Smooth day-night transitions

src/camera.cpp

@@ -544,7 +544,7 @@ void Camera::wield(const ItemStack &item)
 void Camera::drawWieldedTool()
 {
 	// Set vertex colors of wield mesh according to light level
-	u8 li = decode_light(m_wieldlight);
+	u8 li = m_wieldlight;
 	video::SColor color(255,li,li,li);
 	setMeshColor(m_wieldnode->getMesh(), color);
 

src/daynightratio.h

@@ -20,23 +20,49 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef DAYNIGHTRATIO_HEADER
 #define DAYNIGHTRATIO_HEADER
 
-inline u32 time_to_daynight_ratio(u32 time_of_day)
+inline u32 time_to_daynight_ratio(float time_of_day, bool smooth)
 {
-	s32 t = time_of_day%24000;
-	if(t < 4500 || t >= 19500)
-		return 150;
-	else if(t < 4750 || t >= 19250)
-		return 250;
-	else if(t < 5000 || t >= 19000)
-		return 350;
-	else if(t < 5250 || t >= 18750)
-		return 500;
-	else if(t < 5500 || t >= 18500)
-		return 675;
-	else if(t < 5750 || t >= 18250)
-		return 875;
-	else
+	float t = time_of_day;
+	if(t < 0)
+		t += ((int)(-t)/24000)*24000;
+	if(t >= 24000)
+		t -= ((int)(t)/24000)*24000;
+	if(t > 12000)
+		t = 24000 - t;
+	float values[][2] = {
+		{4250+125, 150},
+		{4500+125, 150},
+		{4750+125, 250},
+		{5000+125, 350},
+		{5250+125, 500},
+		{5500+125, 675},
+		{5750+125, 875},
+		{6000+125, 1000},
+		{6250+125, 1000},
+	};
+	if(!smooth){
+		float lastt = values[0][0];
+		for(u32 i=1; i<sizeof(values)/sizeof(*values); i++){
+			float t0 = values[i][0];
+			float switch_t = (t0 + lastt) / 2;
+			lastt = t0;
+			if(switch_t <= t)
+				continue;
+			return values[i][1];
+		}
 		return 1000;
+	} else {
+		for(u32 i=0; i<sizeof(values)/sizeof(*values); i++){
+			if(values[i][0] <= t)
+				continue;
+			if(i == 0)
+				return values[i][1];
+			float td0 = values[i][0] - values[i-1][0];
+			float f = (t - values[i-1][0]) / td0;
+			return f * values[i][1] + (1.0 - f) * values[i-1][1];
+		}
+		return 1000;
+	}
 }
 
 #endif

src/environment.cpp

@@ -203,7 +203,8 @@ void Environment::printPlayers(std::ostream &o)
 
 u32 Environment::getDayNightRatio()
 {
-	return time_to_daynight_ratio(m_time_of_day);
+	bool smooth = (g_settings->getS32("enable_shaders") != 0);
+	return time_to_daynight_ratio(m_time_of_day_f*24000, smooth);
 }
 
 void Environment::stepTimeOfDay(float dtime)
@@ -2132,15 +2133,15 @@ void ClientEnvironment::step(float dtime)
 		}
 		
 		// Update lighting on all players on client
-		u8 light = LIGHT_MAX;
+		float light = 1.0;
 		try{
 			// Get node at head
 			v3s16 p = player->getLightPosition();
 			MapNode n = m_map->getNode(p);
-			light = n.getLightBlend(getDayNightRatio(), m_gamedef->ndef());
+			light = n.getLightBlendF1((float)getDayNightRatio()/1000, m_gamedef->ndef());
 		}
 		catch(InvalidPositionException &e){
-			light = blend_light(getDayNightRatio(), LIGHT_SUN, 0);
+			light = blend_light_f1((float)getDayNightRatio()/1000, LIGHT_SUN, 0);
 		}
 		player->light = light;
 	}

src/game.cpp

@@ -2505,8 +2505,7 @@ void the_game(
 			Calculate general brightness
 		*/
 		u32 daynight_ratio = client.getEnv().getDayNightRatio();
-		float time_brightness = (float)decode_light(
-				(daynight_ratio * LIGHT_SUN) / 1000) / 255.0;
+		float time_brightness = decode_light_f((float)daynight_ratio/1000.0);
 		float direct_brightness = 0;
 		bool sunlight_seen = false;
 		if(g_settings->getBool("free_move")){

src/light.h

@@ -85,6 +85,24 @@ inline u8 decode_light(u8 light)
 	return light_decode_table[light];
 }
 
+// 0.0 <= light <= 1.0
+// 0.0 <= return value <= 1.0
+inline float decode_light_f(float light_f)
+{
+	s32 i = (u32)(light_f * LIGHT_MAX + 0.5);
+
+	if(i <= 0)
+		return (float)light_decode_table[0] / 255.0;
+	if(i >= LIGHT_MAX)
+		return (float)light_decode_table[LIGHT_MAX] / 255.0;
+
+	float v1 = (float)light_decode_table[i-1] / 255.0;
+	float v2 = (float)light_decode_table[i] / 255.0;
+	float f0 = (float)i - 0.5;
+	float f = light_f * LIGHT_MAX - f0;
+	return f * v2 + (1.0 - f) * v1;
+}
+
 // 0 <= daylight_factor <= 1000
 // 0 <= lightday, lightnight <= LIGHT_SUN
 // 0 <= return value <= LIGHT_SUN
@@ -97,5 +115,15 @@ inline u8 blend_light(u32 daylight_factor, u8 lightday, u8 lightnight)
 	return l;
 }
 
+// 0.0 <= daylight_factor <= 1.0
+// 0 <= lightday, lightnight <= LIGHT_SUN
+// 0 <= return value <= 255
+inline u8 blend_light_f1(float daylight_factor, u8 lightday, u8 lightnight)
+{
+	u8 l = ((daylight_factor * decode_light(lightday) +
+			(1.0-daylight_factor) * decode_light(lightnight)));
+	return l;
+}
+
 #endif
 

src/mapnode.h

@@ -163,6 +163,16 @@ struct MapNode
 		return blend_light(daylight_factor, lightday, lightnight);
 	}
 
+	// 0.0 <= daylight_factor <= 1.0
+	// 0 <= return value <= LIGHT_SUN
+	u8 getLightBlendF1(float daylight_factor, INodeDefManager *nodemgr) const
+	{
+		u8 lightday = 0;
+		u8 lightnight = 0;
+		getLightBanks(lightday, lightnight, nodemgr);
+		return blend_light_f1(daylight_factor, lightday, lightnight);
+	}
+
 	u8 getFaceDir(INodeDefManager *nodemgr) const;
 	u8 getWallMounted(INodeDefManager *nodemgr) const;
 	v3s16 getWallMountedDir(INodeDefManager *nodemgr) const;

src/scriptapi.cpp

@@ -3604,7 +3604,7 @@ private:
 		if(lua_isnumber(L, 3))
 			time_of_day = 24000.0 * lua_tonumber(L, 3);
 		time_of_day %= 24000;
-		u32 dnr = time_to_daynight_ratio(time_of_day);
+		u32 dnr = time_to_daynight_ratio(time_of_day, true);
 		MapNode n = env->getMap().getNodeNoEx(pos);
 		try{
 			MapNode n = env->getMap().getNode(pos);