Or, in short, does SM 4 support "double4x4"?
I tried asking Google. I found everything *But* the variable types reference.
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Does Shader Model 4 support matrices composed of 64-bit floating-point values
Started by Narf the Mouse, Jul 26 2012 02:30 PM
3 replies to this topic
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Posted 26 July 2012 - 02:47 PM
SM4.0 has no double support. It's an (optional) feature that was added for SM5.0. You can check for it with ID3D11Device::CheckFeatureSupport. Wikipedia also has comparison tables for AMD and Nvidia GPU's that tell you which ones support double precision.
As for "double4x4" in particular, the HLSL docs say that "double" is a valid type for matrices.
As for "double4x4" in particular, the HLSL docs say that "double" is a valid type for matrices.
Edited by MJP, 26 July 2012 - 02:49 PM.
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Posted 26 July 2012 - 03:19 PM
Thanks.SM4.0 has no double support. It's an (optional) feature that was added for SM5.0. You can check for it with ID3D11Device::CheckFeatureSupport. Wikipedia also has comparison tables for AMD and Nvidia GPU's that tell you which ones support double precision.
As for "double4x4" in particular, the HLSL docs say that "double" is a valid type for matrices.
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Posted 26 July 2012 - 03:37 PM
It's important to note that current generation GPUs are MUCH slower when in double processing mode.
For example AMD's latest runs double precision at 1/4 the rate of floating point on it's top end chip (Tahiti) while NV's Kepler series (6x0) runs double precision at 1/12th floating point speed (slower than the previous gen which run at 1/4 rate).
In short; unless you really need doubles and can afford the ALU speed hit it's really not a good idea on consumer cards.
For example AMD's latest runs double precision at 1/4 the rate of floating point on it's top end chip (Tahiti) while NV's Kepler series (6x0) runs double precision at 1/12th floating point speed (slower than the previous gen which run at 1/4 rate).
In short; unless you really need doubles and can afford the ALU speed hit it's really not a good idea on consumer cards.
