A common use case in GL for some applications is to be able to draw the same object, or groups of similar objects that share vertex data, primitive count and type, multiple times. This extension provides a means of accelerating such use cases while restricting the number of API calls, and keeping the amount of duplicate data to a minimum.
In particular, this extension specifies an alternative to the read-only shader variable introduced by ARB_draw_instanced. It uses the same draw calls introduced by that extension, but redefines them so that a vertex shader can instead use vertex array attributes as a source of instance data.
This extension introduces an array "divisor" for generic vertex array attributes, which when non-zero specifies that the attribute is "instanced". An
instanced attribute does not advance per-vertex as usual, but rather after every divisor conceptual draw calls.
(Attributes which aren't instanced are repeated in their entirety for every conceptual draw call.)
By specifying transform data in an instanced attribute or series of instanced attributes, vertex shaders can, in concert with the instancing draw calls, draw multiple instances of an object with one draw call.
Promoted to core in OpenGL 3..
| Modifier and Type | Field and Description |
|---|---|
| public static final int | GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ARB
Accepted by the |
| Access | Constructor and Description |
|---|---|
| protected |
| Modifier and Type | Method and Description |
|---|---|
| public static native void | glVertexArrayVertexAttribDivisorEXT(int
the vertex array object vaobj, int the attribute index index, int the divisor value divisor)
|
| public static native void | glVertexAttribDivisorARB(int
the attribute index index, int the divisor value divisor)Modifies the rate at which generic vertex attributes advance when rendering multiple instances of primitives in a single draw call. |
| GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ARB | back to summary |
|---|---|
| public static final int GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ARB Accepted by the | |
| ARBInstancedArrays | back to summary |
|---|---|
| protected ARBInstancedArrays() | |
| glVertexArrayVertexAttribDivisorEXT | back to summary |
|---|---|
| public static native void glVertexArrayVertexAttribDivisorEXT(int vaobj, int index, int divisor)
This function was added to the extension specification in July 2013. Implemenations are allowed to expose ARB_instanced_arrays without providing this function. The correct way to test its availability is:
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| glVertexAttribDivisorARB | back to summary |
|---|---|
| public static native void glVertexAttribDivisorARB(int index, int divisor) Modifies the rate at which generic vertex attributes advance when rendering multiple instances of primitives in a single draw call. If
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