Move ambient-occlusion gamma into static lighting API

Author: sfan5

builtin/settingtypes.txt

@@ -514,12 +514,6 @@ fov (Field of view) int 72 45 160
 #    light, it has very little effect on natural night light.
 display_gamma (Light curve gamma) float 1.0 0.33 3.0
 
-#    The strength (darkness) of node ambient-occlusion shading.
-#    Lower is darker, Higher is lighter. The valid range of values for this
-#    setting is 0.25 to 4.0 inclusive. If the value is out of range it will be
-#    set to the nearest valid value.
-ambient_occlusion_gamma (Ambient occlusion gamma) float 1.8 0.25 4.0
-
 [**Screenshots]
 
 #    Path to save screenshots at. Can be an absolute or relative path.

doc/lua_api.md

@@ -9156,6 +9156,9 @@ child will follow movement and rotation of that bone.
           * table containing 16 numbers or an empty table to reset to the default
           * The values should be monotonically increasing and the last value should
             be 255. Otherwise there might be lighting bugs.
+        * `ao_gamma`: Strength of node ambient-occlusion shading. Lower is darker, Higher is lighter.
+          * Recommended range: from 0.25 to 3.0, default: 1.8
+          * A value of 0.0 will disable this shading entirely.
 
 * `get_lighting()`: returns the current state of lighting for the player.
     * Result is a table with the same fields as `light_definition` in `set_lighting`.

src/client/mapblock_mesh.cpp

@@ -144,6 +144,8 @@ static u16 getSmoothLightCombined(const v3s16 &p,
 {
 	const NodeDefManager *ndef = data->m_nodedef;
 
+	assert(data->m_smooth_lighting);
+
 	u16 ambient_occlusion = 0;
 	u16 light_count = 0;
 	u8 light_source_max = 0;
@@ -160,12 +162,12 @@ static u16 getSmoothLightCombined(const v3s16 &p,
 		if (n.getContent() == CONTENT_IGNORE)
 			return true;
 		const ContentFeatures &f = ndef->get(n);
-		if (f.light_source > light_source_max)
-			light_source_max = f.light_source;
+		light_source_max = std::max(light_source_max, f.light_source);
 		// Check f.solidness because fast-style leaves look better this way
 		if (f.param_type == CPT_LIGHT && f.visuals->solidness != 2) {
-			u8 light_level_day = n.getLight(LIGHTBANK_DAY, f.getLightingFlags());
-			u8 light_level_night = n.getLight(LIGHTBANK_NIGHT, f.getLightingFlags());
+			const auto lf = f.getLightingFlags();
+			u8 light_level_day = n.getLight(LIGHTBANK_DAY, lf);
+			u8 light_level_night = n.getLight(LIGHTBANK_NIGHT, lf);
 			if (light_level_day == LIGHT_SUN)
 				direct_sunlight = true;
 			light_day += decode_light(light_level_day);
@@ -219,25 +221,20 @@ static u16 getSmoothLightCombined(const v3s16 &p,
 	}
 
 	if (ambient_occlusion > 4) {
-		static thread_local const float ao_gamma = rangelim(
-			g_settings->getFloat("ambient_occlusion_gamma"), 0.25, 4.0);
-
-		// Table of gamma space multiply factors.
-		static thread_local const float light_amount[3] = {
-			powf(0.75, 1.0 / ao_gamma),
-			powf(0.5,  1.0 / ao_gamma),
-			powf(0.25, 1.0 / ao_gamma)
-		};
-
-		//calculate table index for gamma space multiplier
-		ambient_occlusion -= 5;
+		float light_amount; // gamma space multiplier
+		if (ambient_occlusion == 5)
+			light_amount = std::pow(0.75f, data->m_ao_gamma_inv);
+		else if (ambient_occlusion == 6)
+			light_amount = std::pow(0.75f, data->m_ao_gamma_inv);
+		else // >= 7
+			light_amount = std::pow(0.25f, data->m_ao_gamma_inv);
 
 		if (!skip_ambient_occlusion_day)
 			light_day = rangelim(core::round32(
-					light_day * light_amount[ambient_occlusion]), 0, 255);
+					light_day * light_amount), 0, 255);
 		if (!skip_ambient_occlusion_night)
 			light_night = rangelim(core::round32(
-					light_night * light_amount[ambient_occlusion]), 0, 255);
+					light_night * light_amount), 0, 255);
 	}
 
 	return light_day | (light_night << 8);

src/client/mapblock_mesh.h

@@ -45,6 +45,7 @@ struct MeshMakeData
 
 	// relative to blockpos
 	v3s16 m_crack_pos_relative = v3s16(-1337,-1337,-1337);
+	float m_ao_gamma_inv = 0.0f;
 	bool m_generate_minimap = false;
 	bool m_smooth_lighting = false;
 	bool m_enable_water_reflections = false;

src/client/mesh_generator_thread.cpp

@@ -236,6 +236,12 @@ void MeshUpdateQueue::fillDataFromMapBlocks(QueuedMeshUpdate *q)
 	}
 
 	data->setCrack(q->crack_level, q->crack_pos);
+
+	// Changes to static lighting will cause a re-mesh of the entire map, so
+	// this doesn't need an update mechanism.
+	float ao_gamma = m_client->getCommittedStaticLighting().ao_gamma;
+	data->m_ao_gamma_inv = ao_gamma == 0.0f ? 0.0f : (1.0f / ao_gamma);
+
 	data->m_generate_minimap = !!m_client->getMinimap();
 	data->m_smooth_lighting = m_cache_smooth_lighting;
 	data->m_enable_water_reflections = m_cache_enable_water_reflections;

src/defaultsettings.cpp

@@ -295,7 +295,6 @@ void set_default_settings()
 	settings->setDefault("hud_hotbar_max_width", "1.0");
 	settings->setDefault("enable_local_map_saving", "false");
 	settings->setDefault("show_entity_selectionbox", "false");
-	settings->setDefault("ambient_occlusion_gamma", "1.8");
 	settings->setDefault("arm_inertia", "true");
 	settings->setDefault("show_nametag_backgrounds", "true");
 	settings->setDefault("show_block_bounds_radius_near", "4");

src/lighting.cpp

@@ -8,7 +8,8 @@
 
 bool StaticLighting::operator==(const StaticLighting &other) const
 {
-	if (light_curve_set != other.light_curve_set)
+	if (light_curve_set != other.light_curve_set ||
+		ao_gamma != other.ao_gamma)
 		return false;
 	if (light_curve_set && memcmp(light_curve, other.light_curve, sizeof(light_curve)) != 0)
 		return false;

src/lighting.h

@@ -50,9 +50,13 @@ struct StaticLighting
 {
 	static constexpr int LIGHT_CURVE_SIZE = 16;
 
+	// Light curve: used to decode map light (0-15) into intensity (0-255)
 	bool light_curve_set = false;
 	u8 light_curve[LIGHT_CURVE_SIZE];
 
+	// Ambient occlusion gamma
+	float ao_gamma = 1.8f;
+
 	bool operator==(const StaticLighting &other) const;
 	bool operator!=(const StaticLighting &other) const {
 		return !(*this == other);

src/network/clientpackethandler.cpp

@@ -1841,6 +1841,7 @@ void Client::handleCommand_SetLighting(NetworkPacket *pkt)
 	*pkt >> s.light_curve_set;
 	if (s.light_curve_set)
 		pkt->readRawString(reinterpret_cast<char*>(s.light_curve), sizeof(s.light_curve));
+	*pkt >> s.ao_gamma;
 
 #undef IF_DONE_RETURN
 }

src/script/lua_api/l_object.cpp

@@ -2735,6 +2735,7 @@ int ObjectRef::l_set_lighting(lua_State *L)
 			s.light_curve_set = any;
 		}
 		lua_pop(L, 1); // light_curve
+		getfloatfield(L, -1, "ao_gamma", s.ao_gamma);
 	}
 	lua_pop(L, 1); // static
 
@@ -2803,6 +2804,8 @@ int ObjectRef::l_get_lighting(lua_State *L)
 		}
 	}
 	lua_setfield(L, -2, "light_curve");
+	lua_pushnumber(L, s.ao_gamma);
+	lua_setfield(L, -2, "ao_gamma");
 	lua_setfield(L, -2, "static");
 
 	return 1;