SDL_Surface(3) SDL API Reference SDL_Surface(3)NAME
SDL_Surface - Graphical Surface Structure
STRUCTURE DEFINITION
typedef struct SDL_Surface {
Uint32 flags; /* Read-only */
SDL_PixelFormat *format; /* Read-only */
int w, h; /* Read-only */
Uint16 pitch; /* Read-only */
void *pixels; /* Read-write */
/* clipping information */
SDL_Rect clip_rect; /* Read-only */
/* Reference count -- used when freeing surface */
int refcount; /* Read-mostly */
/* This structure also contains private fields not shown here */
} SDL_Surface;
STRUCTURE DATA
flags Surface flags
format Pixel format
w, h Width and height of the surface
pitch Length of a surface scanline in bytes
pixels Pointer to the actual pixel data
clip_rect surface clip rectangle
DESCRIPTION
SDL_Surface's represent areas of "graphical" memory, memory that can be drawn to. The video framebuffer is returned as a SDL_Surface by
SDL_SetVideoMode and SDL_GetVideoSurface. Most of the fields should be pretty obvious. w and h are the width and height of the surface in
pixels. pixels is a pointer to the actual pixel data, the surface should be locked before accessing this field. The clip_rect field is the
clipping rectangle as set by SDL_SetClipRect.
The following are supported in the flags field.
SDL_SWSURFACE Surface is stored in system memory
SDL_HWSURFACE Surface is stored in video memory
SDL_ASYNCBLIT Surface uses asynchronous blits if possible
SDL_ANYFORMAT Allows any pixel-format (Display surface)
SDL_HWPALETTE Surface has exclusive palette
SDL_DOUBLEBUF Surface is double buffered (Display surface)
SDL_FULLSCREEN Surface is full screen (Display Surface)
SDL_OPENGL Surface has an OpenGL context (Display Surface)
SDL_OPENGLBLIT Surface supports OpenGL blitting (Display Surface)
SDL_RESIZABLE Surface is resizable (Display Surface)
SDL_HWACCEL Surface blit uses hardware acceleration
SDL_SRCCOLORKEY Surface use colorkey blitting
SDL_RLEACCEL Colorkey blitting is accelerated with RLE
SDL_SRCALPHA Surface blit uses alpha blending
SDL_PREALLOC Surface uses preallocated memory
SEE ALSO
SDL_PixelFormat
SDL Tue 11 Sep 2001, 23:01 SDL_Surface(3)
Check Out this Related Man Page
SDL_BlitSurface(3) SDL API Reference SDL_BlitSurface(3)NAME
SDL_BlitSurface- This performs a fast blit from the source surface to the destination surface.
SYNOPSIS
#include "SDL.h"
int SDL_BlitSurface(SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect);
DESCRIPTION
This performs a fast blit from the source surface to the destination surface.
Only the position is used in the dstrect (the width and height are ignored).
If either srcrect or dstrect are NULL, the entire surface (src or dst) is copied.
The final blit rectangle is saved in dstrect after all clipping is performed (srcrect is not modified).
The blit function should not be called on a locked surface.
The results of blitting operations vary greatly depending on whether SDL_SRCAPLHA is set or not. See SDL_SetAlpha 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.
if (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
}
RETURN VALUE
If the blit is successful, it returns 0, otherwise it returns -1.
If either of the surfaces were in video memory, and the blit returns -2, the video memory was lost, so it should be reloaded with artwork
and re-blitted:
while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) {
while ( SDL_LockSurface(image)) < 0 )
Sleep(10);
-- Write image pixels to image->pixels --
SDL_UnlockSurface(image);
}
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.
SEE ALSO
SDL_LockSurface, SDL_FillRect, SDL_Surface, SDL_Rect
SDL Tue 11 Sep 2001, 23:01 SDL_BlitSurface(3)