From 5cb5dcd785aed986179a3b8997fb606218984182 Mon Sep 17 00:00:00 2001
From: CrispyPin <crispin@tasa.se>
Date: Wed, 26 Jul 2023 18:25:45 +0200
Subject: [PATCH] libgarbage: fix depth in reflections when using
 LIMIT_DEPTH_TO_MESH; fix flickering when camera is inside volume

---
 Assets/raymarched/lib/libgarbage.cginc | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/Assets/raymarched/lib/libgarbage.cginc b/Assets/raymarched/lib/libgarbage.cginc
index 23b114e..b49ce6b 100644
--- a/Assets/raymarched/lib/libgarbage.cginc
+++ b/Assets/raymarched/lib/libgarbage.cginc
@@ -26,6 +26,11 @@ START_RAYS_IN_BOX // TODO: implement
 START_RAYS_IN_SPHERE // TODO: implement
 */
 
+// sky used as background unless DISCARD_ON_MISS is set, and used in reflections
+// TODO: implement
+#ifndef SKY_FN
+#define SKY_FN default_sky
+#endif
 
 // scene sdf that includes material data
 #ifndef SCENE_FN
@@ -159,15 +164,14 @@ FragOut frag (V2F i) {
 	float ray_len = 0;
 	float3 ray_dir = normalize(i.hit_pos - i.cam_pos);
 
-	float3 ray_origin = i.cam_pos;
-	ray_origin /= SCENE_SCALE;
-	SurfacePoint point_data;
+	float3 ray_origin = i.cam_pos / SCENE_SCALE;
 	Ray ray;
 
 	float3 col;
 	float color_used = 0;// what amount of the final color has been calculated
 	float prev_gloss = 0;
 	float3 first_hit;
+	bool inside_shape;
 
 	int ray_num = 0;
 	for (; ray_num < REFLECTIONS + 1;) {
@@ -175,10 +179,7 @@ FragOut frag (V2F i) {
 		if (ray_num == 0) { // before any bounces
 			col = LIGHT_FN(ray);
 			first_hit = ray.hit_pos;
-			if (ray.steps == 0) {
-				// discard;
-				// TODO: sky fn
-			}
+			inside_shape = ray.steps == 0;
 		} else {
 			float col_amount = color_used + ((1 - prev_gloss) * (1 - color_used));
 			col = lerp(LIGHT_FN(ray), col, col_amount);
@@ -206,10 +207,14 @@ FragOut frag (V2F i) {
 			depth_point = i.hit_pos;
 
 		#ifdef LIMIT_DEPTH_TO_MESH
-			if (length(ray.start - ray.hit_pos) > length(i.cam_pos - i.hit_pos))
+			if (length(ray.start - first_hit) > length(i.cam_pos - i.hit_pos))
 				depth_point = i.hit_pos;
 		#endif
 
+		if (inside_shape) {
+			depth_point = i.cam_pos + normalize(i.hit_pos - i.cam_pos) * 0.01;
+		}
+
 		#ifdef USE_WORLD_SPACE
 			float4 clip_pos = mul(UNITY_MATRIX_VP, float4(depth_point, 1));
 		#else
@@ -265,6 +270,10 @@ Ray cast_ray(float3 start, float3 dir, float start_len) {
 	return ray;
 }
 
+float3 default_sky(float3 dir) {
+	return lRenderSky(dir, normalize(float3(2, 1, 0)));
+}
+
 float default_distance_sdf(float3 p) {
 	return sdSphere(p, 0.5);
 }
@@ -286,5 +295,4 @@ float3 default_lighting(Ray ray) {
 	return col;
 }
 
-
 #endif // LIBGARBAGE_INCLUDED