Comment some (vertex) texture lookup functionality.

Issue=95
TRAC #16568
Signed-off-by: Daniel Koch
Author: Nicolas Capens

git-svn-id: https://angleproject.googlecode.com/svn/trunk@643 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libGLESv2/Program.cpp b/src/libGLESv2/Program.cpp
index c41f1c4..16a0b08 100644
--- a/src/libGLESv2/Program.cpp
+++ b/src/libGLESv2/Program.cpp
@@ -191,8 +191,8 @@
     return mSemanticIndex[attributeIndex];
 }
 
-// Returns the index of the texture unit corresponding to a Direct3D 9 sampler
-// index referenced in the compiled HLSL shader
+// Returns the index of the texture image unit (0-19) corresponding to a Direct3D 9 sampler
+// index (0-15 for the pixel shader and 0-3 for the vertex shader).
 GLint Program::getSamplerMapping(SamplerType type, unsigned int samplerIndex)
 {
     GLint logicalTextureUnit = -1;
@@ -226,6 +226,8 @@
     return -1;
 }
 
+// Returns the texture type for a given Direct3D 9 sampler type and
+// index (0-15 for the pixel shader and 0-3 for the vertex shader).
 TextureType Program::getSamplerTextureType(SamplerType type, unsigned int samplerIndex)
 {
     switch (type)