glCreateShader example c c++ java objc

Name
        glCreateShader — Creates a shader object

C Specification
       GLuint glCreateShader(GLenum  shaderType);

Parameters
     shaderType
            Specifies the type of shader to be created.
            Must be either GL_VERTEX_SHADER
            or GL_FRAGMENT_SHADER.

 Description
    glCreateShader creates an empty shader object and returns a non-zero value
    by which it can be referenced. A shader object is used to maintain the source code
    strings that define a shader. shaderType indicates the type of shader to be created.
    Two types of shaders are supported. A shader of type GL_VERTEX_SHADER is a
    shader that is intended to run on the programmable vertex processor and replace
    the fixed functionality vertex processing in OpenGL. A shader of
    type GL_FRAGMENT_SHADER is a shader that is
    intended to run on the programmable fragment processor and
    replace the fixed functionality fragment processing in OpenGL.When created,
    a shader object's GL_SHADER_TYPE parameter is set to either
    GL_VERTEX_SHADER or GL_FRAGMENT_SHADER, depending on the value
    of shaderType.

Notes
    glCreateShader is available only if the GL version is 2.0 or
    greater.Like display lists and texture objects, the name space for
    shader objects may be shared across a set of contexts, as long
    as the server sides of the contexts share the same address
    space. If the name space is shared across contexts, any attached
    objects and the data associated with those attached objects are
    shared as well.Applications are responsible for providing the
    synchronization across API calls when objects are accessed from
    different execution threads.ErrorsThis function returns 0 if an error occurs creating the
    shader object.GL_INVALID_ENUM is generated if
    shaderType is not an accepted value.GL_INVALID_OPERATION is generated if
    glCreateShader is executed between the execution of glBegin and the corresponding
    execution of glEnd.

Associated Gets
    glGetShader  with a valid shader object and the parameter to be queried
    glGetShaderInfoLog with a valid shader object
    glGetShaderSource with a valid shader object
    glIsShader

See Also
    glAttachShader,
    glCompileShader,
    glDeleteShader,
    glDetachShader,
    glShaderSource

Copyright
            Copyright © 2003-2005 3Dlabs Inc. Ltd.
            This material may be distributed subject to the terms and conditions set forth in
            the Open Publication License, v 1.0, 8 June 1999.
            http://opencontent.org/openpub/.

Code collected from GLWiki.

/* The vertex shader */
 char *vsSource = file2string("wave.vert");
 char *fsSource = file2string("wave.frag");
 
 /* Compile and load the program */
 
 GLuint vs, /* Vertex Shader */
     fs, /* Fragment Shader */
     sp; /* Shader Program */
 
 
 vs = glCreateShader(GL_VERTEX_SHADER);
 glShaderSource(vs, 1, &vsSource, NULL);
 glCompileShader(vs);
 printLog(vs);
 
 fs = glCreateShader(GL_FRAGMENT_SHADER);
 glShaderSource(fs, 1, &fsSource, NULL);
 glCompileShader(fs);
 printLog(fs);
 
 free(vsSource);
 free(fsSource);
 
 sp = glCreateProgram();
 glAttachShader(sp, vs);
 glAttachShader(sp, fs);
 glLinkProgram(sp);
 printLog(sp);
 
 glUseProgram(sp);