Example/SPIRV Full Compile Linking

From OpenGL Wiki
< Example
Revision as of 20:45, 16 September 2017 by Alfonse (talk | contribs) (SPIR-V compilation example.)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Full compile/link through SPIR-V of a Vertex and Fragment Shader.

//Read our shaders into the appropriate buffers
std::vector<unsigned char> vertexSpirv = //Get SPIR-V for vertex shader.
std::vector<unsigned char> fragmentSpirv = //Get SPIR-V for fragment shader.

//Create an empty vertex shader handle
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);

//Apply the vertex shader SPIR-V to the shader object.
glShaderBinary(1, &vertexShader, GL_SHADER_BINARY_FORMAT_SPIR_V, vertexSpirv.data(), vertexSpirv.size());

//Specialize the vertex shader.
std::string vsEntrypoint = ...; //Get VS entry point name
glSpecializeShader(vertexShader, (const GLchar*)vsEntrypoint.c_str(), 0, nullptr, nullptr);

//Specialization is equivalent to compilation.
GLint isCompiled = 0;
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &isCompiled);
if(isCompiled == GL_FALSE)
{
	GLint maxLength = 0;
	glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &maxLength);

	//The maxLength includes the NULL character
	std::vector<GLchar> infoLog(maxLength);
	glGetShaderInfoLog(vertexShader, maxLength, &maxLength, &infoLog[0]);
	
	//We don't need the shader anymore.
	glDeleteShader(vertexShader);

	//Use the infoLog as you see fit.
	
	//In this simple program, we'll just leave
	return;
}



//Create an empty fragment shader handle
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);

//Apply the fragment shader SPIR-V to the shader object.
glShaderBinary(1, &fragmentShader, GL_SHADER_BINARY_FORMAT_SPIR_V, fragmentSpirv.data(), fragmentSpirv.size());

//Specialize the fragment shader.
std::string fsEntrypoint = ...; //Get VS entry point name
glSpecializeShader(fragmentShader, (const GLchar*)fsEntrypoint.c_str(), 0, nullptr, nullptr);

//Specialization is equivalent to compilation.
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &isCompiled);
if(isCompiled == GL_FALSE)
{
	GLint maxLength = 0;
	glGetShaderiv(fragmentShader, GL_INFO_LOG_LENGTH, &maxLength);

	//The maxLength includes the NULL character
	std::vector<GLchar> infoLog(maxLength);
	glGetShaderInfoLog(fragmentShader, maxLength, &maxLength, &infoLog[0]);
	
	//We don't need the shader anymore.
	glDeleteShader(fragmentShader);
	//Either of them. Don't leak shaders.
	glDeleteShader(vertexShader);

	//Use the infoLog as you see fit.
	
	//In this simple program, we'll just leave
	return;
}

//Vertex and fragment shaders are successfully compiled.
//Now time to link them together into a program.
//Get a program object.
GLuint program = glCreateProgram();

//Attach our shaders to our program
glAttachShader(program, vertexShader);
glAttachShader(program, fragmentShader);

//Link our program
glLinkProgram(program);

//Note the different functions here: glGetProgram* instead of glGetShader*.
GLint isLinked = 0;
glGetProgramiv(program, GL_LINK_STATUS, (int *)&isLinked);
if(isLinked == GL_FALSE)
{
	GLint maxLength = 0;
	glGetProgramiv(program, GL_INFO_LOG_LENGTH, &maxLength);

	//The maxLength includes the NULL character
	std::vector<GLchar> infoLog(maxLength);
	glGetProgramInfoLog(program, maxLength, &maxLength, &infoLog[0]);
	
	//We don't need the program anymore.
	glDeleteProgram(program);
	//Don't leak shaders either.
	glDeleteShader(vertexShader);
	glDeleteShader(fragmentShader);

	//Use the infoLog as you see fit.
	
	//In this simple program, we'll just leave
	return;
}

//Always detach shaders after a successful link.
glDetachShader(program, vertexShader);
glDetachShader(program, fragmentShader);