diff --git a/emath.h b/emath.h
index 45047e8..6dd2af7 100644
--- a/emath.h
+++ b/emath.h
@@ -3,7 +3,6 @@
 
 #include <iostream>
 #include <cmath>
-#include <SDL_opengl.h>
 
 namespace segl {
 
diff --git a/geotypes.cpp b/geotypes.cpp
index 84f8d5f..c17f03a 100644
--- a/geotypes.cpp
+++ b/geotypes.cpp
@@ -21,7 +21,14 @@ bool Sphere::collision(const Sphere &s) const {
 }
 
 bool Sphere::collision(const Ray &r) const {
-	return true;
+	/*
+	// way more complex (i think), maybe usefull to calc the collpoints
+	const float bsum = r.dir.x + r.dir.y + r.dir.z;
+	float p = (2.0f*(r.pos*r.dir)-pos*r.dir) / bsum;
+	float q = (r.pos*r.pos-2.0f*r.pos*pos+pos*pos-radius*radius) / bsum;
+	return (p*p/4.0f-q >= 0.0f);
+	*/
+	return (r.dist(pos)<=radius);
 }
 
 bool Sphere::collision(const Box & b) const {
@@ -29,7 +36,7 @@ bool Sphere::collision(const Box & b) const {
 }
 
 bool Sphere::collision(const Plane &p) const {
-	return true;
+	return (p.dist(pos)<=radius);
 }
 
 bool Sphere::inSphere(Punkt3D p) const {
@@ -53,12 +60,12 @@ void Ray::set(Punkt3D _pos, Punkt3D _dir) {
 	dir = _dir;
 }
 
-Punkt3D Ray::get(float x) {
+Punkt3D Ray::get(float x) const {
 	return pos + dir*x;
 }
 
 // TODO: Heavy Testing
-bool Ray::onRay(Punkt3D p, int rnd) {
+bool Ray::onRay(Punkt3D p, int rnd) const {
 	float r1 = 0.0f, r2 = 0.0f, r3 = 0.0f;
 	short fcount = 0;
 	bool g1=true, g2=true, g3=true;
@@ -105,14 +112,14 @@ bool Ray::onRay(Punkt3D p, int rnd) {
 	else if(g3)
 		return (r1 == r2);
 	else
-		return (r1 == r2 == r3);
+		return (r1 == r2 && r1 == r3);
 }
 
-float Ray::dist(Punkt3D p) {
+float Ray::dist(Punkt3D p) const {
 	return abs(p - get( getParam(p) ));
 }
 
-float Ray::getParam(Punkt3D p, bool onray) {
+float Ray::getParam(Punkt3D p, bool onray) const {
 	if(onray) {
 		if(!onRay(p))
 			return 0.0f;
@@ -193,7 +200,7 @@ bool Plane::collision(const Plane &p) const {
 }
 
 float Plane::dist(Punkt3D p) const {
-	
+		
 }
 
 } // namespace segl
diff --git a/geotypes.h b/geotypes.h
index 7deb7c4..8e9e824 100644
--- a/geotypes.h
+++ b/geotypes.h
@@ -5,6 +5,7 @@
 
 namespace segl {
 
+class Sphere;
 class Ray;
 class Box;
 class Plane;
@@ -38,10 +39,10 @@ class Ray {
 		Ray(Punkt3D _pos, Punkt3D _dir);
 		
 		void set(Punkt3D _pos, Punkt3D _dir);
-		Punkt3D get(float x);
-		bool onRay(Punkt3D p, int rnd=-1);
-		float dist(Punkt3D p);
-		float getParam(Punkt3D p, bool onray=false);
+		Punkt3D get(float x) const;
+		bool onRay(Punkt3D p, int rnd=-1) const;
+		float dist(Punkt3D p) const;
+		float getParam(Punkt3D p, bool onray=false) const;
 		
 		bool collision(const Sphere &s) const;
 		bool collision(const Ray &r) const;
diff --git a/punkt2d.h b/punkt2d.h
index 52e68a9..1bb5580 100644
--- a/punkt2d.h
+++ b/punkt2d.h
@@ -3,6 +3,7 @@
 
 #include <iostream>
 #include <cmath>
+#include <SDL_opengl.h>
 #include "emath.h"
 
 namespace segl {
@@ -53,12 +54,13 @@ class Punkt2D {
 
 } // namespace segl
 
+// #ifdef GLAPI
 void glTexCoord2f(segl::Punkt2D);
 float abs(segl::Punkt2D);
 
 // Fixed Headers
 void glTexCoordP2D(segl::Punkt2D p);
-
+// #endif /* GLAPI */
 
 
 #endif
diff --git a/punkt3d.h b/punkt3d.h
index 6363c89..139e2ae 100644
--- a/punkt3d.h
+++ b/punkt3d.h
@@ -3,6 +3,7 @@
 
 #include <iostream>
 #include <cmath>
+#include <SDL_opengl.h>
 #include "emath.h"
 
 namespace segl {
@@ -62,7 +63,7 @@ class Punkt3D {
 float abs(const segl::Punkt3D&);
 
 // OpenGL-Functions for Punkt3D
-
+// #ifdef GLAPI
 void glVertex3f(const segl::Punkt3D&);
 void glTranslatef(const segl::Punkt3D&);
 void glNormal3f(const segl::Punkt3D&);
@@ -76,5 +77,5 @@ void glNormalP3D(const segl::Punkt3D&);
 
 void glRotateP3D(const float&, const segl::Punkt3D&);
 void gluLookAt(const segl::Punkt3D &pos, const segl::Punkt3D &viewport, const segl::Punkt3D &normal);
-
+// #endif /* GLAPI */
 #endif