glDrawArraysInstanced — draw multiple instances of a range of elements
void glDrawArraysInstanced( | GLenum | mode, |
GLint | first, | |
GLsizei | count, | |
GLsizei | primcount) ; |
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
, GL_TRIANGLES
GL_LINES_ADJACENCY
, GL_LINE_STRIP_ADJACENCY
,
GL_TRIANGLES_ADJACENCY
andGL_TRIANGLE_STRIP_ADJACENCY
are accepted.
first
Specifies the starting index in the enabled arrays.
count
Specifies the number of indices to be rendered.
primcount
Specifies the number of instances of the specified range of indices to be rendered.
glDrawArraysInstanced
behaves identically to glDrawArrays
except that primcount
instances of the range of elements are executed and the value of the internal counter
instanceID
advances for each iteration. instanceID
is an internal 32-bit integer counter
that may be read by a vertex shader as gl_InstanceID
.
glDrawArraysInstanced
has the same effect as:
if ( mode or count is invalid ) generate appropriate error else { for (int i = 0; i < primcount ; i++) { instanceID = i; glDrawArrays(mode, first, count); } instanceID = 0; }
glDrawArraysInstanced
is available only if the GL version is 3.1 or greater.
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.
GL_INVALID_ENUM
is generated if mode
is not one of
the accepted values.
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_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.
Copyright © 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.