Updated raylib generic uber shader and custom shaders (markdown)

raylib-generic-uber-shader-and-custom-shaders.md

@@ -45,16 +45,29 @@ typedef enum {
 #define LOC_MAP_SPECULAR     LOC_MAP_METALNESS
 ```
 
-On shader loading, the following GLSL location names are checked:
+When loading a shader, raylib tries to bind by default the following **vertex shader** attributes:
+```c
+// Default shader vertex attribute names to set location points
+#define DEFAULT_SHADER_ATTRIB_NAME_POSITION    "vertexPosition"    // Binded by default to shader location: 0
+#define DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD    "vertexTexCoord"    // Binded by default to shader location: 1
+#define DEFAULT_SHADER_ATTRIB_NAME_NORMAL      "vertexNormal"      // Binded by default to shader location: 2
+#define DEFAULT_SHADER_ATTRIB_NAME_COLOR       "vertexColor"       // Binded by default to shader location: 3
+#define DEFAULT_SHADER_ATTRIB_NAME_TANGENT     "vertexTangent"     // Binded by default to shader location: 4
+#define DEFAULT_SHADER_ATTRIB_NAME_TEXCOORD2   "vertexTexCoord2"   // Binded by default to shader location: 5
+```
+
+And also the following uniform location names are checked:
 ```glsl
 uniform mat4 mvp;             // VS: ModelViewProjection matrix
 uniform mat4 projection;      // VS: Projection matrix
 uniform mat4 view;            // VS: View matrix
+
 uniform vec4 colDiffuse;      // FS: Diffuse color
 uniform sampler2D texture0;   // FS: GL_TEXTURE0
 uniform sampler2D texture1;   // FS: GL_TEXTURE1
 uniform sampler2D texture2;   // FS: GL_TEXTURE2
 ```
+Those are the attributes/uniform names used by the internal [default shader](https://github.com/raysan5/raylib/wiki/raylib-default-shader). It's recommended to use that naming convention also on custom shaders to make sure everything will be automatically setup on `LoadShader()` but some of the default attribute names could re-defined in [config.h](https://github.com/raysan5/raylib/blob/master/src/config.h) in case it was necessary.
 
 Shaders are also directly related to the Material struct:
 ```c