From a1030ca528e96c6afd4c1d755c214023aa524a0e Mon Sep 17 00:00:00 2001
From: CrispyPin <crispin@tasa.se>
Date: Tue, 25 Jul 2023 12:34:08 +0200
Subject: [PATCH] libgarbage: fix depth of sky, allow limiting depth to mesh,
 add step multiplier setting

---
 Assets/raymarched/lib/libgarbage.cginc | 28 ++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/Assets/raymarched/lib/libgarbage.cginc b/Assets/raymarched/lib/libgarbage.cginc
index 705a4f5..dff2c74 100644
--- a/Assets/raymarched/lib/libgarbage.cginc
+++ b/Assets/raymarched/lib/libgarbage.cginc
@@ -19,6 +19,9 @@
 # don't write depth (will have the depth defined by the original mesh)
 	DISABLE_DEPTH
 
+# meant for frontface culled meshes, makes depth no further than the mesh edges
+	LIMIT_DEPTH_TO_MESH
+
 START_RAYS_IN_BOX // TODO: implement
 START_RAYS_IN_SPHERE // TODO: implement
 */
@@ -43,6 +46,11 @@ START_RAYS_IN_SPHERE // TODO: implement
 #define LIGHT_FN default_lighting
 #endif
 
+// set to less than one if there are artifacts in distorted sdfs
+#ifndef STEP_MULTIPLIER
+#define STEP_MULTIPLIER 1
+#endif
+
 // max ray steps, from last bounce (reset on each reflection)
 #ifndef MAX_STEPS
 #define MAX_STEPS 128
@@ -156,16 +164,22 @@ FragOut frag (V2F i) {
 	float prev_gloss = 0;
 	float3 first_hit;
 
-	for (int ray_num = 0; ray_num < REFLECTIONS + 1; ray_num++) {
+	int ray_num = 0;
+	for (; ray_num < REFLECTIONS + 1;) {
 		ray = cast_ray(ray_origin, ray_dir);
 		if (ray_num == 0) { // before any bounces
 			col = LIGHT_FN(ray);
 			first_hit = ray.hit_pos;
+			if (ray.steps == 0) {
+				// discard;
+				// TODO: sky fn
+			}
 		} else {
 			float col_amount = color_used + ((1 - prev_gloss) * (1 - color_used));
 			col = lerp(LIGHT_FN(ray), col, col_amount);
 			color_used = col_amount;
 		}
+		ray_num++;
 		if (ray.missed || ray.mat.gloss < 0.01) {
 			break;
 		}
@@ -175,7 +189,7 @@ FragOut frag (V2F i) {
 	}
 
 	#ifdef DISCARD_ON_MISS
-	if (ray.missed && ray_num == 0) discard;
+	if (ray.missed && ray_num == 1) discard;
 	#endif
 
 	FragOut o;
@@ -183,8 +197,14 @@ FragOut frag (V2F i) {
 
 	#ifndef DISABLE_DEPTH
 		float3 depth_point = first_hit * SCENE_SCALE;
-		if (ray.missed && ray_num == 0)
+		if (ray.missed && ray_num == 1)
 			depth_point = i.hit_pos;
+
+		#ifdef LIMIT_DEPTH_TO_MESH
+			if (length(ray.start - ray.hit_pos) > length(i.cam_pos - i.hit_pos))
+				depth_point = i.hit_pos;
+		#endif
+
 		#ifdef USE_WORLD_SPACE
 			float4 clip_pos = mul(UNITY_MATRIX_VP, float4(depth_point, 1));
 		#else
@@ -225,7 +245,7 @@ Ray cast_ray(float3 start, float3 dir, float start_len) {
 			break;
 		}
 		ray.min_dist = min(ray.min_dist, ray.dist);
-		ray_len += ray.dist;
+		ray_len += ray.dist * STEP_MULTIPLIER;
 		if (ray_len > MAX_DIST) break;
 	}