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#include <stdint.h>
#include <multiboot2.h>
#include <graphics.h>
#include <debug.h>
uint64_t* pixel_offset(fb_t fb, uint32_t x, uint32_t y)
{
return (uint64_t*)((uint32_t*)fb.addr + y * fb.pitch / 4 + x);
}
void fb_draw_pixel(fb_t fb, uint32_t x, uint32_t y, uint32_t col)
{
uint64_t* fb_offset = pixel_offset(fb, x, y);
*fb_offset = col;
}
void fb_draw_line_low(fb_t fb, uint32_t x0, uint32_t y0, uint32_t x1, uint32_t y1, uint32_t col)
{
uint32_t dx = x1 - x0;
uint32_t dy = y1 - y0;
uint32_t yi = 1;
if (dy < 0) {
yi = -1;
dy = -dy;
}
uint32_t D = (2 * dy) - dx;
uint32_t y = y0;
for (uint32_t x = x0; x < x1; x++) {
fb_draw_pixel(fb, x, y, col);
if (D > 0) {
y = y + yi;
D = D + (2 * (dy - dx));
} else {
D = D + 2*dy;
}
}
}
void fb_draw_line_high(fb_t fb, int32_t x0, int32_t y0, int32_t x1, int32_t y1, int32_t col)
{
int32_t dx = x1 - x0;
int32_t dy = y1 - y0;
int32_t xi = 1;
if (dx < 0) {
xi = -1;
dx = -dx;
}
int32_t D = (2 * dx) - dy;
int32_t x = x0;
for (int32_t y = y0; y <= y1; y++) {
fb_draw_pixel(fb, x, y, col);
if (D > 0) {
x = x + xi;
D = D + (2 * (dx - dy));
} else {
D = D + 2*dx;
}
}
}
uint32_t abs(int64_t val)
{
if (val < 0) return -val;
return val;
}
void fb_draw_line(fb_t fb, int32_t x0, int32_t y0, int32_t x1, int32_t y1, int32_t col)
{
if (abs(y1 - y0) < abs(x1 - x0)) {
if (x0 > x1)
fb_draw_line_low(fb, x1, y1, x0, y0, col);
else
fb_draw_line_low(fb, x0, y0, x1, y1, col);
} else {
if (y0 > y1)
fb_draw_line_high(fb, x1, y1, x0, y0, col);
else
fb_draw_line_high(fb, x0, y0, x1, y1, col);
}
}
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