Merge pull request #24 from orange-cpp/u/orange-cpp/improved-triangle-class

U/orange cpp/improved triangle class

Author: orange-cpp

include/omath/Triangle.hpp

@@ -0,0 +1,74 @@
+//
+// Created by Orange on 11/13/2024.
+//
+#pragma once
+#include "omath/Vector3.hpp"
+
+namespace omath
+{
+ template<class Vector>
+ class Triangle final
+ {
+ public:
+ constexpr Triangle() = default;
+ constexpr Triangle(const Vector& vertex1, const Vector& vertex2, const Vector& vertex3)
+ : m_vertex1(vertex1), m_vertex2(vertex2), m_vertex3(vertex3)
+ {
+ }
+
+ Vector3 m_vertex1;
+ Vector3 m_vertex2;
+ Vector3 m_vertex3;
+
+ [[nodiscard]]
+ constexpr Vector3 CalculateNormal() const
+ {
+ const auto b = SideBVector();
+ const auto a = SideAVector();
+ return b.Cross(a).Normalized();
+ }
+
+ [[nodiscard]]
+ float SideALength() const
+ {
+ return m_vertex1.DistTo(m_vertex2);
+ }
+
+ [[nodiscard]]
+ float SideBLength() const
+ {
+ return m_vertex3.DistTo(m_vertex2);
+ }
+
+ [[nodiscard]]
+ constexpr Vector3 SideAVector() const
+ {
+ return m_vertex1 - m_vertex2;
+ }
+
+ [[nodiscard]]
+ constexpr float Hypot() const
+ {
+ return m_vertex1.DistTo(m_vertex3);
+ }
+ [[nodiscard]]
+ constexpr bool IsRectangular() const
+ {
+ const auto sideA = SideALength();
+ const auto sideB = SideBLength();
+ const auto hypot = Hypot();
+
+ return std::abs(sideA*sideA + sideB*sideB - hypot*hypot) <= 0.0001f;
+ }
+ [[nodiscard]]
+ constexpr Vector3 SideBVector() const
+ {
+ return m_vertex3 - m_vertex2;
+ }
+ [[nodiscard]]
+ constexpr Vector3 MidPoint() const
+ {
+ return (m_vertex1 + m_vertex2 + m_vertex3) / 3;
+ }
+ };
+} // namespace omath

include/omath/Triangle3d.hpp

@@ -4,7 +4,7 @@
 #pragma once
 
 #include "omath/Vector3.hpp"
-#include "omath/Triangle3d.hpp"
+#include "omath/Triangle.hpp"
 
 namespace omath::collision
 {
@@ -27,12 +27,12 @@ namespace omath::collision
 
 
  [[nodiscard]]
- static bool CanTraceLine(const Ray& ray, const Triangle3d& triangle);
+ static bool CanTraceLine(const Ray& ray, const Triangle<Vector3>& triangle);
 
 
  // Realization of Möller–Trumbore intersection algorithm
  // https://en.wikipedia.org/wiki/M%C3%B6ller%E2%80%93Trumbore_intersection_algorithm
  [[nodiscard]]
- static Vector3 GetRayHitPoint(const Ray& ray, const Triangle3d& triangle);
+ static Vector3 GetRayHitPoint(const Ray& ray, const Triangle<Vector3>& triangle);
  };
 }

include/omath/collision/LineTracer.hpp

@@ -4,7 +4,6 @@ target_sources(omath PRIVATE
  color.cpp
  Vector4.cpp
  Vector2.cpp
- Triangle3d.cpp
 )
 
 add_subdirectory(prediction)

source/CMakeLists.txt

@@ -5,7 +5,7 @@
 
 namespace omath::collision
 {
- bool LineTracer::CanTraceLine(const Ray &ray, const Triangle3d &triangle)
+ bool LineTracer::CanTraceLine(const Ray& ray, const Triangle<Vector3>& triangle)
  {
  return GetRayHitPoint(ray, triangle) == ray.end;
  }
@@ -19,7 +19,7 @@ namespace omath::collision
  return DirectionVector().Normalized();
  }
 
- Vector3 LineTracer::GetRayHitPoint(const Ray &ray, const Triangle3d &triangle)
+ Vector3 LineTracer::GetRayHitPoint(const Ray& ray, const Triangle<Vector3>& triangle)
  {
  constexpr float kEpsilon = std::numeric_limits<float>::epsilon();
 
@@ -41,7 +41,7 @@ namespace omath::collision
  const auto u = t.Dot(p) * invDet;
 
 
- if ((u < 0 && std::abs(u) > kEpsilon) || (u > 1 && std::abs(u-1) > kEpsilon))
+ if ((u < 0 && std::abs(u) > kEpsilon) || (u > 1 && std::abs(u - 1) > kEpsilon))
  return ray.end;
 
  const auto q = t.Cross(sideA);
@@ -59,4 +59,4 @@ namespace omath::collision
 
  return ray.start + rayDir * tHit;
  }
-}
+} // namespace omath::collision

source/Triangle3d.cpp

@@ -18,6 +18,7 @@ add_executable(unit-tests
  general/UnitTestAngles.cpp
  general/UnitTestViewAngles.cpp
  general/UnitTestAngle.cpp
+ general/UnitTestTriangle.cpp
 
  engines/UnitTestOpenGL.cpp
  engines/UnitTestUnityEngine.cpp

source/collision/LineTracer.cpp

@@ -1,6 +1,6 @@
 #include "gtest/gtest.h"
 #include "omath/collision/LineTracer.hpp"
-#include "omath/Triangle3d.hpp"
+#include "omath/Triangle.hpp"
 #include "omath/Vector3.hpp"
 
 using namespace omath;
@@ -13,7 +13,7 @@ class LineTracerTest : public ::testing::Test
  Vector3 vertex1{0.0f, 0.0f, 0.0f};
  Vector3 vertex2{1.0f, 0.0f, 0.0f};
  Vector3 vertex3{0.0f, 1.0f, 0.0f};
- Triangle3d triangle{vertex1, vertex2, vertex3};
+ Triangle<Vector3> triangle{vertex1, vertex2, vertex3};
 };
 
 // Test that a ray intersecting the triangle returns false for CanTraceLine
@@ -71,7 +71,7 @@ TEST_F(LineTracerTest, TriangleFarBeyondRayEndPoint)
  constexpr Ray ray{{0.0f, 0.0f, 0.0f}, {0.0f, 0.0f, 1.0f}};
 
  // Define a triangle far beyond the ray's endpoint
- const Triangle3d distantTriangle{
+ constexpr Triangle<Vector3> distantTriangle{
  {1000.0f, 1000.0f, 1000.0f}, {1001.0f, 1000.0f, 1000.0f}, {1000.0f, 1001.0f, 1000.0f}
  };
 

tests/CMakeLists.txt

@@ -0,0 +1,132 @@
+//
+// Created by Orange on 1/6/2025.
+//
+#include "omath/Triangle.hpp"
+#include <gtest/gtest.h>
+#include <omath/Vector3.hpp>
+#include <cmath> // For std::sqrt, std::isinf, std::isnan
+
+
+using namespace omath;
+
+class UnitTestTriangle : public ::testing::Test
+{
+protected:
+ // Define some Triangles to use in tests
+ Triangle<Vector3> t1;
+ Triangle<Vector3> t2;
+ Triangle<Vector3> t3;
+
+ constexpr void SetUp() override
+ {
+ // Triangle with vertices (0, 0, 0), (1, 0, 0), (0, 1, 0)
+ t1 = Triangle<Vector3>(
+ Vector3(0.0f, 0.0f, 0.0f),
+ Vector3(1.0f, 0.0f, 0.0f),
+ Vector3(0.0f, 1.0f, 0.0f)
+ );
+
+ // Triangle with vertices (1, 2, 3), (4, 5, 6), (7, 8, 9)
+ t2 = Triangle<Vector3>(
+ Vector3(1.0f, 2.0f, 3.0f),
+ Vector3(4.0f, 5.0f, 6.0f),
+ Vector3(7.0f, 8.0f, 9.0f)
+ );
+
+ // An isosceles right triangle
+ t3 = Triangle<Vector3>(
+ Vector3(0.0f, 0.0f, 0.0f),
+ Vector3(2.0f, 0.0f, 0.0f),
+ Vector3(0.0f, 2.0f, 0.0f)
+ );
+ }
+};
+
+// Test constructor and vertices
+TEST_F(UnitTestTriangle, Constructor)
+{
+ constexpr Triangle<Vector3> t(
+ Vector3(1.0f, 2.0f, 3.0f),
+ Vector3(4.0f, 5.0f, 6.0f),
+ Vector3(7.0f, 8.0f, 9.0f)
+ );
+
+ EXPECT_FLOAT_EQ(t.m_vertex1.x, 1.0f);
+ EXPECT_FLOAT_EQ(t.m_vertex1.y, 2.0f);
+ EXPECT_FLOAT_EQ(t.m_vertex1.z, 3.0f);
+
+ EXPECT_FLOAT_EQ(t.m_vertex2.x, 4.0f);
+ EXPECT_FLOAT_EQ(t.m_vertex2.y, 5.0f);
+ EXPECT_FLOAT_EQ(t.m_vertex2.z, 6.0f);
+
+ EXPECT_FLOAT_EQ(t.m_vertex3.x, 7.0f);
+ EXPECT_FLOAT_EQ(t.m_vertex3.y, 8.0f);
+ EXPECT_FLOAT_EQ(t.m_vertex3.z, 9.0f);
+}
+
+// Test CalculateNormal
+TEST_F(UnitTestTriangle, CalculateNormal)
+{
+ // For t1, the normal should point in the +Z direction (0, 0, 1) or (0, 0, -1)
+ const Vector3 normal_t1 = t1.CalculateNormal();
+ // Check if it's normalized and pointed along Z (sign can differ, so use absolute check)
+ EXPECT_NEAR(std::fabs(normal_t1.z), 1.0f, 1e-5f);
+ EXPECT_NEAR(normal_t1.Length(), 1.0f, 1e-5f);
+
+
+ // For t3, we expect the normal to be along +Z as well
+ const Vector3 normal_t3 = t3.CalculateNormal();
+ EXPECT_NEAR(std::fabs(normal_t3.z), 1.0f, 1e-5f);
+}
+
+// Test side lengths
+TEST_F(UnitTestTriangle, SideLengths)
+{
+ // For t1 side lengths
+ EXPECT_FLOAT_EQ(t1.SideALength(), std::sqrt(1.0f)); // distance between (0,0,0) and (1,0,0)
+ EXPECT_FLOAT_EQ(t1.SideBLength(), std::sqrt(1.0f + 1.0f)); // distance between (4,5,6) & (7,8,9)... but we are testing t1, so let's be accurate:
+ // Actually, for t1: vertex2=(1,0,0), vertex3=(0,1,0)
+ // Dist between (0,1,0) and (1,0,0) = sqrt((1-0)^2 + (0-1)^2) = sqrt(1 + 1) = sqrt(2)
+ EXPECT_FLOAT_EQ(t1.SideBLength(), std::sqrt(2.0f));
+
+ // For t3, side a = distance between vertex1=(0,0,0) and vertex2=(2,0,0), which is 2
+ // side b = distance between vertex3=(0,2,0) and vertex2=(2,0,0), which is sqrt(2^2 + (-2)^2)= sqrt(8)= 2.828...
+ // We'll just check side a first:
+ EXPECT_FLOAT_EQ(t3.SideALength(), 2.0f);
+ // Then side b:
+ EXPECT_FLOAT_EQ(t3.SideBLength(), std::sqrt(8.0f));
+}
+
+// Test side vectors
+TEST_F(UnitTestTriangle, SideVectors)
+{
+ const Vector3 sideA_t1 = t1.SideAVector(); // m_vertex1 - m_vertex2
+ EXPECT_FLOAT_EQ(sideA_t1.x, 0.0f - 1.0f);
+ EXPECT_FLOAT_EQ(sideA_t1.y, 0.0f - 0.0f);
+ EXPECT_FLOAT_EQ(sideA_t1.z, 0.0f - 0.0f);
+
+ const Vector3 sideB_t1 = t1.SideBVector(); // m_vertex3 - m_vertex2
+ EXPECT_FLOAT_EQ(sideB_t1.x, 0.0f - 1.0f);
+ EXPECT_FLOAT_EQ(sideB_t1.y, 1.0f - 0.0f);
+ EXPECT_FLOAT_EQ(sideB_t1.z, 0.0f - 0.0f);
+}
+
+TEST_F(UnitTestTriangle, IsRectangular)
+{
+ EXPECT_TRUE(Triangle<Vector3>({2,0,0}, {}, {0,2,0}).IsRectangular());
+}
+// Test midpoint
+TEST_F(UnitTestTriangle, MidPoint)
+{
+ // For t1, midpoint of (0,0,0), (1,0,0), (0,1,0)
+ const Vector3 mid1 = t1.MidPoint();
+ EXPECT_FLOAT_EQ(mid1.x, (0.0f + 1.0f + 0.0f) / 3.0f);
+ EXPECT_FLOAT_EQ(mid1.y, (0.0f + 0.0f + 1.0f) / 3.0f);
+ EXPECT_FLOAT_EQ(mid1.z, 0.0f);
+
+ // For t2, midpoint of (1,2,3), (4,5,6), (7,8,9)
+ const Vector3 mid2 = t2.MidPoint();
+ EXPECT_FLOAT_EQ(mid2.x, (1.0f + 4.0f + 7.0f) / 3.0f);
+ EXPECT_FLOAT_EQ(mid2.y, (2.0f + 5.0f + 8.0f) / 3.0f);
+ EXPECT_FLOAT_EQ(mid2.z, (3.0f + 6.0f + 9.0f) / 3.0f);
+}