Mercurial > sdl-ios-xcode
view docs/man3/SDL_keysym.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_keysym" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_keysym\- Keysym structure .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct{ Uint8 scancode; SDLKey sym; SDLMod mod; Uint16 unicode; } SDL_keysym;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBscancode\fR Hardware specific scancode .TP 20 \fBsym\fR SDL virtual keysym .TP 20 \fBmod\fR Current key modifiers .TP 20 \fBunicode\fR Translated character .SH "DESCRIPTION" .PP The \fBSDL_keysym\fR structure is used by reporting key presses and releases since it is a part of the \fI\fBSDL_KeyboardEvent\fR\fR\&. .PP The \fBscancode\fR field should generally be left alone, it is the hardware dependent scancode returned by the keyboard\&. The \fBsym\fR field is extremely useful\&. It is the SDL-defined value of the key (see \fISDL Key Syms\fR\&. This field is very useful when you are checking for certain key presses, like so: .PP .nf \f(CW\&. \&. while(SDL_PollEvent(&event)){ switch(event\&.type){ case SDL_KEYDOWN: if(event\&.key\&.keysym\&.sym==SDLK_LEFT) move_left(); break; \&. \&. \&. } } \&. \&.\fR .fi .PP \fBmod\fR stores the current state of the keyboard modifiers as explained in \fI\fBSDL_GetModState\fP\fR\&. The \fBunicode\fR is only used when UNICODE translation is enabled with \fI\fBSDL_EnableUNICODE\fP\fR\&. If \fBunicode\fR is non-zero then this a the UNICODE character corresponding to the keypress\&. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character: .PP .nf \f(CWchar ch; if ( (keysym\&.unicode & 0xFF80) == 0 ) { ch = keysym\&.unicode & 0x7F; } else { printf("An International Character\&. "); }\fR .fi .PP UNICODE translation does have a slight overhead so don\&'t enable it unless its needed\&. .SH "SEE ALSO" .PP \fI\fBSDLKey\fR\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00