Name

glDrawElements — render primitives from array data

C Specification

void glDrawElements(GLenum mode,
 GLsizei count,
 GLenum type,
 const GLvoid * indices);
 

Parameters

mode

Specifies what kind of primitives to render. Symbolic constants GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, and GL_TRIANGLES are accepted.

count

Specifies the number of elements to be rendered.

type

Specifies the type of the values in indices. Must be either GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT.

indices

Specifies a pointer to the location where the indices are stored.

Description

glDrawElements specifies multiple geometric primitives with very few subroutine calls. You can prespecify separate arrays of vertices, normals, colors, and texture coordinates and use them to construct a sequence of primitives with a single call to glDrawElements.

When glDrawElements is called, it uses count sequential indices from indices to lookup elements in enabled arrays to construct a sequence of geometric primitives. mode specifies what kind of primitives are constructed, and how the array elements construct these primitives. If GL_VERTEX_ARRAY is not enabled, no geometric primitives are constructed.

Vertex attributes that are modified by glDrawElements have an unspecified value after glDrawElements returns. For example, if GL_COLOR_ARRAY is enabled, the value of the current color is undefined after glDrawElements executes. Attributes that aren't modified maintain their previous values.

Errors

GL_INVALID_ENUM is generated if mode is not an accepted value.

GL_INVALID_ENUM is generated if type is not an accepted value.

GL_INVALID_VALUE is generated if count is negative.

See Also

glClientActiveTexture, glColorPointer, glDrawArrays, glNormalPointer, glTexCoordPointer, glVertexPointer

Copyright

Copyright © 2003-2004 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.