Mercurial > sdl-ios-xcode
view docs/man3/SDL_BlitSurface.3 @ 3100:7dc982143c06
Date: Sun, 22 Mar 2009 12:52:29 +0000
From: Luke Benstead
Subject: OpenGL 3.0 Context Creation
I've attached a patch which implements OpenGL 3.x context creation on
the latest SVN. I've added two options to SDL_GL_SetAttribute, these
are SDL_GL_CONTEXT_MAJOR_VERSION and SDL_GL_CONTEXT_MINOR_VERSION.
These default to 2 and 1 respectively. If the major version is less
than 3 then the current context creation method is used, otherwise the
appropriate new context creation function is called (depending on the
platform).
Sample code:
if (SDL_Init(SDL_INIT_VIDEO) != 0) {
printf("Unable to initialize SDL: %s\n", SDL_GetError());
return 1;
}
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3); //Without these 2 lines, SDL will create a GL 2.x context
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_Surface* screen = SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL | SDL_FULLSCREEN );
I've implemented context creation on both Win32 and X and run basic
tests on both. This patch doesn't provide access to all the options
allowed by the new context creation (e.g. shared contexts, forward
compatible contexts) but they can be added pretty easily.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 24 Mar 2009 10:43:53 +0000 |
| parents | 546f7c1eb755 |
| children | 1238da4a7112 |
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.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