Method of shading using sample vectors
A method of shading, by: storing shading information in a sample vector comprising a plurality of packets, wherein each packet represents a shading property; performing a series of sequential actions on the sample vector, wherein each of the sequential actions operates on at least one, but less than all of the plurality of packets in the sample vector, such that the sample vector is updated by each sequential action; and then performing a lighting computation on the updated sample vector, wherein the lighting computation operates on all of the plurality of packets in the sample vector, thereby calculating a final sample vector to be rendered for the sample vector.
1. A method of shader slicing, comprising the steps of:
selecting a master shader which operates on sample vectors, wherein the sample vectors each comprise a plurality of packets, wherein each packet represents a shading property;
selecting a desired set of output packets;
creating a sliced shader from the master shader to compute only the desired set of output packets; and
performing the following method on the sliced shader:
storing shading information in a sample vector comprising a plurality of packets, wherein each packet represents a shading property;
performing a series of sequential actions on the sample vector, wherein each of the sequential actions operates on at least one, but less than all of the plurality of packets in the sample vector, such that the sample vector is updated by each sequential action, the series of sequential actions consisting of:
first, performing a base material calculation,
second, performing a general shader calculation,
third, performing an effect calculation, and
fourth, performing a lighting computation; and then,
reading out shading results from modified or unmodified packets in a final sample vector.
2. The method of claim 1 , wherein the master shader is composed of sequential actions; and wherein the sliced shader is created from the minimal sequential actions required to compute the desired set of output packets.
3. The method of claim 1 , wherein the master shader is composed of a shader directed acyclic graph (DAG); and wherein the sliced shader is created by instancing the DAG with restricted outputs.
4. The method of claim 1 , wherein the sequential actions index the packets by object.
5. The method of claim 1 , wherein the sequential actions index the packets by type.
6. The method of claim 1 , wherein the sequential actions are converted to a DAG by:
converting each sequential action into a computation node;
creating data nodes for each input and output packet; and
linking computational nodes to their input nodes from a previous stage and to their output nodes in a next stage.
7. The method of claim 6 , further comprising:
converting sequential actions to separate DAGs for each render thread.
8. The method of claim 1 , wherein output packets from the sliced shader are cached and reused as inputs to a different sliced shader.
9. The method of claim 1 , further comprising:
reading a required set of input packets to compute the desired set of output packets.
10. The method of claim 1 , wherein at least one of the series of sequential actions reads values from sample vector packets using a read-only effect.