Mercurial > sdl-ios-xcode
view docs/man3/SDL_Surface.3 @ 1542:a8bf1aa21020
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 | e5bc29de3f0a |
children | 546f7c1eb755 |
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.TH "SDL_Surface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_Surface\- Graphical Surface Structure .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct SDL_Surface { Uint32 flags; /* Read-only */ SDL_PixelFormat *format; /* Read-only */ int w, h; /* Read-only */ Uint16 pitch; /* Read-only */ void *pixels; /* Read-write */ /* clipping information */ SDL_Rect clip_rect; /* Read-only */ /* Reference count -- used when freeing surface */ int refcount; /* Read-mostly */ /* This structure also contains private fields not shown here */ } SDL_Surface;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBflags\fR Surface flags .TP 20 \fBformat\fR Pixel \fIformat\fR .TP 20 \fBw, h\fR Width and height of the surface .TP 20 \fBpitch\fR Length of a surface scanline in bytes .TP 20 \fBpixels\fR Pointer to the actual pixel data .TP 20 \fBclip_rect\fR surface clip \fIrectangle\fR .SH "DESCRIPTION" .PP \fBSDL_Surface\fR\&'s represent areas of "graphical" memory, memory that can be drawn to\&. The video framebuffer is returned as a \fBSDL_Surface\fR by \fI\fBSDL_SetVideoMode\fP\fR and \fI\fBSDL_GetVideoSurface\fP\fR\&. Most of the fields should be pretty obvious\&. \fBw\fR and \fBh\fR are the width and height of the surface in pixels\&. \fBpixels\fR is a pointer to the actual pixel data, the surface should be \fIlocked\fR before accessing this field\&. The \fBclip_rect\fR field is the clipping rectangle as set by \fI\fBSDL_SetClipRect\fP\fR\&. .PP The following are supported in the \fBflags\fR field\&. .TP 20 \fBSDL_SWSURFACE\fP Surface is stored in system memory .TP 20 \fBSDL_HWSURFACE\fP Surface is stored in video memory .TP 20 \fBSDL_ASYNCBLIT\fP Surface uses asynchronous blits if possible .TP 20 \fBSDL_ANYFORMAT\fP Allows any pixel-format (Display surface) .TP 20 \fBSDL_HWPALETTE\fP Surface has exclusive palette .TP 20 \fBSDL_DOUBLEBUF\fP Surface is double buffered (Display surface) .TP 20 \fBSDL_FULLSCREEN\fP Surface is full screen (Display Surface) .TP 20 \fBSDL_OPENGL\fP Surface has an OpenGL context (Display Surface) .TP 20 \fBSDL_OPENGLBLIT\fP Surface supports OpenGL blitting (Display Surface) .TP 20 \fBSDL_RESIZABLE\fP Surface is resizable (Display Surface) .TP 20 \fBSDL_HWACCEL\fP Surface blit uses hardware acceleration .TP 20 \fBSDL_SRCCOLORKEY\fP Surface use colorkey blitting .TP 20 \fBSDL_RLEACCEL\fP Colorkey blitting is accelerated with RLE .TP 20 \fBSDL_SRCALPHA\fP Surface blit uses alpha blending .TP 20 \fBSDL_PREALLOC\fP Surface uses preallocated memory .SH "SEE ALSO" .PP \fI\fBSDL_PixelFormat\fR\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01