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Fixed bug #15 SDL_blit_A.mmx-speed.patch.txt -- Speed improvements and a bugfix for the current GCC inline mmx asm code: - Changed some ops and removed some resulting useless ones. - Added some instruction parallelism (some gain) The resulting speed on my Xeon improved upto 35% depending on the function (measured in fps). - Fixed a bug where BlitRGBtoRGBSurfaceAlphaMMX() was setting the alpha component on the destination surfaces (to opaque-alpha) even when the surface had none. SDL_blit_A.mmx-msvc.patch.txt -- MSVC mmx intrinsics version of the same GCC asm code. MSVC compiler tries to parallelize the code and to avoid register stalls, but does not always do a very good job. Per-surface blending MSVC functions run quite a bit faster than their pure-asm counterparts (upto 55% faster for 16bit ones), but the per-pixel blending runs somewhat slower than asm. - BlitRGBtoRGBSurfaceAlphaMMX and BlitRGBtoRGBPixelAlphaMMX (and all variants) can now also handle formats other than (A)RGB8888. Formats like RGBA8888 and some quite exotic ones are allowed -- like RAGB8888, or actually anything having channels aligned on 8bit boundary and full 8bit alpha (for per-pixel alpha blending). The performance cost of this change is virtually 0 for per-surface alpha blending (no extra ops inside the loop) and a single non-MMX op inside the loop for per-pixel blending. In testing, the per-pixel alpha blending takes a ~2% performance hit, but it still runs much faster than the current code in CVS. If necessary, a separate function with this functionality can be made. This code requires Processor Pack for VC6.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:39:29 +0000
parents 355632dca928
children
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>SDL_SetGammaRamp</TITLE
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>SDL_SetGammaRamp</H1
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>Name</H2
>SDL_SetGammaRamp&nbsp;--&nbsp;Sets the color gamma lookup tables for the display</DIV
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>Synopsis</H2
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
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><CODE
><CODE
CLASS="FUNCDEF"
>int <B
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>SDL_SetGammaRamp</B
></CODE
>(Uint16 *redtable, Uint16 *greentable, Uint16 *bluetable);</CODE
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>Description</H2
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>Sets the gamma lookup tables for the display for each color component.
Each table is an array of 256 Uint16 values, representing a mapping
between the input and output for that channel. The input is the index
into the array, and the output is the 16-bit gamma value at that index,
scaled to the output color precision. You may pass NULL to any of the
channels to leave them unchanged.</P
><P
>This function adjusts the gamma based on lookup tables, you can also
have the gamma calculated based on a "gamma function" parameter with
<A
HREF="sdlsetgamma.html"
>SDL_SetGamma</A
>.</P
><P
>Not all display hardware is able to change gamma.</P
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>Return Value</H2
><P
>Returns -1 on error (or if gamma adjustment is not supported).</P
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><P
><A
HREF="sdlsetgamma.html"
>SDL_SetGamma</A
>
<A
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>SDL_GetGammaRamp</A
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