GLAPI/glDrawElements

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glDrawElements
Core in version 4.4
Core since version 1.1

glDrawElements: render primitives from array data

Function Definition

 void glDrawElements(GLenum mode​, 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.
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

glDrawElements specifies multiple geometric primitives with very few subroutine calls. Instead of calling a GL function to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and so on, and use them to construct a sequence of primitives with a single call to glDrawElements.

When glDrawElements is called, it uses count​ sequential elements from an enabled array, starting at indices​ (interpreted as a byte count) 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 glDrawElements have an unspecified value after glDrawElements 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

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

GL_INVALID_VALUE​ is generated if count​ is negative.

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.

See Also

glBindVertexArray, glDrawArrays, glDrawElementsBaseVertex, glDrawElementsIndirect, glDrawElementsInstanced, glDrawElementsInstancedBaseInstance, glDrawElementsInstancedBaseVertex, glDrawElementsInstancedBaseVertexBaseInstance, glDrawRangeElements, 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/.