glCreateProgram
Create a program object
C Specification
GLuint glCreateProgram(void);
Description
glCreateProgram creates an empty program object and returns a nonzero value by which it can be referenced. A program object is an object to which shader objects can be attached. This provides a mechanism to specify the shader objects that will be linked to create a program. It also provides a means for checking the compatibility of the shaders that will be used to create a program (for instance, checking the compatibility between a vertex shader and a fragment shader). When no longer needed as part of a program object, shader objects can be detached.
One or more executables are created in a program object by successfully attaching shader objects to it with glAttachShader, successfully compiling the shader objects with glCompileShader, and successfully linking the program object with glLinkProgram. These executables are made part of current state when glUseProgram is called. Program objects can be deleted by calling glDeleteProgram. The memory associated with the program object will be deleted when it is no longer part of current rendering state for any context.
Notes
glCreateProgram is available only if the GL version is 2.0 or greater.
Like display lists and texture objects, the name space for program 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.
Errors
This function returns 0 if an error occurs creating the program object.
GL_INVALID_OPERATION is generated if glCreateProgram is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glGet with the argument GL_CURRENT_PROGRAM
glGetActiveAttrib with a valid program object and the index of an active attribute variable
glGetActiveUniform with a valid program object and the index of an active uniform variable
glGetAttachedShaders with a valid program object
glGetAttribLocation with a valid program object and the name of an attribute variable
glGetProgram with a valid program object and the parameter to be queried
glGetProgramInfoLog with a valid program object
glGetUniform with a valid program object and the location of a uniform variable
glGetUniformLocation with a valid program object and the name of a uniform variable glIsProgram
See Also
glAttachShader, glBindAttribLocation, glCreateShader, glDeleteProgram, glDetachShader, glLinkProgram, glUniform, glUseProgram, glValidateProgram
glCreateShader
Create a shader object
C Specification
GLuint glCreateShader(GLenum shaderType);
Parameters
Description
glCreateShader creates an empty shader object and returns a nonzero 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.
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.
Errors
This 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
glCullFace
Specify whether front- or back-facing facets can be culled
C Specification
void glCullFace(GLenum mode);
Parameters
Description
glCullFace specifies whether front- or back-facing facets are culled (as specified by mode) when facet culling is enabled. Facet culling is initially disabled. To enable and disable facet culling, call the glEnable and glDisable commands with the argument GL_CULL_FACE. Facets include triangles, quadrilaterals, polygons, and rectangles.
glFrontFace specifies which of the clockwise and counterclockwise facets are front-facing and back-facing. See glFrontFace.
Notes
If mode is GL_FRONT_AND_BACK, no facets are drawn, but other primitives such as points and lines are drawn.
Errors
GL_INVALID_ENUM is generated if mode is not an accepted value.
GL_INVALID_OPERATION is generated if glCullFace is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glIsEnabled with argument GL_CULL_FACE
glGet with argument GL_CULL_FACE_MODE
See Also
glEnable, glFrontFace
glDeleteBuffers
C Specification
void glDeleteBuffers(GLsizei n,
const GLuint * buffers);
Parameters
Description
glDeleteBuffers deletes n buffer objects named by the elements of the array buffers. After a buffer object is deleted, it has no contents, and its name is free for reuse (for example by glGenBuffers). If a buffer object that is currently bound is deleted, the binding reverts to 0 (the absence of any buffer object, which reverts to client memory usage).
glDeleteBuffers silently ignores 0’s and names that do not correspond to existing buffer objects.
Notes
glDeleteBuffers is available only if the GL version is 1.5 or greater.
Errors
GL_INVALID_VALUE is generated if n is negative.
GL_INVALID_OPERATION is generated if glDeleteBuffers is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glIsBuffer
See Also
glBindBuffer, glGenBuffers, glGet
glDeleteLists
Delete a contiguous group of display lists
C Specification
void glDeleteLists(GLuint list,
GLsizei range);
Parameters
Description
glDeleteLists causes a contiguous group of display lists to be deleted. list is the name of the first display list to be deleted, and range is the number of display lists to delete. All display lists d with list <= d <= list + range – 1 are deleted.
All storage locations allocated to the specified display lists are freed, and the names are available for reuse at a later time. Names within the range that do not have an associated display list are ignored. If range is 0, nothing happens.
Errors
GL_INVALID_VALUE is generated if range is negative.
GL_INVALID_OPERATION is generated if glDeleteLists is executed between the execution of glBegin and the corresponding execution of glEnd.
See Also
glCallList, glCallLists, glGenLists, glIsList, glNewList
glDeleteProgram
C Specification
void glDeleteProgram(GLuint program);
Parameters
Description
glDeleteProgram frees the memory and invalidates the name associated with the program object specified by program. This command effectively undoes the effects of a call to glCreateProgram.
If a program object is in use as part of current rendering state, it will be flagged for deletion, but it will not be deleted until it is no longer part of current state for any rendering context. If a program object to be deleted has shader objects attached to it, those shader objects will be automatically detached but not deleted unless they have already been flagged for deletion by a previous call to glDeleteShader. A value of 0 for program will be silently ignored.
To determine whether a program object has been flagged for deletion, call glGetProgram with arguments program and GL_DELETE_STATUS.
Notes
glDeleteProgram is available only if the GL version is 2.0 or greater.
Errors
GL_INVALID_VALUE is generated if program is not a value generated by OpenGL.
GL_INVALID_OPERATION is generated if glDeleteProgram is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glGet with argument GL_CURRENT_PROGRAM
glGetProgram with arguments program and GL_DELETE_STATUS
glIsProgram
See Also
glCreateShader, glDetachShader, glUseProgram
glDeleteQueries
Delete named query objects
C Specification
void glDeleteQueries(GLsizei n,
const GLuint * ids);
Parameters
Description
glDeleteQueries deletes n query objects named by the elements of the array ids. After a query object is deleted, it has no contents, and its name is free for reuse (for example by glGenQueries). glDeleteQueries silently ignores 0’s and names that do not correspond to existing query objects.
Notes
glDeleteQueries is available only if the GL version is 1.5 or greater.
GL_INVALID_VALUE is generated if n is negative.
GL_INVALID_OPERATION is generated if glDeleteQueries is executed between the execution of glBeginQuery and the corresponding execution of glEndQuery.
GL_INVALID_OPERATION is generated if glDeleteQueries is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glIsQuery
See Also
glBeginQuery, glEndQuery, glGenQueries, glGetQueryiv, glGetQueryObject
glDeleteShader
Delete a shader object
C Specification
void glDeleteShader(GLuint shader);
Parameters
Description
glDeleteShader frees the memory and invalidates the name associated with the shader object specified by shader. This command effectively undoes the effects of a call to glCreateShader.
If a shader object to be deleted is attached to a program object, it will be flagged for deletion, but it will not be deleted until it is no longer attached to any program object, for any rendering context (i.e., it must be detached from wherever it was attached before it will be deleted). A value of 0 for shader will be silently ignored.
To determine whether an object has been flagged for deletion, call glGetShader with arguments shader and GL_DELETE_STATUS.
Notes
glDeleteShader is available only if the GL version is 2.0 or greater.
Errors
GL_INVALID_VALUE is generated if shader is not a value generated by OpenGL.
GL_INVALID_OPERATION is generated if glDeleteShader is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glGetAttachedShaders with the program object to be queried
glGetShader with arguments shader and GL_DELETE_STATUS
glIsShader
See Also
glCreateProgram, glCreateShader, glDetachShader, glUseProgram
glDeleteTextures
Delete named textures
C Specification
void glDeleteTextures(GLsizei n,
const GLuint * textures);
Description
glDeleteTextures deletes n textures named by the elements of the array textures. After a texture is deleted, it has no contents or dimensionality, and its name is free for reuse (for example by glGenTextures). If a texture that is currently bound is deleted, the binding reverts to 0 (the default texture). glDeleteTextures silently ignores 0’s and names that do not correspond to existing textures.
Notes
glDeleteTextures is available only if the GL version is 1.1 or greater.
Errors
GL_INVALID_VALUE is generated if n is negative.
GL_INVALID_OPERATION is generated if glDeleteTextures is executed between the execution of glBegin and the corresponding execution of glEnd.
Associated Gets
glIsTexture
See Also
glAreTexturesResident, glBindTexture, glCopyTexImage1D, glCopyTexImage2D, glGenTextures, glGet, glGetTexParameter, glPrioritizeTextures, glTexImage1D, glTexImage2D, glTexParameter
glDepthFunc
Specify the value used for depth buffer comparisons
C Specification
void glDepthFunc(GLenum func);
Parameters
Description
glDepthFunc specifies the function used to compare each incoming pixel depth value with the depth value present in the depth buffer. The comparison is performed only if depth testing is enabled. (See glEnable and glDisable of GL_DEPTH_TEST.)
func specifies the conditions under which the pixel will be drawn. The comparison functions are as follows:
GL_NEVER
Never passes.
GL_LESS
Passes if the incoming depth value is less than the stored depth value.
GL_EQUAL
Passes if the incoming depth value is equal to the stored depth value.
GL_LEQUAL
Passes if the incoming depth value is less than or equal to the stored depth value.
GL_GREATER
Passes if the incoming depth value is greater than the stored depth value.
GL_NOTEQUAL
Passes if the incoming depth value is not equal to the stored depth value.