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glDrawElementsInstanced

Name

glDrawElementsInstanced — draw multiple instances of a set of elements

C Specification

void glDrawElementsInstanced( GLenum mode,
  GLsizei count,
  GLenum type,
  const void * indices,
  GLsizei primcount);
 

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 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. If no buffer is bound, specifies a pointer to the location where the indices are stored.

primcount

Specifies the number of instances of the specified range of indices to be rendered.

Description

glDrawElementsInstanced behaves identically to glDrawElements except that primcount instances of the set of elements are executed. Those attributes that have divisor N where N is other than zero (as specified by glVertexAttribDivisor) advance once every N instances. Thus, the element transferred from instanced vertex attributes is given by:

instance divisor

The value of instance may be read by a vertex shader as gl_InstanceID.

To enable and disable a generic vertex attribute array, call glEnableVertexAttribArray and glDisableVertexAttribArray.

If an array corresponding to a generic attribute required by a vertex shader is not enabled, then the corresponding element is taken from the current generic attribute state.

Errors

GL_INVALID_ENUM is generated if mode is not one of GL_POINTS, GL_LINE_STRIP, GL_LINE_LOOP, GL_LINES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, or GL_TRIANGLES.

GL_INVALID_VALUE is generated if count or primcount are negative.

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

GL_INVALID_FRAMEBUFFER_OPERATION is generated if the currently bound framebuffer is not framebuffer complete (i.e. the return value from glCheckFramebufferStatus is not GL_FRAMEBUFFER_COMPLETE).

GL_INVALID_OPERATION is generated if transform feedback is active and not paused.

API Version Support

OpenGL ES API Version
Function Name 2.0 3.0 3.1
glDrawElementsInstanced -
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