Mercurial > sdl-ios-xcode

view docs/man3/SDL_BlitSurface.3 @ 2884:9dde605c7540

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Date: Fri, 19 Dec 2008 20:17:35 +0100 From: Couriersud Subject: Re: Aw: Experience using SDL1.3 in sdlmame/Proposal for api additions > For consistency you'd probably want: > SDL_SetRenderDrawColor(Uint8 r, Uint8 g, Uint8 b, Uint8 a); > SDL_SetRenderDrawBlendMode(SDL_BlendMode blendMode); > SDL_RenderLine(int x1, int y1, int x2, int y2); > SDL_RenderFill(SDL_Rect *rect); > > You probably also want to add API functions query the current state. > I have implemented the above api for the opengl, x11, directfb and software renderers. I have also renamed *TEXTUREBLENDMODE* constants to BLENDMODE*. The unix build compiles. The windows renderer still needs to be updated, but I have no windows development machine at hand. Have a look at the x11 renderer for a sample. Vector games now run at 90% both on opengl and directfb in comparison to sdlmame's own opengl renderer. The same applies to raster games. The diff also includes a) Changed XDrawRect to XFillRect in x11 renderer b) A number of changes to fix blending and modulation issues in the directfb renderer.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 20 Dec 2008 12:00:00 +0000
parents 546f7c1eb755
children 1238da4a7112
line wrap: on
line source

.TH "SDL_BlitSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_BlitSurface \- This performs a fast blit from the source surface to the destination surface\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_BlitSurface\fP\fR(\fBSDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect\fR);
.SH "DESCRIPTION"
.PP
This performs a fast blit from the source surface to the destination surface\&.
.PP
Only the position is used in the \fBdstrect\fR (the width and height are ignored)\&.
.PP
If either \fBsrcrect\fR or \fBdstrect\fR are \fBNULL\fP, the entire surface (\fBsrc\fR or \fBdst\fR) is copied\&.
.PP
The final blit rectangle is saved in \fBdstrect\fR after all clipping is performed (\fBsrcrect\fR is not modified)\&.
.PP
The blit function should not be called on a locked surface\&.
.PP
The results of blitting operations vary greatly depending on whether \fBSDL_SRCAPLHA\fP is set or not\&. See \fISDL_SetAlpha\fR for an explaination of how this affects your results\&. Colorkeying and alpha attributes also interact with surface blitting, as the following pseudo-code should hopefully explain\&. 
.PP
.nf
\f(CWif (source surface has SDL_SRCALPHA set) {
    if (source surface has alpha channel (that is, format->Amask != 0))
        blit using per-pixel alpha, ignoring any colour key
    else {
        if (source surface has SDL_SRCCOLORKEY set)
            blit using the colour key AND the per-surface alpha value
        else
            blit using the per-surface alpha value
    }
} else {
    if (source surface has SDL_SRCCOLORKEY set)
        blit using the colour key
    else
        ordinary opaque rectangular blit
}\fR
.fi
.PP
.SH "RETURN VALUE"
.PP
If the blit is successful, it returns \fB0\fR, otherwise it returns \fB-1\fR\&.
.PP
If either of the surfaces were in video memory, and the blit returns \fB-2\fR, the video memory was lost, so it should be reloaded with artwork and re-blitted: 
.PP
.nf
\f(CW        while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) {
                while ( SDL_LockSurface(image)) < 0 )
                        Sleep(10);
                -- Write image pixels to image->pixels --
                SDL_UnlockSurface(image);
        }\fR
.fi
.PP
 This happens under DirectX 5\&.0 when the system switches away from your fullscreen application\&. Locking the surface will also fail until you have access to the video memory again\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_LockSurface\fP\fR, \fI\fBSDL_FillRect\fP\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_Rect\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01