borgware-2d/pixel.c

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C
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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;
}
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void line(pixel p1, pixel p2 ,unsigned char value){
char dx, dy, stepx, stepy, fraction;
dy = p2.y - p1.y;
dx = p2.x - p1.x;
if ( dy < 0 )
{
dy = -dy;
stepy = -1;
}
else
{
stepy = 1;
}
if ( dx < 0 )
{
dx = -dx;
stepx = -1;
}
else
{
stepx = 1;
}
dx <<= 1;
dy <<= 1;
setpixel(p1 , value );
if ( dx > dy )
{
fraction = dy - (dx >> 1);
while ( p1.x != p2.x )
{
if ( fraction >= 0 )
{
p1.y += stepy;
fraction -= dx;
}
p1.x += stepx;
fraction += dy;
setpixel(p1 , value );
}
}
else
{
fraction = dx - (dy >> 1);
while ( p1.y != p2.y )
{
if ( fraction >= 0 )
{
p1.x += stepx;
fraction -= dy;
}
p1.y += stepy;
fraction += dx;
setpixel(p1 , value );
}
}
}
void filled_rectangle(pixel p1, unsigned char w, unsigned char h ,unsigned char value){
unsigned char y;
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for (y=p1.y;y<(p1.y+h);y++){
line((pixel){p1.x,y}, (pixel){(p1.x+w-1),y} ,value);
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}
}
//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]);
}
}
unsigned char get_next_pixel(pixel p, direction dir){
pixel tmp;
switch (dir){
case right:
tmp = (pixel){p.x-1, p.y};
break;
case left:
tmp = (pixel){p.x+1, p.y};
break;
case down:
tmp = (pixel){p.x, p.y+1};
break;
case up:
tmp = (pixel){p.x, p.y-1};
break;
default:
tmp = p;
break;
}
return get_pixel(tmp);
}
direction direction_r(direction dir){
switch (dir){
case right:
return(down);
case down:
return(left);
case left:
return(up);
case up:
return (right);
}
return(0);
}
void set_cursor(cursor* cur, pixel p){
cur->pos = p;
switch (cur->mode){
case clear:
clearpixel(p);
break;
case set:
setpixel(p,3);
break;
}
}
pixel next_pixel(pixel pix, direction dir){
switch (dir){
case right:
return((pixel){pix.x-1, pix.y});
break;
case left:
return((pixel){pix.x+1, pix.y});
break;
case down:
return((pixel){pix.x, pix.y+1});
break;
case up:
return((pixel){pix.x, pix.y-1});
break;
}
return (pixel){0,0};
}