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#include <stdio.h>
#include <stdlib.h>
#include "render.h"
typedef struct {
float r, g, b;
} vec3;
void lerp(vec3* d, const vec3* a, const vec3* b, float t) {
d->r = a->r + t * (b->r - a->r);
d->g = a->g + t * (b->g - a->g);
d->b = a->b + t * (b->b - a->b);
}
Colour get_pixel(unsigned* data, int x, int y, int w) {
vec3 start, end, col;
float t;
int i;
Colour r = { 0 };
unsigned palette = data[(x / 4 + y / 4 * (w / 4)) * 2];
unsigned indices = data[(x / 4 + y / 4 * (w / 4)) * 2 + 1];
start.r = (float)((palette & (31 << 27)) >> 27) / 32.0f;
start.g = (float)((palette & (63 << 21)) >> 21) / 64.0f;
start.b = (float)((palette & (31 << 16)) >> 16) / 32.0f;
end.r = (float)((palette & (31 << 11)) >> 11) / 32.0f;
end.g = (float)((palette & (63 << 5)) >> 5) / 64.0f;
end.b = (float)((palette & (31 )) ) / 32.0f;
i = x % 4 + (y % 4) * 4;
i = (indices & (3 << i * 2)) >> i * 2;
t = (float)i / 3.0f;
lerp(&col, &start, &end, t);
r.r = (int)(col.r * 255.0f);
r.g = (int)(col.g * 255.0f);
r.b = (int)(col.b * 255.0f);
return r;
}
int main(int argc, const char** argv) {
FILE* infile, * outfile;
unsigned* data;
int w, h, x, y, cw, ch;
unsigned palette, indices;
vec3 colour;
if (argc < 3) {
fprintf(stderr, "Usage: %s infile outfile.\n", argv[0]);
return 1;
}
infile = fopen(argv[1], "rb");
if (!infile) {
fprintf(stderr, "Failed to open %s.\n", argv[1]);
return 2;
}
outfile = fopen(argv[2], "w");
if (!infile) {
fprintf(stderr, "Failed to open %s.\n", argv[2]);
return 3;
}
fread(&w, 1, 4, infile);
fread(&h, 1, 4, infile);
cw = w / 4;
ch = h / 4;
data = malloc(cw * ch * 8);
fread(data, 1, cw * ch * 8, infile);
fprintf(outfile, "P3\n");
fprintf(outfile, "%d %d\n", w, h);
fprintf(outfile, "255\n");
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
Colour c = get_pixel(data, x, y, w);
fprintf(outfile, "%d %d %d\n", c.r, c.g, c.b);
}
}
}
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