ARB_indirect_parameters
Overview
Numbers ARB Extension #154
Requires OpenGL 4.2
Since OpenGL 4.6 Core Profile Specification
和它相关的OpenGL概念是Indirect Draw, 相关的扩展是GL_ARB_draw_indirect(since OpenGL 3.2 Compatible Profile and since OpenGL 4.0 Core Profile)和GL_ARB_multi_draw_indirect(since OpenGL 4.1 Core Profile). 这个扩展引入了"parameter buffer"的概念，可以让indirect draw的大量的参数集合存储在buffer object, 然后用一个API调用分发整个indirect draw列表，从而提高OpenGL管线的执行效率。
更确切地说，这个扩展新增了一个buffer target，专门用来存放某个indirect drawing command的参数。
1 | PARAMETER_BUFFER_ARB 0x80EE |
它可以作为下列命令的参数
- BindBuffer
- BufferData
- BufferSubData
- MapBuffer
- UnmapBuffer
- GetBufferSubData
- GetBufferPointerv
- MapBufferRange
- FlushMappedBufferRange
- GetBufferParameteriv
- CopyBufferSubData
新增的MultiDraw*Indirect命令的变种是
1 | MultiDrawArraysIndirectCountARB |