Rounding off Beyond3D?s look at Hardware Geometry Processing, today Part 2 of the article, ?Programmable Vertex Unit?, is available. As the title suggests this takes a good look at the newer form of Hardware Geometry Processing, the Vertex Shader, and how they are implemented.
The issue of instruction length also points at a potential issue that developers need to take into account: don?t change the Vertex Shader program unless you really have to, because uploading a new vertex program comes at the expensive of using bandwidth. Toggling between two Vertex Shader programs is thus definitely not a good idea for high throughput. Future Vertex Shader implementations might move to a loading (caching) mechanism for instructions but to make this possible the instruction size has to be kept as small as possible and the instruction re-use has to be substantial (e.g. processing of the same instruction on a large set of different vertices before moving to the next instruction). Hardware Geometry Article (Part 2)
And just in case you missed the First part! here it is Hardware Geometry Article (Part 1)
The issue of instruction length also points at a potential issue that developers need to take into account: don?t change the Vertex Shader program unless you really have to, because uploading a new vertex program comes at the expensive of using bandwidth. Toggling between two Vertex Shader programs is thus definitely not a good idea for high throughput. Future Vertex Shader implementations might move to a loading (caching) mechanism for instructions but to make this possible the instruction size has to be kept as small as possible and the instruction re-use has to be substantial (e.g. processing of the same instruction on a large set of different vertices before moving to the next instruction). Hardware Geometry Article (Part 2)
And just in case you missed the First part! here it is Hardware Geometry Article (Part 1)
