Two Methods of Multitexture In Cg

Method 1: Using OpenGL's native multi-texture support (using semantics)

// In C++ File:

// Identify the textures to use for the pixel shader...

cgGLSetTextureParameter( g_CGparam_testTexture, g_testTextureID );

cgGLSetTextureParameter( g_CGparam_checkerTexture, g_checkerTextureID );

// STAGE 0

glActiveTextureARB( GL_TEXTURE0_ARB );

glBindTexture( GL_TEXTURE_2D, g_testTextureID );

// STAGE 1

glActiveTextureARB( GL_TEXTURE1_ARB );

glBindTexture( GL_TEXTURE_2D, g_checkerTextureID );

cgGLBindProgram( g_CGprogram_pixel );

cgGLEnableProfile( g_CGprofile_pixel );

// Draw primitives

cgGLDisableProfile( g_CGprofile_pixel );

// In Cg File:

uniform sampler2D testTexture : TEXUNIT0,

uniform sampler2D checkerTexture : TEXUNIT1

Method 2: Using Cg's special texture functions:cgGLSetTextureParameter, cgGLEnableTextureParameter, and cgGLDisableTextureParameter

// In C++ File:

g_CGparam_testTexture = cgGetNamedParameter(g_CGprogram_pixel, "testTexture");

g_CGparam_checkerTexture = cgGetNamedParameter(g_CGprogram_pixel, "checkerTexture");

// Identify the textures to use for the pixel shader...

cgGLSetTextureParameter( g_CGparam_testTexture, g_testTextureID );

cgGLSetTextureParameter( g_CGparam_checkerTexture, g_checkerTextureID );

cgGLBindProgram( g_CGprogram_pixel );

cgGLEnableProfile( g_CGprofile_pixel );

cgGLEnableTextureParameter( g_CGparam_testTexture );

cgGLEnableTextureParameter( g_CGparam_checkerTexture );

// Draw primitives

cgGLDisableTextureParameter( g_CGparam_checkerTexture );

cgGLDisableTextureParameter( g_CGparam_testTexture );

cgGLDisableProfile( g_CGprofile_pixel );

// In Cg File:

uniform sampler2D testTexture,

uniform sampler2D checkerTexture