Avoid warning and make local variable lower-case.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6000 dfc29bdd-3216-0410-991c-e03cc46cb475

media/pp_opengl.vert

@@ -0,0 +1,24 @@
+
+// Pass to fragment shader with the same name
+varying vec2 TexCoords;
+
+void main(void)
+{
+    gl_Position = gl_Vertex;
+    
+    // The origin of the texture coordinates locates at bottom-left 
+    // corner rather than top-left corner as defined on screen quad.
+    // Instead of using texture coordinates passed in by OpenGL, we
+    // calculate TexCoords based on vertex position as follows.
+    //
+    // Vertex[0] (-1, -1) to (0, 0)
+    // Vertex[1] (-1,  1) to (0, 1)
+    // Vertex[2] ( 1,  1) to (1, 1)
+    // Vertex[3] ( 1, -1) to (1, 0)
+    // 
+    // Texture coordinate system in OpenGL operates differently from 
+    // DirectX 3D. It is not necessary to offset TexCoords to texel 
+    // center by adding 1.0 / TextureSize / 2.0
+    
+    TexCoords = (gl_Vertex.xy * 0.5 + 0.5);
+}