Triangles!!!

source/shapes/triangle.cpp

@@ -0,0 +1,57 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Cone implementation
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#include <ray.h>
+#include <shape.h>
+#include <triangle.h>
+#include <math_helper.h>
+
+Triangle::Triangle(Point p1, Point p2, Point p3) : Shape(SHAPE_TRIANGLE), p1(p1), p2(p2), p3(p3)
+{
+    this->e1 = p2 - p1;
+    this->e2 = p3 - p1;
+    this->normal = e2.cross(e1).normalise();
+}
+
+Intersect Triangle::localIntersect(Ray r)
+{
+    Intersect ret;
+
+    Tuple dirCrossE2 = r.direction.cross(this->e2);
+    double determinant = this->e1.dot(dirCrossE2);
+    if (fabs(determinant) < getEpsilon())
+    {
+        return ret;
+    }
+
+    double f = 1.0 / determinant;
+    Tuple p1ToOrigin = r.origin - this->p1;
+    Tuple originCrossE1 = p1ToOrigin.cross(this->e1);
+    double u = f * p1ToOrigin.dot(dirCrossE2);
+    double v = f * r.direction.dot(originCrossE1);
+
+    if ((u < 0) || (u > 1))
+    {
+        return ret;
+    }
+
+    if ((v < 0) || ((u + v) > 1))
+    {
+        return ret;
+    }
+
+    double t = f * this->e2.dot(originCrossE1);
+    ret.add(Intersection(t, this));
+
+    return ret;
+}
+
+Tuple Triangle::localNormalAt(Tuple point)
+{
+    return this->normal;
+}