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#define PIXEL_C
#include "config.h"
#include "pixel.h"
#include "borg_hw/borg_hw.h"
unsigned char shl_table[] = {0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};
void clear_screen(unsigned char value){
unsigned char p,*pix,v=0xff;
unsigned int i;
for(p=0;p<NUMPLANE;p++){
pix=&pixmap[p][0][0];
if(p==value)
v=0;
for(i=0;i<NUM_ROWS*LINEBYTES;i++)
pix[i]=v;
}
}
void setpixel(pixel p, unsigned char value ){
p.x %= NUM_COLS;
if(value>NUMPLANE)
value=NUMPLANE;
unsigned char pos = (p.y%NUM_ROWS)*LINEBYTES + (p.x/8);
unsigned char mask = shl_table[p.x%8];
unsigned char plane;
for(plane=0;plane<value;plane++)
pixmap[plane][0][pos]|=mask;
mask ^=0xff;
for(;plane<NUMPLANE;plane++)
pixmap[plane][0][pos]&=mask;
}
16 years ago
//shifts pixmap left. It is really shifted right, but because col0 is left in the Display it's left.
void shift_pixmap_l(){
unsigned char plane, row, byte;
for(plane=0; plane<NUMPLANE; plane++){
for(row=0;row<NUM_ROWS; row++){
for(byte=0;byte<(LINEBYTES-1);byte++){
pixmap[plane][row][byte] >>= 1;
pixmap[plane][row][byte] |= (pixmap[plane][row][byte+1] & 0x01) * 0x80;;
}
pixmap[plane][row][LINEBYTES-1] >>= 1;
}
}
}
unsigned char get_pixel(pixel p){
if( (p.x >= NUM_COLS) || (p.y >= NUM_ROWS) ){
return 0xff;
}else{
return 0!= (pixmap[0][p.y][p.x/8] & shl_table[p.x%8]);
}
}
/**
* An implementation of Bresenham's line drawing algorithm.
* @param p1 first coordinate of the line
* @param p2 second coordinate of the line
* @param color brightness level of the line
*/
void line(pixel p1,
pixel const p2,
unsigned char const color)
{
operand_t const dx = p1.x < p2.x ? p2.x - p1.x : p1.x - p2.x;
operand_t const sx = p1.x < p2.x ? 1 : -1;
operand_t const dy = p1.y < p2.y ? p2.y - p1.y : p1.y - p2.y;
operand_t const sy = p1.y < p2.y ? 1 : -1;
operand_t error = dx - dy;
while(1)
{
setpixel(p1, color);
if ((p1.x == p2.x) && (p1.y == p2.y))
break;
operand_t const error2 = 2 * error;
if (error2 > -dy)
{
error -= dy;
p1.x += sx;
}
if (error2 < dx)
{
error += dx;
p1.y += sy;
}
}
}