--- a/src/proto2/Physics.cc	Thu Nov 20 15:01:17 2008 +0000
+++ b/src/proto2/Physics.cc	Thu Nov 20 16:23:01 2008 +0000
@@ -90,6 +90,25 @@
     }
 }
 
+bool PhysicsWorld::collided (Vector oldPos, Vector newPos) {
+	int deltaX = oldPos.x - newPos.x; 
+	int deltaY = oldPos.y - newPos.y; 
+	double distance = sqrt(deltaX * deltaX + deltaY * deltaY);
+	double xInc = (double) deltaX / distance;
+	double yInc = (double) deltaY / distance;
+    double currentX = oldPos.x;
+    double currentY = oldPos.y;
+
+	// This implementation is bit slow since it checks some squares twice.
+    for(unsigned int i = 1; i < distance; i++) {
+		currentX += xInc;
+		currentY += yInc;
+		if(terrain[(int)currentX][(int)currentY] != EMPTY)
+			return false;
+	}
+	return true;
+}
+
 void PhysicsObject::integrate(Vector force, uint16_t dt) {
     // TODO
 }

--- a/src/proto2/Physics.hh	Thu Nov 20 15:01:17 2008 +0000
+++ b/src/proto2/Physics.hh	Thu Nov 20 16:23:01 2008 +0000
@@ -34,6 +34,8 @@
     void addObject (PhysicsObject *object);
 
     void tick (void);
+	void generateTerrain (int seed);
+	bool collided (Vector oldPos, Vector newPos);
 };
 
 class PhysicsObject {
@@ -42,8 +44,8 @@
     float mass;
     Vector position;
     Vector velocity;
-	// Whether the object (worms mainly) is in the air or on the ground.
-	// Affects to physics.
+	// Whether the object (worms mainly) is in the air 
+	// or firmly on the ground. Affects to physics.
 	bool inAir;
     
     PhysicsObject (PhysicsWorld &world, float mass, Vector position, Vector velocity);