    Destroy();

    glGenTextures(1, &Texture);

    this->Width = Width;
    this->Height = Height;

    glBindTexture(GL_TEXTURE_CUBE_MAP, Texture);

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    if(GLEW_EXT_texture_filter_anisotropic)
    {
        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAX_ANISOTROPY_EXT, gl_max_texture_max_anisotropy_ext);
    }

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_GENERATE_MIPMAP, GL_TRUE);

    for(int i = 0; i < 6; i++)
    {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA8, Width, Height, 0, Format, GL_UNSIGNED_BYTE, FreeImage_GetBits(dib[i]));
    }

    glBindTexture(GL_TEXTURE_CUBE_MAP, 0);

    for(int i = 0; i < 6; i++)
    {
        FreeImage_Unload(dib[i]);
    }

    return true;
}

void CTexture::Destroy()
{
    if(Texture != 0)
    {
        glDeleteTextures(1, &Texture);
    }

    SetDefaults();
}

int CTexture::GetWidth()
{
    return Width;
}

int CTexture::GetHeight()
{
    return Height;
}

// ----------------------------------------------------------------------------------------------------------------------------

CShaderProgram::CShaderProgram()
{
    SetDefaults();
}

CShaderProgram::~CShaderProgram()
{
}

void CShaderProgram::SetDefaults()
{
    VertexShader = 0;
    FragmentShader = 0;

    Program = 0;

    UniformLocations = NULL;
    AttribLocations = NULL;
}

CShaderProgram::operator GLuint ()
{
    return Program;
}

GLuint CShaderProgram::LoadShader(char *FileName, GLenum Type)
{
    CString DirectoryFileName = ModuleDirectory + FileName;

    FILE *File;

    if(fopen_s(&File, DirectoryFileName, "rb") != 0)
    {
        ErrorLog.Append("Error loading file " + DirectoryFileName + "!\r\n");
        return 0;
    }

    fseek(File, 0, SEEK_END);
    long Size = ftell(File);
    fseek(File, 0, SEEK_SET);
    char *Source = new char[Size + 1];
    fread(Source, 1, Size, File);
    fclose(File);
    Source[Size] = 0;

    GLuint Shader = glCreateShader(Type);

    glShaderSource(Shader, 1, (const char**)&Source, NULL);
    delete [] Source;
    glCompileShader(Shader);

    int CompileStatus;
    glGetShaderiv(Shader, GL_COMPILE_STATUS, &CompileStatus);

    if(CompileStatus == GL_FALSE)
    {
        ErrorLog.Append("Error compiling shader %s!\r\n", FileName);

        int InfoLogLength = 0;
        glGetShaderiv(Shader, GL_INFO_LOG_LENGTH, &InfoLogLength);

        if(InfoLogLength > 0)
        {
            char *InfoLog = new char[InfoLogLength];
            int CharsWritten  = 0;
            glGetShaderInfoLog(Shader, InfoLogLength, &CharsWritten, InfoLog);
            ErrorLog.Append(InfoLog);
            delete [] InfoLog;
        }

        glDeleteShader(Shader);

        return 0;
    }

    return Shader;
}

bool CShaderProgram::Load(char *VertexShaderFileName, char *FragmentShaderFileName)
{
    bool Error = false;

    Destroy();

    Error |= ((VertexShader = LoadShader(VertexShaderFileName, GL_VERTEX_SHADER)) == 0);
    Error |= ((FragmentShader = LoadShader(FragmentShaderFileName, GL_FRAGMENT_SHADER)) == 0);

    if(Error)
    {
        Destroy();
        return false;
    }

    Program = glCreateProgram();
    glAttachShader(Program, VertexShader);
    glAttachShader(Program, FragmentShader);
    glLinkProgram(Program);

    int LinkStatus;
    glGetProgramiv(Program, GL_LINK_STATUS, &LinkStatus);

    if(LinkStatus == GL_FALSE)
    {
        ErrorLog.Append("Error linking program (%s, %s)!\r\n", VertexShaderFileName, FragmentShaderFileName);

        int InfoLogLength = 0;
        glGetProgramiv(Program, GL_INFO_LOG_LENGTH, &InfoLogLength);

        if(InfoLogLength > 0)
        {
            char *InfoLog = new char[InfoLogLength];
            int CharsWritten  = 0;
            glGetProgramInfoLog(Program, InfoLogLength, &CharsWritten, InfoLog);
            ErrorLog.Append(InfoLog);
            delete [] InfoLog;
        }

        Destroy();

        return false;
    }

    return true;
}

void CShaderProgram::Destroy()
{
    if(Program != 0)
    {
        if(VertexShader != 0)
        {
            glDetachShader(Program, VertexShader);
        }

        if(FragmentShader != 0)
        {
            glDetachShader(Program, FragmentShader);
        }
    }

    if(VertexShader != 0)
    {
        glDeleteShader(VertexShader);
    }

    if(FragmentShader)
    {
        glDeleteShader(FragmentShader);
    }

    if(Program != 0)
    {
        glDeleteProgram(Program);
    }

    if(UniformLocations != NULL)
    {
        delete [] UniformLocations;
    }

    if(AttribLocations != NULL)
    {
        delete [] AttribLocations;
    }

    SetDefaults();
}

// ----------------------------------------------------------------------------------------------------------------------------

CPlane::CPlane()
{
}

CPlane::~CPlane()
{
}

void CPlane::Set(const vec3 &A, const vec3 &B, const vec3 &C)
{
    N = normalize(cross(B - A, C - A));
    ND = dot(N, A);
    O = N.z < 0.0f ? (N.y < 0.0f ? (N.x < 0.0f ? 0 : 1) : (N.x < 0.0f ? 2 : 3)) : (N.y < 0.0f ? (N.x < 0.0f ? 4 : 5) : (N.x < 0.0f ? 6 : 7));
}

bool CPlane::AABBBehind(const vec3 *AABBVertices)
{
    return dot(N, AABBVertices[O]) < ND;
}

float CPlane::AABBDistance(const vec3 *AABBVertices)
{
    return dot(N, AABBVertices[O]);
}

// ----------------------------------------------------------------------------------------------------------------------------

CFrustum::CFrustum()
{
}

CFrustum::~CFrustum()
{
}

void CFrustum::Set(const mat4x4 &ViewProjectionMatrixInverse)
{
    vec4 A = ViewProjectionMatrixInverse * vec4(-1.0f, -1.0f,  1.0f, 1.0f);
    vec4 B = ViewProjectionMatrixInverse * vec4( 1.0f, -1.0f,  1.0f, 1.0f);
    vec4 C = ViewProjectionMatrixInverse * vec4(-1.0f,  1.0f,  1.0f, 1.0f);
    vec4 D = ViewProjectionMatrixInverse * vec4( 1.0f,  1.0f,  1.0f, 1.0f);
    vec4 E = ViewProjectionMatrixInverse * vec4(-1.0f, -1.0f, -1.0f, 1.0f);
    vec4 F = ViewProjectionMatrixInverse * vec4( 1.0f, -1.0f, -1.0f, 1.0f);
    vec4 G = ViewProjectionMatrixInverse * vec4(-1.0f,  1.0f, -1.0f, 1.0f);
    vec4 H = ViewProjectionMatrixInverse * vec4( 1.0f,  1.0f, -1.0f, 1.0f);

    Vertices[0] = vec3(A.x / A.w, A.y / A.w, A.z / A.w);
    Vertices[1] = vec3(B.x / B.w, B.y / B.w, B.z / B.w);
    Vertices[2] = vec3(C.x / C.w, C.y / C.w, C.z / C.w);
    Vertices[3] = vec3(D.x / D.w, D.y / D.w, D.z / D.w);
    Vertices[4] = vec3(E.x / E.w, E.y / E.w, E.z / E.w);
    Vertices[5] = vec3(F.x / F.w, F.y / F.w, F.z / F.w);
    Vertices[6] = vec3(G.x / G.w, G.y / G.w, G.z / G.w);
    Vertices[7] = vec3(H.x / H.w, H.y / H.w, H.z / H.w);

    Planes[0].Set(Vertices[4], Vertices[0], Vertices[2]);
    Planes[1].Set(Vertices[1], Vertices[5], Vertices[7]);
    Planes[2].Set(Vertices[4], Vertices[5], Vertices[1]);
    Planes[3].Set(Vertices[2], Vertices[3], Vertices[7]);
    Planes[4].Set(Vertices[0], Vertices[1], Vertices[3]);
    Planes[5].Set(Vertices[5], Vertices[4], Vertices[6]);
}

bool CFrustum::AABBVisible(const vec3 *AABBVertices)
{
    for(int i = 0; i < 6; i++)
    {
        if(Planes[i].AABBBehind(AABBVertices))
        {
            return false;
        }
    }

    return true;
}

float CFrustum::AABBDistance(const vec3 *AABBVertices)
{
    return Planes[5].AABBDistance(AABBVertices);
}

void CFrustum::Render()
{
    glBegin(GL_LINES);

    glVertex3fv(&Vertices[0]); glVertex3fv(&Vertices[1]);
    glVertex3fv(&Vertices[2]); glVertex3fv(&Vertices[3]);
    glVertex3fv(&Vertices[4]); glVertex3fv(&Vertices[5]);
    glVertex3fv(&Vertices[6]); glVertex3fv(&Vertices[7]);

    glVertex3fv(&Vertices[0]); glVertex3fv(&Vertices[2]);
    glVertex3fv(&Vertices[1]); glVertex3fv(&Vertices[3]);
    glVertex3fv(&Vertices[4]); glVertex3fv(&Vertices[6]);
    glVertex3fv(&Vertices[5]); glVertex3fv(&Vertices[7]);

    glVertex3fv(&Vertices[0]); glVertex3fv(&Vertices[4]);
    glVertex3fv(&Vertices[1]); glVertex3fv(&Vertices[5]);
    glVertex3fv(&Vertices[2]); glVertex3fv(&Vertices[6]);
    glVertex3fv(&Vertices[3]); glVertex3fv(&Vertices[7]);

    glEnd();
}

// ----------------------------------------------------------------------------------------------------------------------------

CCamera::CCamera()
{
    X = vec3(1.0f, 0.0f, 0.0f);
    Y = vec3(0.0f, 1.0f, 0.0f);
    Z = vec3(0.0f, 0.0f, 1.0f);

    Position = vec3(0.0f, 0.0f, 5.0f);
    Reference = vec3(0.0f, 0.0f, 0.0f);

    CalculateViewMatrix();
}

CCamera::~CCamera()
{
}

void CCamera::Look(const vec3 &Position, const vec3 &Reference, bool RotateAroundReference)
{
    this->Position = Position;
    this->Reference = Reference;

    Z = normalize(Position - Reference);

    GetXY(Z, X, Y);

    if(!RotateAroundReference)
    {
        this->Reference = this->Position - Z * 0.05f;
    }

    CalculateViewMatrix();
}

void CCamera::Move(const vec3 &Movement)
{
    Position += Movement;
    Reference += Movement;

    CalculateViewMatrix();
}

vec3 CCamera::OnKeys(BYTE Keys, float FrameTime)
{
    float Speed = 5.0f;

    if(Keys & 0x40) Speed *= 2.0f;
    if(Keys & 0x80) Speed *= 0.5f;

    float Distance = Speed * FrameTime;

    vec3 Up(0.0f, 1.0f, 0.0f);
    vec3 Right = X;
    vec3 Forward = cross(Up, Right);

    Up *= Distance;
    Right *= Distance;
    Forward *= Distance;

    vec3 Movement;

    if(Keys & 0x01) Movement += Forward;
    if(Keys & 0x02) Movement -= Forward;
    if(Keys & 0x04) Movement -= Right;
    if(Keys & 0x08) Movement += Right;
    if(Keys & 0x10) Movement += Up;
    if(Keys & 0x20) Movement -= Up;

    return Movement;
}

void CCamera::OnMouseMove(int dx, int dy)
{
    float Sensitivity = 0.25f;

    Position -= Reference;

    if(dx != 0)
    {
        float DeltaX = (float)dx * Sensitivity;

        X = rotate(X, DeltaX, vec3(0.0f, 1.0f, 0.0f));
        Y = rotate(Y, DeltaX, vec3(0.0f, 1.0f, 0.0f));
        Z = rotate(Z, DeltaX, vec3(0.0f, 1.0f, 0.0f));
    }

    if(dy != 0)
    {
        float DeltaY = (float)dy * Sensitivity;

        Y = rotate(Y, DeltaY, X);
        Z = rotate(Z, DeltaY, X);

        if(Y.y < 0.0f)
        {
            Z = vec3(0.0f, Z.y > 0.0f ? 1.0f : -1.0f, 0.0f);
            Y = cross(Z, X);
        }
    }

    Position = Reference + Z * length(Position);

    CalculateViewMatrix();
}

void CCamera::OnMouseWheel(float zDelta)
{
    Position -= Reference;

    if(zDelta < 0 && length(Position) < 500.0f)
    {
        Position += Position * 0.1f;
    }

    if(zDelta > 0 && length(Position) > 0.05f)
    {
        Position -= Position * 0.1f;
    }

    Position += Reference;

    CalculateViewMatrix();
}

void CCamera::SetPerspective(float fovy, float aspect, float n, float f)
{
    ProjectionMatrix = perspective(fovy, aspect, n, f);
    ProjectionMatrixInverse = inverse(ProjectionMatrix);
    ViewProjectionMatrix = ProjectionMatrix * ViewMatrix;
    ViewProjectionMatrixInverse = ViewMatrixInverse * ProjectionMatrixInverse;

    Frustum.Set(ViewProjectionMatrixInverse);
}

void CCamera::CalculateViewMatrix()
{
    ViewMatrix = mat4x4(X.x, Y.x, Z.x, 0.0f, X.y, Y.y, Z.y, 0.0f, X.z, Y.z, Z.z, 0.0f, -dot(X, Position), -dot(Y, Position), -dot(Z, Position), 1.0f);
    ViewMatrixInverse = inverse(ViewMatrix);
    ViewProjectionMatrix = ProjectionMatrix * ViewMatrix;
    ViewProjectionMatrixInverse = ViewMatrixInverse * ProjectionMatrixInverse;

    Frustum.Set(ViewProjectionMatrixInverse);
}

// ----------------------------------------------------------------------------------------------------------------------------

CAABB::CAABB()
{
}

CAABB::~CAABB()
{
}

void CAABB::Set(const vec3 &Min, const vec3 &Max)
{
    Vertices[0] = vec3(Min.x, Min.y, Min.z);
    Vertices[1] = vec3(Max.x, Min.y, Min.z);
    Vertices[2] = vec3(Min.x, Max.y, Min.z);
    Vertices[3] = vec3(Max.x, Max.y, Min.z);
    Vertices[4] = vec3(Min.x, Min.y, Max.z);
    Vertices[5] = vec3(Max.x, Min.y, Max.z);
    Vertices[6] = vec3(Min.x, Max.y, Max.z);
    Vertices[7] = vec3(Max.x, Max.y, Max.z);
}

bool CAABB::PointInside(const vec3 &Point)
{
    if(Point.x < Vertices[0].x) return false;
    if(Point.y < Vertices[0].y) return false;
    if(Point.z < Vertices[0].z) return false;

    if(Point.x > Vertices[7].x) return false;
    if(Point.y > Vertices[7].y) return false;
    if(Point.z > Vertices[7].z) return false;

    return true;
}

bool CAABB::Visible(CFrustum &Frustum)
{
    return Frustum.AABBVisible(Vertices);
}

float CAABB::Distance(CFrustum &Frustum)
{
    return Frustum.AABBDistance(Vertices);
}

void CAABB::Render()
{
    glBegin(GL_LINES);

    glVertex3fv(&Vertices[0]); glVertex3fv(&Vertices[1]);
    glVertex3fv(&Vertices[2]); glVertex3fv(&Vertices[3]);
    glVertex3fv(&Vertices[4]); glVertex3fv(&Vertices[5]);
    glVertex3fv(&Vertices[6]); glVertex3fv(&Vertices[7]);

    glVertex3fv(&Vertices[0]); glVertex3fv(&Vertices[2]);
    glVertex3fv(&Vertices[1]); glVertex3fv(&Vertices[3]);
    glVertex3fv(&Vertices[4]); glVertex3fv(&Vertices[6]);
    glVertex3fv(&Vertices[5]); glVertex3fv(&Vertices[7]);

    glVertex3fv(&Vertices[0]); glVertex3fv(&Vertices[4]);
    glVertex3fv(&Vertices[1]); glVertex3fv(&Vertices[5]);
    glVertex3fv(&Vertices[2]); glVertex3fv(&Vertices[6]);
    glVertex3fv(&Vertices[3]); glVertex3fv(&Vertices[7]);

    glEnd();
}

// ----------------------------------------------------------------------------------------------------------------------------

CBSPTreeNode::CBSPTreeNode()
{
    SetDefaults();
}

CBSPTreeNode::~CBSPTreeNode()
{
}

void CBSPTreeNode::SetDefaults()
{
    Min = Max = vec3(0.0f);

    Depth = 0;

    Indices = NULL;

    IndicesCount = 0;

    IndexBufferObject = 0;

    Children[0] = NULL;
    Children[1] = NULL;
}

void CBSPTreeNode::InitAABB(const vec3 &Min, const vec3 &Max, int Depth, float MinAABBSize)
{
    this->Min = Min;
    this->Max = Max;

    this->Depth = Depth;

    vec3 Mid = (Min + Max) / 2.0f;
    vec3 Size = Max - Min;

    AABB.Set(Min, Max);

    if(Size.x > MinAABBSize || Size.z > MinAABBSize)
    {
        Children[0] = new CBSPTreeNode();
        Children[1] = new CBSPTreeNode();

        if(Size.x >= Size.z)
        {
            Children[0]->InitAABB(vec3(Min.x, Min.y, Min.z), vec3(Mid.x, Max.y, Max.z), Depth + 1, MinAABBSize);
            Children[1]->InitAABB(vec3(Mid.x, Min.y, Min.z), vec3(Max.x, Max.y, Max.z), Depth + 1, MinAABBSize);
        }
        else
        {
            Children[0]->InitAABB(vec3(Min.x, Min.y, Min.z), vec3(Max.x, Max.y, Mid.z), Depth + 1, MinAABBSize);
            Children[1]->InitAABB(vec3(Min.x, Min.y, Mid.z), vec3(Max.x, Max.y, Max.z), Depth + 1, MinAABBSize);
        }
    }
}

bool CBSPTreeNode::CheckTriangle(CVertex *Vertices, int *Indices, int A, int B, int C)
{
    if(AABB.PointInside(Vertices[Indices[A]].Position))
    {
        if(AABB.PointInside(Vertices[Indices[B]].Position))
        {
            if(AABB.PointInside(Vertices[Indices[C]].Position))
            {
                bool BelongsToAChild = false;

                if(Children[0] != NULL)
                {
                    BelongsToAChild |= Children[0]->CheckTriangle(Vertices, Indices, A, B, C);
                }

                if(Children[1] != NULL && !BelongsToAChild)
                {
                    BelongsToAChild |= Children[1]->CheckTriangle(Vertices, Indices, A, B, C);
                }

                if(!BelongsToAChild)
                {
                    IndicesCount += 3;
                }

                return true;
            }
        }
    }

    return false;
}

void CBSPTreeNode::AllocateMemory()
{
    if(IndicesCount > 0)
    {
        Indices = new int[IndicesCount];
        IndicesCount = 0;
    }

    if(Children[0] != NULL)
    {
        Children[0]->AllocateMemory();
    }

    if(Children[1] != NULL)
    {
        Children[1]->AllocateMemory();
    }
}

bool CBSPTreeNode::AddTriangle(CVertex *Vertices, int *Indices, int A, int B, int C)
{
    if(AABB.PointInside(Vertices[Indices[A]].Position))
    {
        if(AABB.PointInside(Vertices[Indices[B]].Position))
        {
            if(AABB.PointInside(Vertices[Indices[C]].Position))
            {
                bool BelongsToAChild = false;

                if(Children[0] != NULL)
                {
                    BelongsToAChild |= Children[0]->AddTriangle(Vertices, Indices, A, B, C);
                }

                if(Children[1] != NULL && !BelongsToAChild)
                {
                    BelongsToAChild |= Children[1]->AddTriangle(Vertices, Indices, A, B, C);
                }

                if(!BelongsToAChild)
                {
                    this->Indices[IndicesCount++] = Indices[A];
                    this->Indices[IndicesCount++] = Indices[B];
                    this->Indices[IndicesCount++] = Indices[C];
                }

                return true;
            }
        }
    }

    return false;
}

void CBSPTreeNode::ResetAABB(CVertex *Vertices)
{
    float MinY = Min.y, MaxY = Max.y;

    Min.y = MaxY;
    Max.y = MinY;

    if(IndicesCount > 0)
    {
        for(int i = 0; i < IndicesCount; i++)
        {
            if(Vertices[Indices[i]].Position.y < Min.y) Min.y = Vertices[Indices[i]].Position.y;
            if(Vertices[Indices[i]].Position.y > Max.y) Max.y = Vertices[Indices[i]].Position.y;
        }
    }

    if(Children[0] != NULL)
    {
        Children[0]->ResetAABB(Vertices);

        if(Children[0]->Min.y < Min.y) Min.y = Children[0]->Min.y;
        if(Children[0]->Max.y > Max.y) Max.y = Children[0]->Max.y;
    }

    if(Children[1] != NULL)
    {
        Children[1]->ResetAABB(Vertices);

        if(Children[1]->Min.y < Min.y) Min.y = Children[1]->Min.y;
        if(Children[1]->Max.y > Max.y) Max.y = Children[1]->Max.y;
    }

    AABB.Set(Min, Max);
}

int CBSPTreeNode::InitIndexBufferObject()
{
    int GeometryNodesCount = 0;

    if(IndicesCount > 0)
    {
        glGenBuffers(1, &IndexBufferObject);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IndexBufferObject);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, IndicesCount * sizeof(int), Indices, GL_STATIC_DRAW);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

        delete [] Indices;
        Indices = NULL;

        GeometryNodesCount++;
    }

    if(Children[0] != NULL)
    {
        GeometryNodesCount += Children[0]->InitIndexBufferObject();
    }

    if(Children[1] != NULL)
    {
        GeometryNodesCount += Children[1]->InitIndexBufferObject();
    }

    return GeometryNodesCount;
}

int CBSPTreeNode::CheckVisibility(CFrustum &Frustum, CBSPTreeNode **VisibleGeometryNodes, int &VisibleGeometryNodesCount)
{
    int TrianglesRendered = 0;

    Visible = AABB.Visible(Frustum);

    if(Visible)
    {
        if(IndicesCount > 0)
        {
            Distance = AABB.Distance(Frustum);

            VisibleGeometryNodes[VisibleGeometryNodesCount++] = this;

            TrianglesRendered += IndicesCount / 3;
        }

        if(Children[0] != NULL)
        {
            TrianglesRendered += Children[0]->CheckVisibility(Frustum, VisibleGeometryNodes, VisibleGeometryNodesCount);
        }

        if(Children[1] != NULL)
        {
            TrianglesRendered += Children[1]->CheckVisibility(Frustum, VisibleGeometryNodes, VisibleGeometryNodesCount);
        }
    }

    return TrianglesRendered;
}

float CBSPTreeNode::GetDistance()
{
    return Distance;
}

void CBSPTreeNode::Render()
{
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IndexBufferObject);

    glDrawElements(GL_TRIANGLES, IndicesCount, GL_UNSIGNED_INT, NULL);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}

void CBSPTreeNode::RenderAABB(int Depth)
{
    if(Visible)
    {
        if(Depth == -1 || Depth == this->Depth)
        {
            AABB.Render();
        }

        if(Children[0] != NULL)
        {
            Children[0]->RenderAABB(Depth);
        }

        if(Children[1] != NULL)
        {
            Children[1]->RenderAABB(Depth);
        }
    }
}

void CBSPTreeNode::Destroy()
{
    if(Indices != NULL)
    {
        delete [] Indices;
    }

    if(IndexBufferObject != 0)
    {
        glDeleteBuffers(1, &IndexBufferObject);
    }

    if(Children[0] != NULL)
    {
        Children[0]->Destroy();
        delete Children[0];
    }

    if(Children[1] != NULL)
    {
        Children[1]->Destroy();
        delete Children[1];
    }

    SetDefaults();
}

// ----------------------------------------------------------------------------------------------------------------------------

CBSPTree::CBSPTree()
{
    SetDefaults();
}

CBSPTree::~CBSPTree()
{
}

void CBSPTree::SetDefaults()
{
    Root = NULL;

    VisibleGeometryNodes = NULL;
}

void CBSPTree::Init(CVertex *Vertices, int *Indices, int IndicesCount, const vec3 &Min, const vec3 &Max, float MinAABBSize)
{
    Destroy();

    if(Vertices != NULL && Indices != NULL && IndicesCount > 0)
    {
        Root = new CBSPTreeNode();

        Root->InitAABB(Min, Max, 0, MinAABBSize);

        for(int i = 0; i < IndicesCount; i += 3)
        {
            Root->CheckTriangle(Vertices, Indices, i, i + 1, i + 2);
        }

        Root->AllocateMemory();

        for(int i = 0; i < IndicesCount; i += 3)
        {
            Root->AddTriangle(Vertices, Indices, i, i + 1, i + 2);
        }

        Root->ResetAABB(Vertices);

        int GeometryNodesCount = Root->InitIndexBufferObject();

        VisibleGeometryNodes = new CBSPTreeNode*[GeometryNodesCount];
    }
}

void CBSPTree::QuickSortVisibleGeometryNodes(int Left, int Right)
{
    float Pivot = VisibleGeometryNodes[(Left + Right) / 2]->GetDistance();
    int i = Left, j = Right;

    while(i <= j)
    {
        while(VisibleGeometryNodes[i]->GetDistance() < Pivot) i++;
        while(VisibleGeometryNodes[j]->GetDistance() > Pivot) j--;

        if(i <= j)
        {
            if(i != j)
            {
                CBSPTreeNode *Temp = VisibleGeometryNodes[i];
                VisibleGeometryNodes[i] = VisibleGeometryNodes[j];
                VisibleGeometryNodes[j] = Temp;
            }

            i++;
            j--;
        }
    }

    if(Left < j)
    {
        QuickSortVisibleGeometryNodes(Left, j);
    }

    if(i < Right)
    {
        QuickSortVisibleGeometryNodes(i, Right);
    }
}

int CBSPTree::CheckVisibility(CFrustum &Frustum, bool SortVisibleGeometryNodes)
{
    int TrianglesRendered = 0;

    VisibleGeometryNodesCount = 0;

    if(Root != NULL)
    {
        TrianglesRendered = Root->CheckVisibility(Frustum, VisibleGeometryNodes, VisibleGeometryNodesCount);

        if(SortVisibleGeometryNodes)
        {
            if(VisibleGeometryNodesCount > 1)
            {
                QuickSortVisibleGeometryNodes(0, VisibleGeometryNodesCount - 1);
            }
        }
    }

    return TrianglesRendered;
}

void CBSPTree::Render(bool VisualizeRenderingOrder)
{
    if(VisibleGeometryNodesCount > 0)
    {
        if(!VisualizeRenderingOrder)
        {
            for(int i = 0; i < VisibleGeometryNodesCount; i++)
            {
                VisibleGeometryNodes[i]->Render();
            }
        }
        else
        {
            for(int i = 0; i < VisibleGeometryNodesCount; i++)
            {
                float Color = (float)i / (float)VisibleGeometryNodesCount;

                glColor3f(Color, Color, Color);

                VisibleGeometryNodes[i]->Render();
            }
        }
    }
}

void CBSPTree::RenderAABB(int Depth)
{
    if(Root != NULL)
    {
        Root->RenderAABB(Depth);
    }
}

void CBSPTree::Destroy()
{
    if(Root != NULL)
    {
        Root->Destroy();
        delete Root;
    }

    if(VisibleGeometryNodes != NULL)
    {
        delete [] VisibleGeometryNodes;
    }

    SetDefaults();
}

// ----------------------------------------------------------------------------------------------------------------------------

CTerrain::CTerrain()
{
    SetDefaults();
}

CTerrain::~CTerrain()
{
}

void CTerrain::SetDefaults()
{
    Size = 0;
    SizeP1 = 0;
    SizeD2 = 0.0f;

    Min = Max = vec3(0.0f);

    Heights = NULL;

    VerticesCount = 0;

    VertexBufferObject = 0;
}

bool CTerrain::LoadTexture2D(char *FileName, float Scale, float Offset)
{
    CTexture Texture;

    if(!Texture.LoadTexture2D(FileName))
    {
        return false;
    }

    if(Texture.GetWidth() != Texture.GetHeight())
    {
        ErrorLog.Append("Unsupported texture dimensions (%s)!\r\n", FileName);
        Texture.Destroy();
        return false;
    }

    Destroy();

    Size = Texture.GetWidth();
    SizeP1 = Size + 1;
    SizeD2 = (float)Size / 2.0f;

    VerticesCount = SizeP1 * SizeP1;

    float *TextureHeights = new float[Size * Size];

    glBindTexture(GL_TEXTURE_2D, Texture);
    glGetTexImage(GL_TEXTURE_2D, 0, GL_GREEN, GL_FLOAT, TextureHeights);
    glBindTexture(GL_TEXTURE_2D, 0);

    Texture.Destroy();

    for(int i = 0; i < Size * Size; i++)
    {
        TextureHeights[i] = TextureHeights[i] * Scale + Offset;
    }

    Heights = new float[VerticesCount];

    int i = 0;

    for(int z = 0; z <= Size; z++)
    {
        for(int x = 0; x <= Size; x++)
        {
            Heights[i++] = GetHeight(TextureHeights, Size, (float)x - 0.5f, (float)z - 0.5f);
        }
    }

    delete [] TextureHeights;

    float *SmoothedHeights = new float[VerticesCount];

    i = 0;

    for(int z = 0; z <= Size; z++)
    {
        for(int x = 0; x <= Size; x++)
        {
            SmoothedHeights[i] = 0.0f;

            SmoothedHeights[i] += GetHeight(x - 1, z + 1) + GetHeight(x, z + 1) * 2 + GetHeight(x + 1, z + 1);
            SmoothedHeights[i] += GetHeight(x - 1, z) * 2 + GetHeight(x, z) * 3 + GetHeight(x + 1, z) * 2;
            SmoothedHeights[i] += GetHeight(x - 1, z - 1) + GetHeight(x, z - 1) * 2 + GetHeight(x + 1, z - 1);

            SmoothedHeights[i] /= 15.0f;

            i++;
        }
    }

    delete [] Heights;

    Heights = SmoothedHeights;

    Min.x = Min.z = -SizeD2;
    Max.x = Max.z = SizeD2;

    Min.y = Max.y = Heights[0];

    for(int i = 1; i < VerticesCount; i++)
    {
        if(Heights[i] < Min.y) Min.y = Heights[i];
        if(Heights[i] > Max.y) Max.y = Heights[i];
    }

    CVertex *Vertices = new CVertex[VerticesCount];

    i = 0;

    for(int z = 0; z <= Size; z++)
    {
        for(int x = 0; x <= Size; x++)
        {
            Vertices[i].Position = vec3((float)x - SizeD2, Heights[i], SizeD2 - (float)z);
            Vertices[i].Normal = normalize(vec3(GetHeight(x - 1, z) - GetHeight(x + 1, z), 2.0f, GetHeight(x, z + 1) - GetHeight(x, z - 1)));

            i++;
        }
    }

    glGenBuffers(1, &VertexBufferObject);

    glBindBuffer(GL_ARRAY_BUFFER, VertexBufferObject);
    glBufferData(GL_ARRAY_BUFFER, VerticesCount * sizeof(CVertex), Vertices, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    int IndicesCount = Size * Size * 2 * 3;

    int *Indices = new int[IndicesCount];

    i = 0;

    for(int z = 0; z < Size; z++)
    {
        for(int x = 0; x < Size; x++)
        {
            Indices[i++] = GetIndex(x, z);
            Indices[i++] = GetIndex(x + 1, z);
            Indices[i++] = GetIndex(x + 1, z + 1);

            Indices[i++] = GetIndex(x + 1, z + 1);
            Indices[i++] = GetIndex(x, z + 1);
            Indices[i++] = GetIndex(x, z);
        }
    }

    BSPTree.Init(Vertices, Indices, IndicesCount, Min, Max);

    delete [] Vertices;
    delete [] Indices;

    return true;
}

bool CTerrain::LoadBinary(char *FileName)
{
    CString DirectoryFileName = ModuleDirectory + FileName;

    FILE *File;

    if(fopen_s(&File, DirectoryFileName, "rb") != 0)
    {
        ErrorLog.Append("Error opening file " + DirectoryFileName + "!\r\n");
        return false;
    }

    int Size;

    if(fread(&Size, sizeof(int), 1, File) != 1 || Size <= 0)
    {
        ErrorLog.Append("Error reading file " + DirectoryFileName + "!\r\n");
        fclose(File);
        return false;
    }

    Destroy();

    this->Size = Size;
    SizeP1 = Size + 1;
    SizeD2 = (float)Size / 2.0f;

    VerticesCount = SizeP1 * SizeP1;

    Heights = new float[VerticesCount];

    if(fread(Heights, sizeof(float), VerticesCount, File) != VerticesCount)
    {
        ErrorLog.Append("Error reading file " + DirectoryFileName + "!\r\n");
        fclose(File);
        Destroy();
        return false;
    }

    fclose(File);

    Min.x = Min.z = -SizeD2;
    Max.x = Max.z = SizeD2;

    Min.y = Max.y = Heights[0];

    for(int i = 1; i < VerticesCount; i++)
    {
        if(Heights[i] < Min.y) Min.y = Heights[i];
        if(Heights[i] > Max.y) Max.y = Heights[i];
    }

    CVertex *Vertices = new CVertex[VerticesCount];

    int i = 0;

    for(int z = 0; z <= Size; z++)
    {
        for(int x = 0; x <= Size; x++)
        {
            Vertices[i].Position = vec3((float)x - SizeD2, Heights[i], SizeD2 - (float)z);
            Vertices[i].Normal = normalize(vec3(GetHeight(x - 1, z) - GetHeight(x + 1, z), 2.0f, GetHeight(x, z + 1) - GetHeight(x, z - 1)));

            i++;
        }
    }

    glGenBuffers(1, &VertexBufferObject);

    glBindBuffer(GL_ARRAY_BUFFER, VertexBufferObject);
    glBufferData(GL_ARRAY_BUFFER, VerticesCount * sizeof(CVertex), Vertices, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    int IndicesCount = Size * Size * 2 * 3;

    int *Indices = new int[IndicesCount];

    i = 0;

    for(int z = 0; z < Size; z++)
    {
        for(int x = 0; x < Size; x++)
        {
            Indices[i++] = GetIndex(x, z);
            Indices[i++] = GetIndex(x + 1, z);
            Indices[i++] = GetIndex(x + 1, z + 1);

            Indices[i++] = GetIndex(x + 1, z + 1);
            Indices[i++] = GetIndex(x, z + 1);
            Indices[i++] = GetIndex(x, z);
        }
    }

    BSPTree.Init(Vertices, Indices, IndicesCount, Min, Max);

    delete [] Vertices;
    delete [] Indices;

    return true;
}

bool CTerrain::SaveBinary(char *FileName)
{
    CString DirectoryFileName = ModuleDirectory + FileName;

    FILE *File;

    if(fopen_s(&File, DirectoryFileName, "wb+") != 0)
    {
        return false;
    }

    fwrite(&Size, sizeof(int), 1, File);

    fwrite(Heights, sizeof(float), VerticesCount, File);

    fclose(File);

    return true;
}

int CTerrain::CheckVisibility(CFrustum &Frustum, bool SortVisibleGeometryNodes)
{
    return BSPTree.CheckVisibility(Frustum, SortVisibleGeometryNodes);
}

void CTerrain::Render(bool VisualizeRenderingOrder)
{
    glBindBuffer(GL_ARRAY_BUFFER, VertexBufferObject);

    glEnableClientState(GL_VERTEX_ARRAY);
    glVertexPointer(3, GL_FLOAT, sizeof(CVertex), (void*)(sizeof(vec3) * 0));

    glEnableClientState(GL_NORMAL_ARRAY);
    glNormalPointer(GL_FLOAT, sizeof(CVertex), (void*)(sizeof(vec3) * 1));

    BSPTree.Render(VisualizeRenderingOrder);

    glDisableClientState(GL_NORMAL_ARRAY);
    glDisableClientState(GL_VERTEX_ARRAY);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

void CTerrain::RenderAABB(int Depth)
{
    BSPTree.RenderAABB(Depth);
}

void CTerrain::Destroy()
{
    if(Heights != NULL)
    {
        delete [] Heights;
    }

    if(VertexBufferObject != 0)
    {
        glDeleteBuffers(1, &VertexBufferObject);
    }

    BSPTree.Destroy();

    SetDefaults();
}

vec3 CTerrain::GetMin()
{
    return Min;
}

vec3 CTerrain::GetMax()
{
    return Max;
}

int CTerrain::GetIndex(int X, int Z)
{
    return SizeP1 * Z + X;
}

float CTerrain::GetHeight(int X, int Z)
{
    return Heights[GetIndex(X < 0 ? 0 : X > Size ? Size : X, Z < 0 ? 0 : Z > Size ? Size : Z)];
}

float CTerrain::GetHeight(float X, float Z)
{
    Z = -Z;

    X += SizeD2;
    Z += SizeD2;

    float Size = (float)this->Size;

    if(X < 0.0f) X = 0.0f;
    if(X > Size) X = Size;
    if(Z < 0.0f) Z = 0.0f;
    if(Z > Size) Z = Size;

    int ix = (int)X, ixp1 = ix + 1;
    int iz = (int)Z, izp1 = iz + 1;

    float fx = X - (float)ix;
    float fz = Z - (float)iz;

    float a = GetHeight(ix, iz);
    float b = GetHeight(ixp1, iz);
    float c = GetHeight(ix, izp1);
    float d = GetHeight(ixp1, izp1);

    float ab = a + (b - a) * fx;
    float cd = c + (d - c) * fx;

    return ab + (cd - ab) * fz;
}

float CTerrain::GetHeight(float *Heights, int Size, float X, float Z)
{
    float SizeM1F = (float)Size - 1.0f;

    if(X < 0.0f) X = 0.0f;
    if(X > SizeM1F) X = SizeM1F;
    if(Z < 0.0f) Z = 0.0f;
    if(Z > SizeM1F) Z = SizeM1F;

    int ix = (int)X, ixp1 = ix + 1;
    int iz = (int)Z, izp1 = iz + 1;

    int SizeM1 = Size - 1;

    if(ixp1 > SizeM1) ixp1 = SizeM1;
    if(izp1 > SizeM1) izp1 = SizeM1;

    float fx = X - (float)ix;
    float fz = Z - (float)iz;

    int izMSize = iz * Size, izp1MSize = izp1 * Size;

    float a = Heights[izMSize + ix];
    float b = Heights[izMSize + ixp1];
    float c = Heights[izp1MSize + ix];
    float d = Heights[izp1MSize + ixp1];

    float ab = a + (b - a) * fx;
    float cd = c + (d - c) * fx;

    return ab + (cd - ab) * fz;
}

// ----------------------------------------------------------------------------------------------------------------------------

COpenGLRenderer::COpenGLRenderer()
{
    ViewMatrix = mat4x4(1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f);

    Wireframe = false;
    RenderAABB = false;
    RenderTree2D = false;
    VisualizeRenderingOrder = false;
    SortVisibleGeometryNodes = true;
    VisibilityCheckingPerformanceTest = false;

    Depth = -1;
}

COpenGLRenderer::~COpenGLRenderer()
{
}

bool COpenGLRenderer::Init()
{
    bool Error = false;

    Error |= !Shader.Load("glsl120shader.vs", "glsl120shader.fs");

    Error |= !Terrain.LoadBinary("terrain1.bin");

    if(Error)
    {
        return false;
    }

    Shader.UniformLocations = new GLuint[1];
    Shader.UniformLocations[0] = glGetUniformLocation(Shader, "CameraPosition");

    float Height = Terrain.GetHeight(0.0f, 0.0f);

    Camera.Look(vec3(0.0f, Height + 1.75f, 0.0f), vec3(0.0f, Height + 1.75f, -1.0f));

    return true;
}

void COpenGLRenderer::Render()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    if(!VisibilityCheckingPerformanceTest)
    {
        if(!RenderTree2D)
        {
            glMatrixMode(GL_PROJECTION);
            glLoadMatrixf(&Camera.ProjectionMatrix);

            glMatrixMode(GL_MODELVIEW);
            glLoadMatrixf(&Camera.ViewMatrix);

            glEnable(GL_DEPTH_TEST);
            glEnable(GL_CULL_FACE);
        }
        else
        {
            glMatrixMode(GL_PROJECTION);
            glLoadMatrixf(&ProjectionMatrix);

            glMatrixMode(GL_MODELVIEW);
            glLoadMatrixf(&ViewMatrix);
        }
    }

    int TrianglesRendered = Terrain.CheckVisibility(Camera.Frustum, SortVisibleGeometryNodes);

    if(!VisibilityCheckingPerformanceTest)
    {
        if(!RenderTree2D && Wireframe)
        {
            TrianglesRendered *= 2;
        }
    }

    Text.Set("Triangles rendered: %d", TrianglesRendered);

    if(!VisibilityCheckingPerformanceTest)
    {
        if(!RenderTree2D && Wireframe)
        {
            glColor3f(0.0f, 0.0f, 0.0f);

            glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

            Terrain.Render();

            glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
        }

        glColor3f(1.0f, 1.0f, 1.0f);

        glUseProgram(Shader);
        glUniform3fv(Shader.UniformLocations[0], 1, !RenderTree2D ? &Camera.Position : &vec3(0.0f, 4096.0f, 0.0f));

        Terrain.Render(VisualizeRenderingOrder);

        glUseProgram(0);

        if(RenderAABB)
        {
            glColor3f(0.0f, 1.0f, 0.0f);

            Terrain.RenderAABB(Depth);
        }

        if(!RenderTree2D)
        {
            glDisable(GL_CULL_FACE);
            glDisable(GL_DEPTH_TEST);
        }
        else
        {
            glColor3f(1.0f, 0.5f, 0.25f);

            Camera.Frustum.Render();
        }
    }
}

void COpenGLRenderer::Animate(float FrameTime)
{
}

void COpenGLRenderer::Resize(int Width, int Height)
{
    this->Width = Width;
    this->Height = Height;

    glViewport(0, 0, Width, Height);

    Camera.SetPerspective(45.0f, (float)Width / (float)Height, 0.125f, 1024.0f);

    CalculateProjectionMatrix();
}

void COpenGLRenderer::Destroy()
{
    Shader.Destroy();

    Terrain.Destroy();
}

void COpenGLRenderer::CalculateProjectionMatrix()
{
    float Aspect = (float)Width / (float)Height;

    vec3 Min = Terrain.GetMin(), Max = Terrain.GetMax();

    ProjectionMatrix = ortho(Min.x * Aspect, Max.x * Aspect, -Max.z, -Min.z, -4096.0f, 4096.0f);
}

void COpenGLRenderer::CheckCameraTerrainPosition(vec3 &Movement)
{
    vec3 CameraPosition = Camera.Reference + Movement, Min = Terrain.GetMin(), Max = Terrain.GetMax();

    if(CameraPosition.x < Min.x) Movement += vec3(Min.x - CameraPosition.x, 0.0f, 0.0f);
    if(CameraPosition.x > Max.x) Movement += vec3(Max.x - CameraPosition.x, 0.0f, 0.0f);
    if(CameraPosition.z < Min.z) Movement += vec3(0.0f, 0.0f, Min.z - CameraPosition.z);
    if(CameraPosition.z > Max.z) Movement += vec3(0.0f, 0.0f, Max.z - CameraPosition.z);

    CameraPosition = Camera.Reference + Movement;

    float Height = Terrain.GetHeight(CameraPosition.x, CameraPosition.z);

    Movement += vec3(0.0f, Height + 1.75f - Camera.Reference.y, 0.0f);
}

void COpenGLRenderer::CheckCameraKeys(float FrameTime)
{
    BYTE Keys = 0x00;

    if(GetKeyState('W') & 0x80) Keys |= 0x01;
    if(GetKeyState('S') & 0x80) Keys |= 0x02;
    if(GetKeyState('A') & 0x80) Keys |= 0x04;
    if(GetKeyState('D') & 0x80) Keys |= 0x08;
    // if(GetKeyState('R') & 0x80) Keys |= 0x10;
    // if(GetKeyState('F') & 0x80) Keys |= 0x20;

    if(GetKeyState(VK_SHIFT) & 0x80) Keys |= 0x40;
    if(GetKeyState(VK_CONTROL) & 0x80) Keys |= 0x80;

    if(Keys & 0x3F)
    {
        vec3 Movement = Camera.OnKeys(Keys, FrameTime * 0.5f);

        CheckCameraTerrainPosition(Movement);

        Camera.Move(Movement);
    }
}

void COpenGLRenderer::OnKeyDown(UINT Key)
{
    switch(Key)
    {
        case VK_F1:
            Wireframe = !Wireframe;
            break;

        case VK_F2:
            RenderAABB = !RenderAABB;
            break;

        case VK_F3:
            RenderTree2D = !RenderTree2D;
            break;

        case VK_F4:
            VisualizeRenderingOrder = !VisualizeRenderingOrder;
            break;

        case VK_F5:
            SortVisibleGeometryNodes = !SortVisibleGeometryNodes;
            break;

        case VK_F6:
            VisibilityCheckingPerformanceTest = !VisibilityCheckingPerformanceTest;
            break;

        case VK_F7:
            Terrain.SaveBinary("terrain-saved.bin");
            break;

        case '1':
            if(Terrain.LoadBinary("terrain1.bin")) { CalculateProjectionMatrix(); vec3 Movement; CheckCameraTerrainPosition(Movement); Camera.Move(Movement); }
            break;

        case '2':
            if(Terrain.LoadTexture2D("terrain2.jpg", 32.0f, -16.0f)) { CalculateProjectionMatrix(); vec3 Movement; CheckCameraTerrainPosition(Movement); Camera.Move(Movement); }
            break;

        case '3':
            if(Terrain.LoadTexture2D("terrain3.jpg", 128.0f, -64.0f)) { CalculateProjectionMatrix(); vec3 Movement; CheckCameraTerrainPosition(Movement); Camera.Move(Movement); }
            break;

        case '4':
            if(Terrain.LoadTexture2D("terrain4.jpg", 128.0f, -64.0f)) { CalculateProjectionMatrix(); vec3 Movement; CheckCameraTerrainPosition(Movement); Camera.Move(Movement); }
            break;

        case VK_ADD:
            Depth++;
            break;

        case VK_SUBTRACT:
            if(Depth > -1) Depth--;
            break;
    }
}

void COpenGLRenderer::OnLButtonDown(int X, int Y)
{
    LastClickedX = X;
    LastClickedY = Y;
}

void COpenGLRenderer::OnLButtonUp(int X, int Y)
{
    if(X == LastClickedX && Y == LastClickedY)
    {
    }
}

void COpenGLRenderer::OnMouseMove(int X, int Y)
{
    if(GetKeyState(VK_RBUTTON) & 0x80)
    {
        Camera.OnMouseMove(LastX - X, LastY - Y);
    }

    LastX = X;
    LastY = Y;
}

void COpenGLRenderer::OnMouseWheel(short zDelta)
{
    Camera.OnMouseWheel(zDelta);
}

void COpenGLRenderer::OnRButtonDown(int X, int Y)
{
    LastClickedX = X;
    LastClickedY = Y;
}

void COpenGLRenderer::OnRButtonUp(int X, int Y)
{
    if(X == LastClickedX && Y == LastClickedY)
    {
    }
}

// ----------------------------------------------------------------------------------------------------------------------------

CString ModuleDirectory, ErrorLog;

// ----------------------------------------------------------------------------------------------------------------------------

void GetModuleDirectory()
{
    char *moduledirectory = new char[256];
    GetModuleFileName(GetModuleHandle(NULL), moduledirectory, 256);
    *(strrchr(moduledirectory, '\\') + 1) = 0;
    ModuleDirectory = moduledirectory;
    delete [] moduledirectory;
}

// ----------------------------------------------------------------------------------------------------------------------------

COpenGLView::COpenGLView()
{
}

COpenGLView::~COpenGLView()
{
}

bool COpenGLView::Init(HINSTANCE hInstance, char *Title, int Width, int Height, int Samples)
{
    this->Title = Title;
    this->Width = Width;
    this->Height = Height;

    WNDCLASSEX WndClassEx;

    memset(&WndClassEx, 0, sizeof(WNDCLASSEX));

    WndClassEx.cbSize = sizeof(WNDCLASSEX);
    WndClassEx.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
    WndClassEx.lpfnWndProc = WndProc;
    WndClassEx.hInstance = hInstance;
    WndClassEx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    WndClassEx.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    WndClassEx.hCursor = LoadCursor(NULL, IDC_ARROW);
    WndClassEx.lpszClassName = "Win32OpenGLWindowClass";

    if(RegisterClassEx(&WndClassEx) == 0)
    {
        ErrorLog.Set("RegisterClassEx failed!");
        return false;
    }

    DWORD Style = WS_OVERLAPPEDWINDOW | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;

    hWnd = CreateWindowEx(WS_EX_APPWINDOW, WndClassEx.lpszClassName, Title, Style, 0, 0, Width, Height, NULL, NULL, hInstance, NULL);

    if(hWnd == NULL)
    {
        ErrorLog.Set("CreateWindowEx failed!");
        return false;
    }

    HDC hDC = GetDC(hWnd);

    if(hDC == NULL)
    {
        ErrorLog.Set("GetDC failed!");
        return false;
    }

    PIXELFORMATDESCRIPTOR pfd;

    memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));

    pfd.nSize = sizeof(PIXELFORMATDESCRIPTOR);
    pfd.nVersion = 1;
    pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
    pfd.iPixelType = PFD_TYPE_RGBA;
    pfd.cColorBits = 32;
    pfd.cDepthBits = 24;
    pfd.iLayerType = PFD_MAIN_PLANE;

    int PixelFormat = ChoosePixelFormat(hDC, &pfd);

    if(PixelFormat == 0)
    {
        ErrorLog.Set("ChoosePixelFormat failed!");
        return false;
    }

    static int MSAAPixelFormat = 0;

    if(SetPixelFormat(hDC, MSAAPixelFormat == 0 ? PixelFormat : MSAAPixelFormat, &pfd) == FALSE)
    {
        ErrorLog.Set("SetPixelFormat failed!");
        return false;
    }

    hGLRC = wglCreateContext(hDC);

    if(hGLRC == NULL)
    {
        ErrorLog.Set("wglCreateContext failed!");
        return false;
    }

    if(wglMakeCurrent(hDC, hGLRC) == FALSE)
    {
        ErrorLog.Set("wglMakeCurrent failed!");
        return false;
    }

    if(glewInit() != GLEW_OK)
    {
        ErrorLog.Set("glewInit failed!");
        return false;
    }

    if(!GLEW_VERSION_2_1)
    {
        ErrorLog.Set("OpenGL 2.1 not supported!");
        return false;
    }

    if(MSAAPixelFormat == 0 && Samples > 0)
    {
        if(GLEW_ARB_multisample && WGLEW_ARB_pixel_format)
        {
            while(Samples > 0)
            {
                UINT NumFormats = 0;

                int PFAttribs[] =
                {
                    WGL_DRAW_TO_WINDOW_ARB, GL_TRUE,
                    WGL_SUPPORT_OPENGL_ARB, GL_TRUE,
                    WGL_DOUBLE_BUFFER_ARB, GL_TRUE,
                    WGL_PIXEL_TYPE_ARB, WGL_TYPE_RGBA_ARB,
                    WGL_COLOR_BITS_ARB, 32,
                    WGL_DEPTH_BITS_ARB, 24,
                    WGL_ACCELERATION_ARB, WGL_FULL_ACCELERATION_ARB,
                    WGL_SAMPLE_BUFFERS_ARB, GL_TRUE,
                    WGL_SAMPLES_ARB, Samples,
                    0
                };

                if(wglChoosePixelFormatARB(hDC, PFAttribs, NULL, 1, &MSAAPixelFormat, &NumFormats) == TRUE && NumFormats > 0) break;

                Samples--;
            }

            wglDeleteContext(hGLRC);
            DestroyWindow(hWnd);
            UnregisterClass(WndClassEx.lpszClassName, hInstance);

            return Init(hInstance, Title, Width, Height, Samples);
        }
        else
        {
            Samples = 0;
        }
    }

    this->Samples = Samples;

    GetModuleDirectory();

    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &gl_max_texture_size);

    if(GLEW_EXT_texture_filter_anisotropic)
    {
        glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &gl_max_texture_max_anisotropy_ext);
    }

    if(WGLEW_EXT_swap_control)
    {
        wglSwapIntervalEXT(0);
    }

    return OpenGLRenderer.Init();
}

void COpenGLView::Show(bool Maximized)
{
    RECT dRect, wRect, cRect;

    GetWindowRect(GetDesktopWindow(), &dRect);
    GetWindowRect(hWnd, &wRect);
    GetClientRect(hWnd, &cRect);

    wRect.right += Width - cRect.right;
    wRect.bottom += Height - cRect.bottom;
    wRect.right -= wRect.left;
    wRect.bottom -= wRect.top;
    wRect.left = dRect.right / 2 - wRect.right / 2;
    wRect.top = dRect.bottom / 2 - wRect.bottom / 2;

    MoveWindow(hWnd, wRect.left, wRect.top, wRect.right, wRect.bottom, FALSE);

    ShowWindow(hWnd, Maximized ? SW_SHOWMAXIMIZED : SW_SHOWNORMAL);
}

void COpenGLView::MessageLoop()
{
    MSG Msg;

    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
}

void COpenGLView::Destroy()
{
    if(GLEW_VERSION_2_1)
    {
        OpenGLRenderer.Destroy();
    }

    wglDeleteContext(hGLRC);
    DestroyWindow(hWnd);
}

void COpenGLView::OnKeyDown(UINT Key)
{
    OpenGLRenderer.OnKeyDown(Key);
}

void COpenGLView::OnLButtonDown(int X, int Y)
{
    OpenGLRenderer.OnLButtonDown(X, Y);
}

void COpenGLView::OnLButtonUp(int X, int Y)
{
    OpenGLRenderer.OnLButtonUp(X, Y);
}

void COpenGLView::OnMouseMove(int X, int Y)
{
    OpenGLRenderer.OnMouseMove(X, Y);
}

void COpenGLView::OnMouseWheel(short zDelta)
{
    OpenGLRenderer.OnMouseWheel(zDelta);
}

void COpenGLView::OnPaint()
{
    static DWORD LastFPSTime = GetTickCount(), LastFrameTime = LastFPSTime, FPS = 0;

    PAINTSTRUCT ps;

    HDC hDC = BeginPaint(hWnd, &ps);

    DWORD Time = GetTickCount();

    float FrameTime = (Time - LastFrameTime) * 0.001f;

    LastFrameTime = Time;

    if(Time - LastFPSTime > 1000)
    {
        CString Text = Title;

        if(OpenGLRenderer.Text[0] != 0)
        {
            Text.Append(" - " + OpenGLRenderer.Text);
        }

        Text.Append(" - %dx%d", Width, Height);
        Text.Append(", ATF %dx", gl_max_texture_max_anisotropy_ext);
        Text.Append(", MSAA %dx", Samples);
        Text.Append(", FPS: %d", FPS);
        Text.Append(" - %s", glGetString(GL_RENDERER));

        SetWindowText(hWnd, Text);

        LastFPSTime = Time;
        FPS = 0;
    }
    else
    {
        FPS++;
    }

    OpenGLRenderer.CheckCameraKeys(FrameTime);

    OpenGLRenderer.Render();

    OpenGLRenderer.Animate(FrameTime);

    SwapBuffers(hDC);

    EndPaint(hWnd, &ps);

    InvalidateRect(hWnd, NULL, FALSE);
}

void COpenGLView::OnRButtonDown(int X, int Y)
{
    OpenGLRenderer.OnRButtonDown(X, Y);
}

void COpenGLView::OnRButtonUp(int X, int Y)
{
    OpenGLRenderer.OnRButtonUp(X, Y);
}

void COpenGLView::OnSize(int Width, int Height)
{
    this->Width = Width;
    this->Height = Height;

    OpenGLRenderer.Resize(Width, Height);
}

// ----------------------------------------------------------------------------------------------------------------------------

COpenGLView OpenGLView;

// ----------------------------------------------------------------------------------------------------------------------------

LRESULT CALLBACK WndProc(HWND hWnd, UINT uiMsg, WPARAM wParam, LPARAM lParam)
{
    switch(uiMsg)
    {
        case WM_CLOSE:
            PostQuitMessage(0);
            break;

        case WM_KEYDOWN:
            OpenGLView.OnKeyDown((UINT)wParam);
            break;

        case WM_LBUTTONDOWN:
            OpenGLView.OnLButtonDown(LOWORD(lParam), HIWORD(lParam));
            break;

        case WM_LBUTTONUP:
            OpenGLView.OnLButtonUp(LOWORD(lParam), HIWORD(lParam));
            break;

        case WM_MOUSEMOVE:
            OpenGLView.OnMouseMove(LOWORD(lParam), HIWORD(lParam));
            break;

        case WM_MOUSWHEEL:
            OpenGLView.OnMouseWheel(HIWORD(wParam));
            break;

        case WM_PAINT:
            OpenGLView.OnPaint();
            break;

        case WM_RBUTTONDOWN:
            OpenGLView.OnRButtonDown(LOWORD(lParam), HIWORD(lParam));
            break;

        case WM_RBUTTONUP:
            OpenGLView.OnRButtonUp(LOWORD(lParam), HIWORD(lParam));
            break;

        case WM_SIZE:
            OpenGLView.OnSize(LOWORD(lParam), HIWORD(lParam));
            break;

        default:
            return DefWindowProc(hWnd, uiMsg, wParam, lParam);
    }

    return 0;
}

// ----------------------------------------------------------------------------------------------------------------------------

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR sCmdLine, int iShow)
{
    char *AppName = "Binary space partitioning tree";

    if(OpenGLView.Init(hInstance, AppName, 800, 600, 4))
    {
        OpenGLView.Show();
        OpenGLView.MessageLoop();
    }
    else
    {
        MessageBox(NULL, ErrorLog, AppName, MB_OK | MB_ICONERROR);
    }

    OpenGLView.Destroy();

    return 0;
}

#version 120

uniform vec3 CameraPosition;

varying vec3 var_Normal, var_LightDirection;

void main()
{
    gl_FrontColor = gl_Color;
    var_Normal = gl_Normal;
    var_LightDirection = CameraPosition - gl_Vertex.xyz;
    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
}

#version 120

varying vec3 var_Normal, var_LightDirection;

void main()
{
    gl_FragColor = gl_Color;

    float NdotLD = dot(normalize(var_Normal), normalize(var_LightDirection));

    gl_FragColor.rgb *= 0.5 + 0.5 * NdotLD;
}