Sphere-Ray-Intersection (untested)

geotypes.cpp

@@ -62,6 +62,51 @@ Punkt3D Sphere::getPos() const {
 	return pos;
 }
 
+int Sphere::getIntersectionParam(const Ray &ray, float *param1, float *param2) {
+	int numerg;
+	// ax^2 + bx + c = 0
+	segl::Punkt3D ehv(1.0f, 1.0f, 1.0f);
+	float a = ray.dir*ehv;
+	float b = 2*(ray.pos*ehv + pos*ehv);
+	float c = ray.pos*ray.pos + pos*pos - 2*(ray.pos*pos) - radius*radius;
+	
+	float p = b/a;
+	float q = c/a;
+	
+	if((p*p)/4.0f<q) {
+		numerg = 0;
+	} else if((p*p)/4.0f==q) {
+		numerg = 1;
+		if(param1!=0) {
+			*param1 = -p/2.0f;
+		}
+	} else {
+		numerg = 2;
+		if(param1!=0 || param2!=0) {
+			if(param1!=0) {
+				*param1 = -p/2.0f + sqrt(((p*p)/4.0f)-q);
+			}
+			if(param2!=0) {
+				*param2 = -p/2.0f - sqrt(((p*p)/4.0f)-q);
+			}
+		}
+	}
+	
+	return numerg;	
+}
+
+int Sphere::getIntersectionPoints(const Ray &ray, segl::Punkt3D *a, segl::Punkt3D *b) {
+	float pa, pb;
+	int numerg = getIntersectionParam(ray, &pa, &pb);
+	if(a)
+		*a = ray.get(pa);
+	
+	if(b)
+		*b = ray.get(pb);
+	
+	return numerg;
+}
+
 Ray::Ray() {
 	dir.set(0.0f, 1.0f, 0.0f);
 }
@@ -139,14 +184,6 @@ float Ray::dist(Punkt3D p) const {
 	return abs(p - get( getParam(p) ));
 }
 
-int getIntersectionParam(const Ray &ray, float *param1, float *param2) {
-
-}
-
-int getIntersectionParam(const Ray &ray, segl::Punkt3D *a, segl::Punkt3D *b) {
-
-}
-
 float Ray::getParam(Punkt3D p, bool onray) const {
 	if(onray) {
 		if(!onRay(p))

geotypes.h

@@ -47,6 +47,9 @@ class Sphere {
 		bool collision(const Box & b) const;
 		bool collision(const Plane &p) const;
 		
+		int getIntersectionParam(const Ray &ray, float *param1, float *param2);
+		int getIntersectionPoints(const Ray &ray, segl::Punkt3D *a, segl::Punkt3D *b);
+		
 		bool inSphere(Punkt3D p) const;
 		Punkt3D getPos() const;
 };
@@ -66,9 +69,6 @@ class Ray {
 		float dist(Punkt3D p) const;
 		float getParam(Punkt3D p, bool onray=false) const;
 		
-		int getIntersectionParam(const Ray &ray, float *param1, float *param2);
-		int getIntersectionParam(const Ray &ray, segl::Punkt3D *a, segl::Punkt3D *b);
-		
 		bool collision(const Sphere &s) const;
 		bool collision(const Ray &r) const;
 		bool collision(const Box & b) const;