Review PBR shaders

Issue was related to vertex tangent attibutes not uploaded to GPU, a quick solution was implemented for new vertex attributes loading for already existing meshes... I don't like it specially but it will work for now.

src/rlgl.h

@@ -456,6 +456,7 @@ void rlDeleteBuffers(unsigned int id);                  // Unload vertex data (V
 void rlClearColor(byte r, byte g, byte b, byte a);      // Clear color buffer with color
 void rlClearScreenBuffers(void);                        // Clear used screen buffers (color and depth)
 void rlUpdateBuffer(int bufferId, void *data, int dataSize); // Update GPU buffer with new data
+unsigned int rlLoadAttribBuffer(unsigned int vaoId, int shaderLoc, void *buffer, int size, bool dynamic);   // Load a new attributes buffer
 
 //------------------------------------------------------------------------------------
 // Functions Declaration - rlgl functionality
@@ -2532,6 +2533,29 @@ void rlLoadMesh(Mesh *mesh, bool dynamic)
 #endif
 }
 
+// Load a new attributes buffer
+unsigned int rlLoadAttribBuffer(unsigned int vaoId, int shaderLoc, void *buffer, int size, bool dynamic)
+{
+    unsigned int id = 0;
+    
+#if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
+    int drawHint = GL_STATIC_DRAW;
+    if (dynamic) drawHint = GL_DYNAMIC_DRAW;
+    
+    if (vaoSupported) glBindVertexArray(vaoId);
+    
+    glGenBuffers(1, &id);
+    glBindBuffer(GL_ARRAY_BUFFER, id);
+    glBufferData(GL_ARRAY_BUFFER, size, buffer, drawHint);
+    glVertexAttribPointer(shaderLoc, 2, GL_FLOAT, 0, 0, 0);
+    glEnableVertexAttribArray(shaderLoc);
+    
+    if (vaoSupported) glBindVertexArray(0);
+#endif
+
+    return id;
+}
+
 // Update vertex data on GPU (upload new data to one buffer)
 void rlUpdateMesh(Mesh mesh, int buffer, int numVertex)
 {