Remove Oculus support from code

Moved to custom example, now raylib only supports simulated VR
rendering.
Oculus code was too device dependant... waiting for OpenXR.

1 files changed, 461 insertions, 8 deletions

diff --git a/examples/core_oculus_rift.c b/examples/core_oculus_rift.c
index eb628cd7..f1b0bd3b 100644
--- a/examples/core_oculus_rift.c
+++ b/examples/core_oculus_rift.c
@@ -3,7 +3,12 @@
 *   raylib [core] example - Oculus Rift CV1
 *
 *   Compile example using:
-*   gcc -o $(NAME_PART).exe $(FILE_NAME) -L. -L..\src\external\OculusSDK\LibOVR -lLibOVRRT32_1 -lraylib -lglfw3 -lopengl32 -lgdi32 -std=c99
+*   gcc -o $(NAME_PART).exe $(FILE_NAME) -I..\src\external -I..\src\external\OculusSDK\LibOVR\Include /
+*       -L. -L..\src\external\OculusSDK\LibOVR -lLibOVRRT32_1 -lraylib -lglfw3 -lopengl32 -lgdi32 -std=c99 /
+*       -Wl,-allow-multiple-definition
+*
+*   #define SUPPORT_OCULUS_RIFT_CV1 / RLGL_OCULUS_SUPPORT
+*       Enable Oculus Rift CV1 functionality
 *
 *   This example has been created using raylib 1.5 (www.raylib.com)
 *   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
@@ -14,6 +19,95 @@
 
 #include "raylib.h"
 
+#include "glad.h"                   // Required for: OpenGL types and functions declarations
+#include "raymath.h"                // Required for: Vector3, Quaternion and Matrix functionality
+
+#include <string.h>                 // Required for: memset()
+#include <stdlib.h>                 // Required for: exit()
+#include <stdio.h>                  // required for: vfprintf()
+#include <stdarg.h>                 // Required for: va_list, va_start(), vfprintf(), va_end()
+
+#define RLGL_OCULUS_SUPPORT         // Enable Oculus Rift code
+#if defined(RLGL_OCULUS_SUPPORT)
+    #include "OVR_CAPI_GL.h"        // Oculus SDK for OpenGL
+#endif
+
+//----------------------------------------------------------------------------------
+// Defines and Macros
+//----------------------------------------------------------------------------------
+// ...
+
+//----------------------------------------------------------------------------------
+// Types and Structures Definition
+//----------------------------------------------------------------------------------
+
+// TraceLog message types
+typedef enum { INFO = 0, ERROR, WARNING, DEBUG, OTHER } TraceLogType;
+
+#if defined(RLGL_OCULUS_SUPPORT)
+// Oculus buffer type
+typedef struct OculusBuffer {
+    ovrTextureSwapChain textureChain;
+    GLuint depthId;
+    GLuint fboId;
+    int width;
+    int height;
+} OculusBuffer;
+
+// Oculus mirror texture type
+typedef struct OculusMirror {
+    ovrMirrorTexture texture;
+    GLuint fboId;
+    int width;
+    int height;
+} OculusMirror;
+
+// Oculus layer type
+typedef struct OculusLayer {
+    ovrViewScaleDesc viewScaleDesc;
+    ovrLayerEyeFov eyeLayer;      // layer 0
+    //ovrLayerQuad quadLayer;     // TODO: layer 1: '2D' quad for GUI
+    Matrix eyeProjections[2];
+    int width;
+    int height;
+} OculusLayer;
+#endif
+
+//----------------------------------------------------------------------------------
+// Global Variables Definition
+//----------------------------------------------------------------------------------
+#if defined(RLGL_OCULUS_SUPPORT)
+// OVR device variables
+static ovrSession session;              // Oculus session (pointer to ovrHmdStruct)
+static ovrHmdDesc hmdDesc;              // Oculus device descriptor parameters
+static ovrGraphicsLuid luid;            // Oculus locally unique identifier for the program (64 bit)
+static OculusLayer layer;               // Oculus drawing layer (similar to photoshop)
+static OculusBuffer buffer;             // Oculus internal buffers (texture chain and fbo)
+static OculusMirror mirror;             // Oculus mirror texture and fbo
+static unsigned int frameIndex = 0;     // Oculus frames counter, used to discard frames from chain
+#endif
+
+//----------------------------------------------------------------------------------
+// Module specific Functions Declaration
+//----------------------------------------------------------------------------------
+#if defined(RLGL_OCULUS_SUPPORT)
+static bool InitOculusDevice(void);                 // Initialize Oculus device (returns true if success)
+static void CloseOculusDevice(void);                // Close Oculus device
+static void UpdateOculusTracking(Camera *camera);   // Update Oculus head position-orientation tracking
+static void BeginOculusDrawing(void);               // Setup Oculus buffers for drawing
+static void EndOculusDrawing(void);                 // Finish Oculus drawing and blit framebuffer to mirror
+
+static OculusBuffer LoadOculusBuffer(ovrSession session, int width, int height);    // Load Oculus required buffers
+static void UnloadOculusBuffer(ovrSession session, OculusBuffer buffer);            // Unload texture required buffers
+static OculusMirror LoadOculusMirror(ovrSession session, int width, int height);    // Load Oculus mirror buffers
+static void UnloadOculusMirror(ovrSession session, OculusMirror mirror);            // Unload Oculus mirror buffers
+static void BlitOculusMirror(ovrSession session, OculusMirror mirror);              // Copy Oculus screen buffer to mirror texture
+static OculusLayer InitOculusLayer(ovrSession session);                             // Init Oculus layer (similar to photoshop)
+static Matrix FromOvrMatrix(ovrMatrix4f ovrM);  // Convert from Oculus ovrMatrix4f struct to raymath Matrix struct
+#endif
+
+static void TraceLog(int msgType, const char *text, ...);
+
 int main()
 {
     // Initialization
@@ -25,8 +119,9 @@ int main()
     
     InitWindow(screenWidth, screenHeight, "raylib [core] example - oculus rift");
     
-    // NOTE: If device is not available, it fallbacks to default device (simulator)
-    InitVrDevice(HMD_OCULUS_RIFT_CV1);                  // Init VR device (Oculus Rift CV1)
+    bool vrDeviceReady = InitOculusDevice();            // Init VR device Oculus Rift CV1
+    
+    if (!vrDeviceReady) InitVrSimulator(HMD_OCULUS_RIFT_CV1); // Init VR simulator if device fails
     
     // Define the camera to look into our 3d world
     Camera camera;
@@ -47,10 +142,10 @@ int main()
     {
         // Update
         //----------------------------------------------------------------------------------
-        if (IsVrSimulator()) UpdateCamera(&camera);             // Update camera (simulator mode)
-        else if (IsVrDeviceReady()) UpdateVrTracking(&camera);  // Update camera with device tracking data
-        
-        if (IsKeyPressed(KEY_SPACE)) ToggleVrMode();            // Toggle VR mode
+        if (!vrDeviceReady) UpdateCamera(&camera);      // Update camera (simulator mode)
+        else UpdateOculusTracking(&camera);             // Update camera with device tracking data
+    
+        if (IsKeyPressed(KEY_SPACE)) ToggleVrMode();    // Toggle VR mode
         //----------------------------------------------------------------------------------
 
         // Draw
@@ -58,6 +153,9 @@ int main()
         BeginDrawing();
 
             ClearBackground(RAYWHITE);
+            
+            if (vrDeviceReady) BeginOculusDrawing();
+            else BeginVrDrawing();
 
             Begin3dMode(camera);
 
@@ -67,6 +165,9 @@ int main()
                 DrawGrid(40, 1.0f);
 
             End3dMode();
+            
+            if (vrDeviceReady) EndOculusDrawing();
+            else EndVrDrawing();
 
             DrawFPS(10, 10);
 
@@ -76,10 +177,362 @@ int main()
 
     // De-Initialization
     //--------------------------------------------------------------------------------------
-    CloseVrDevice();        // Close VR device
+    if (vrDeviceReady) CloseOculusDevice();
+    else CloseVrSimulator();
     
     CloseWindow();          // Close window and OpenGL context
     //--------------------------------------------------------------------------------------
 
     return 0;
 }
+
+//----------------------------------------------------------------------------------
+// Module specific Functions Definition
+//----------------------------------------------------------------------------------
+
+#if defined(RLGL_OCULUS_SUPPORT)
+// Set internal projection and modelview matrix depending on eyes tracking data
+static void SetStereoView(int eye, Matrix matProjection, Matrix matModelView)
+{
+    Matrix eyeProjection = matProjection;
+    Matrix eyeModelView = matModelView;
+
+    glViewport(layer.eyeLayer.Viewport[eye].Pos.x, layer.eyeLayer.Viewport[eye].Pos.y,
+               layer.eyeLayer.Viewport[eye].Size.w, layer.eyeLayer.Viewport[eye].Size.h);
+
+    Quaternion eyeRenderPose = (Quaternion){ layer.eyeLayer.RenderPose[eye].Orientation.x,
+                                             layer.eyeLayer.RenderPose[eye].Orientation.y,
+                                             layer.eyeLayer.RenderPose[eye].Orientation.z,
+                                             layer.eyeLayer.RenderPose[eye].Orientation.w };
+    QuaternionInvert(&eyeRenderPose);
+    Matrix eyeOrientation = QuaternionToMatrix(eyeRenderPose);
+    Matrix eyeTranslation = MatrixTranslate(-layer.eyeLayer.RenderPose[eye].Position.x,
+                                            -layer.eyeLayer.RenderPose[eye].Position.y,
+                                            -layer.eyeLayer.RenderPose[eye].Position.z);
+
+    Matrix eyeView = MatrixMultiply(eyeTranslation, eyeOrientation);    // Matrix containing eye-head movement
+    eyeModelView = MatrixMultiply(matModelView, eyeView);               // Combine internal camera matrix (modelview) wih eye-head movement
+
+    eyeProjection = layer.eyeProjections[eye];
+}
+
+// Initialize Oculus device (returns true if success)
+static bool InitOculusDevice(void)
+{
+    bool oculusReady = false;
+
+    ovrResult result = ovr_Initialize(NULL);
+
+    if (OVR_FAILURE(result)) TraceLog(WARNING, "OVR: Could not initialize Oculus device");
+    else
+    {
+        result = ovr_Create(&session, &luid);
+        if (OVR_FAILURE(result))
+        {
+            TraceLog(WARNING, "OVR: Could not create Oculus session");
+            ovr_Shutdown();
+        }
+        else
+        {
+            hmdDesc = ovr_GetHmdDesc(session);
+
+            TraceLog(INFO, "OVR: Product Name: %s", hmdDesc.ProductName);
+            TraceLog(INFO, "OVR: Manufacturer: %s", hmdDesc.Manufacturer);
+            TraceLog(INFO, "OVR: Product ID: %i", hmdDesc.ProductId);
+            TraceLog(INFO, "OVR: Product Type: %i", hmdDesc.Type);
+            //TraceLog(INFO, "OVR: Serial Number: %s", hmdDesc.SerialNumber);
+            TraceLog(INFO, "OVR: Resolution: %ix%i", hmdDesc.Resolution.w, hmdDesc.Resolution.h);
+
+            // NOTE: Oculus mirror is set to defined screenWidth and screenHeight...
+            // ...ideally, it should be (hmdDesc.Resolution.w/2, hmdDesc.Resolution.h/2)
+
+            // Initialize Oculus Buffers
+            layer = InitOculusLayer(session);
+            buffer = LoadOculusBuffer(session, layer.width, layer.height);
+            mirror = LoadOculusMirror(session, hmdDesc.Resolution.w/2, hmdDesc.Resolution.h/2);     // NOTE: hardcoded...
+            layer.eyeLayer.ColorTexture[0] = buffer.textureChain;     //SetOculusLayerTexture(eyeLayer, buffer.textureChain);
+
+            // Recenter OVR tracking origin
+            ovr_RecenterTrackingOrigin(session);
+
+            oculusReady = true;
+        }
+    }
+
+    return oculusReady;
+}
+
+// Close Oculus device (and unload buffers)
+static void CloseOculusDevice(void)
+{
+    UnloadOculusMirror(session, mirror);    // Unload Oculus mirror buffer
+    UnloadOculusBuffer(session, buffer);    // Unload Oculus texture buffers
+
+    ovr_Destroy(session);   // Free Oculus session data
+    ovr_Shutdown();         // Close Oculus device connection
+}
+
+// Update Oculus head position-orientation tracking
+static void UpdateOculusTracking(Camera *camera)
+{
+    frameIndex++;
+
+    ovrPosef eyePoses[2];
+    ovr_GetEyePoses(session, frameIndex, ovrTrue, layer.viewScaleDesc.HmdToEyeOffset, eyePoses, &layer.eyeLayer.SensorSampleTime);
+
+    layer.eyeLayer.RenderPose[0] = eyePoses[0];
+    layer.eyeLayer.RenderPose[1] = eyePoses[1];
+
+    // TODO: Update external camera with eyePoses data (position, orientation)
+    // NOTE: We can simplify to simple camera if we consider IPD and HMD device configuration again later
+    // it will be useful for the user to draw, lets say, billboards oriented to camera
+
+    // Get session status information
+    ovrSessionStatus sessionStatus;
+    ovr_GetSessionStatus(session, &sessionStatus);
+
+    if (sessionStatus.ShouldQuit) TraceLog(WARNING, "OVR: Session should quit...");
+    if (sessionStatus.ShouldRecenter) ovr_RecenterTrackingOrigin(session);
+    //if (sessionStatus.HmdPresent)  // HMD is present.
+    //if (sessionStatus.DisplayLost) // HMD was unplugged or the display driver was manually disabled or encountered a TDR.
+    //if (sessionStatus.HmdMounted)  // HMD is on the user's head.
+    //if (sessionStatus.IsVisible)   // the game or experience has VR focus and is visible in the HMD.
+}
+
+// Setup Oculus buffers for drawing
+static void BeginOculusDrawing(void)
+{
+    GLuint currentTexId;
+    int currentIndex;
+
+    ovr_GetTextureSwapChainCurrentIndex(session, buffer.textureChain, &currentIndex);
+    ovr_GetTextureSwapChainBufferGL(session, buffer.textureChain, currentIndex, &currentTexId);
+
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, buffer.fboId);
+    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, currentTexId, 0);
+    //glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, buffer.depthId, 0);    // Already binded
+}
+
+// Finish Oculus drawing and blit framebuffer to mirror
+static void EndOculusDrawing(void)
+{
+    // Unbind current framebuffer (Oculus buffer)
+    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+
+    ovr_CommitTextureSwapChain(session, buffer.textureChain);
+
+    ovrLayerHeader *layers = &layer.eyeLayer.Header;
+    ovr_SubmitFrame(session, frameIndex, &layer.viewScaleDesc, &layers, 1);
+
+    // Blit mirror texture to back buffer
+    BlitOculusMirror(session, mirror);
+}
+
+// Load Oculus required buffers: texture-swap-chain, fbo, texture-depth
+static OculusBuffer LoadOculusBuffer(ovrSession session, int width, int height)
+{
+    OculusBuffer buffer;
+    buffer.width = width;
+    buffer.height = height;
+
+    // Create OVR texture chain
+    ovrTextureSwapChainDesc desc = {};
+    desc.Type = ovrTexture_2D;
+    desc.ArraySize = 1;
+    desc.Width = width;
+    desc.Height = height;
+    desc.MipLevels = 1;
+    desc.Format = OVR_FORMAT_R8G8B8A8_UNORM_SRGB;   // Requires glEnable(GL_FRAMEBUFFER_SRGB);
+    desc.SampleCount = 1;
+    desc.StaticImage = ovrFalse;
+
+    ovrResult result = ovr_CreateTextureSwapChainGL(session, &desc, &buffer.textureChain);
+
+    if (!OVR_SUCCESS(result)) TraceLog(WARNING, "OVR: Failed to create swap textures buffer");
+
+    int textureCount = 0;
+    ovr_GetTextureSwapChainLength(session, buffer.textureChain, &textureCount);
+
+    if (!OVR_SUCCESS(result) || !textureCount) TraceLog(WARNING, "OVR: Unable to count swap chain textures");
+
+    for (int i = 0; i < textureCount; ++i)
+    {
+        GLuint chainTexId;
+        ovr_GetTextureSwapChainBufferGL(session, buffer.textureChain, i, &chainTexId);
+        glBindTexture(GL_TEXTURE_2D, chainTexId);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    }
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    /*
+    // Setup framebuffer object (using depth texture)
+    glGenFramebuffers(1, &buffer.fboId);
+    glGenTextures(1, &buffer.depthId);
+    glBindTexture(GL_TEXTURE_2D, buffer.depthId);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT16, buffer.width, buffer.height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, NULL);
+    */
+
+    // Setup framebuffer object (using depth renderbuffer)
+    glGenFramebuffers(1, &buffer.fboId);
+    glGenRenderbuffers(1, &buffer.depthId);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, buffer.fboId);
+    glBindRenderbuffer(GL_RENDERBUFFER, buffer.depthId);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, buffer.width, buffer.height);
+    glBindRenderbuffer(GL_RENDERBUFFER, 0);
+    glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, buffer.depthId);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+
+    return buffer;
+}
+
+// Unload texture required buffers
+static void UnloadOculusBuffer(ovrSession session, OculusBuffer buffer)
+{
+    if (buffer.textureChain)
+    {
+        ovr_DestroyTextureSwapChain(session, buffer.textureChain);
+        buffer.textureChain = NULL;
+    }
+
+    if (buffer.depthId != 0) glDeleteTextures(1, &buffer.depthId);
+    if (buffer.fboId != 0) glDeleteFramebuffers(1, &buffer.fboId);
+}
+
+// Load Oculus mirror buffers
+static OculusMirror LoadOculusMirror(ovrSession session, int width, int height)
+{
+    OculusMirror mirror;
+    mirror.width = width;
+    mirror.height = height;
+
+    ovrMirrorTextureDesc mirrorDesc;
+    memset(&mirrorDesc, 0, sizeof(mirrorDesc));
+    mirrorDesc.Format = OVR_FORMAT_R8G8B8A8_UNORM_SRGB;
+    mirrorDesc.Width = mirror.width;
+    mirrorDesc.Height = mirror.height;
+
+    if (!OVR_SUCCESS(ovr_CreateMirrorTextureGL(session, &mirrorDesc, &mirror.texture))) TraceLog(WARNING, "Could not create mirror texture");
+
+    glGenFramebuffers(1, &mirror.fboId);
+
+    return mirror;
+}
+
+// Unload Oculus mirror buffers
+static void UnloadOculusMirror(ovrSession session, OculusMirror mirror)
+{
+    if (mirror.fboId != 0) glDeleteFramebuffers(1, &mirror.fboId);
+    if (mirror.texture) ovr_DestroyMirrorTexture(session, mirror.texture);
+}
+
+// Copy Oculus screen buffer to mirror texture
+static void BlitOculusMirror(ovrSession session, OculusMirror mirror)
+{
+    GLuint mirrorTextureId;
+
+    ovr_GetMirrorTextureBufferGL(session, mirror.texture, &mirrorTextureId);
+
+    glBindFramebuffer(GL_READ_FRAMEBUFFER, mirror.fboId);
+    glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mirrorTextureId, 0);
+#if defined(GRAPHICS_API_OPENGL_33)
+    // NOTE: glBlitFramebuffer() requires extension: GL_EXT_framebuffer_blit (not available in OpenGL ES 2.0)
+    glBlitFramebuffer(0, 0, mirror.width, mirror.height, 0, mirror.height, mirror.width, 0, GL_COLOR_BUFFER_BIT, GL_NEAREST);
+#endif
+    glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+}
+
+// Init Oculus layer (similar to photoshop)
+static OculusLayer InitOculusLayer(ovrSession session)
+{
+    OculusLayer layer = { 0 };
+
+    layer.viewScaleDesc.HmdSpaceToWorldScaleInMeters = 1.0f;
+
+    memset(&layer.eyeLayer, 0, sizeof(ovrLayerEyeFov));
+    layer.eyeLayer.Header.Type = ovrLayerType_EyeFov;
+    layer.eyeLayer.Header.Flags = ovrLayerFlag_TextureOriginAtBottomLeft;
+
+    ovrEyeRenderDesc eyeRenderDescs[2];
+
+    for (int eye = 0; eye < 2; eye++)
+    {
+        eyeRenderDescs[eye] = ovr_GetRenderDesc(session, eye, hmdDesc.DefaultEyeFov[eye]);
+        ovrMatrix4f ovrPerspectiveProjection = ovrMatrix4f_Projection(eyeRenderDescs[eye].Fov, 0.01f, 10000.0f, ovrProjection_None); //ovrProjection_ClipRangeOpenGL);
+        layer.eyeProjections[eye] = FromOvrMatrix(ovrPerspectiveProjection);      // NOTE: struct ovrMatrix4f { float M[4][4] } --> struct Matrix
+
+        layer.viewScaleDesc.HmdToEyeOffset[eye] = eyeRenderDescs[eye].HmdToEyeOffset;
+        layer.eyeLayer.Fov[eye] = eyeRenderDescs[eye].Fov;
+
+        ovrSizei eyeSize = ovr_GetFovTextureSize(session, eye, layer.eyeLayer.Fov[eye], 1.0f);
+        layer.eyeLayer.Viewport[eye].Size = eyeSize;
+        layer.eyeLayer.Viewport[eye].Pos.x = layer.width;
+        layer.eyeLayer.Viewport[eye].Pos.y = 0;
+
+        layer.height = eyeSize.h;     //std::max(renderTargetSize.y, (uint32_t)eyeSize.h);
+        layer.width += eyeSize.w;
+    }
+
+    return layer;
+}
+
+// Convert from Oculus ovrMatrix4f struct to raymath Matrix struct
+static Matrix FromOvrMatrix(ovrMatrix4f ovrmat)
+{
+    Matrix rmat;
+
+    rmat.m0 = ovrmat.M[0][0];
+    rmat.m1 = ovrmat.M[1][0];
+    rmat.m2 = ovrmat.M[2][0];
+    rmat.m3 = ovrmat.M[3][0];
+    rmat.m4 = ovrmat.M[0][1];
+    rmat.m5 = ovrmat.M[1][1];
+    rmat.m6 = ovrmat.M[2][1];
+    rmat.m7 = ovrmat.M[3][1];
+    rmat.m8 = ovrmat.M[0][2];
+    rmat.m9 = ovrmat.M[1][2];
+    rmat.m10 = ovrmat.M[2][2];
+    rmat.m11 = ovrmat.M[3][2];
+    rmat.m12 = ovrmat.M[0][3];
+    rmat.m13 = ovrmat.M[1][3];
+    rmat.m14 = ovrmat.M[2][3];
+    rmat.m15 = ovrmat.M[3][3];
+
+    MatrixTranspose(&rmat);
+
+    return rmat;
+}
+#endif
+
+// Output a trace log message
+// NOTE: Expected msgType: (0)Info, (1)Error, (2)Warning
+static void TraceLog(int msgType, const char *text, ...)
+{
+    va_list args;
+    va_start(args, text);
+
+    switch (msgType)
+    {
+        case INFO: fprintf(stdout, "INFO: "); break;
+        case ERROR: fprintf(stdout, "ERROR: "); break;
+        case WARNING: fprintf(stdout, "WARNING: "); break;
+        case DEBUG: fprintf(stdout, "DEBUG: "); break;
+        default: break;
+    }
+
+    vfprintf(stdout, text, args);
+    fprintf(stdout, "\n");
+
+    va_end(args);
+
+    if (msgType == ERROR) exit(1);
+}
+