WIP lightmap baking

1 files changed, 173 insertions, 1 deletions

diff --git a/map.c b/map.c
index 5dbe236..d1dcbb8 100644
--- a/map.c
+++ b/map.c
@@ -1,7 +1,12 @@
 #include "map.h"
+#include "maths.h"
+#include <stdlib.h>
 
 int map_size(int w, int h) {
-	return sizeof(Map) + w * h * sizeof(Map_Tile);
+	return
+		sizeof(Map) +
+		w * h * sizeof(Map_Tile) +
+		w * h * sizeof(Map_Light_Tile);
 }
 
 Map_Tile* map_tiles(Map* m) {
@@ -11,3 +16,170 @@ Map_Tile* map_tiles(Map* m) {
 const Map_Tile* map_tilesc(const Map* m) {
 	return (Map_Tile*)&m[1];
 }
+
+Map_Light_Tile* map_light_tiles(Map* m) {
+	return (Map_Light_Tile*)&map_tiles(m)[m->w * m->h];
+}
+
+const Map_Light_Tile* map_light_tilesc(const Map* m) {
+	return (Map_Light_Tile*)&map_tilesc(m)[m->w * m->h];
+}
+
+typedef struct {
+	Line a, b;
+} Ray;
+
+void init_ray(Ray* r, const int* f, const int* t) {
+	int fa[2], ta[2];
+	int fb[2], tb[2];
+	fa[0] = f[0];
+	fa[1] = f[1];
+	ta[0] = t[0];
+	ta[1] = t[1];
+	fb[0] = f[0];
+	fb[1] = f[2];
+	tb[0] = t[0];
+	tb[1] = t[2];
+	init_line(&r->a, fa, ta);
+	init_line(&r->b, fb, tb);
+}
+
+void step_ray(Ray* r) {
+	step_line(&r->a);
+	while (r->a.x != r->b.x)
+		step_line(&r->b);
+}
+
+void get_ray(const Ray* r, int* d) {
+	d[0] = r->a.x;
+	d[1] = r->a.y;
+	d[2] = r->b.y;
+}
+
+int trace_ray(
+	Map* m,
+	const int* f,
+	const int* t
+) {
+	Ray r;
+	int pos[3], w[3];
+	init_ray(&r, f, t);
+	while (1) {
+		int mp[2], coord;
+		get_ray(&r, pos);
+		mp[0] = pos[0] >> fbits;
+		mp[1] = pos[1] >> fbits;
+		if (mp[0] < 0) goto end;
+		if (mp[1] < 0) goto end;
+		if (mp[0] >= m->w) goto end;
+		if (mp[1] >= m->h) goto end;
+		if (pos[2] < 0) { /* hit the floor */
+			goto end;
+		}
+		if (pos[2] >= f1) { /* hit the ceiling */
+			goto end;
+		}
+		coord = mp[0] + mp[1] * m->w;
+		if (map_tilesc(m)[coord]) {
+			goto end;
+		}
+		step_ray(&r);
+	}
+end:
+	return vec_dist(w, pos, t, 3) < 100;
+}
+
+void init_tile(Map* m, int tx, int ty, Map_Light_Tile* t) {
+	int i, x, y;
+	Map_Fragment full = {
+		{ 0xff, 0xff, 0xff, 0xff },
+		{ 0xff, 0xff, 0xff, 0xff }, {
+		{ 0xff, 0xff, 0xff, 0xff },
+		{ 0xff, 0xff, 0xff, 0xff },
+		{ 0xff, 0xff, 0xff, 0xff },
+		{ 0xff, 0xff, 0xff, 0xff },
+	}};
+	(void)m;
+	(void)tx;
+	(void)ty;
+	for (i = y = 0; y < map_light_tile_size; y++) {
+		for (x = 0; x < map_light_tile_size; x++, i++) {
+			t->fragments[i] = full;
+		}
+	}
+}
+
+void bake_tile(
+	Map* m,
+	int tx,
+	int ty,
+	Map_Light_Tile* t,
+	const Map_Light* light
+) {
+	int i, x, y, fr[3], w[3];
+	Map_Tile wall = map_tilesc(m)[tx + ty * m->w];
+	tx <<= fbits;
+	ty <<= fbits;
+	fr[0] = light->x;
+	fr[1] = light->y;
+	fr[2] = f1/2;
+	for (i = y = 0; y < map_light_tile_size; y++) {
+		for (x = 0; x < map_light_tile_size; x++, i++) {
+			int to[3];
+			int atten;
+			Colour c;
+			to[0] = tx + x * 32;
+			to[1] = ty + y * 32;
+			to[2] = f1;
+			atten = vec_dist(w, fr, to, 3);
+			atten /= 5;
+			atten = mini(
+				(f1 << fbits) / maxi(1, (atten * atten) >> fbits),
+				f1
+			) - 1;
+			c = col_scl(
+				light->c,
+				(unsigned char)(atten / 2)
+			);
+			if (trace_ray(m, fr, to))
+				t->fragments[i].u = c;
+			to[2] = 0;
+			if (trace_ray(m, fr, to))
+				t->fragments[i].d = c;
+		}
+	}
+}
+
+void bake_light(Map* m, const Map_Light* light) {
+	int x, y, i;
+	Map_Light_Tile* lt = map_light_tiles(m);
+	for (i = y = 0; y < m->h; y++) {
+		for (x = 0; x < m->w; x++, i++) {
+			bake_tile(m, x, y, &lt[i], light);
+		}
+	}
+}
+
+void bake_map(Map* m) {
+	Map_Light l = { f1 * 3, f1 * 3, f1, { 0xff, 0xff, 0xff, 0xff } };
+	bake_light(m, &l);
+}
+
+const Map_Fragment* sample_map_light(
+	const Map* m, 
+	int tx,
+	int ty,
+	int u,
+	int v
+) {
+	int coord;
+	const Map_Light_Tile* t =
+		&map_light_tilesc(m)[tx + ty * m->w];
+	int x = (u * map_light_tile_size) >> fbits;
+	int y = (v * map_light_tile_size) >> fbits;
+	x &= map_light_tile_size - 1;
+	y &= map_light_tile_size - 1;
+	coord = x + y * map_light_tile_size;
+	return &t->fragments[coord];
+}
+