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authorKenneth Graunke <[email protected]>2012-08-24 01:22:58 -0700
committerKenneth Graunke <[email protected]>2012-08-25 12:01:10 -0700
commit85e8e9e000732908b259a7e2cbc1724a1be2d447 (patch)
tree699e7f922f3091087cb158bbbcc8116b526cbfb5 /src/mesa/main/uniform_query.cpp
parent2faa592e7f54ef21b799b61ffa50c6bc8039ddc1 (diff)
i965: Use linker-assigned sampler IDs in instruction encoding.
When assigning uniform locations, the linker assigns each sampler uniform a sequential numerical ID. gl_shader_program::SamplerUnits maps these sampler variable IDs to the actual texture units they reference (specified via glUniform1i). Previously, we encoded this mapping in the SEND instruction encoding: the "sampler" was the texture unit number, and the binding table index was SURF_INDEX_TEXTURE(the texture unit number). This unfortunately meant that whenever the application changed the value of a sampler uniform, we had to recompile the shader to change the SEND instructions. This was horrible for the game Cogs, which repeatedly switches between using texture unit 0 and 1. It also made fragment shader precompiles useless: we'd do the precompile at glLinkShader() time, before the application called glUniform1i to set the sampler values. As soon as it did that, we'd have to recompile, wasting time and space in the program cache. This patch encodes the SamplerUnits indirection in the binding table, sampler state, and sampler default color tables. Instead of baking the texture unit number into the shader, we bake in the sampler variable ID assigned by the linker. Since those never change, we don't need to recompile programs on uniform changes. This does mean that the tables now depend on the linked shader program being used for rendering, rather than simply representing all available texture units. This could cause an increase in state emission. Another plus is that the sampler state and sampler default color tables are now compact: we only emit as many entries as there are sampler uniforms, with no holes in the table since the new sampler IDs are sequential. Previously we had to emit a full 16 entries every time, since the tables tracked the state of all active texture units. Signed-off-by: Kenneth Graunke <[email protected]> Acked-by: Paul Berry <[email protected]> Reviewed-by: Eric Anholt <[email protected]>
Diffstat (limited to 'src/mesa/main/uniform_query.cpp')
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