Revision 5 | By
Muhammad Haggag | On Tue Jun 7 05:51:00 CDT 2005Precomputed Radiance Transfer (PRT) is a lighting method that uses precomputed transfer vectors
? to render objects with soft shadows
?, interreflections
?, and subsurface scattering
?.
D3DX includes the
ID3DXPRTEngine. This interface
? is used during the simulation
? part of PRT and precomputes direct lighting
? and subsurface scattering
? to name a couple. Data from the PRT engine is stored in an
ID3DXPRTBuffer and can be saved to file using the
D3DXSavePRTBufferToFile function.
Transfer vectors can require a large amount of memory and real-time
? computation. By using a compression
? algorithm you can greatly reduce the amount of work needed. Use the
D3DXCreatePRTCompBuffer to significantly reduce transfer data size. Compression can be done before saving the buffer to file in which case you will need to use
D3DXSavePRTCompBufferToFile to write the compressed buffer to file.