Relatively snappy object-ground collision detection

data/mods/default/init.lua

@@ -651,8 +651,7 @@ end
 
 local TNT = {
 	-- Static definition
-	-- Maybe handle gravity and collision this way? dunno
-	-- physical = true,
+	physical = true, -- Collides with things
 	-- weight = 5,
 	collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
 	visual = "cube",
@@ -662,17 +661,14 @@ local TNT = {
 	-- Initial value for our timer
 	timer = 0,
 	-- Number of punches required to defuse
-	health = 3,
-	-- List names of state variables, for serializing object state
-	-- (NOTE: not implemented and implementation will not be like this)
-	-- state_variables = {"timer"},
+	health = 1,
 }
 
 -- Called when a TNT object is created
 function TNT:on_activate(staticdata)
 	print("TNT:on_activate()")
-	self.object:setvelocity({x=0, y=1, z=0})
-	self.object:setacceleration({x=0, y=-5, z=0})
+	self.object:setvelocity({x=0, y=2, z=0})
+	self.object:setacceleration({x=0, y=-10, z=0})
 end
 
 -- Called periodically
@@ -709,6 +705,7 @@ minetest.register_entity("TNT", TNT)
 function register_falling_node(nodename, texture)
 	minetest.register_entity("falling_"..nodename, {
 		-- Static definition
+		physical = true,
 		collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
 		visual = "cube",
 		textures = {texture,texture,texture,texture,texture,texture},
@@ -719,7 +716,7 @@ function register_falling_node(nodename, texture)
 			self.object:setacceleration({x=0, y=-10, z=0})
 			-- Turn to actual sand when collides to ground or just move
 			pos = self.object:getpos()
-			bcp = {x=pos.x, y=pos.y-0.5, z=pos.z} -- Position of bottom center point
+			bcp = {x=pos.x, y=pos.y-0.6, z=pos.z} -- Position of bottom center point
 			bcn = minetest.env:get_node(bcp)
 			if bcn.name ~= "air" then
 				-- Turn to a sand node

src/collision.cpp

@@ -177,6 +177,7 @@ collisionMoveResult collisionMoveSimple(Map *map, IGameDef *gamedef,
 				speed_f -= speed_f.dotProduct(dirs[i]) * dirs[i];
 				pos_f -= pos_f.dotProduct(dirs[i]) * dirs[i];
 				pos_f += oldpos_f.dotProduct(dirs[i]) * dirs[i];
+				result.collides = true;
 			}
 		
 		}
@@ -232,6 +233,8 @@ collisionMoveResult collisionMovePrecise(Map *map, IGameDef *gamedef,
 
 		if(result.touching_ground)
 			final_result.touching_ground = true;
+		if(result.collides)
+			final_result.collides = true;
 	}
 	while(dtime_downcount > 0.001);
 		

src/collision.h

@@ -28,9 +28,11 @@ class IGameDef;
 struct collisionMoveResult
 {
 	bool touching_ground;
+	bool collides;
 
 	collisionMoveResult():
-		touching_ground(false)
+		touching_ground(false),
+		collides(false)
 	{}
 };
 

src/content_cao.cpp

@@ -1457,11 +1457,34 @@ void LuaEntityCAO::updateNodePos()
 
 void LuaEntityCAO::step(float dtime, ClientEnvironment *env)
 {
+	if(m_prop->physical){
+		core::aabbox3d<f32> box = m_prop->collisionbox;
+		box.MinEdge *= BS;
+		box.MaxEdge *= BS;
+		collisionMoveResult moveresult;
+		f32 pos_max_d = BS*0.25; // Distance per iteration
+		v3f p_pos = m_position;
+		v3f p_velocity = m_velocity;
+		IGameDef *gamedef = env->getGameDef();
+		moveresult = collisionMovePrecise(&env->getMap(), gamedef,
+				pos_max_d, box, dtime, p_pos, p_velocity);
+		// Apply results
+		m_position = p_pos;
+		m_velocity = p_velocity;
+		
+		bool is_end_position = moveresult.collides;
+		pos_translator.update(m_position, is_end_position, dtime);
+		pos_translator.translate(dtime);
+		updateNodePos();
+
+		m_velocity += dtime * m_acceleration;
+	} else {
 		m_position += dtime * m_velocity + 0.5 * dtime * dtime * m_acceleration;
 		m_velocity += dtime * m_acceleration;
 		pos_translator.update(m_position, pos_translator.aim_is_end, pos_translator.anim_time);
 		pos_translator.translate(dtime);
 		updateNodePos();
+	}
 }
 
 void LuaEntityCAO::processMessage(const std::string &data)
@@ -1487,10 +1510,12 @@ void LuaEntityCAO::processMessage(const std::string &data)
 		// update_interval
 		float update_interval = readF1000(is);
 		
-		if(do_interpolate)
+		if(do_interpolate){
+			if(!m_prop->physical)
 				pos_translator.update(m_position, is_end_position, update_interval);
-		else
+		} else {
 			pos_translator.init(m_position);
+		}
 		updateNodePos();
 	}
 }

src/content_cao.h

@@ -92,7 +92,7 @@ struct SmoothTranslator
 		if(anim_time > 0.001)
 			moveratio = anim_time_counter / anim_time;
 		// Move a bit less than should, to avoid oscillation
-		moveratio = moveratio * 0.5;
+		moveratio = moveratio * 0.8;
 		float move_end = 1.5;
 		if(aim_is_end)
 			move_end = 1.0;

src/content_sao.cpp

@@ -1555,6 +1555,7 @@ LuaEntitySAO::LuaEntitySAO(ServerEnvironment *env, v3f pos,
 	m_yaw(0),
 	m_last_sent_yaw(0),
 	m_last_sent_position(0,0,0),
+	m_last_sent_velocity(0,0,0),
 	m_last_sent_position_timer(0),
 	m_last_sent_move_precision(0)
 {
@@ -1612,8 +1613,27 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 {
 	m_last_sent_position_timer += dtime;
 	
-	m_base_position += dtime * m_velocity + 0.5 * dtime * dtime * m_acceleration;
+	if(m_prop->physical){
+		core::aabbox3d<f32> box = m_prop->collisionbox;
+		box.MinEdge *= BS;
+		box.MaxEdge *= BS;
+		collisionMoveResult moveresult;
+		f32 pos_max_d = BS*0.25; // Distance per iteration
+		v3f p_pos = getBasePosition();
+		v3f p_velocity = m_velocity;
+		IGameDef *gamedef = m_env->getGameDef();
+		moveresult = collisionMovePrecise(&m_env->getMap(), gamedef,
+				pos_max_d, box, dtime, p_pos, p_velocity);
+		// Apply results
+		setBasePosition(p_pos);
+		m_velocity = p_velocity;
+
 		m_velocity += dtime * m_acceleration;
+	} else {
+		m_base_position += dtime * m_velocity + 0.5 * dtime
+				* dtime * m_acceleration;
+		m_velocity += dtime * m_acceleration;
+	}
 
 	if(m_registered){
 		lua_State *L = m_env->getLua();
@@ -1623,7 +1643,7 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 	if(send_recommended == false)
 		return;
 	
-	// TODO: force send when velocity/acceleration changes enough
+	// TODO: force send when acceleration changes enough?
 	float minchange = 0.2*BS;
 	if(m_last_sent_position_timer > 1.0){
 		minchange = 0.01*BS;
@@ -1632,7 +1652,9 @@ void LuaEntitySAO::step(float dtime, bool send_recommended)
 	}
 	float move_d = m_base_position.getDistanceFrom(m_last_sent_position);
 	move_d += m_last_sent_move_precision;
-	if(move_d > minchange || fabs(m_yaw - m_last_sent_yaw) > 1.0){
+	float vel_d = m_velocity.getDistanceFrom(m_last_sent_velocity);
+	if(move_d > minchange || vel_d > minchange ||
+			fabs(m_yaw - m_last_sent_yaw) > 1.0){
 		sendPosition(true, false);
 	}
 }
@@ -1675,6 +1697,7 @@ std::string LuaEntitySAO::getStaticData()
 
 InventoryItem* LuaEntitySAO::createPickedUpItem()
 {
+	// TODO: Ask item from scriptapi
 	std::istringstream is("CraftItem testobject1 1", std::ios_base::binary);
 	IGameDef *gamedef = m_env->getGameDef();
 	InventoryItem *item = InventoryItem::deSerialize(is, gamedef);
@@ -1732,7 +1755,7 @@ void LuaEntitySAO::sendPosition(bool do_interpolate, bool is_movement_end)
 	m_last_sent_position_timer = 0;
 	m_last_sent_yaw = m_yaw;
 	m_last_sent_position = m_base_position;
-	//m_last_sent_velocity = m_velocity;
+	m_last_sent_velocity = m_velocity;
 	//m_last_sent_acceleration = m_acceleration;
 
 	float update_interval = m_env->getSendRecommendedInterval();

src/content_sao.h

@@ -231,6 +231,7 @@ private:
 	float m_yaw;
 	float m_last_sent_yaw;
 	v3f m_last_sent_position;
+	v3f m_last_sent_velocity;
 	float m_last_sent_position_timer;
 	float m_last_sent_move_precision;
 };

src/environment.h

@@ -362,14 +362,13 @@ public:
 	~ClientEnvironment();
 
 	Map & getMap()
-	{
-		return *m_map;
-	}
+	{ return *m_map; }
 
 	ClientMap & getClientMap()
-	{
-		return *m_map;
-	}
+	{ return *m_map; }
+
+	IGameDef *getGameDef()
+	{ return m_gamedef; }
 
 	void step(f32 dtime);
 

src/luaentity_common.cpp

@@ -24,7 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
 
 LuaEntityProperties::LuaEntityProperties():
-	physical(true),
+	physical(false),
 	weight(5),
 	collisionbox(-0.5,-0.5,-0.5, 0.5,0.5,0.5),
 	visual("single_sprite")