37 lines
1.5 KiB
C
37 lines
1.5 KiB
C
/* ************************************************************************** */
|
|
/* */
|
|
/* ML_bmp_xor.c */
|
|
/* | Project : libmonochrome */
|
|
/* */
|
|
/* By: Pierre "PierrotLL" Le Gall <legallpierre89@gmail.com> */
|
|
/* Last updated: 2011/11/22 */
|
|
/* */
|
|
/* ************************************************************************** */
|
|
|
|
#include <monochrome/internals.h>
|
|
|
|
void ML_bmp_xor(const unsigned char *bmp, int x, int y, int width, int height)
|
|
{
|
|
unsigned short line;
|
|
char shift, *screen, *p=(char*)&line;
|
|
int i, j, begin=0, end=height, real_width=(width-1>>3<<3)+8;
|
|
if(!bmp || x<0 || x>128-width || y<1-height || y>63 || width<1 || height<1) return;
|
|
if(y < 0) begin = -y;
|
|
if(y+height > 64) end = 64-y;
|
|
shift = 8-(x&7);
|
|
screen = ML_vram_adress()+(y+begin<<4)+(x>>3);
|
|
for(i=begin ; i<end ; i++)
|
|
{
|
|
for(j=0 ; j<width-1>>3 ; j++)
|
|
{
|
|
line = bmp[i*(real_width>>3)+j]<<shift;
|
|
screen[j] ^= *p;
|
|
if(shift!=8) screen[j+1] ^= *(p+1);
|
|
}
|
|
line = (bmp[i*(real_width>>3)+j] & -1<<(real_width-width))<<shift;
|
|
screen[j] ^= *p;
|
|
if(shift!=8 && x+real_width<129) screen[j+1] ^= *(p+1);
|
|
screen += 16;
|
|
}
|
|
}
|