因為要往nsg中填加shader框架，所以從昨天開始著手學習cg，上午跟lzd問了一下傳參的問題，發現了glColor設置的顏色其實只對COLOR的語義變量起作用，那DIFFUSE和SPECULAR的就不好使了，所以每次都要set一下parameter.
下邊是我看到的cg使用的流程。
cg
使用流程：
- #ifdef
__APPLE__
static
CGprofile VertexProfile = CG_PROFILE_ARBVP1;
#else
static
CGprofile VertexProfile = CG_PROFILE_VP20;
#endif
-
CGContext
context =
cgCreateContext()
;
-
CGProgram
VertexProgram =
cgCreateProgramFromFile(Context,CG_SOURCE,
"vertexShader.cg",VertexProfile,NULL, NULL
);
- if(VertexProgram
!= NULL)
{
/* Vertex shader only needs to be loaded once */
cgGLLoadProgram(VertexProgram);
/* Bind parameters to give access to variables in the shader
*/
KdParam = cgGetNamedParameter(VertexProgram, "Kd");
ModelViewProjParam = cgGetNamedParameter(VertexProgram,
"ModelViewProj");
VertexColorParam = cgGetNamedParameter(VertexProgram,
"IN.VertexColor");
}
-
//
上邊做一次初始化工作即可，下邊是每次循環要用到的
- cgGLBindProgram(VertexProgram);
- if(KdParam !=
NULL)
cgGLSetParameter4f(KdParam, 1.0, 1.0, 0.0, 1.0);
if(ModelViewProjParam
!= NULL)
cgGLSetStateMatrixParameter(ModelViewProjParam,CG_GL_MODELVIEW_PROJECTION_MATRIX,CG_GL_MATRIX_IDENTITY);
- cgGLEnableProfile(VertexProfile);
- glBegin(GL_QUADS);
{
glNormal3fv(&CubeNormals[i][0]);
cgGLSetParameter3f(VertexColorParam, 1.0, 0.0, 0.0);
glVertex3fv(&CubeVertices[CubeFaces[i][0]][0]);
cgGLSetParameter3f(VertexColorParam, 0.0, 1.0, 0.0);
glVertex3fv(&CubeVertices[CubeFaces[i][1]][0]);
cgGLSetParameter3f(VertexColorParam, 0.0, 0.0, 1.0);
glVertex3fv(&CubeVertices[CubeFaces[i][2]][0]);
cgGLSetParameter3f(VertexColorParam, 1.0, 1.0, 1.0);
glVertex3fv(&CubeVertices[CubeFaces[i][3]][0]);
}
glEnd();
- cgGLDisableProfile(VertexProfile);
//
后邊是收尾工作
-
cgDestroyProgram(vertexProgram)
-
cgDestroyContext(context);
?