From f2c808b1235b9d76e4d4753c025f404e7736ca3c Mon Sep 17 00:00:00 2001
From: Jonathan Bradley <jcb@pikum.xyz>
Date: Tue, 31 Oct 2023 12:46:09 -0400
Subject: use model for collision + refactor physics init and rigidbody
 creation

---
 src/physics.cpp | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 src/physics.cpp

(limited to 'src/physics.cpp')

diff --git a/src/physics.cpp b/src/physics.cpp
new file mode 100644
index 0000000..b8d093d
--- /dev/null
+++ b/src/physics.cpp
@@ -0,0 +1,90 @@
+
+#include "physics.hpp"
+
+#include "dynamic-array.hpp"
+#include "game-settings.hpp"
+
+#include <btBulletDynamicsCommon.h>
+#include <LinearMath/btAlignedAllocator.h>
+
+MemBucket *MemBkt_Bullet = nullptr;
+btDiscreteDynamicsWorld *BtDynamicsWorld = nullptr;
+
+struct AllocedData {
+	void *data;
+	std::size_t size;
+};
+DynArray<AllocedData> *bulletAllocs;
+
+btDefaultCollisionConfiguration *btConfiguration = nullptr;
+btCollisionDispatcher *btDispatcher = nullptr;
+btBroadphaseInterface *btBroadphase = nullptr;
+btConstraintSolver *btSolver = nullptr;
+
+void *pke_btAlignedAllocFunc(size_t size, int alignment) {
+	void *ptr = Pke_New(size, alignment, MemBkt_Bullet);
+	bulletAllocs->Push({ptr, size});
+	return ptr;
+}
+void pke_btAlignedFreeFunc(void *memBlock) {
+	auto &arr = *bulletAllocs;
+	auto count = arr.Count();
+	long index = -1;
+	for (long i = 0; i < count; ++i) {
+		if (arr[i].data == memBlock) {
+			index = i;
+			break;
+		}
+	}
+	assert(index != -1);
+	Pke_Delete(const_cast<void *>(memBlock), arr[index].size, MemBkt_Bullet);
+	bulletAllocs->Remove(index);
+}
+void *pke_btAllocFunc(size_t size) {
+	void *ptr = Pke_New(size, MINIMUM_ALIGNMENT, MemBkt_Bullet);
+	bulletAllocs->Push({ptr, size});
+	return ptr;
+}
+void pke_btFreeFunc(void *memBlock) {
+	auto &arr = *bulletAllocs;
+	auto count = arr.Count();
+	long index = -1;
+	for (long i = 0; i < count; ++i) {
+		if (arr[i].data == memBlock) {
+			index = i;
+			break;
+		}
+	}
+	assert(index != -1);
+	Pke_Delete(const_cast<void *>(memBlock), arr[index].size, MemBkt_Bullet);
+	bulletAllocs->Remove(index);
+}
+
+void Physics_Init() {
+	MemBkt_Bullet = Pke_BeginTransientBucket();
+	bulletAllocs = Pke_New<DynArray<AllocedData>>(MemBkt_Bullet);
+	new (bulletAllocs) DynArray<AllocedData>(MemBkt_Bullet);
+	bulletAllocs->Reserve(1024);
+	btAlignedAllocSetCustom(pke_btAllocFunc, pke_btFreeFunc);
+	btAlignedAllocSetCustomAligned(pke_btAlignedAllocFunc, pke_btAlignedFreeFunc);
+
+	btConfiguration = Pke_New<btDefaultCollisionConfiguration>(MemBkt_Bullet);
+	btDispatcher = Pke_New<btCollisionDispatcher>(MemBkt_Bullet);
+	new (btDispatcher) btCollisionDispatcher(btConfiguration);
+	btBroadphase = Pke_New<btDbvtBroadphase>(MemBkt_Bullet);
+	btSolver = Pke_New<btSequentialImpulseConstraintSolver>(MemBkt_Bullet);
+	BtDynamicsWorld = Pke_New<btDiscreteDynamicsWorld>(MemBkt_Bullet);
+	new (BtDynamicsWorld) btDiscreteDynamicsWorld(btDispatcher, btBroadphase, btSolver, btConfiguration);
+	auto grav = BtDynamicsWorld->getGravity();
+	BtDynamicsWorld->setGravity(btVector3(grav.getX(), grav.getZ(), grav.getY()));
+}
+
+int32_t Physics_Tick(double delta) {
+	if (pkeSettings.isSimulationPaused == true)
+		return 0;
+	return BtDynamicsWorld->stepSimulation(delta, 0);
+}
+
+void Physics_Teardown() {
+	Pke_EndTransientBucket(MemBkt_Bullet);
+}
-- 
cgit v1.2.3