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GPU/Procedural Texture Generation (edit)
Revision as of 09:23, 5 December 2015
, 09:23, 5 December 2015no edit summary
The 3DS GPU supports procedural generation of texture data using [[GPU_Textures|texture unit 3]]. Little is known about this feature, albeit a few public hints have been dropped. The contents of this page are solely based on reports on a [http://www.4gamer.net/games/017/G001762/20120822007/ presentation] given by DMP.
[[Category:GPU]]
The 3DS GPU supports procedural generation of texture data using [[GPU/Internal_Registers#GPUREG_TEXUNIT3_PROCTEX0|texture unit 3]]. Little is known about this feature, albeit a few public hints have been dropped. The contents of this page are solely based on reports on a [http://www.4gamer.net/games/017/G001762/20120822007/ presentation] given by DMP.
The related GPU registers can be found starting [[GPU/Internal_Registers#GPUREG_TEXUNIT3_PROCTEX0|here]].
== Overview ==
== Overview ==
Procedural texture generation has four stages:
Procedural texture generation has four stages:
* Noise Module
* Noise Module (outputs u′,v′)
* Repeat Module
* Repeat Module (outputs u′′,v′′)
* Base Shape
* Base Shape (also notated as G(u′′,v′′), output g)
* F(g) and Lookup Table
* F(g) and Lookup Table
== Noise Module ==
== Noise Module ==
This stage applies noise on the input coordinates. Little is known about this other than that there are three noise parameters:
This stage applies noise on the input coordinates. Little is known about this other than that there are three noise parameters:
* Amplitude
* Amplitude
* Frequency
* Phase
* Phase
These parameters are configured starting [[GPU/Internal_Registers#GPUREG_TEXUNIT3_PROCTEX1|here]].
== Repeat Module ==
== Repeat Module ==
== Base Shape ==
== Base Shape ==
The U’’ and V’’ coordinates are used to generate a scalar value in the range [0;1] from the wrapped coordinates using one of six functions:
The U’’ and V’’ coordinates are used to generate a scalar value in the range [0;1] from the wrapped coordinates using one of six functions documented [[GPU/Internal_Registers#GPUREG_TEXUNIT3_PROCTEX0|here]].
The output of this function is named "g".
The output of this function is named "g".
* a triangle function
* a triangle function
The final texel color is determined by using the value of F(g) as an index into a configurable lookup table (which is presumed to span 3 kilobytes of data).
The final texel color is determined by using the value of F(g) as an index into a configurable [[GPU/Internal_Registers#GPUREG_PROCTEX_LUT|lookup table]].