Mercurial > sdl-ios-xcode
view docs/man3/SDL_Overlay.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_Overlay" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_Overlay\- YUV video overlay .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct{ Uint32 format; int w, h; int planes; Uint16 *pitches; Uint8 **pixels; Uint32 hw_overlay:1; } SDL_Overlay;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBformat\fR Overlay format (see below) .TP 20 \fBw, h\fR Width and height of overlay .TP 20 \fBplanes\fR Number of planes in the overlay\&. Usually either 1 or 3 .TP 20 \fBpitches\fR An array of pitches, one for each plane\&. Pitch is the length of a row in bytes\&. .TP 20 \fBpixels\fR An array of pointers to teh data of each plane\&. The overlay should be locked before these pointers are used\&. .TP 20 \fBhw_overlay\fR This will be set to 1 if the overlay is hardware accelerated\&. .SH "DESCRIPTION" .PP A \fBSDL_Overlay\fR is similar to a \fI\fBSDL_Surface\fR\fR except it stores a YUV overlay\&. All the fields are read only, except for \fBpixels\fR which should be \fIlocked\fR before use\&. The \fBformat\fR field stores the format of the overlay which is one of the following: .PP .nf \f(CW#define SDL_YV12_OVERLAY 0x32315659 /* Planar mode: Y + V + U */ #define SDL_IYUV_OVERLAY 0x56555949 /* Planar mode: Y + U + V */ #define SDL_YUY2_OVERLAY 0x32595559 /* Packed mode: Y0+U0+Y1+V0 */ #define SDL_UYVY_OVERLAY 0x59565955 /* Packed mode: U0+Y0+V0+Y1 */ #define SDL_YVYU_OVERLAY 0x55595659 /* Packed mode: Y0+V0+Y1+U0 */\fR .fi .PP More information on YUV formats can be found at \fIhttp://www\&.webartz\&.com/fourcc/indexyuv\&.htm (link to URL http://www.webartz.com/fourcc/indexyuv.htm) \fR\&. .SH "SEE ALSO" .PP \fI\fBSDL_CreateYUVOverlay\fP\fR, \fI\fBSDL_LockYUVOverlay\fP\fR, \fI\fBSDL_UnlockYUVOverlay\fP\fR, \fI\fBSDL_FreeYUVOverlay\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01