Main.cpp

// Using GLM and math headers
#include <math.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
// Using SDL, GLEW
#include <GL/glew.h>
#include <SDL2/SDL.h>
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#endif

#include "GLScene.h"

//Debug.cpp
extern void GLDebug_Init();
//Shaders.cpp
extern bool GL_LoadShader(GLuint & uiShader, GLenum ShaderType, const GLchar * p_cShader);
extern bool GL_LoadShaders(GLuint & uiShader, GLuint uiVertexShader, GLuint uiFragmentShader, GLuint uiGeometryShader = -1, GLuint uiTessControlShader = -1, GLuint uiTessEvalShader = -1);
extern bool GL_LoadShaderFile(GLuint & uiShader, GLenum ShaderType, const char * p_cFileName, int iFileID);
//Textures.cpp
extern bool GL_LoadTextureKTX(GLuint uiTexture, const char * p_cTextureFile);
//Reflection.cpp
extern bool GL_InitReflection();
extern void GL_QuitReflection();
extern void GL_RenderPlanarReflection(ReflectObjectData * p_RObject, ObjectData * p_Object, const vec3 & v3Direction, const vec3 & v3Up,
                                      const vec3 & v3Position, float fFOV, float fAspect, const vec2 & v2NearFar);
extern void GL_RenderEnvironmentReflection(ReflectObjectData * p_RObject, ObjectData * p_Object);
//Shadow.cpp
extern bool GL_InitShadow();
extern void GL_QuitShadow();
extern void GL_RenderShadows();
//Deferred.cpp
extern bool GL_InitDeferred();
extern void GL_QuitDeferred();
extern void GL_RenderDeferred(ObjectData * p_Object = NULL, GLuint uiAccumBuffer = 0, GLenum uiTextureTarget = GL_TEXTURE_2D);
extern void GL_RenderPostProcess();

// Declare window variables
int g_iWindowWidth = 1280;
int g_iWindowHeight = 1024;
bool g_bWindowFullscreen = false;
// Declare OpenGL variables
GLuint g_uiMainProgram;
GLuint g_uiShadowProgram;
GLuint g_uiShadowTransProgram;
GLuint g_uiDeferredProgram2;
GLuint g_uiPostProcProgram;
SceneData g_SceneData = {}; // Init to 0
GLuint g_uiSkyBox;
// Subroutine index for GBuffer display
unsigned g_uiOutputSubroutine = 0;

struct CameraData
{
    aligned_mat4 m_m4ViewProjection;
    aligned_vec3 m_v3Position;
    aligned_mat4 m_m4InvViewProjection;
};

bool GL_Init()
{
    // Initialize GLEW
    glewExperimental = GL_TRUE; // Allow experimental or pre-release drivers to return all supported extensions
    GLenum GlewError = glewInit();
    if (GlewError != GLEW_OK) {
        SDL_LogCritical(SDL_LOG_CATEGORY_APPLICATION, "Failed to initialize GLEW: %s\n", glewGetErrorString(GlewError));
        return false;
    }
#ifdef _DEBUG
    // Initialise debug callback
    GLDebug_Init();
#endif

    // Set up initial GL attributes
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set the cleared back buffer to black
    glCullFace(GL_BACK);                  // Set back-face culling
    glEnable(GL_CULL_FACE);               // Enable use of back/front face culling
    glEnable(GL_DEPTH_TEST);              // Enable use of depth testing
    glDisable(GL_STENCIL_TEST);           // Disable stencil test for speed
    glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS); // Enable texturing filtering across cube map faces

    // Load in scene from file
    if (!GL_LoadScene("Cathedral/TutorialCathedral.fbx", g_SceneData)) {
        return false;
    }

    // Create vertex shader
    GLuint uiVertexShader;
    if (!GL_LoadShaderFile(uiVertexShader, GL_VERTEX_SHADER, "MainPNUTVert.glsl", 100))
        return false;

    // Create deferred fragment shader
    GLuint uiFragmentShader;
    if (!GL_LoadShaderFile(uiFragmentShader, GL_FRAGMENT_SHADER, "Deferred1stFrag.glsl", 200))
        return false;

    // Create tessellation shader
    GLuint uiTessControl;
    GLuint uiTessEval;
    if (!GL_LoadShaderFile(uiTessControl, GL_TESS_CONTROL_SHADER, "PNTriangleTessControl.glsl", 1100))
        return false;
    if (!GL_LoadShaderFile(uiTessEval, GL_TESS_EVALUATION_SHADER, "PNTriangleTessEval.glsl", 1200))
        return false;

    // Create program
    if (!GL_LoadShaders(g_uiMainProgram, uiVertexShader, uiFragmentShader, -1, uiTessControl, uiTessEval))
        return false;

    // Clean up unneeded shaders
    glDeleteShader(uiVertexShader);
    glDeleteShader(uiFragmentShader);
    glDeleteShader(uiTessControl);
    glDeleteShader(uiTessEval);

    // Load in second deferred pass shader
    if (!GL_LoadShaderFile(uiVertexShader, GL_VERTEX_SHADER, "QuadVert.glsl", 300))
        return false;
    if (!GL_LoadShaderFile(uiFragmentShader, GL_FRAGMENT_SHADER, "Deferred2ndFrag.glsl", 400))
        return false;
    if (!GL_LoadShaders(g_uiDeferredProgram2, uiVertexShader, uiFragmentShader))
        return false;

    // Clean up unneeded shaders
    glDeleteShader(uiFragmentShader);

    // Load in post processing pass shader
    if (!GL_LoadShaderFile(uiFragmentShader, GL_FRAGMENT_SHADER, "PostProcessFrag.glsl", 1300))
        return false;
    if (!GL_LoadShaders(g_uiPostProcProgram, uiVertexShader, uiFragmentShader))
        return false;

    // Clean up unneeded shaders
    glDeleteShader(uiVertexShader);
    glDeleteShader(uiFragmentShader);

    // Load in shadow map shader
    GLuint uiGeometryShader;
    if (!GL_LoadShaderFile(uiVertexShader, GL_VERTEX_SHADER, "ShadowVert.glsl", 500))
        return false;
    if (!GL_LoadShaderFile(uiGeometryShader, GL_GEOMETRY_SHADER, "ShadowGeom.glsl", 600))
        return false;
    if (!GL_LoadShaderFile(uiFragmentShader, GL_FRAGMENT_SHADER, "ShadowFrag.glsl", 700))
        return false;
    if (!GL_LoadShaders(g_uiShadowProgram, uiVertexShader, uiFragmentShader, uiGeometryShader))
        return false;

    // Clean up unneeded shaders
    glDeleteShader(uiVertexShader);
    glDeleteShader(uiGeometryShader);
    glDeleteShader(uiFragmentShader);

    // Load in shadow map transparency shader
    if (!GL_LoadShaderFile(uiVertexShader, GL_VERTEX_SHADER, "ShadowTransVert.glsl", 800))
        return false;
    if (!GL_LoadShaderFile(uiGeometryShader, GL_GEOMETRY_SHADER, "ShadowTransGeom.glsl", 900))
        return false;
    if (!GL_LoadShaderFile(uiFragmentShader, GL_FRAGMENT_SHADER, "ShadowTransFrag.glsl", 1000))
        return false;
    if (!GL_LoadShaders(g_uiShadowTransProgram, uiVertexShader, uiFragmentShader, uiGeometryShader))
        return false;

    // Clean up unneeded shaders
    glDeleteShader(uiVertexShader);
    glDeleteShader(uiGeometryShader);
    glDeleteShader(uiFragmentShader);

    // Bind light UBO
    glBindBufferBase(GL_UNIFORM_BUFFER, 2, g_SceneData.m_uiPointLightUBO);
    glBindBufferBase(GL_UNIFORM_BUFFER, 5, g_SceneData.m_uiSpotLightUBO);

    // Load SkyBox
    glGenTextures(1, &g_uiSkyBox);
    GL_LoadTextureKTX(g_uiSkyBox, "Cathedral/textures/SkyBox.ktx");

    // Bind and set up SkyBox texture
    glBindTexture(GL_TEXTURE_CUBE_MAP, g_uiSkyBox);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAX_ANISOTROPY_EXT, 4);

    // Setup tessellation parameters
    glPatchParameteri(GL_PATCH_VERTICES, 3);
    glProgramUniform2f(g_uiMainProgram, 4, (float)g_iWindowWidth, (float)g_iWindowHeight);

    // Initialise deferred rendering
    GL_InitDeferred();

    // Initialise shadows
    GL_InitShadow();

    // Initialise reflections
    GL_InitReflection();

    // Set Mouse capture and hide cursor
    SDL_ShowCursor(0);
    SDL_SetRelativeMouseMode(SDL_TRUE);

    return true;
}

void GL_Quit()
{
    // Release the shader programs
    glDeleteProgram(g_uiMainProgram);
    glDeleteProgram(g_uiShadowProgram);
    glDeleteProgram(g_uiShadowTransProgram);
    glDeleteProgram(g_uiDeferredProgram2);
    glDeleteProgram(g_uiPostProcProgram);

    // Release deferred data
    GL_QuitDeferred();

    // Release shadow data
    GL_QuitShadow();

    // Release reflection data
    GL_QuitReflection();

    // Release Scene data
    GL_UnloadScene(g_SceneData);
}

void GL_RenderObjects(ObjectData * p_SkipObject = NULL)
{
    // Clear the render output and depth buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Initialise sub routine selectors
    const GLuint uiEmissiveSubs[] = {0, 1};
    const GLuint uiRefractSubs[] = {2, 3};
    const GLuint uiReflectSubs[] = {4, 5, 6};

    // Loop through each object
    for (unsigned i = 0; i < g_SceneData.m_uiNumObjects; i++) {
        const ObjectData * p_Object = &g_SceneData.mp_Objects[i];

        // Check if this object should be rendered
        if (p_Object == p_SkipObject)
            continue;

        // Set subroutines
        GLuint uiSubRoutines[3] = {uiEmissiveSubs[p_Object->m_fEmissive != 0.0f],
            uiRefractSubs[p_Object->m_bTransparent],
            uiReflectSubs[p_Object->m_uiReflective]};
        glUniformSubroutinesuiv(GL_FRAGMENT_SHADER, 3, uiSubRoutines);

        // Bind VAO
        glBindVertexArray(p_Object->m_uiVAO);

        // Bind the Transform UBO
        glBindBufferBase(GL_UNIFORM_BUFFER, 0, p_Object->m_uiTransformUBO);

        // Bind the textures to texture units
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, p_Object->m_uiDiffuse);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, p_Object->m_uiSpecular);
        glActiveTexture(GL_TEXTURE2);
        glBindTexture(GL_TEXTURE_2D, p_Object->m_uiRough);
        glActiveTexture(GL_TEXTURE9);
        glBindTexture(GL_TEXTURE_2D, p_Object->m_uiNormal);
        glActiveTexture(GL_TEXTURE10);
        glBindTexture(GL_TEXTURE_2D, p_Object->m_uiBump);

        // If emissive then update uniform
        if (p_Object->m_fEmissive != 0.0f) {
            glUniform1f(1, p_Object->m_fEmissive);
        }

        // If transparent then update texture
        if (p_Object->m_bTransparent) {
            glActiveTexture(GL_TEXTURE3);
            glBindTexture(GL_TEXTURE_CUBE_MAP, g_uiSkyBox);
        }

        // If reflective then update texture and uniform
        if (p_Object->m_uiReflective == 1) {
            glActiveTexture(GL_TEXTURE4);
            glBindTexture(GL_TEXTURE_2D, p_Object->m_uiReflect);

            glBindBufferBase(GL_UNIFORM_BUFFER, 3, p_Object->m_uiReflectVPUBO);
        } else if (p_Object->m_uiReflective == 2) {
            glActiveTexture(GL_TEXTURE5);
            glBindTexture(GL_TEXTURE_CUBE_MAP, p_Object->m_uiReflect);
        }

        //Set the parallax map scaling
        glUniform1f(3, p_Object->m_fBumpScale);

        // Draw the Object
        glDrawElements(GL_PATCHES, p_Object->m_uiNumIndices, GL_UNSIGNED_INT, 0);
    }
}

void GL_Render()
{
    // Generate shadows
    //GL_RenderShadows();

    // Generate reflection maps
    //for (unsigned i = 0; i < g_SceneData.m_uiNumReflecObjects; i++) {
    //    ReflectObjectData * p_RObject = &g_SceneData.mp_ReflecObjects[i];
    //    ObjectData * p_Object = &g_SceneData.mp_Objects[p_RObject->m_uiObjectPos];
    //
    //    // Check if cube reflection
    //    if (p_Object->m_uiReflective == 2) {
    //        // Calculate cube maps first as they recalculate planar reflections as well
    //        GL_RenderEnvironmentReflection(p_RObject, p_Object);
    //    }
    //}
    for (unsigned i = 0; i < g_SceneData.m_uiNumReflecObjects; i++) {
        ReflectObjectData * p_RObject = &g_SceneData.mp_ReflecObjects[i];
        ObjectData * p_Object = &g_SceneData.mp_Objects[p_RObject->m_uiObjectPos];

        // Check if planar or cube reflection
        if (p_Object->m_uiReflective == 1) {
            GL_RenderPlanarReflection(p_RObject, p_Object,
                                      g_SceneData.m_LocalCamera.m_v3Direction, cross(g_SceneData.m_LocalCamera.m_v3Right, g_SceneData.m_LocalCamera.m_v3Direction),
                                      g_SceneData.m_LocalCamera.m_v3Position, g_SceneData.m_LocalCamera.m_fFOV, g_SceneData.m_LocalCamera.m_fAspect,
                                      vec2(g_SceneData.m_LocalCamera.m_fNear, g_SceneData.m_LocalCamera.m_fFar));
        }
    }

    // Bind default camera
    glBindBufferBase(GL_UNIFORM_BUFFER, 1, g_SceneData.m_uiCameraUBO);

    // Perform deferred render pass
    GL_RenderDeferred();

    // Perform final pass
    GL_RenderPostProcess();
}

void GL_Update(float fElapsedTime)
{
    // Update the cameras position
    g_SceneData.m_LocalCamera.m_v3Position += g_SceneData.m_LocalCamera.m_fMoveZ * fElapsedTime * g_SceneData.m_LocalCamera.m_v3Direction;
    g_SceneData.m_LocalCamera.m_v3Position += g_SceneData.m_LocalCamera.m_fMoveX * fElapsedTime * g_SceneData.m_LocalCamera.m_v3Right;

    // Determine rotation matrix for camera angles
    mat4 m4Rotation = rotate(mat4(1.0f), g_SceneData.m_LocalCamera.m_fAngleX, vec3(0.0f, 1.0f, 0.0f));
    m4Rotation = rotate(m4Rotation, g_SceneData.m_LocalCamera.m_fAngleY, vec3(1.0f, 0.0f, 0.0f));

    // Determine new view and right vectors
    g_SceneData.m_LocalCamera.m_v3Direction = mat3(m4Rotation) * vec3(0.0f, 0.0f, 1.0f);
    g_SceneData.m_LocalCamera.m_v3Right = mat3(m4Rotation) * vec3(-1.0f, 0.0f, 0.0f);

    // Create updated camera View matrix
    mat4 m4View = lookAt(
        g_SceneData.m_LocalCamera.m_v3Position,
        g_SceneData.m_LocalCamera.m_v3Position + g_SceneData.m_LocalCamera.m_v3Direction,
        cross(g_SceneData.m_LocalCamera.m_v3Right, g_SceneData.m_LocalCamera.m_v3Direction)
    );

    // Create updated camera projection matrix
    mat4 m4Projection = perspective(
        g_SceneData.m_LocalCamera.m_fFOV,
        g_SceneData.m_LocalCamera.m_fAspect,
        g_SceneData.m_LocalCamera.m_fNear, g_SceneData.m_LocalCamera.m_fFar
    );

    // Create updated ViewProjection matrix
    mat4 m4ViewProjection = m4Projection * m4View;

    // Calculate inverse view projection
    mat4 m4InvViewProjection = inverse(m4ViewProjection);

    // Create updated camera data
    CameraData Camera = {
        m4ViewProjection,
        g_SceneData.m_LocalCamera.m_v3Position,
        m4InvViewProjection
    };

    // Update the camera buffer
    glBindBuffer(GL_UNIFORM_BUFFER, g_SceneData.m_uiCameraUBO);
    glBufferData(GL_UNIFORM_BUFFER, sizeof(CameraData), &Camera, GL_DYNAMIC_DRAW);
}

#ifdef _WIN32
int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int)
#else
int main(int argc, char **argv)
#endif
{
    // Initialize SDL
    if (SDL_Init(SDL_INIT_VIDEO) != 0) {
        SDL_LogCritical(SDL_LOG_CATEGORY_APPLICATION, "Failed to initialize SDL: %s\n", SDL_GetError());
        return 1;
    }

    // Use OpenGL 4.3 core profile
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
#ifdef _DEBUG
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
#endif

    // Turn on double buffering with a 24bit Z buffer
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

    //Get desktop resolution
    SDL_DisplayMode CurrentDisplay;
    g_bWindowFullscreen &= (SDL_GetCurrentDisplayMode(0, &CurrentDisplay) == 0);

    // Update screen resolution
    g_iWindowWidth = (g_bWindowFullscreen) ? CurrentDisplay.w : g_iWindowWidth;
    g_iWindowHeight = (g_bWindowFullscreen) ? CurrentDisplay.h : g_iWindowHeight;

    // Create a SDL window
    SDL_Window * Window = SDL_CreateWindow("AGT Tutorial", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
                                           g_iWindowWidth, g_iWindowHeight,
                                           SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL | (g_bWindowFullscreen * SDL_WINDOW_FULLSCREEN));
    if (Window == NULL) {
        SDL_LogCritical(SDL_LOG_CATEGORY_APPLICATION, "Failed to create OpenGL window: %s\n", SDL_GetError());
        SDL_Quit();
        return 1;
    }

    // Create a OpenGL Context
    SDL_GLContext Context = SDL_GL_CreateContext(Window);
    if (Context == NULL) {
        SDL_LogCritical(SDL_LOG_CATEGORY_APPLICATION, "Failed to create OpenGL context: %s\n", SDL_GetError());
        SDL_DestroyWindow(Window);
        SDL_Quit();
        return 1;
    }

    // Enable VSync with the OpenGL context
    SDL_GL_SetSwapInterval(-1);

    //Initialize OpenGL
    if (GL_Init()) {
        // Initialise elapsed time
        Uint32 uiOldTime, uiCurrentTime;
        uiCurrentTime = SDL_GetTicks();
        // Start the program message pump
        SDL_Event Event;
        bool bQuit = false;
        while (!bQuit) {
            // Update elapsed frame time
            uiOldTime = uiCurrentTime;
            uiCurrentTime = SDL_GetTicks();
            float fElapsedTime = (float)(uiCurrentTime - uiOldTime) / 1000.0f;

            // Poll SDL for buffered events
            while (SDL_PollEvent(&Event)) {
                if (Event.type == SDL_QUIT)
                    bQuit = true;
                else if ((Event.type == SDL_KEYDOWN) && (Event.key.repeat == 0)) {
                    if (Event.key.keysym.sym == SDLK_ESCAPE)
                        bQuit = true;
                    // Update camera movement vector
                    else if (Event.key.keysym.sym == SDLK_w)
                        g_SceneData.m_LocalCamera.m_fMoveZ += 2.0f;
                    else if (Event.key.keysym.sym == SDLK_a)
                        g_SceneData.m_LocalCamera.m_fMoveX -= 2.0f;
                    else if (Event.key.keysym.sym == SDLK_s)
                        g_SceneData.m_LocalCamera.m_fMoveZ -= 2.0f;
                    else if (Event.key.keysym.sym == SDLK_d)
                        g_SceneData.m_LocalCamera.m_fMoveX += 2.0f;
                    // Toggle mouse mode for debugging
                    else if (Event.key.keysym.sym == SDLK_z && Event.key.keysym.mod == KMOD_LSHIFT) {
                        SDL_SetRelativeMouseMode((SDL_bool)!SDL_GetRelativeMouseMode());
                    }
                    // Swap subroutines
                    else if (Event.key.keysym.sym == SDLK_1) {
                        g_uiOutputSubroutine = 0;
                    } else if (Event.key.keysym.sym == SDLK_2) {
                        g_uiOutputSubroutine = 1;
                    } else if (Event.key.keysym.sym == SDLK_3) {
                        g_uiOutputSubroutine = 2;
                    } else if (Event.key.keysym.sym == SDLK_4) {
                        g_uiOutputSubroutine = 3;
                    } else if (Event.key.keysym.sym == SDLK_5) {
                        g_uiOutputSubroutine = 4;
                    } else if (Event.key.keysym.sym == SDLK_6) {
                        g_uiOutputSubroutine = 5;
                    }
                } else if ((Event.type == SDL_KEYUP)) {
                    // Reset camera movement vector
                    if (Event.key.keysym.sym == SDLK_w)
                        g_SceneData.m_LocalCamera.m_fMoveZ -= 2.0f;
                    else if (Event.key.keysym.sym == SDLK_a)
                        g_SceneData.m_LocalCamera.m_fMoveX += 2.0f;
                    else if (Event.key.keysym.sym == SDLK_s)
                        g_SceneData.m_LocalCamera.m_fMoveZ += 2.0f;
                    else if (Event.key.keysym.sym == SDLK_d)
                        g_SceneData.m_LocalCamera.m_fMoveX -= 2.0f;
                } else if (Event.type == SDL_MOUSEMOTION) {
                    // Update camera view angles
                    g_SceneData.m_LocalCamera.m_fAngleX += -0.05f * fElapsedTime * Event.motion.xrel;
                    // Y Coordinates are in screen space so don't get negated
                    g_SceneData.m_LocalCamera.m_fAngleY += 0.05f * fElapsedTime * Event.motion.yrel;
                    // Clip total pitch range to prevent gimbal lock
                    if (g_SceneData.m_LocalCamera.m_fAngleY <= -((float)M_PI_2 * 0.7f))
                        g_SceneData.m_LocalCamera.m_fAngleY = -((float)M_PI_2 * 0.7f);
                    if (g_SceneData.m_LocalCamera.m_fAngleY >= ((float)M_PI_2 * 0.7f))
                        g_SceneData.m_LocalCamera.m_fAngleY = ((float)M_PI_2 * 0.7f);
                } else if (Event.type == SDL_MOUSEWHEEL) {
                    // Update the cameras field of view
                    g_SceneData.m_LocalCamera.m_fFOV += -0.5f * fElapsedTime * Event.motion.x;
                    // Clip FOV to prevent extreme values
                    if (g_SceneData.m_LocalCamera.m_fFOV <= ((float)M_PI_2 * 0.1f))
                        g_SceneData.m_LocalCamera.m_fFOV = ((float)M_PI_2 * 0.1f);
                    if (g_SceneData.m_LocalCamera.m_fFOV >= ((float)M_PI * 0.9f))
                        g_SceneData.m_LocalCamera.m_fFOV = ((float)M_PI * 0.9f);
                }
            }

            // Update the Scene
            GL_Update(fElapsedTime);

            // Render the scene
            GL_Render();

            // Swap the back-buffer and present the render
            SDL_GL_SwapWindow(Window);
        }

        // Delete any created GL resources
        GL_Quit();
    }

    // Delete the OpenGL context, SDL window and shutdown SDL
    SDL_GL_DeleteContext(Context);
    SDL_DestroyWindow(Window);
    SDL_Quit();

    return 0;
}