[rlgl] Implement vertex normals for RLGL immediate drawing mode (#3866)

* Fix several non-functional `target_compile_definitions`

* Avoid hardcoding the default vertex attribute locations

* Implement functional `rlNormal3f`

* Add normal definitions for `DrawCube`

* Update the basic lighting example to use `DrawCube` and `DrawPlane`

1 files changed, 242 insertions, 56 deletions

diff --git a/src/rlgl.h b/src/rlgl.h
index a645aa03..1787d97a 100644
--- a/src/rlgl.h
+++ b/src/rlgl.h
@@ -62,12 +62,12 @@
 *       When loading a shader, the following vertex attributes and uniform
 *       location names are tried to be set automatically:
 *
-*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION     "vertexPosition"    // Bound by default to shader location: 0
-*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD     "vertexTexCoord"    // Bound by default to shader location: 1
-*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL       "vertexNormal"      // Bound by default to shader location: 2
-*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR        "vertexColor"       // Bound by default to shader location: 3
-*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT      "vertexTangent"     // Bound by default to shader location: 4
-*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2    "vertexTexCoord2"   // Bound by default to shader location: 5
+*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION     "vertexPosition"    // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION
+*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD     "vertexTexCoord"    // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD
+*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL       "vertexNormal"      // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL
+*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR        "vertexColor"       // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR
+*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT      "vertexTangent"     // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT
+*       #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2    "vertexTexCoord2"   // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_MVP         "mvp"               // model-view-projection matrix
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_VIEW        "matView"           // view matrix
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_PROJECTION  "matProjection"     // projection matrix
@@ -349,6 +349,7 @@ typedef struct rlVertexBuffer {
 
     float *vertices;            // Vertex position (XYZ - 3 components per vertex) (shader-location = 0)
     float *texcoords;           // Vertex texture coordinates (UV - 2 components per vertex) (shader-location = 1)
+    float *normals;             // Vertex normal (XYZ - 3 components per vertex) (shader-location = 2)
     unsigned char *colors;      // Vertex colors (RGBA - 4 components per vertex) (shader-location = 3)
 #if defined(GRAPHICS_API_OPENGL_11) || defined(GRAPHICS_API_OPENGL_33)
     unsigned int *indices;      // Vertex indices (in case vertex data comes indexed) (6 indices per quad)
@@ -357,7 +358,7 @@ typedef struct rlVertexBuffer {
     unsigned short *indices;    // Vertex indices (in case vertex data comes indexed) (6 indices per quad)
 #endif
     unsigned int vaoId;         // OpenGL Vertex Array Object id
-    unsigned int vboId[4];      // OpenGL Vertex Buffer Objects id (4 types of vertex data)
+    unsigned int vboId[5];      // OpenGL Vertex Buffer Objects id (5 types of vertex data)
 } rlVertexBuffer;
 
 // Draw call type
@@ -930,24 +931,44 @@ RLAPI void rlLoadDrawQuad(void);     // Load and draw a quad
     #endif
 #endif
 
+// Default shader vertex attribute locations
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION  0
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD  1
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL    2
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR     3
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT   4
+#endif
+#ifndef RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2
+    #define RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2 5
+#endif
+
 // Default shader vertex attribute names to set location points
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION
-    #define RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION     "vertexPosition"    // Bound by default to shader location: 0
+    #define RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION     "vertexPosition"    // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION
 #endif
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD
-    #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD     "vertexTexCoord"    // Bound by default to shader location: 1
+    #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD     "vertexTexCoord"    // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD
 #endif
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL
-    #define RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL       "vertexNormal"      // Bound by default to shader location: 2
+    #define RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL       "vertexNormal"      // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL
 #endif
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR
-    #define RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR        "vertexColor"       // Bound by default to shader location: 3
+    #define RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR        "vertexColor"       // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR
 #endif
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT
-    #define RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT      "vertexTangent"     // Bound by default to shader location: 4
+    #define RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT      "vertexTangent"     // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT
 #endif
 #ifndef RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2
-    #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2    "vertexTexCoord2"   // Bound by default to shader location: 5
+    #define RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2    "vertexTexCoord2"   // Bound by default to shader location: RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2
 #endif
 
 #ifndef RL_DEFAULT_SHADER_UNIFORM_NAME_MVP
@@ -1092,8 +1113,15 @@ static const char *rlGetCompressedFormatName(int format); // Get compressed form
 static int rlGetPixelDataSize(int width, int height, int format);   // Get pixel data size in bytes (image or texture)
 
 // Auxiliar matrix math functions
+typedef struct rl_float16 {
+    float v[16];
+} rl_float16;
+static rl_float16 rlMatrixToFloatV(Matrix mat);             // Get float array of matrix data
+#define rlMatrixToFloat(mat) (rlMatrixToFloatV(mat).v)      // Get float vector for Matrix
 static Matrix rlMatrixIdentity(void);                       // Get identity matrix
 static Matrix rlMatrixMultiply(Matrix left, Matrix right);  // Multiply two matrices
+static Matrix rlMatrixTranspose(Matrix mat);                // Transposes provided matrix
+static Matrix rlMatrixInvert(Matrix mat);                   // Invert provided matrix
 
 //----------------------------------------------------------------------------------
 // Module Functions Definition - Matrix operations
@@ -1456,7 +1484,10 @@ void rlVertex3f(float x, float y, float z)
     RLGL.currentBatch->vertexBuffer[RLGL.currentBatch->currentBuffer].texcoords[2*RLGL.State.vertexCounter] = RLGL.State.texcoordx;
     RLGL.currentBatch->vertexBuffer[RLGL.currentBatch->currentBuffer].texcoords[2*RLGL.State.vertexCounter + 1] = RLGL.State.texcoordy;
 
-    // WARNING: By default rlVertexBuffer struct does not store normals
+    // Add current normal
+    RLGL.currentBatch->vertexBuffer[RLGL.currentBatch->currentBuffer].normals[3*RLGL.State.vertexCounter] = RLGL.State.normalx;
+    RLGL.currentBatch->vertexBuffer[RLGL.currentBatch->currentBuffer].normals[3*RLGL.State.vertexCounter + 1] = RLGL.State.normaly;
+    RLGL.currentBatch->vertexBuffer[RLGL.currentBatch->currentBuffer].normals[3*RLGL.State.vertexCounter + 2] = RLGL.State.normalz;
 
     // Add current color
     RLGL.currentBatch->vertexBuffer[RLGL.currentBatch->currentBuffer].colors[4*RLGL.State.vertexCounter] = RLGL.State.colorr;
@@ -1492,9 +1523,26 @@ void rlTexCoord2f(float x, float y)
 // NOTE: Normals limited to TRIANGLES only?
 void rlNormal3f(float x, float y, float z)
 {
-    RLGL.State.normalx = x;
-    RLGL.State.normaly = y;
-    RLGL.State.normalz = z;
+    float normalx = x;
+    float normaly = y;
+    float normalz = z;
+    if (RLGL.State.transformRequired)
+    {
+        normalx = RLGL.State.transform.m0*x + RLGL.State.transform.m4*y + RLGL.State.transform.m8*z;
+        normaly = RLGL.State.transform.m1*x + RLGL.State.transform.m5*y + RLGL.State.transform.m9*z;
+        normalz = RLGL.State.transform.m2*x + RLGL.State.transform.m6*y + RLGL.State.transform.m10*z;
+    }
+    float length = sqrtf(normalx*normalx + normaly*normaly + normalz*normalz);
+    if (length != 0.0f)
+    {
+        float ilength = 1.0f / length;
+        normalx *= ilength;
+        normaly *= ilength;
+        normalz *= ilength;
+    }
+    RLGL.State.normalx = normalx;
+    RLGL.State.normaly = normaly;
+    RLGL.State.normalz = normalz;
 }
 
 // Define one vertex (color)
@@ -2163,7 +2211,10 @@ void rlglInit(int width, int height)
     RLGL.State.currentShaderLocs = RLGL.State.defaultShaderLocs;
 
     // Init default vertex arrays buffers
+    // Simulate that the default shader has the location RL_SHADER_LOC_VERTEX_NORMAL to bind the normal buffer for the default render batch
+    RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_NORMAL] = RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL;
     RLGL.defaultBatch = rlLoadRenderBatch(RL_DEFAULT_BATCH_BUFFERS, RL_DEFAULT_BATCH_BUFFER_ELEMENTS);
+    RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_NORMAL] = -1;
     RLGL.currentBatch = &RLGL.defaultBatch;
 
     // Init stack matrices (emulating OpenGL 1.1)
@@ -2608,6 +2659,7 @@ rlRenderBatch rlLoadRenderBatch(int numBuffers, int bufferElements)
 
         batch.vertexBuffer[i].vertices = (float *)RL_MALLOC(bufferElements*3*4*sizeof(float));        // 3 float by vertex, 4 vertex by quad
         batch.vertexBuffer[i].texcoords = (float *)RL_MALLOC(bufferElements*2*4*sizeof(float));       // 2 float by texcoord, 4 texcoord by quad
+        batch.vertexBuffer[i].normals = (float *)RL_MALLOC(bufferElements*3*4*sizeof(float));        // 3 float by vertex, 4 vertex by quad
         batch.vertexBuffer[i].colors = (unsigned char *)RL_MALLOC(bufferElements*4*4*sizeof(unsigned char));   // 4 float by color, 4 colors by quad
 #if defined(GRAPHICS_API_OPENGL_33)
         batch.vertexBuffer[i].indices = (unsigned int *)RL_MALLOC(bufferElements*6*sizeof(unsigned int));      // 6 int by quad (indices)
@@ -2618,6 +2670,7 @@ rlRenderBatch rlLoadRenderBatch(int numBuffers, int bufferElements)
 
         for (int j = 0; j < (3*4*bufferElements); j++) batch.vertexBuffer[i].vertices[j] = 0.0f;
         for (int j = 0; j < (2*4*bufferElements); j++) batch.vertexBuffer[i].texcoords[j] = 0.0f;
+        for (int j = 0; j < (3*4*bufferElements); j++) batch.vertexBuffer[i].normals[j] = 0.0f;
         for (int j = 0; j < (4*4*bufferElements); j++) batch.vertexBuffer[i].colors[j] = 0;
 
         int k = 0;
@@ -2667,16 +2720,23 @@ rlRenderBatch rlLoadRenderBatch(int numBuffers, int bufferElements)
         glEnableVertexAttribArray(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_TEXCOORD01]);
         glVertexAttribPointer(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_TEXCOORD01], 2, GL_FLOAT, 0, 0, 0);
 
-        // Vertex color buffer (shader-location = 3)
+        // Vertex normal buffer (shader-location = 2)
         glGenBuffers(1, &batch.vertexBuffer[i].vboId[2]);
         glBindBuffer(GL_ARRAY_BUFFER, batch.vertexBuffer[i].vboId[2]);
+        glBufferData(GL_ARRAY_BUFFER, bufferElements*3*4*sizeof(float), batch.vertexBuffer[i].normals, GL_DYNAMIC_DRAW);
+        glEnableVertexAttribArray(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_NORMAL]);
+        glVertexAttribPointer(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_NORMAL], 3, GL_FLOAT, 0, 0, 0);
+
+        // Vertex color buffer (shader-location = 3)
+        glGenBuffers(1, &batch.vertexBuffer[i].vboId[3]);
+        glBindBuffer(GL_ARRAY_BUFFER, batch.vertexBuffer[i].vboId[3]);
         glBufferData(GL_ARRAY_BUFFER, bufferElements*4*4*sizeof(unsigned char), batch.vertexBuffer[i].colors, GL_DYNAMIC_DRAW);
         glEnableVertexAttribArray(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_COLOR]);
         glVertexAttribPointer(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_COLOR], 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, 0);
 
         // Fill index buffer
-        glGenBuffers(1, &batch.vertexBuffer[i].vboId[3]);
-        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, batch.vertexBuffer[i].vboId[3]);
+        glGenBuffers(1, &batch.vertexBuffer[i].vboId[4]);
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, batch.vertexBuffer[i].vboId[4]);
 #if defined(GRAPHICS_API_OPENGL_33)
         glBufferData(GL_ELEMENT_ARRAY_BUFFER, bufferElements*6*sizeof(int), batch.vertexBuffer[i].indices, GL_STATIC_DRAW);
 #endif
@@ -2731,10 +2791,10 @@ void rlUnloadRenderBatch(rlRenderBatch batch)
         if (RLGL.ExtSupported.vao)
         {
             glBindVertexArray(batch.vertexBuffer[i].vaoId);
-            glDisableVertexAttribArray(0);
-            glDisableVertexAttribArray(1);
-            glDisableVertexAttribArray(2);
-            glDisableVertexAttribArray(3);
+            glDisableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION);
+            glDisableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD);
+            glDisableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL);
+            glDisableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR);
             glBindVertexArray(0);
         }
 
@@ -2743,6 +2803,7 @@ void rlUnloadRenderBatch(rlRenderBatch batch)
         glDeleteBuffers(1, &batch.vertexBuffer[i].vboId[1]);
         glDeleteBuffers(1, &batch.vertexBuffer[i].vboId[2]);
         glDeleteBuffers(1, &batch.vertexBuffer[i].vboId[3]);
+        glDeleteBuffers(1, &batch.vertexBuffer[i].vboId[4]);
 
         // Delete VAOs from GPU (VRAM)
         if (RLGL.ExtSupported.vao) glDeleteVertexArrays(1, &batch.vertexBuffer[i].vaoId);
@@ -2750,6 +2811,7 @@ void rlUnloadRenderBatch(rlRenderBatch batch)
         // Free vertex arrays memory from CPU (RAM)
         RL_FREE(batch.vertexBuffer[i].vertices);
         RL_FREE(batch.vertexBuffer[i].texcoords);
+        RL_FREE(batch.vertexBuffer[i].normals);
         RL_FREE(batch.vertexBuffer[i].colors);
         RL_FREE(batch.vertexBuffer[i].indices);
     }
@@ -2784,8 +2846,13 @@ void rlDrawRenderBatch(rlRenderBatch *batch)
         glBufferSubData(GL_ARRAY_BUFFER, 0, RLGL.State.vertexCounter*2*sizeof(float), batch->vertexBuffer[batch->currentBuffer].texcoords);
         //glBufferData(GL_ARRAY_BUFFER, sizeof(float)*2*4*batch->vertexBuffer[batch->currentBuffer].elementCount, batch->vertexBuffer[batch->currentBuffer].texcoords, GL_DYNAMIC_DRAW); // Update all buffer
 
-        // Colors buffer
+        // Normals buffer
         glBindBuffer(GL_ARRAY_BUFFER, batch->vertexBuffer[batch->currentBuffer].vboId[2]);
+        glBufferSubData(GL_ARRAY_BUFFER, 0, RLGL.State.vertexCounter*3*sizeof(float), batch->vertexBuffer[batch->currentBuffer].normals);
+        //glBufferData(GL_ARRAY_BUFFER, sizeof(float)*3*4*batch->vertexBuffer[batch->currentBuffer].elementCount, batch->vertexBuffer[batch->currentBuffer].normals, GL_DYNAMIC_DRAW); // Update all buffer
+
+        // Colors buffer
+        glBindBuffer(GL_ARRAY_BUFFER, batch->vertexBuffer[batch->currentBuffer].vboId[3]);
         glBufferSubData(GL_ARRAY_BUFFER, 0, RLGL.State.vertexCounter*4*sizeof(unsigned char), batch->vertexBuffer[batch->currentBuffer].colors);
         //glBufferData(GL_ARRAY_BUFFER, sizeof(float)*4*4*batch->vertexBuffer[batch->currentBuffer].elementCount, batch->vertexBuffer[batch->currentBuffer].colors, GL_DYNAMIC_DRAW);    // Update all buffer
 
@@ -2838,13 +2905,30 @@ void rlDrawRenderBatch(rlRenderBatch *batch)
 
             // Create modelview-projection matrix and upload to shader
             Matrix matMVP = rlMatrixMultiply(RLGL.State.modelview, RLGL.State.projection);
-            float matMVPfloat[16] = {
-                matMVP.m0, matMVP.m1, matMVP.m2, matMVP.m3,
-                matMVP.m4, matMVP.m5, matMVP.m6, matMVP.m7,
-                matMVP.m8, matMVP.m9, matMVP.m10, matMVP.m11,
-                matMVP.m12, matMVP.m13, matMVP.m14, matMVP.m15
-            };
-            glUniformMatrix4fv(RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_MVP], 1, false, matMVPfloat);
+            glUniformMatrix4fv(RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_MVP], 1, false, rlMatrixToFloat(matMVP));
+
+            if (RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_PROJECTION] != -1)
+            {
+                glUniformMatrix4fv(RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_PROJECTION], 1, false, rlMatrixToFloat(RLGL.State.projection));
+            }
+
+            // WARNING: For the following setup of the view, model, and normal matrices, it is expected that
+            // transformations and rendering occur between rlPushMatrix and rlPopMatrix.
+
+            if (RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_VIEW] != -1)
+            {
+                glUniformMatrix4fv(RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_VIEW], 1, false, rlMatrixToFloat(RLGL.State.modelview));
+            }
+
+            if (RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_MODEL] != -1)
+            {
+                glUniformMatrix4fv(RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_MODEL], 1, false, rlMatrixToFloat(RLGL.State.transform));
+            }
+
+            if (RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_NORMAL] != -1)
+            {
+                glUniformMatrix4fv(RLGL.State.currentShaderLocs[RL_SHADER_LOC_MATRIX_NORMAL], 1, false, rlMatrixToFloat(rlMatrixTranspose(rlMatrixInvert(RLGL.State.transform))));
+            }
 
             if (RLGL.ExtSupported.vao) glBindVertexArray(batch->vertexBuffer[batch->currentBuffer].vaoId);
             else
@@ -2859,12 +2943,17 @@ void rlDrawRenderBatch(rlRenderBatch *batch)
                 glVertexAttribPointer(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_TEXCOORD01], 2, GL_FLOAT, 0, 0, 0);
                 glEnableVertexAttribArray(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_TEXCOORD01]);
 
-                // Bind vertex attrib: color (shader-location = 3)
+                // Bind vertex attrib: normal (shader-location = 2)
                 glBindBuffer(GL_ARRAY_BUFFER, batch->vertexBuffer[batch->currentBuffer].vboId[2]);
+                glVertexAttribPointer(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_NORMAL], 3, GL_FLOAT, 0, 0, 0);
+                glEnableVertexAttribArray(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_NORMAL]);
+
+                // Bind vertex attrib: color (shader-location = 3)
+                glBindBuffer(GL_ARRAY_BUFFER, batch->vertexBuffer[batch->currentBuffer].vboId[3]);
                 glVertexAttribPointer(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_COLOR], 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, 0);
                 glEnableVertexAttribArray(RLGL.State.currentShaderLocs[RL_SHADER_LOC_VERTEX_COLOR]);
 
-                glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, batch->vertexBuffer[batch->currentBuffer].vboId[3]);
+                glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, batch->vertexBuffer[batch->currentBuffer].vboId[4]);
             }
 
             // Setup some default shader values
@@ -4014,12 +4103,12 @@ unsigned int rlLoadShaderProgram(unsigned int vShaderId, unsigned int fShaderId)
     glAttachShader(program, fShaderId);
 
     // NOTE: Default attribute shader locations must be Bound before linking
-    glBindAttribLocation(program, 0, RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION);
-    glBindAttribLocation(program, 1, RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD);
-    glBindAttribLocation(program, 2, RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL);
-    glBindAttribLocation(program, 3, RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR);
-    glBindAttribLocation(program, 4, RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT);
-    glBindAttribLocation(program, 5, RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2);
+    glBindAttribLocation(program, RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION, RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION);
+    glBindAttribLocation(program, RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD, RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD);
+    glBindAttribLocation(program, RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL, RL_DEFAULT_SHADER_ATTRIB_NAME_NORMAL);
+    glBindAttribLocation(program, RL_DEFAULT_SHADER_ATTRIB_LOCATION_COLOR, RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR);
+    glBindAttribLocation(program, RL_DEFAULT_SHADER_ATTRIB_LOCATION_TANGENT, RL_DEFAULT_SHADER_ATTRIB_NAME_TANGENT);
+    glBindAttribLocation(program, RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD2, RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2);
 
     // NOTE: If some attrib name is no found on the shader, it locations becomes -1
 
@@ -4482,10 +4571,10 @@ void rlLoadDrawQuad(void)
     glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), &vertices, GL_STATIC_DRAW);
 
     // Bind vertex attributes (position, texcoords)
-    glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void *)0); // Positions
-    glEnableVertexAttribArray(1);
-    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void *)(3*sizeof(float))); // Texcoords
+    glEnableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION);
+    glVertexAttribPointer(RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION, 3, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void *)0); // Positions
+    glEnableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD);
+    glVertexAttribPointer(RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD, 2, GL_FLOAT, GL_FALSE, 5*sizeof(float), (void *)(3*sizeof(float))); // Texcoords
 
     // Draw quad
     glBindVertexArray(quadVAO);
@@ -4556,12 +4645,12 @@ void rlLoadDrawCube(void)
 
     // Bind vertex attributes (position, normals, texcoords)
     glBindVertexArray(cubeVAO);
-    glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)0); // Positions
-    glEnableVertexAttribArray(1);
-    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(3*sizeof(float))); // Normals
-    glEnableVertexAttribArray(2);
-    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(6*sizeof(float))); // Texcoords
+    glEnableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION);
+    glVertexAttribPointer(RL_DEFAULT_SHADER_ATTRIB_LOCATION_POSITION, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)0); // Positions
+    glEnableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL);
+    glVertexAttribPointer(RL_DEFAULT_SHADER_ATTRIB_LOCATION_NORMAL, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(3*sizeof(float))); // Normals
+    glEnableVertexAttribArray(RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD);
+    glVertexAttribPointer(RL_DEFAULT_SHADER_ATTRIB_LOCATION_TEXCOORD, 2, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(6*sizeof(float))); // Texcoords
     glBindBuffer(GL_ARRAY_BUFFER, 0);
     glBindVertexArray(0);
 
@@ -4709,14 +4798,14 @@ static void rlLoadShaderDefault(void)
         TRACELOG(RL_LOG_INFO, "SHADER: [ID %i] Default shader loaded successfully", RLGL.State.defaultShaderId);
 
         // Set default shader locations: attributes locations
-        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_VERTEX_POSITION] = glGetAttribLocation(RLGL.State.defaultShaderId, "vertexPosition");
-        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_VERTEX_TEXCOORD01] = glGetAttribLocation(RLGL.State.defaultShaderId, "vertexTexCoord");
-        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_VERTEX_COLOR] = glGetAttribLocation(RLGL.State.defaultShaderId, "vertexColor");
+        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_VERTEX_POSITION] = glGetAttribLocation(RLGL.State.defaultShaderId, RL_DEFAULT_SHADER_ATTRIB_NAME_POSITION);
+        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_VERTEX_TEXCOORD01] = glGetAttribLocation(RLGL.State.defaultShaderId, RL_DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD);
+        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_VERTEX_COLOR] = glGetAttribLocation(RLGL.State.defaultShaderId, RL_DEFAULT_SHADER_ATTRIB_NAME_COLOR);
 
         // Set default shader locations: uniform locations
-        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_MATRIX_MVP]  = glGetUniformLocation(RLGL.State.defaultShaderId, "mvp");
-        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_COLOR_DIFFUSE] = glGetUniformLocation(RLGL.State.defaultShaderId, "colDiffuse");
-        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_MAP_DIFFUSE] = glGetUniformLocation(RLGL.State.defaultShaderId, "texture0");
+        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_MATRIX_MVP]  = glGetUniformLocation(RLGL.State.defaultShaderId, RL_DEFAULT_SHADER_UNIFORM_NAME_MVP);
+        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_COLOR_DIFFUSE] = glGetUniformLocation(RLGL.State.defaultShaderId, RL_DEFAULT_SHADER_UNIFORM_NAME_COLOR);
+        RLGL.State.defaultShaderLocs[RL_SHADER_LOC_MAP_DIFFUSE] = glGetUniformLocation(RLGL.State.defaultShaderId, RL_DEFAULT_SHADER_SAMPLER2D_NAME_TEXTURE0);
     }
     else TRACELOG(RL_LOG_WARNING, "SHADER: [ID %i] Failed to load default shader", RLGL.State.defaultShaderId);
 }
@@ -4868,6 +4957,31 @@ static int rlGetPixelDataSize(int width, int height, int format)
 
 // Auxiliar math functions
 
+// Get float array of matrix data
+static rl_float16 rlMatrixToFloatV(Matrix mat)
+{
+    rl_float16 result = { 0 };
+
+    result.v[0] = mat.m0;
+    result.v[1] = mat.m1;
+    result.v[2] = mat.m2;
+    result.v[3] = mat.m3;
+    result.v[4] = mat.m4;
+    result.v[5] = mat.m5;
+    result.v[6] = mat.m6;
+    result.v[7] = mat.m7;
+    result.v[8] = mat.m8;
+    result.v[9] = mat.m9;
+    result.v[10] = mat.m10;
+    result.v[11] = mat.m11;
+    result.v[12] = mat.m12;
+    result.v[13] = mat.m13;
+    result.v[14] = mat.m14;
+    result.v[15] = mat.m15;
+
+    return result;
+}
+
 // Get identity matrix
 static Matrix rlMatrixIdentity(void)
 {
@@ -4907,4 +5021,76 @@ static Matrix rlMatrixMultiply(Matrix left, Matrix right)
     return result;
 }
 
+// Transposes provided matrix
+static Matrix rlMatrixTranspose(Matrix mat)
+{
+    Matrix result = { 0 };
+
+    result.m0 = mat.m0;
+    result.m1 = mat.m4;
+    result.m2 = mat.m8;
+    result.m3 = mat.m12;
+    result.m4 = mat.m1;
+    result.m5 = mat.m5;
+    result.m6 = mat.m9;
+    result.m7 = mat.m13;
+    result.m8 = mat.m2;
+    result.m9 = mat.m6;
+    result.m10 = mat.m10;
+    result.m11 = mat.m14;
+    result.m12 = mat.m3;
+    result.m13 = mat.m7;
+    result.m14 = mat.m11;
+    result.m15 = mat.m15;
+
+    return result;
+}
+
+// Invert provided matrix
+static Matrix rlMatrixInvert(Matrix mat)
+{
+    Matrix result = { 0 };
+
+    // Cache the matrix values (speed optimization)
+    float a00 = mat.m0, a01 = mat.m1, a02 = mat.m2, a03 = mat.m3;
+    float a10 = mat.m4, a11 = mat.m5, a12 = mat.m6, a13 = mat.m7;
+    float a20 = mat.m8, a21 = mat.m9, a22 = mat.m10, a23 = mat.m11;
+    float a30 = mat.m12, a31 = mat.m13, a32 = mat.m14, a33 = mat.m15;
+
+    float b00 = a00*a11 - a01*a10;
+    float b01 = a00*a12 - a02*a10;
+    float b02 = a00*a13 - a03*a10;
+    float b03 = a01*a12 - a02*a11;
+    float b04 = a01*a13 - a03*a11;
+    float b05 = a02*a13 - a03*a12;
+    float b06 = a20*a31 - a21*a30;
+    float b07 = a20*a32 - a22*a30;
+    float b08 = a20*a33 - a23*a30;
+    float b09 = a21*a32 - a22*a31;
+    float b10 = a21*a33 - a23*a31;
+    float b11 = a22*a33 - a23*a32;
+
+    // Calculate the invert determinant (inlined to avoid double-caching)
+    float invDet = 1.0f/(b00*b11 - b01*b10 + b02*b09 + b03*b08 - b04*b07 + b05*b06);
+
+    result.m0 = (a11*b11 - a12*b10 + a13*b09)*invDet;
+    result.m1 = (-a01*b11 + a02*b10 - a03*b09)*invDet;
+    result.m2 = (a31*b05 - a32*b04 + a33*b03)*invDet;
+    result.m3 = (-a21*b05 + a22*b04 - a23*b03)*invDet;
+    result.m4 = (-a10*b11 + a12*b08 - a13*b07)*invDet;
+    result.m5 = (a00*b11 - a02*b08 + a03*b07)*invDet;
+    result.m6 = (-a30*b05 + a32*b02 - a33*b01)*invDet;
+    result.m7 = (a20*b05 - a22*b02 + a23*b01)*invDet;
+    result.m8 = (a10*b10 - a11*b08 + a13*b06)*invDet;
+    result.m9 = (-a00*b10 + a01*b08 - a03*b06)*invDet;
+    result.m10 = (a30*b04 - a31*b02 + a33*b00)*invDet;
+    result.m11 = (-a20*b04 + a21*b02 - a23*b00)*invDet;
+    result.m12 = (-a10*b09 + a11*b07 - a12*b06)*invDet;
+    result.m13 = (a00*b09 - a01*b07 + a02*b06)*invDet;
+    result.m14 = (-a30*b03 + a31*b01 - a32*b00)*invDet;
+    result.m15 = (a20*b03 - a21*b01 + a22*b00)*invDet;
+
+    return result;
+}
+
 #endif  // RLGL_IMPLEMENTATION