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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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<HTML
><HEAD
><TITLE
>SDL_GetClipRect</TITLE
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>SDL_GetClipRect</H1
><DIV
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><A
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></A
><H2
>Name</H2
>SDL_GetClipRect&nbsp;--&nbsp;Gets the clipping rectangle for a surface.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
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></A
><H2
>Synopsis</H2
><DIV
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></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>void <B
CLASS="FSFUNC"
>SDL_GetClipRect</B
></CODE
>(SDL_Surface *surface, SDL_Rect *rect);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2240"
></A
><H2
>Description</H2
><P
>Gets the clipping rectangle for a surface.  When this surface is the
destination of a blit, only the area within the clip rectangle is
drawn into.</P
><P
>The rectangle pointed to by <TT
CLASS="PARAMETER"
><I
>rect</I
></TT
> will be
filled with the clipping rectangle of the surface.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2245"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlsetcliprect.html"
><TT
CLASS="FUNCTION"
>SDL_SetClipRect</TT
></A
>,
<A
HREF="sdlblitsurface.html"
><TT
CLASS="FUNCTION"
>SDL_BlitSurface</TT
></A
>,
<A
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>SDL_Surface</SPAN
></A
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