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docs.GL

glShaderSource

Name

glShaderSource — Replaces the source code in a shader object

C Specification

void glShaderSource( GLuint shader,
GLsizei count,
const GLchar **string,
const GLint *length);

Parameters

shader

Specifies the handle of the shader object whose source code is to be replaced.

count

Specifies the number of elements in the string and length arrays.

string

Specifies an array of pointers to strings containing the source code to be loaded into the shader.

length

Specifies an array of string lengths.

Description

glShaderSource sets the source code in shader to the source code in the array of strings specified by string. Any source code previously stored in the shader object is completely replaced. The number of strings in the array is specified by count. If length is NULL, each string is assumed to be null terminated. If length is a value other than NULL, it points to an array containing a string length for each of the corresponding elements of string. Each element in the length array may contain the length of the corresponding string (the null character is not counted as part of the string length) or a value less than 0 to indicate that the string is null terminated. The source code strings are not scanned or parsed at this time; they are simply copied into the specified shader object.

Notes

The GL copies the shader source code strings when glShaderSource is called, so an application may free its copy of the source code strings immediately after the function returns.

Errors

GL_INVALID_VALUE is generated if shader is not a value generated by OpenGL.

GL_INVALID_OPERATION is generated if shader is not a shader object.

GL_INVALID_VALUE is generated if count is less than 0.

Associated Gets

glGetShaderiv with arguments shader and GL_SHADER_SOURCE_LENGTH

glGetShaderSource with argument shader

glIsShader

Examples

Compile a program from a vertex shader and a fragment shader.
GLuint vshader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vshader, 1, &vertex_shader_source, NULL); // vertex_shader_source is a GLchar* containing glsl shader source code
glCompileShader(vshader);

GLint vertex_compiled;
glGetShaderiv(vshader, GL_COMPILE_STATUS, &vertex_compiled);
if (vertex_compiled != GL_TRUE)
{
    GLsizei log_length = 0;
    GLchar message[1024];
    glGetShaderInfoLog(vshader, 1024, &log_length, message);
    // Write the error to a log
}

GLuint fshader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fshader, 1, &fragment_shader_source, NULL); // fragment_shader_source is a GLchar* containing glsl shader source code
glCompileShader(fshader);

GLint fragment_compiled;
glGetShaderiv(fshader, GL_COMPILE_STATUS, &fragment_compiled);
if (fragment_compiled != GL_TRUE)
{
    GLsizei log_length = 0;
    GLchar message[1024];
    glGetShaderInfoLog(fshader, 1024, &log_length, message);
    // Write the error to a log
}

GLuint program = glCreateProgram();

// This step is unnecessary if you use the location specifier in your shader
// e.g. layout (location = 0) in vec3 position;
glBindAttribLocation(program, 0, "position"); // The index passed into glBindAttribLocation is
glBindAttribLocation(program, 1, "texcoord"); // used by glEnableVertexAttribArray. "position"
glBindAttribLocation(program, 2, "normal");   // "texcoord" "normal" and "color" are the names of the
glBindAttribLocation(program, 3, "color");    // respective inputs in your fragment shader.

glAttachShader(program, vshader);
glAttachShader(program, fshader);
glLinkProgram(program);

GLint program_linked;
glGetProgramiv(program, GL_LINK_STATUS, &program_linked);
if (program_linked != GL_TRUE)
{
    GLsizei log_length = 0;
    GLchar message[1024];
    glGetProgramInfoLog(program, 1024, &log_length, message);
    // Write the error to a log
}

API Version Support

OpenGL ES API Version
Function Name 2.0 3.0 3.1
glShaderSource ✔ ✔ ✔
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