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/* internal.c
* Written By: Garrett Banuk <mongoose@mongeese.org>
* This is free, just be sure to give me credit when using it
* in any of your programs.
*/
/* internal.[c,h] are various routines used internally
* by SDL_console and DrawText. */
#include "SDL.h"
/*
* Return the pixel value at (x, y)
* NOTE: The surface must be locked before calling this!
*/
Uint32 DT_GetPixel(SDL_Surface *surface, int x, int y)
{
int bpp = surface->format->BytesPerPixel;
/* Here p is the address to the pixel we want to retrieve */
Uint8 *p = (Uint8 *) surface->pixels + y * surface->pitch + x * bpp;
switch (bpp)
{
case 1:
return *p;
case 2:
return *(Uint16 *) p;
case 3:
if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
return p[0] << 16 | p[1] << 8 | p[2];
else
return p[0] | p[1] << 8 | p[2] << 16;
case 4:
return *(Uint32 *) p;
default:
return 0; /* shouldn't happen, but avoids warnings */
}
}
/*
* Set the pixel at (x, y) to the given value
* NOTE: The surface must be locked before calling this!
*/
void DT_PutPixel(SDL_Surface *surface, int x, int y, Uint32 pixel)
{
int bpp = surface->format->BytesPerPixel;
/* Here p is the address to the pixel we want to set */
Uint8 *p = (Uint8 *) surface->pixels + y * surface->pitch + x * bpp;
switch (bpp)
{
case 1:
*p = pixel;
break;
case 2:
*(Uint16 *) p = pixel;
break;
case 3:
if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
{
p[0] = (pixel >> 16) & 0xff;
p[1] = (pixel >> 8) & 0xff;
p[2] = pixel & 0xff;
}
else
{
p[0] = pixel & 0xff;
p[1] = (pixel >> 8) & 0xff;
p[2] = (pixel >> 16) & 0xff;
}
break;
case 4:
*(Uint32 *) p = pixel;
break;
default:
break;
}
}
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