work on raytracing

geo/Triangle3.h

@@ -0,0 +1,118 @@
+#ifndef TRIANGLE3_H
+#define TRIANGLE3_H
+
+#include "Point3.h"
+#include "Ray3.h"
+
+struct Triangle3 {
+
+	Point3 p1;
+	Point3 p2;
+	Point3 p3;
+
+public:
+
+	/** empty ctor */
+	Triangle3() : p1(), p2(), p3() {;}
+
+	/** ctor */
+	Triangle3(Point3 p1, Point3 p2, Point3 p3) : p1(p1), p2(p2), p3(p3) {;}
+
+
+//	Point3 cross(Point3 b, Point3 c) const {
+//		return Point3(
+//			b.y*c.z - c.y*b.z,
+//			b.z*c.x - c.z*b.x,
+//			b.x*c.y - c.x*b.y
+//		);
+//	}
+
+//	float dot(Point3 b, Point3 c) const {
+//		return b.x*c.x + b.y*c.y + b.z*c.z;
+//	}
+
+	Triangle3 operator - (const Point3 o) const {
+		return Triangle3(p1-o, p2-o, p3-o);
+	}
+
+	Point3 getNormal() const {
+		return cross( p2-p1, p3-p1 ).normalized();
+	}
+
+
+	// http://www.lighthouse3d.com/tutorials/maths/ray-triangle-intersection/
+	bool intersects(Ray3 ray, Point3& pos) const {
+
+		const Point3 e1 = p2-p1;
+		const Point3 e2 = p3-p1;
+
+		const Point3 h = cross(ray.dir, e2);
+		const float a = dot(e1, h);
+
+		if (a > -0.00001 && a < 0.00001) {return false;}
+
+		const float f = 1/a;
+
+		const Point3 s = ray.start - p1;
+		const float u = f * dot(s,h);
+
+		if (u < 0.0 || u > 1.0) {return false;}
+
+		const Point3 q = cross(s, e1);
+		const float v = f * dot(ray.dir, q);
+
+		if (v < 0.0 || u + v > 1.0) {return false;}
+		const float t = f * dot(e2,q);
+
+
+		if (t > 0.00001) {
+			pos = ray.start + (ray.dir * t);
+			return true;
+		}
+
+		return false;
+
+	}
+
+/*
+	int rayIntersectsTriangle(float *p, float *d,
+				float *v0, float *v1, float *v2) {
+
+		float e1[3],e2[3],h[3],s[3],q[3];
+		float a,f,u,v;
+
+		//crossProduct(h,d,e2);
+		a = innerProduct(e1,h);
+
+		if (a > -0.00001 && a < 0.00001)
+			return(false);
+
+		f = 1/a;
+		vector(s,p,v0);
+		u = f * (innerProduct(s,h));
+
+		if (u < 0.0 || u > 1.0)
+			return(false);
+
+		crossProduct(q,s,e1);
+		v = f * innerProduct(d,q);
+
+		if (v < 0.0 || u + v > 1.0)
+			return(false);
+
+		// at this stage we can compute t to find out where
+		// the intersection point is on the line
+		t = f * innerProduct(e2,q);
+
+		if (t > 0.00001) // ray intersection
+			return(true);
+
+		else // this means that there is a line intersection
+			 // but not a ray intersection
+			 return (false);
+
+	}
+*/
+};
+
+#endif // TRIANGLE3_H