我正在尝试渲染一个带有法线的简单立方体。我正在使用以下代码来初始化着色器。
void initShader(const char* vertexShaderPath, const char* fragmentShaderPath){
cout<<"Initializing Shaders"<<endl<<"==="<<endl;
cout<<"Vertex shader ";
vs = loadShader(vertexShaderPath, GL_VERTEX_SHADER);
cout<<"Fragment shader ";
fs = loadShader(fragmentShaderPath, GL_FRAGMENT_SHADER);
cout<<"Creating program: ";
program = glCreateProgram();
if(0==program) cout<< "Failed"<<endl; else cout<< "OK"<<endl;
glAttachShader(program, vs);
glAttachShader(program, fs);
cout<<"Linking program: ";
glLinkProgram(program);
GLint linkstatus = 0;
glGetProgramiv(program, GL_LINK_STATUS, &linkstatus);
if(GL_TRUE==linkstatus) cout<<"OK"<<endl; else cout<<"Failed" <<endl;
cout<<endl<<endl<<"Memory status"<<endl<<"==="<<endl;
mvpmat = glGetUniformLocation(program,"mvpMatrix");
mvmat = glGetUniformLocation(program,"mvMatrix");
normalmat = glGetUniformLocation(program,"normalMatrix");
cout << "mvpMatrix: "<<mvpmat<<" mvMatrix: "<<mvmat<<" normalMatrix: " << normalmat<<endl;
}
最后一条cout语句的输出结果如下(编译或链接时均无错误)。
mvpMatrix: 0 mvMatrix: -1 normalMatrix: 1
这是我的顶点着色器代码
uniform mat4 mvpMatrix;
uniform mat4 mvMatrix;
uniform mat3 normalMatrix;
attribute vec3 vertex;
attribute vec3 normal;
varying vec3 outNormal;
varying vec3 outPos;
void main(){
gl_Position = mvpMatrix*vec4(vertex,1.0);
outPos = (mvMatrix*vec4(vertex,1.0)).xyz;
outNormal = normalize(normalMatrix*normal);
}
我在代码中使用了所有的 mvpMatrix、mvMatrix 和 normalMatrix。因此我真的很困惑为什么 getUniformLocation() 返回 mvMatrix = -1?
最佳答案
如果您的片段着色器不使用 outPos 的输入,它将被优化掉。制服是在链接后定义的。所以片段着色器和顶点着色器都很重要。
关于c++ - 即使在顶点着色器中使用,glGetUniformLocation() 也返回 -1,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23319288/