Example/GLSL Full Compile Linking: Difference between revisions

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mNo edit summary
Using bad coding style (ie: not initializing variables) is NOT simplifying.
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<source lang="cpp">
<source lang="cpp">
// Read our shaders into the appropriate buffers
//Read our shaders into the appropriate buffers
std::string vertexSource = // Get source code for vertex shader.
std::string vertexSource = //Get source code for vertex shader.
std::string fragmentSource = // Get source code for fragment shader.
std::string fragmentSource = //Get source code for fragment shader.


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


// Send the vertex shader source code to GL
//Send the vertex shader source code to GL
// Note that std::string's .c_str is NULL character terminated.
//Note that std::string's .c_str is NULL character terminated.
const GLchar *source = (const GLchar *)vertexSource.c_str();
const GLchar *source = (const GLchar *)vertexSource.c_str();
glShaderSource(vertexShader, 1, &source, 0);
glShaderSource(vertexShader, 1, &source, 0);


// Compile the vertex shader
//Compile the vertex shader
glCompileShader(vertexShader);
glCompileShader(vertexShader);


GLint isCompiled;
GLint isCompiled = 0;
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &isCompiled);
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &isCompiled);
if(isCompiled == GL_FALSE)
if(isCompiled == GL_FALSE)
{
{
GLint maxLength;
GLint maxLength = 0;
glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &maxLength);
glGetShaderiv(vertexShader, GL_INFO_LOG_LENGTH, &maxLength);


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


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


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


// Send the fragment shader source code to GL
//Send the fragment shader source code to GL
// Note that std::string's .c_str is NULL character terminated.
//Note that std::string's .c_str is NULL character terminated.
source = (const GLchar *)fragmentSource.c_str();
source = (const GLchar *)fragmentSource.c_str();
glShaderSource(fragmentShader, 1, &source, 0);
glShaderSource(fragmentShader, 1, &source, 0);


// Compile the fragment shader
//Compile the fragment shader
glCompileShader(fragmentShader);
glCompileShader(fragmentShader);


Line 51: Line 51:
if(isCompiled == GL_FALSE)
if(isCompiled == GL_FALSE)
{
{
GLint maxLength;
GLint maxLength = 0;
glGetShaderiv(fragmentShader, GL_INFO_LOG_LENGTH, &maxLength);
glGetShaderiv(fragmentShader, GL_INFO_LOG_LENGTH, &maxLength);


// The maxLength includes the NULL character
//The maxLength includes the NULL character
GLchar infoLog[maxLength];
std::vector<GLchar> infoLog(maxLength);
glGetShaderInfoLog(fragmentShader, maxLength, &maxLength, infoLog);
glGetShaderInfoLog(fragmentShader, maxLength, &maxLength, &infoLog[0]);
// Use infoLog as you see fit.
//We don't need the shader anymore.
 
// We don't need the shader anymore.
glDeleteShader(fragmentShader);
glDeleteShader(fragmentShader);
// Either of them. Don't leak shaders.
//Either of them. Don't leak shaders.
glDeleteShader(vertexShader);
glDeleteShader(vertexShader);
//Use the infoLog as you see fit.
// In this simple program, we'll just leave
//In this simple program, we'll just leave
return;
return;
}
}


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


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


// Link our program
//Link our program
glLinkProgram(program);
glLinkProgram(program);


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


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


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


// Always detach shaders after a successful link.
//Always detach shaders after a successful link.
glDetachShader(program, vertexShader);
glDetachShader(program, vertexShader);
glDetachShader(program, fragmentShader);
glDetachShader(program, fragmentShader);
</source><noinclude>[[Category:Example Code]]</noinclude>
</source><noinclude>[[Category:Example Code]]</noinclude>

Revision as of 14:25, 6 December 2014

Full compile/link of a Vertex and Fragment Shader.

//Read our shaders into the appropriate buffers
std::string vertexSource = //Get source code for vertex shader.
std::string fragmentSource = //Get source code for fragment shader.

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

//Send the vertex shader source code to GL
//Note that std::string's .c_str is NULL character terminated.
const GLchar *source = (const GLchar *)vertexSource.c_str();
glShaderSource(vertexShader, 1, &source, 0);

//Compile the vertex shader
glCompileShader(vertexShader);

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);

//Send the fragment shader source code to GL
//Note that std::string's .c_str is NULL character terminated.
source = (const GLchar *)fragmentSource.c_str();
glShaderSource(fragmentShader, 1, &source, 0);

//Compile the fragment shader
glCompileShader(fragmentShader);

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);