Starting basic physics, nothing fancy

src/dawn/physics/3d/AABB3D.hpp

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+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include "dawnlibs.hpp"
+
+namespace Dawn {
+  struct AABB3D {
+    glm::vec3 min;
+    glm::vec3 max;
+  };
+}

src/dawn/physics/3d/CMakeLists.txt

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+# Copyright (c) 2023 Dominic Masters
+# 
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+# Sources
+target_sources(${DAWN_TARGET_NAME}
+  PRIVATE
+    Ray3D.cpp
+)

src/dawn/physics/3d/PhysicsSphere.hpp

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+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include "dawnlibs.hpp"
+
+namespace Dawn {
+  struct PhysicsSphere {
+    glm::vec3 center;
+    float_t radius;
+  };
+}

src/dawn/physics/3d/PhysicsTriangle.hpp

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+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include "dawnlibs.hpp"
+
+namespace Dawn {
+  struct PhysicsTriangle {
+    glm::vec3 v0;
+    glm::vec3 v1;
+    glm::vec3 v2;
+  };
+}

src/dawn/physics/3d/Ray3D.cpp

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+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#include "Ray3D.hpp"
+
+using namespace Dawn;
+
+struct Ray3D {
+  glm::vec3 origin;
+  glm::vec3 direction;
+};
+
+struct PhysicsSphere {
+  glm::vec3 center;
+  float_t radius;
+};
+
+bool_t Dawn::raytestSphere(
+  struct Ray3D ray,
+  struct PhysicsSphere sphere,
+  glm::vec3 *hit,
+  glm::vec3 *normal
+) {
+  glm::vec3 h, n;
+  auto result = glm::intersectRaySphere(
+    ray.origin, ray.direction,
+    sphere.center, sphere.radius,
+    h, n
+  );
+
+  if(hit != nullptr) *hit = h;
+  if(normal != nullptr) *normal = n;
+
+  return result;
+}
+
+bool_t Dawn::raytestTriangle(
+  struct Ray3D ray,
+  struct PhysicsTriangle triangle,
+  glm::vec2 *hit,
+  float_t *distance
+) {
+  glm::vec2 h;
+  float_t d;
+  auto result = glm::intersectRayTriangle(
+    ray.origin, ray.direction,
+    triangle.v0, triangle.v1, triangle.v2,
+    h, d
+  );
+  if(hit != nullptr) *hit = h;
+  if(distance != nullptr) *distance = d;
+  return result;
+}
+
+bool_t Dawn::raytestAABB(
+  struct Ray3D ray,
+  struct AABB3D box,
+  glm::vec3 *point,
+  glm::vec3 *normal,
+  float_t *distance
+) {
+  // Compute the inverse direction of the ray, for numerical stability
+  glm::vec3 invDir(1.0f / ray.direction.x, 1.0f / ray.direction.y, 1.0f / ray.direction.z);
+
+  // Compute the t-values for the two intersection candidates
+  glm::vec3 tMin = (box.min - ray.origin) * invDir;
+  glm::vec3 tMax = (box.max - ray.origin) * invDir;
+
+  // Make sure tMin is less than or equal to tMax for all components
+  glm::vec3 t1 = glm::min(tMin, tMax);
+  glm::vec3 t2 = glm::max(tMin, tMax);
+  float tNear = glm::compMax(t1);
+  float tFar = glm::compMin(t2);
+
+  // If tNear is greater than or equal to tFar, there is no intersection
+  if (tNear >= tFar) return false;
+
+  // If tFar is negative, the ray is pointing away from the box
+  if(tFar < 0.0f) return false;
+
+  // Compute the hit point and normal
+  glm::vec3 hitPoint = ray.origin + tNear * ray.direction;
+
+  if(point != nullptr) *point = hitPoint;
+  if(distance != nullptr) *distance = tNear;
+  if(normal != nullptr) {
+    if (hitPoint.x == box.min.x) {
+      *normal = glm::vec3(-1, 0, 0);
+    } else if (hitPoint.x == box.max.x) {
+      *normal = glm::vec3(1, 0, 0);
+    } else if (hitPoint.y == box.min.y) {
+      *normal = glm::vec3(0, -1, 0);
+    } else if (hitPoint.y == box.max.y) {
+      *normal = glm::vec3(0, 1, 0);
+    } else if (hitPoint.z == box.min.z) {
+      *normal = glm::vec3(0, 0, -1);
+    } else if (hitPoint.z == box.max.z) {
+      *normal = glm::vec3(0, 0, 1);
+    }
+  }
+
+  // The ray intersects the box
+  return true;
+}

src/dawn/physics/3d/Ray3D.hpp

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+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include "dawnlibs.hpp"
+#include "assert/assert.hpp"
+#include "PhysicsTriangle.hpp"
+#include "PhysicsSphere.hpp"
+#include "AABB3D.hpp"
+
+namespace Dawn {
+  struct Ray3D {
+    glm::vec3 origin;
+    glm::vec3 direction;
+  };
+
+  bool_t raytestSphere(
+    struct Ray3D ray,
+    struct PhysicsSphere sphere,
+    glm::vec3 *hit,
+    glm::vec3 *normal
+  );
+
+  bool_t raytestTriangle(
+    struct Ray3D ray,
+    struct PhysicsTriangle triangle,
+    glm::vec2 *hit,
+    float_t *distance
+  );
+
+  bool_t raytestAABB(
+    struct Ray3D ray,
+    struct AABB3D box,
+    glm::vec3 *point,
+    glm::vec3 *normal,
+    float_t *distance
+  );
+}

src/dawn/physics/CMakeLists.txt

@@ -1,10 +1,13 @@
-# Copyright (c) 2023 Dominic Masters
-# 
-# This software is released under the MIT License.
-# https://opensource.org/licenses/MIT
-
-# Sources
-target_sources(${DAWN_TARGET_NAME}
-PRIVATE
-  PhysicsManager.cpp
-)
+# Copyright (c) 2023 Dominic Masters
+# 
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+# Sources
+target_sources(${DAWN_TARGET_NAME}
+  PRIVATE
+    PhysicsManager.cpp
+)
+
+# Subdirs
+add_subdirectory(3d)