GLAPI/glDrawRangeElements

From OpenGL.org
Jump to: navigation, search
glDrawRangeElements
Core in version 4.4
Core since version 1.2

glDrawRangeElements: render primitives from array data

Function Definition

 void glDrawRangeElements(GLenum mode​, GLuint start​, GLuint end​, GLsizei count​, GLenum type​, const GLvoid * indices​);
mode
Specifies what kind of primitives to render. Symbolic constants GL_POINTS​, GL_LINE_STRIP​, GL_LINE_LOOP​, GL_LINES​, GL_LINE_STRIP_ADJACENCY​, GL_LINES_ADJACENCY​, GL_TRIANGLE_STRIP​, GL_TRIANGLE_FAN​, GL_TRIANGLES​, GL_TRIANGLE_STRIP_ADJACENCY​, GL_TRIANGLES_ADJACENCY​ and GL_PATCHES​ are accepted.
start
Specifies the minimum array index contained in indices​.
end
Specifies the maximum array index contained in indices​.
count
Specifies the number of elements to be rendered.
type
Specifies the type of the values in indices​. Must be one of GL_UNSIGNED_BYTE​, GL_UNSIGNED_SHORT​, or GL_UNSIGNED_INT​.
indices
Specifies a byte offset (cast to a pointer type) into the buffer bound to GL_ELEMENT_ARRAY_BUFFER​ to start reading indices from.

Description

glDrawRangeElements is a restricted form of glDrawElements. mode​, count​, type​, and indices​ match the corresponding arguments to glDrawElements, with the additional constraint that all values in the arrays through count​ must lie between start​ and end​, inclusive.

Implementations denote recommended maximum amounts of vertex and index data, which may be queried by calling glGet with argument GL_MAX_ELEMENTS_VERTICES​ and GL_MAX_ELEMENTS_INDICES​. If end - start + 1 is greater than the value of GL_MAX_ELEMENTS_VERTICES​, or if count​ is greater than the value of GL_MAX_ELEMENTS_INDICES​, then the call may operate at reduced performance. There is no requirement that all vertices in the range [start, end] be referenced. However, the implementation may partially process unused vertices, reducing performance from what could be achieved with an optimal index set.

When glDrawRangeElements is called, it uses count​ sequential elements from an enabled array, starting at indices​ to construct a sequence of geometric primitives. mode​ specifies what kind of primitives are constructed, and how the array elements construct these primitives. If more than one array is enabled, each is used.

Vertex attributes that are modified by glDrawRangeElements have an unspecified value after glDrawRangeElements returns. Attributes that aren't modified maintain their previous values.

Notes

GL_LINE_STRIP_ADJACENCY​, GL_LINES_ADJACENCY​, GL_TRIANGLE_STRIP_ADJACENCY​ and GL_TRIANGLES_ADJACENCY​ are available only if the GL version is 3.2 or greater.

Errors

It is an error for indices to lie outside the range [start, end], but implementations may not check for this situation. Such indices cause implementation-dependent behavior.

GL_INVALID_ENUM​ is generated if mode​ is not an accepted value.

GL_INVALID_VALUE​ is generated if count​ is negative.

GL_INVALID_VALUE​ is generated if end < start.

GL_INVALID_OPERATION​ is generated if a geometry shader is active and mode​ is incompatible with the input primitive type of the geometry shader in the currently installed program object.

GL_INVALID_OPERATION​ is generated if a non-zero buffer object name is bound to an enabled array or the element array and the buffer object's data store is currently mapped.

Associated Gets

glGet with argument GL_MAX_ELEMENTS_VERTICES​

glGet with argument GL_MAX_ELEMENTS_INDICES​

See Also

glBindVertexArray, glDrawElements, glDrawElementsBaseVertex, glDrawElementsIndirect, glDrawElementsInstanced, glDrawElementsInstancedBaseInstance, glDrawElementsInstancedBaseVertex, glDrawElementsInstancedBaseVertexBaseInstance, glDrawRangeElementsBaseVertex, glMultiDrawElements, glMultiDrawElementsBaseVertex, glMultiDrawElementsIndirect

Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.