我正在开发一个3D引擎,我在使用C语言的GLSL着色器时遇到了一些问题.
顶点着色器:
layout(location = 0) in vec3 vertexUP;
layout(location = 1) in vec3 vertexUV;
out vec3 UP;
out vec3 UV;
void main(){
UP = vertexUP;//Without this line, everything works fine
UV = vertexUV;
gl_Position = ftransform();
}
片段着色器:
in vec3 UP;
in vec3 UV;
out vec3 color;
uniform sampler2D rs0;
uniform sampler2D rs1;
uniform sampler2D rs2;
void main(){
if(UV[2]==0){//Selects between different textures
color = texture( rs0, vec2(UV[0], UV[1]) ).rgb;
}else if(UV[2]==1){
color = texture( rs1, vec2(UV[0], UV[1]) ).rgb;
}else{
color = texture( rs2, vec2(UV[0], UV[1]) ).rgb;
}
if(UP[0]<2){//Test thing
color[0] = 1.0;
}
}
我想将位置数组(位置0)解析为fragement着色器,以便我可以将它用于照明.它编译但链接顶点着色器会出错:
顶点着色器无法链接,片段着色器链接.
我究竟做错了什么?
编辑:
加载着色器的代码:
GLuint LoadShaders(const char * vertex_file_path,const char * fragment_file_path){
// Create the shaders
GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);
// Read the Vertex Shader code from the file
std::string VertexShaderCode;
std::ifstream VertexShaderStream(vertex_file_path, std::ios::in);
if(VertexShaderStream.is_open())
{
std::string Line = "";
while(getline(VertexShaderStream, Line))
VertexShaderCode += "\n" + Line;
VertexShaderStream.close();
}
// Read the Fragment Shader code from the file
std::string FragmentShaderCode;
std::ifstream FragmentShaderStream(fragment_file_path, std::ios::in);
if(FragmentShaderStream.is_open()){
std::string Line = "";
while(getline(FragmentShaderStream, Line))
FragmentShaderCode += "\n" + Line;
FragmentShaderStream.close();
}
GLint Result = GL_FALSE;
int InfoLogLength;
// Compile Vertex Shader
printf("Compiling shader : %s\n", vertex_file_path);
char const * VertexSourcePointer = VertexShaderCode.c_str();
glShaderSource(VertexShaderID, 1, &VertexSourcePointer , NULL);
glCompileShader(VertexShaderID);
// Check Vertex Shader
glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
std::vector<char> VertexShaderErrorMessage(InfoLogLength);
glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
fprintf(stdout, "%s\n", &VertexShaderErrorMessage[0]);
// Compile Fragment Shader
printf("Compiling shader : %s\n", fragment_file_path);
char const * FragmentSourcePointer = FragmentShaderCode.c_str();
glShaderSource(FragmentShaderID, 1, &FragmentSourcePointer , NULL);
glCompileShader(FragmentShaderID);
// Check Fragment Shader
glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
std::vector<char> FragmentShaderErrorMessage(InfoLogLength);
glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
fprintf(stdout, "%s\n", &FragmentShaderErrorMessage[0]);
// Link the program
fprintf(stdout, "Linking program\n");
GLuint ProgramID = glCreateProgram();
glAttachShader(ProgramID, VertexShaderID);
glAttachShader(ProgramID, FragmentShaderID);
glLinkProgram(ProgramID);
// Check the program
glGetProgramiv(ProgramID, GL_LINK_STATUS, &Result);
glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
std::vector<char> ProgramErrorMessage(InfoLogLength);
glGetProgramInfoLog(ProgramID, InfoLogLength, NULL, &ProgramErrorMessage[0]);
fprintf(stdout, "%s\n", &ProgramErrorMessage[0]);
glDeleteShader(VertexShaderID);
glDeleteShader(FragmentShaderID);
return ProgramID;
}
最佳答案 你不能这样做:
layout(location = 0) in vec3 vertexUP;
layout(location = 1) in vec3 vertexUV;
...
gl_Position = ftransform();
ftransform()使用内置的gl_Vertex,GL规范要求对属性索引0进行别名,因此GL不能在没有冲突的情况下分配属性索引.
你真的不应该将旧的,已弃用的内置组件与通用属性混合使用.如果你这样做,你应该带领GL分配属性位置.