Well, perhaps I don’t completely understand your question, but what you ask is pretty obvious: finalColor=(1,0,0,1)*tex1+(0,1,1,0)*tex2
static const float c0[]={0.000000f,1.000000f,1.000000f,0.000000f};
glCombinerStageParameterfvNV(GL_COMBINER0_NV,GL_CONSTANT_COLOR0_NV,c0);
glCombinerParameteriNV(GL_NUM_GENERAL_COMBINERS_NV,1);
glActiveTextureARB(GL_TEXTURE0_ARB);
glTexEnvi(GL_TEXTURE_SHADER_NV,GL_SHADER_OPERATION_NV,GL_TEXTURE_2D);
glActiveTextureARB(GL_TEXTURE1_ARB);
glTexEnvi(GL_TEXTURE_SHADER_NV,GL_SHADER_OPERATION_NV,GL_DEPENDENT_AR_TEXTURE_2D_NV);
glTexEnvi(GL_TEXTURE_SHADER_NV,GL_PREVIOUS_TEXTURE_INPUT_NV,GL_TEXTURE0_ARB);
glActiveTextureARB(GL_TEXTURE2_ARB);
glTexEnvi(GL_TEXTURE_SHADER_NV,GL_SHADER_OPERATION_NV,GL_DEPENDENT_GB_TEXTURE_2D_NV);
glTexEnvi(GL_TEXTURE_SHADER_NV,GL_PREVIOUS_TEXTURE_INPUT_NV,GL_TEXTURE0_ARB);
glCombinerInputNV(GL_COMBINER0_NV,GL_RGB,GL_VARIABLE_A_NV,GL_TEXTURE1_ARB,GL_SIGNED_IDENTITY_NV,GL_RGB);
glCombinerInputNV(GL_COMBINER0_NV,GL_ALPHA,GL_VARIABLE_A_NV,GL_TEXTURE1_ARB,GL_SIGNED_IDENTITY_NV,GL_ALPHA);
glCombinerInputNV(GL_COMBINER0_NV,GL_RGB,GL_VARIABLE_B_NV,GL_CONSTANT_COLOR0_NV,GL_UNSIGNED_INVERT_NV,GL_RGB);
glCombinerInputNV(GL_COMBINER0_NV,GL_ALPHA,GL_VARIABLE_B_NV,GL_CONSTANT_COLOR0_NV,GL_UNSIGNED_INVERT_NV,GL_ALPHA);
glCombinerInputNV(GL_COMBINER0_NV,GL_RGB,GL_VARIABLE_C_NV,GL_TEXTURE2_ARB,GL_SIGNED_IDENTITY_NV,GL_RGB);
glCombinerInputNV(GL_COMBINER0_NV,GL_ALPHA,GL_VARIABLE_C_NV,GL_TEXTURE2_ARB,GL_SIGNED_IDENTITY_NV,GL_ALPHA);
glCombinerInputNV(GL_COMBINER0_NV,GL_RGB,GL_VARIABLE_D_NV,GL_CONSTANT_COLOR0_NV,GL_SIGNED_IDENTITY_NV,GL_RGB);
glCombinerInputNV(GL_COMBINER0_NV,GL_ALPHA,GL_VARIABLE_D_NV,GL_CONSTANT_COLOR0_NV,GL_SIGNED_IDENTITY_NV,GL_ALPHA);
glCombinerOutputNV(GL_COMBINER0_NV,GL_RGB,GL_DISCARD_NV,GL_DISCARD_NV,GL_SPARE0_NV,GL_NONE,GL_NONE,GL_FALSE,GL_FALSE,GL_FALSE);
glCombinerOutputNV(GL_COMBINER0_NV,GL_ALPHA,GL_DISCARD_NV,GL_DISCARD_NV,GL_SPARE0_NV,GL_NONE,GL_NONE,GL_FALSE,GL_FALSE,GL_FALSE);