cocos Uniforms值的赋值

cocos Uniforms值的赋值
举个void Renderer::drawBatchedTriangles()的渲染：
//Start drawing verties in batch
    for(const auto& cmd : _batchedCommands)
    {
        auto newMaterialID = cmd->getMaterialID();
        if(_lastMaterialID != newMaterialID || newMaterialID == MATERIAL_ID_DO_NOT_BATCH)
        {
            //Draw quads
            if(indexToDraw > 0)
            {
                    //使用前面绑定的定点数据，绘制图元
                glDrawElements(GL_TRIANGLES, (GLsizei) indexToDraw, GL_UNSIGNED_SHORT, (GLvoid*) (startIndex*sizeof(_indices[0])) );
                _drawnBatches++;
                _drawnVertices += indexToDraw;

                startIndex += indexToDraw;
                indexToDraw = 0;
            }

            //Use new material
            //这个函数内部就是对Uniforms赋值
            cmd->useMaterial();
            _lastMaterialID = newMaterialID;
        }

        indexToDraw += cmd->getIndexCount();
    }
    
2、
void TrianglesCommand::useMaterial() const
{
    //Set texture
    //设置纹理
    GL::bindTexture2D(_textureID);
    
    //set blend mode
    GL::blendFunc(_blendType.src, _blendType.dst);
    
    _glProgramState->apply(_mv);
}

3、
void GLProgramState::apply(const Mat4& modelView)
{
    //设置cocos内置的Uniforms值
    applyGLProgram(modelView);

        //一般用不到
    applyAttributes();

        //设置用户自定义的Uniforms值，当然也可以通过其他方式直接设置
    applyUniforms();
}
4、
这个函数就是真正的设置Uniform的值
void GLProgram::setUniformsForBuiltins(const Mat4 &matrixMV)
{
    auto& matrixP = _director->getMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_PROJECTION);

    if (_flags.usesP)
        setUniformLocationWithMatrix4fv(_builtInUniforms[UNIFORM_P_MATRIX], matrixP.m, 1);

    if (_flags.usesMV)
        setUniformLocationWithMatrix4fv(_builtInUniforms[UNIFORM_MV_MATRIX], matrixMV.m, 1);

    if (_flags.usesMVP) {
        Mat4 matrixMVP = matrixP * matrixMV;
        setUniformLocationWithMatrix4fv(_builtInUniforms[UNIFORM_MVP_MATRIX], matrixMVP.m, 1);
    }

    if (_flags.usesNormal)
    {
        Mat4 mvInverse = matrixMV;
        mvInverse.m[12] = mvInverse.m[13] = mvInverse.m[14] = 0.0f;
        mvInverse.inverse();
        mvInverse.transpose();
        GLfloat normalMat[9];
        normalMat[0] = mvInverse.m[0];normalMat[1] = mvInverse.m[1];normalMat[2] = mvInverse.m[2];
        normalMat[3] = mvInverse.m[4];normalMat[4] = mvInverse.m[5];normalMat[5] = mvInverse.m[6];
        normalMat[6] = mvInverse.m[8];normalMat[7] = mvInverse.m[9];normalMat[8] = mvInverse.m[10];
        setUniformLocationWithMatrix3fv(_builtInUniforms[UNIFORM_NORMAL_MATRIX], normalMat, 1);
    }

    if (_flags.usesTime) {
        // This doesn't give the most accurate global time value.
        // Cocos2D doesn't store a high precision time value, so this will have to do.
        // Getting Mach time per frame per shader using time could be extremely expensive.
        float time = _director->getTotalFrames() * _director->getAnimationInterval();

        setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_TIME], time/10.0, time, time*2, time*4);
        setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_SIN_TIME], time/8.0, time/4.0, time/2.0, sinf(time));
        setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_COS_TIME], time/8.0, time/4.0, time/2.0, cosf(time));
    }

    if (_flags.usesRandom)
        setUniformLocationWith4f(_builtInUniforms[GLProgram::UNIFORM_RANDOM01], CCRANDOM_0_1(), CCRANDOM_0_1(), CCRANDOM_0_1(), CCRANDOM_0_1());
}