From f651ec76ac6be73387b3967b0d6fffc3d0ea8b49 Mon Sep 17 00:00:00 2001
From: Wellinator <wellcoj@gmail.com>
Date: Mon, 18 Jul 2022 16:11:18 -0300
Subject: [PATCH] feat: implements ray

---
 engine/inc/physics/ray.hpp | 98 ++++++++++++++++++++++++++++++++++++++
 engine/src/physics/ray.cpp | 92 +++++++++++++++++++++++++++++++++++
 2 files changed, 190 insertions(+)
 create mode 100644 engine/inc/physics/ray.hpp
 create mode 100644 engine/src/physics/ray.cpp

diff --git a/engine/inc/physics/ray.hpp b/engine/inc/physics/ray.hpp
new file mode 100644
index 0000000..af6c2ab
--- /dev/null
+++ b/engine/inc/physics/ray.hpp
@@ -0,0 +1,98 @@
+/*
+# ______       ____   ___
+#   |     \/   ____| |___|
+#   |     |   |   \  |   |
+#-----------------------------------------------------------------------
+# Copyright 2020-2022, tyra - https://github.com/h4570/tyra
+# Licenced under Apache License 2.0
+# Wellington Carvalho <wellcoj@gmail.com>
+*/
+
+#include "math/vec4.hpp"
+
+#pragma once
+
+namespace Tyra {
+
+/**
+ * Class for raycasting.
+ */
+class Ray {
+ public:
+  /**
+   * Constructor create a ampty ray
+   *
+   */
+  Ray();
+
+  /**
+   * Constructor
+   * @param origin The origin of the ray
+   * @param direction The direction of the ray (normalized Vec4)
+   *
+   */
+  Ray(Vec4* origin, Vec4* direction);
+  ~Ray();
+
+  Vec4 origin;
+  Vec4 direction;
+
+  // Methods
+
+  /**
+   * Set origin and direction
+   */
+  void set(Vec4 origin, Vec4 direction);
+
+  /**
+   * Set origin only
+   */
+  void setOrigin(Vec4 origin);
+  void setOrigin(const float& t_x, const float& t_y, const float& t_z);
+
+  /**
+   * Set direction only
+   */
+  void setDirection(Vec4 origin);
+  void setDirection(const float& t_x, const float& t_y, const float& t_z);
+
+  /**
+   * Return Vec4 that is a given distance along this Ray
+   * @param t - the distance along the Ray to retrieve a position for.
+   */
+  Vec4 at(float t);
+
+  /**
+   * Return the distance from the Vec4 point to the origin
+   */
+  float distanceToPoint(Vec4 point);
+
+  /**
+   * Returns distance from origin to intersected mesh
+   */
+  float distanceTo(const Vec4& v) const;
+
+  /**
+   * Returns Vec4 of intersection position
+   * @param minCorner - pointer to min corner position. (bottom left)
+   * @param maxCorner - pointer to max corner position. (top right)
+   * @param distance - the box to intersect with.
+   *
+   */
+  u8 intersectBox(Vec4* minCorner, Vec4* maxCorner, float& distance);
+
+  /**
+   * Returns distance from origin to intersected mesh
+   */
+  inline const Vec4 getPosition() { return _position; };
+
+  /**
+   * Returns inverse direction
+   */
+  Vec4 invDir();
+
+ private:
+  Vec4 _position;
+};
+
+}  // namespace Tyra
\ No newline at end of file
diff --git a/engine/src/physics/ray.cpp b/engine/src/physics/ray.cpp
new file mode 100644
index 0000000..e0bd436
--- /dev/null
+++ b/engine/src/physics/ray.cpp
@@ -0,0 +1,92 @@
+/*
+# ______       ____   ___
+#   |     \/   ____| |___|
+#   |     |   |   \  |   |
+#-----------------------------------------------------------------------
+# Copyright 2020-2022, tyra - https://github.com/h4570/tyra
+# Licenced under Apache License 2.0
+# Wellinator Carvalho <wellcoj@gmail.com>
+*/
+
+#include "physics/ray.hpp"
+#include <tamtypes.h>
+#include <math.h>
+#include <algorithm>
+
+namespace Tyra {
+
+Ray::Ray() {}
+Ray::Ray(Vec4* origin, Vec4* direction) {
+  this->origin.set(origin->x, origin->y, origin->z);
+  this->direction.set(direction->x, direction->y, direction->z);
+}
+
+Ray::~Ray() {}
+
+void Ray::set(Vec4 origin, Vec4 direction) {
+  this->origin.set(origin);
+  this->direction.set(direction);
+}
+
+void Ray::setOrigin(Vec4 origin) { this->origin.set(origin); }
+
+void Ray::setOrigin(const float& t_x, const float& t_y, const float& t_z) {
+  this->origin.set(t_x, t_y, t_z);
+}
+
+void Ray::setDirection(Vec4 direction) { this->direction.set(direction); }
+
+void Ray::setDirection(const float& t_x, const float& t_y, const float& t_z) {
+  this->direction.set(t_x, t_y, t_z);
+}
+
+float Ray::distanceToPoint(Vec4 point) { return origin.distanceTo(point); }
+
+Vec4 Ray::at(float t) { return (this->direction * t) + this->origin; }
+
+u8 Ray::intersectBox(Vec4* minCorner, Vec4* maxCorner, float& distance) {
+  float tmin, tmax, tymin, tymax, tzmin, tzmax;
+  Vec4 invDir = this->invDir();
+  invDir.normalize();
+
+  tmin = (minCorner->x - this->origin.x) * invDir.x;
+  tmax = (maxCorner->x - this->origin.x) * invDir.x;
+  tymin = (minCorner->y - this->origin.y) * invDir.y;
+  tymax = (maxCorner->y - this->origin.y) * invDir.y;
+
+  if ((tmin > tymax) || (tymin > tmax)) {
+    distance = -1.0f;
+    return 0;
+  }
+
+  if (tymin > tmin) tmin = tymin;
+
+  if (tymax < tmax) tmax = tymax;
+
+  tzmin = (minCorner->z - this->origin.z) * invDir.z;
+  tzmax = (maxCorner->z - this->origin.z) * invDir.z;
+
+  if ((tmin > tzmax) || (tzmin > tmax)) {
+    distance = -1.0f;
+    return 0;
+  }
+
+  if (tzmin > tmin) tmin = tzmin;
+
+  if (tzmax < tmax) tmax = tzmax;
+
+  if (tmax < 0) {
+    distance = -1.0f;
+    return 0;
+  }
+
+  distance = tmin >= 0 ? tmin : tmax;
+  return 1;
+}
+
+Vec4 Ray::invDir() {
+  return Vec4(1 / this->direction.x, 1 / this->direction.y,
+                 1 / this->direction.z);
+}
+
+}  // Namespace Tyra
\ No newline at end of file