From 1f61a690ac1c1ec1b9b15b358925abbd29c487c6 Mon Sep 17 00:00:00 2001
From: Julian T <julian@jtle.dk>
Date: Mon, 9 Mar 2020 23:29:16 +0100
Subject: Added anti aliasing

---
 main.c   |   2 +-
 ray.c    |  37 ++++++++++++++++++++++++++++++++-----
 ray.h    |   2 +-
 test.png | Bin 55642 -> 60983 bytes
 4 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/main.c b/main.c
index cd66dee..d1b8080 100644
--- a/main.c
+++ b/main.c
@@ -61,7 +61,7 @@ int main()
 	pgm_write_header(stdout, TESTW, TESTH);
 	for (int y = TESTH; y; y--) {
 		for (int x = TESTW; x; x--) {
-			color_t *c = ray_trace(&s, x, y);
+			color_t *c = ray_trace(&s, x, y, 8);
 
 			if (c) {
 				pgm_write_pixel(stdout, c);
diff --git a/ray.c b/ray.c
index 35ec5b1..e91d7e1 100644
--- a/ray.c
+++ b/ray.c
@@ -235,19 +235,46 @@ exit:
 	return 0;
 }
 
-color_t *ray_trace(space_t *s, unsigned int x, unsigned int y)
+color_t *ray_trace(space_t *s, unsigned int x, unsigned int y, unsigned samples)
 {
 	// Init return color. Will be accumilated with all the detected light.
-	color_t *c = color_set(NULL, s->ambient.r, s->ambient.g, s->ambient.b);
+	color_t *c = color_set(NULL, 0, 0, 0);
 
 	// Setup primary ray
 	ray_t r;
 	r.start = &s->view.position;
 	r.direction = vector_copy(NULL, NULL);
-	viewpoint_ray(&s->view, r.direction, x, y);
 
-	// Run the recursive ray trace
-	ray_trace_recur(s, c, &r, 0, 1);
+	// Multiple samples for antialias
+	// TODO better distribution of antialias probes
+	for (int i = 0; i < samples; i++) {
+		color_t ctmp;
+		color_set(&ctmp, 0, 0, 0);
+		//memset(&ctmp, 0, sizeof(color_t));
+		
+		// Multiple samples inside same pixel
+		COORD_T tmp = (COORD_T) i/ (COORD_T) samples;
+		viewpoint_ray(&s->view, r.direction, x + tmp, y + tmp);
+
+		// Run the recursive ray trace
+		ray_trace_recur(s, &ctmp, &r, 0, 1);
+
+		// Color_add will not go above 1. In this case we don't want that.
+		c->r += ctmp.r; c->g += ctmp.g; c->b += ctmp.b;
+
+	}
+	//printf("COlor before devide %f, %f, %f\n", c->r, c->g, c->b);
+
+	free(r.direction);
+
+	// Take the median
+	if (samples > 1) {
+		// Same as deviding by samples
+		color_scale(c, c, 1.0/ (COORD_T) samples);
+	}
+
+	// Add ambient
+	color_add(c, c, &s->ambient);
 
 	return c;
 }
diff --git a/ray.h b/ray.h
index 208dcfc..74749ff 100644
--- a/ray.h
+++ b/ray.h
@@ -17,6 +17,6 @@ COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray, bool skip_dist);
 COORD_T ray_intersect_plane(plane_t *p, ray_t *ray, bool skip_dist);
 
 object_t *ray_cast(space_t *s, ray_t *r, COORD_T *dist_ret, bool chk, COORD_T chk_dist);
-color_t *ray_trace(space_t *s, unsigned int x, unsigned int y);
+color_t *ray_trace(space_t *s, unsigned int x, unsigned int y, unsigned samples);
 
 #endif
diff --git a/test.png b/test.png
index 7d814b7..03b64fb 100644
Binary files a/test.png and b/test.png differ
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