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Vertex shaders used in Fixed Function Pipeline

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Most of the time the vertex shaders used in the Fixed Direct3d pipeline are enough to me, in terms of transformation and lighting, and usually I’d like to add just a couple of instructions to them (for example to shift the texture’s coordinates, in order to simulate the sky’s movement), otherwise the only choice is to render the scene with 2 passes, applying 2 different vertex shaders. My question is: is there any place I can look for in order to retrieve the shaders used in the fixed pipeline (or shaders that simulate the D3D’s fixed pipeline)? There must be some articles or web sites that explain the shaders’ code used to simulate the D3D’s fixed pipeline. So far I’ve seen articles describing the same lighting models (point and diffuse lights) but what if we have more than one light at the same time, do we have to write different shaders according to the number of lights present in the scene? Target

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1. The D3D fixed function DOES NOT use shaders internally. **Conceptually** it does, but in reality it uses custom, hand optimised x86 code for each part (for software vertex processing) or fixed hardware (for hardware vp).

2. However if you look at the nVidia website (developer.nvidia.com), they have examples of how to implement most of the T&L pipeline with shaders. IIRC they also have a paper titled something like "emulating fixed function pipeline with vertex shaders".

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Simon O''Connor
Creative Asylum Ltd
www.creative-asylum.com

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