Randomise scene

demo.c

@@ -7,40 +7,71 @@
 
 #define W 800
 #define H 600
+
+#define OBJ_COUNT 32
+
+#define MAX_DIST 100.0
+#define MAX_RAD 10.0
+#define MIN_RAD 1.0
+
 #define FOV 90
 #define SAMPLES_PER_PIXEL 100
 
-#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
-
-static const vec3_t camera_pos = { 0.0, 1.5, -2.0 };
-static const vec3_t camera_target = { 0.0, 1.0, 1.0 };
+static const vec3_t camera_pos = { -100.0, 25.0, -100.0 };
+static const vec3_t target = { 0.0, 0.0, 0.0 };
 
 static const vec3_t sky = { 0.6, 0.7, 1.0 };
 
-static const obj_t objs[] = {
-	SPHERE(1.0, 1.0, 3.0, 1.0, LAMBERTIAN(0.6, 0.2, 0.8)),
-	SPHERE(-0.8, 1.0, 3.8, 1.0, LAMBERTIAN(1.0, 1.0, 1.0)),
-	SPHERE(-1.0, 0.2, 2.6, 0.2, LAMBERTIAN(0.2, 0.9, 0.3)),
-	SPHERE(0.3, 0.3, 1.8, 0.3, LAMBERTIAN(0.9, 0.6, 0.2)),
-	SPHERE(-1.6, 0.2, 2.0, 0.2, REFLECTIVE(1.0, 0.9, 0.4, 0.0)),
-	SPHERE(-6.0, 6.0, 5.0, 6.0, REFLECTIVE(0.9, 0.9, 0.9, 0.05)),
-	SPHERE(-0.7, 0.25, 1.5, 0.25, DIELECTRIC(1.5)),
-	SPHERE(0.0, -1000.0, 0.0, 1000.0, LAMBERTIAN(0.3, 0.3, 0.3)),
+static const material_t floor = LAMBERTIAN(1.0, 0.94, 0.80);
+static const material_t gold = REFLECTIVE(1.0, 0.9, 0.5, 0.0);
+static const material_t silver = REFLECTIVE(0.9, 0.9, 0.9, 0.0);
+static const material_t bronze = REFLECTIVE(0.9, 0.7, 0.5, 0.0);
+static const material_t glass = DIELECTRIC(1.5);
+
+static const material_t metals[] = { gold, silver, bronze };
+
+static obj_t objs[OBJ_COUNT] = {
+	[0] = SPHERE(0.0, -100000.0, 0.0, 100000.0, floor),
 };
 
 static pix_t pixbuf[W * H];
 
+static void rand_obj(obj_t *out, rng_t *rng)
+{
+	material_t material;
+	const uint32_t rand = rng_uint32(rng);
+	if (rand % 2 == 0) {
+		const double r = rng_canon(rng);
+		const double g = rng_canon(rng);
+		const double b = rng_canon(rng);
+		material = (material_t)LAMBERTIAN(r, g, b);
+	} else if (rand % 3 == 0) {
+		material = glass;
+	} else {
+		material = metals[rng_uint32(rng) % 3];
+	}
+
+	const double r = MIN_RAD + (MAX_RAD - MIN_RAD) * rng_canon(rng);
+	const double x = MAX_DIST * rng_disc(rng);
+	const double z = MAX_DIST * rng_disc(rng);
+	*out = (obj_t)SPHERE(x, r, z, r, material);
+}
+
 int main()
 {
+	rng_t rng = rng_init(0);
+	for (int i = 1; i < OBJ_COUNT; ++i)
+		rand_obj(objs + i, &rng);
+
+	img_t img = { .pix = pixbuf };
+	camera_t camera
+	    = camera_init(camera_pos, target, FOV, W, H, SAMPLES_PER_PIXEL);
+
 	const scene_t scene = {
 		.sky_colour = sky,
 		.objs = objs,
-		.obj_count = NELEMS(objs),
+		.obj_count = OBJ_COUNT,
 	};
-
-	img_t img = { .pix = pixbuf };
-	camera_t camera = camera_init(
-	    camera_pos, camera_target, FOV, W, H, SAMPLES_PER_PIXEL);
 	camera_render(&camera, &scene, &img);
 
 	ff_write(STDOUT_FILENO, img);