default and instance-specific mass

4 files changed, 34 insertions, 4 deletions

diff --git a/src/components.hpp b/src/components.hpp
index a8b4e88..cd79e4b 100644
--- a/src/components.hpp
+++ b/src/components.hpp
@@ -55,6 +55,7 @@ struct CompGrBinds {
 struct InstPos {
 	btTransform posRot;
 	btVector3 scale;
+	btScalar mass;
 };
 struct InstBt {
 	btDefaultMotionState *motionState;
diff --git a/src/ecs.cpp b/src/ecs.cpp
index 654bc71..ee9201e 100644
--- a/src/ecs.cpp
+++ b/src/ecs.cpp
@@ -412,6 +412,9 @@ void ECS_UpdateInstance(EntityHandle entHandle, const InstPos &instPos, bool ove
 	auto *inst = &Comp_Instance_BucketContainer.buckets[b].instances[i];
 
 	if (BtDynamicsWorld && overridePhysics) {
+		btVector3 localInertia(0, 0, 0);
+		inst->bt.rigidBody->getCollisionShape()->calculateLocalInertia(instPos.mass, localInertia);
+		inst->bt.rigidBody->setMassProps(instPos.mass, localInertia);
 		inst->bt.rigidBody->setWorldTransform(instPos.posRot);
 		inst->bt.rigidBody->getCollisionShape()->setLocalScaling(instPos.scale);
 		inst->bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
diff --git a/src/entities.hpp b/src/entities.hpp
index f45f7d3..e16097c 100644
--- a/src/entities.hpp
+++ b/src/entities.hpp
@@ -33,6 +33,7 @@ struct EntityType {
 	} Importer_GLTF;
 	struct {
 		btCollisionShape *shape = nullptr;
+		btScalar startingMass = 1.f;
 	} bt;
 };
 extern DynArray<EntityType> GlobalEntityTypes;
diff --git a/src/game.cpp b/src/game.cpp
index 6cde580..3ff3948 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -19,6 +19,7 @@
 #include <cstring>
 #include <glm/gtc/quaternion.hpp>
 #include <iomanip>
+#include <ostream>
 
 const uint64_t consoleBufferCount = 30;
 const uint64_t consoleLineLength = 128;
@@ -77,12 +78,14 @@ const char *PKE_FILE_ENTITY_TYPE_IMPORTER_GLTF_ACCESSOR_INDEX_VERTEX = "Importer
 const char *PKE_FILE_ENTITY_TYPE_IMPORTER_GLTF_ACCESSOR_INDEX_NORMAL = "Importer_GLTF::AccessorIndexNormal: ";
 const char *PKE_FILE_ENTITY_TYPE_IMPORTER_GLTF_ACCESSOR_INDEX_UV = "Importer_GLTF::AccessorIndexUV: ";
 const char *PKE_FILE_ENTITY_TYPE_IMPORTER_GLTF_ACCESSOR_INDEX_INDEX = "Importer_GLTF::AccessorIndexIndex: ";
+const char *PKE_FILE_ENTITY_TYPE_PHYSICS_STARTING_MASS = "BT::StartingMass: ";
 
 const char *PKE_FILE_INSTANCE_ENTITY_HANDLE = "EntityHandle: ";
 const char *PKE_FILE_INSTANCE_ENTITY_TYPE_CODE = "EntityTypeCode: ";
 const char *PKE_FILE_INSTANCE_POS_POS = "InstPos::Pos: ";
 const char *PKE_FILE_INSTANCE_POS_ROT = "InstPos::Rot: ";
 const char *PKE_FILE_INSTANCE_POS_SCALE = "InstPos::Scale: ";
+const char *PKE_FILE_INSTANCE_MASS = "InstPos::Mass: ";
 
 char consoleBuffer[consoleBufferCount][consoleLineLength];
 long consoleBufferIndex = 0;
@@ -117,6 +120,9 @@ void SerializeEntityType(std::ofstream &stream, const EntityType &et) {
 		stream << PKE_FILE_ENTITY_TYPE_IMPORTER_GLTF_ACCESSOR_INDEX_UV << et.Importer_GLTF.AccessorIndexUV << std::endl;
 	if (et.Importer_GLTF.AccessorIndexIndex != e.Importer_GLTF.AccessorIndexIndex)
 		stream << PKE_FILE_ENTITY_TYPE_IMPORTER_GLTF_ACCESSOR_INDEX_INDEX << et.Importer_GLTF.AccessorIndexIndex << std::endl;
+	if (et.bt.startingMass != e.bt.startingMass) {
+		stream << PKE_FILE_ENTITY_TYPE_PHYSICS_STARTING_MASS << et.bt.startingMass << std::endl;
+	}
 }
 
 void SerializeInstance(std::ofstream &stream, const CompInstance &comp) {
@@ -142,6 +148,7 @@ void SerializeInstance(std::ofstream &stream, const CompInstance &comp) {
 	btTransform trans;
 	comp.bt.motionState->getWorldTransform(trans);
 	btVector3 scale = comp.bt.rigidBody->getCollisionShape()->getLocalScaling();
+	btScalar mass = comp.bt.rigidBody->getMass();
 	if (trans != baseInst.posRot) {
 		btVector3 pos = trans.getOrigin();
 		btQuaternion rot = trans.getRotation();
@@ -160,6 +167,9 @@ void SerializeInstance(std::ofstream &stream, const CompInstance &comp) {
 			<< std::setw(10) << scale[0] << ","
 			<< std::setw(10) << scale[1] << ","
 			<< std::setw(10) << scale[2] << "]" << std::endl;
+	if (mass != baseInst.mass) {
+		stream << PKE_FILE_INSTANCE_MASS << mass << std::endl;
+	}
 }
 
 void ParseEntityType(std::ifstream &stream) {
@@ -240,6 +250,12 @@ void ParseEntityType(std::ifstream &stream) {
 			assert(result == STR2NUM_ERROR::SUCCESS);
 			continue;
 		}
+		if (strstr(readLine, PKE_FILE_ENTITY_TYPE_PHYSICS_STARTING_MASS)) {
+			uint64_t prefixLen = strlen(PKE_FILE_ENTITY_TYPE_PHYSICS_STARTING_MASS);
+			STR2NUM_ERROR result = str2num(et.bt.startingMass, readLine + prefixLen);
+			assert(result == STR2NUM_ERROR::SUCCESS);
+			continue;
+		}
 	}
 }
 
@@ -249,6 +265,7 @@ void ParseInstance(std::ifstream &stream) {
 	instPos.posRot = btTransform{};
 	instPos.posRot.setIdentity();
 	instPos.scale = btVector3(1, 1, 1);
+	instPos.mass = 1.f;
 	char entTypeCode[21];
 	memset(reinterpret_cast<void *>(entTypeCode), '\0', 21);
 	while (stream.getline(readLine, readLineLength)) {
@@ -267,11 +284,11 @@ void ParseInstance(std::ifstream &stream) {
 			auto &compInst = ECS_CreateInstance(entityHandle, et.entityHandle);
 
 			btVector3 localInertia(0, 0, 0);
-			et.bt.shape->calculateLocalInertia(btScalar(1.f), localInertia);
+			et.bt.shape->calculateLocalInertia(instPos.mass, localInertia);
 			compInst.bt.motionState = Pke_New<btDefaultMotionState>(MemBkt_Bullet);
 			new (compInst.bt.motionState) btDefaultMotionState(instPos.posRot);
 			compInst.bt.rigidBody = Pke_New<btRigidBody>(MemBkt_Bullet);
-			new (compInst.bt.rigidBody) btRigidBody(btScalar(1.f), compInst.bt.motionState, et.bt.shape, localInertia);
+			new (compInst.bt.rigidBody) btRigidBody(instPos.mass, compInst.bt.motionState, et.bt.shape, localInertia);
 			compInst.bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
 			compInst.bt.rigidBody->setAngularVelocity(btVector3(0,0,0));
 			compInst.bt.rigidBody->getCollisionShape()->setLocalScaling(instPos.scale);
@@ -342,6 +359,12 @@ void ParseInstance(std::ifstream &stream) {
 			} while (*pEnd != ']');
 			continue;
 		}
+		if (strstr(readLine, PKE_FILE_INSTANCE_MASS)) {
+			uint64_t prefixLen = strlen(PKE_FILE_INSTANCE_MASS);
+			STR2NUM_ERROR result = str2num(instPos.mass, readLine + prefixLen);
+			assert(result == STR2NUM_ERROR::SUCCESS);
+			continue;
+		}
 	}
 }
 
@@ -459,13 +482,13 @@ void Game_Tick(double delta) {
 		auto &compInst = ECS_CreateInstance(newEntity, createInfo.entityTypeEntityHandle);
 
 		btVector3 localInertia(0, 0, 0);
-		et.bt.shape->calculateLocalInertia(btScalar(1.f), localInertia);
+		et.bt.shape->calculateLocalInertia(et.bt.startingMass, localInertia);
 		btTransform posRot{};
 		posRot.setIdentity();
 		compInst.bt.motionState = Pke_New<btDefaultMotionState>(MemBkt_Bullet);
 		new (compInst.bt.motionState) btDefaultMotionState(posRot);
 		compInst.bt.rigidBody = Pke_New<btRigidBody>(MemBkt_Bullet);
-		new (compInst.bt.rigidBody) btRigidBody(btScalar(1.f), compInst.bt.motionState, et.bt.shape, localInertia);
+		new (compInst.bt.rigidBody) btRigidBody(et.bt.startingMass, compInst.bt.motionState, et.bt.shape, localInertia);
 		compInst.bt.rigidBody->setLinearVelocity(btVector3(0,0,0));
 		compInst.bt.rigidBody->setAngularVelocity(btVector3(0,0,0));
 		compInst.bt.rigidBody->getCollisionShape()->setLocalScaling(btVector3(1, 1, 1));
@@ -758,6 +781,7 @@ void RecordImGuiModalCreateEntityType() {
 		ImGui::InputScalar("GLTF Import Index - Normal", ImGuiDataType_S16, &entityTypeToCreate->Importer_GLTF.AccessorIndexNormal);
 		ImGui::InputScalar("GLTF Import Index - UV", ImGuiDataType_S16, &entityTypeToCreate->Importer_GLTF.AccessorIndexUV);
 		ImGui::InputScalar("GLTF Import Index - Index", ImGuiDataType_S16, &entityTypeToCreate->Importer_GLTF.AccessorIndexIndex);
+		ImGui::InputFloat("Physics - Mass", &entityTypeToCreate->bt.startingMass);
 
 		ImGui::Separator();
 
@@ -871,6 +895,7 @@ void RecordImGui_CompInstPos(bool readonly, CompInstance *component) {
 	changed = ImGui::InputScalarN("pos", ImGuiDataType_Float, &pos, 3, nullptr, nullptr, nullptr, inputTextFlags) || changed;
 	changed = ImGui::InputScalarN("rot", ImGuiDataType_Float, &rot, 4, nullptr, nullptr, nullptr, inputTextFlags) || changed;
 	changed = ImGui::InputScalarN("scale", ImGuiDataType_Float, &instPos.scale, 3, nullptr, nullptr, nullptr, inputTextFlags) || changed;
+	changed = ImGui::InputFloat("mass", &instPos.mass, 0.0, 0.0, "%.3f", inputTextFlags) || changed;
 
 	if (changed) {
 		instPos.posRot.setOrigin(pos);