Some Fill-Rate Improvement

[Micromegas]

Hi, reading about V5 environment variables I found something that looks interesting : SSTH3_2PPC_LOG2_BAND_HEIGHT (number of scan lines rendered by each texture unit when 2 pixel-per-clock rendering is enabled) and SSTH3_CBC (Triangle Iterations band. Added this keys to the registry and  make some benchmarks with 3D Mark, here are the results:

3D MARK 2000 build 335:

1024x768x32, Texture Format: 32bits, Z-Buffer: 24bits, Frame Buffer: Triple, CPU Optimization: PIII Optimization

1 Scan Line, 4 Iteration Columns:
253,6 MTexels/s (S. Texturing)
468,4 MTexels/S (M. Texturing)

1 Scan Line, 8 Iteration Columns:  (Driver Default Settings)
274,2 MTexels/s (S. Texturing)
502,2 MTexels/S (M. Texturing)

1 Scan Line, 16 Iteration Columns:
288,6 MTexels/s (S. Texturing)
524,3 MTexels/S (M. Texturing)

1 Scan Line, 32 Iteration Columns:
296,7 MTexels/s (S. Texturing)
540,0 MTexels/S (M. Texturing)

64 Scan Line, 32 Iteration Columns:
311,0 MTexels/s (S. Texturing)
572,9 MTexels/S (M. Texturing)

128 Scan Line, 32 Iteration Columns:
311,0 MTexels/s (S. Texturing)
572,9 MTexels/S (M. Texturing)



3D MARK 2001 SE:

1024x768x32, Frame Buffer: Triple, Z-Buffer: 24bits, Texture Format: Compressed

1 Scan Line, 4 Iteration Columns:
316,9 MTexels/s (S. Texturing)
578,0 MTexels/S (M. Texturing)

1 Scan Line, 8 Iteration Columns:   (Driver Default Settings)
326,0 MTexels/s (S. Texturing)
578,0 MTexels/S (M. Texturing)

1 Scan Line, 16 Iteration Columns:
329,4 MTexels/s (S. Texturing)
577,4 MTexels/S (M. Texturing)

1 Scan Line, 32 Iteration Columns:
331,4 MTexels/s (S. Texturing)
577,4 MTexels/S (M. Texturing)

64 Scan Line, 32 Iteration Columns:
332,4 MTexels/s (S. Texturing)
581,4 MTexels/S (M. Texturing)

128 Scan Line, 32 Iteration Columns:
332,7 MTexels/s (S. Texturing)
581,9 MTexels/S (M. Texturing)


There's a little boost, more noticeable in 16 Bit mode. Maybe it's useless, or all you already know it. Anyway.

Oooooooops!! I Almost forgot, my PC is PIII 900 MHz, 512 MB ram, Voodoo5 5500 AGP.

This are the keys I wrote for it to work with 3Dfx tools:

Triangle Iterations Columns:

Control: Combo
Default: 1
List: 4 Columns,8 Columns,16 Columns,32 Columns
Tweak Map: 3,0,1,2
Tweak Value: SSTH3_CBC
Value: 3

Scan Lines Rendering:

Control: Combo
Default: 0
List: 1 Line,2 Lines,4 Lines,8 Lines,16 Lines,32 Lines,64 Lines,128 Lines
Tweak Map: 0,1,2,3,4,5,6,7
Tweak Value: SSTH3_2PPC_LOG2_BAND_HEIGHT
Value: 7

[mikepedo]

Sorry, the value for 32 Iteration Columns is 3 or 2???
thanks

[Micromegas]

Well, the key SSTH3_CBC (under the D3D branch in regedit) should have a value of 2 in order to use 32 iterations columns. The key "Value=3" (under the "Triangle Iterations Columns" or wathever you called it) means that it's using the third value (starting from zero) from the "Tweak map" key (zero is 3, 1st is 0, 2nd is 1, third is 2).
Kinda confusing, just hope it helps. Saludos.

[mikepedo]

Thanks a lot. I'll try these setting now!