Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetGammaRamp.3 @ 1240:3b8a43c428bb
From Bug #36:
There are a couple of issues with the selection of Altivec alpha-blitting
routines in CalculateAlphaBlit() in src/video/SDL_Blit_A.c.
1) There's no check for the presence of Altivec when checking if the
Blit32to565PixelAlphaAltivec() routine can be selected.
2) Altivec cannot be used in video memory, and there's no check if the
destination surface is a hardware surface. (Alpha-blitting to a hardware
surface with GPU support is a bad idea, but somebody's bound to do it anyway.)
Patch to fix these attached.
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Sun, 08 Jan 2006 21:18:15 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_SetGammaRamp" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetGammaRamp\- Sets the color gamma lookup tables for the display .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_SetGammaRamp\fP\fR(\fBUint16 *redtable, Uint16 *greentable, Uint16 *bluetable\fR); .SH "DESCRIPTION" .PP 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\&. .PP This function adjusts the gamma based on lookup tables, you can also have the gamma calculated based on a "gamma function" parameter with \fISDL_SetGamma\fR\&. .PP Not all display hardware is able to change gamma\&. .SH "RETURN VALUE" .PP Returns -1 on error (or if gamma adjustment is not supported)\&. .SH "SEE ALSO" .PP \fISDL_SetGamma\fR \fISDL_GetGammaRamp\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01