Add fake sss

Author: luboslenco

armorpaint/sources/make_paint.ts

@@ -275,12 +275,8 @@ function make_paint_run(data: material_t, matcon: material_context_t): node_shad
 			// Height used for the first time, also rebuild vertex shader
 			return make_paint_run(data, matcon);
 		}
-		if (emis != "0.0" && emis != "0") {
-			make_material_emis_used = true;
-		}
-		if (subs != "0.0" && subs != "0") {
-			make_material_subs_used = true;
-		}
+		make_material_emis_used = emis != "0.0" && emis != "0";
+		make_material_subs_used = subs != "0.0" && subs != "0";
 	}
 
 	if (context_raw.brush_mask_image != null && context_raw.tool == workspace_tool_t.DECAL) {
@@ -391,13 +387,13 @@ function make_paint_run(data: material_t, matcon: material_context_t): node_shad
 	node_shader_write(frag, "float matid = " + matid_string + ";");
 
 	// matid % 3 == 0 - normal, 1 - emission, 2 - subsurface
-	if (context_raw.material.paint_emis) {
+	if (context_raw.material.paint_emis && make_material_emis_used) {
 		node_shader_write(frag, "if (emis > 0.0) {");
 		node_shader_write(frag, "	matid += 1.0 / 255.0;");
 		node_shader_write(frag, "	if (str == 0.0) discard;");
 		node_shader_write(frag, "}");
 	}
-	else if (context_raw.material.paint_subs) {
+	else if (context_raw.material.paint_subs && make_material_subs_used) {
 		node_shader_write(frag, "if (subs > 0.0) {");
 		node_shader_write(frag, "    matid += 2.0 / 255.0;");
 		node_shader_write(frag, "	if (str == 0.0) discard;");

base/shaders/raytrace/raytrace_brute_forge_full.spirv

@@ -3,8 +3,8 @@
 #define _EMISSION
 #define _SUBSURFACE
 #define _TRANSLUCENCY
-#define _ROULETTE
 #define _TRANSPARENCY
+#define _ROULETTE
 // #define _FRESNEL
 #endif
 // #define _RENDER
@@ -97,11 +97,11 @@ void raygeneration() {
 			}
 			#endif
 
-			#ifdef _SUBSURFACE
-			TraceRay(scene, RAY_FLAG_FORCE_OPAQUE | RAY_FLAG_CULL_BACK_FACING_TRIANGLES, ~0, 0, 1, 0, ray, payload);
-			#else
+			// #ifdef _SUBSURFACE
+			// TraceRay(scene, RAY_FLAG_FORCE_OPAQUE | RAY_FLAG_CULL_BACK_FACING_TRIANGLES, ~0, 0, 1, 0, ray, payload);
+			// #else
 			TraceRay(scene, RAY_FLAG_FORCE_OPAQUE, ~0, 0, 1, 0, ray, payload);
-			#endif
+			// #endif
 
 			#ifdef _EMISSION
 			if (payload.color.a == -3) {
@@ -278,7 +278,13 @@ void closesthit(inout RayPayload payload, in BuiltInTriangleIntersectionAttribut
 
 	#ifdef _SUBSURFACE
 	if (int(texpaint1.a * 255.0f) % 3 == 2) {
-		payload.ray_origin += WorldRayDirection() * f;
+		// Thickness
+		float d = min(1.0 / min(RayTCurrent() * 2.0, 1.0) / 10.0, 0.5);
+		payload.color.xyz += payload.color.xyz * d;
+		// Fake scatter
+		if (f < 0.5) {
+			payload.ray_origin += WorldRayDirection() * f * 0.001;
+		}
 	}
 	#endif
 }