I already know how to check for collisions with the doesintersectNode-method in Cocos3d, but in my case, I want to avoid obstacles, before I get in touch with them. In example, I want to stop in front of a wall, before I crash against it.
For this reasons I wrote the methods getNodeAtLocation in my subclass of CC3Scene and -(BOOL)shouldMoveDirectionallywithDistance:(float)distance in the class of my person, which should move around.
Unfortunately, I have some problems with the algorithm of the last method. Here the code:
-(BOOL)shouldMoveDirectionallywithDistance:(float)distance
{
BOOL shouldMove = NO;
float x = self.person.globalLocation.x;
float z = self.person.globalLocation.z;
int times = 5;
for (int i = 0; i < times; i++) {
CC3Vector newPos = cc3v(x, 0.5, z);
CC3PODResourceNode *obstacle = (CC3PODResourceNode *)[myScene getNodeAtLocation:newPos];
if (obstacle) {
return NO;
}else{
shouldMove = YES;
}
x += self.person.globalForwardDirection.x * distance / times;
z += self.person.globalForwardDirection.z * distance / times;
}
return shouldMove;
}
In this method, I get the important parts of the coordinates (for my proposal just the x- and z-values) and increase them by a fifth of the forwardDirection. I decided, that this makes sense, when the obstacle is i.e. a thin wall. But for reasons I don't know, this method doesn't work, and the person is able to walk through this wall. So where is the problem in my code?
I strongly believe, that the getNodeAtLocation-method works correctly, as I tested it multiple times, but maybe there are my mistakes:
-(CC3Node *)getNodeAtLocation:(CC3Vector )position
{
CC3Node *node = nil;
for (CC3PODResourceNode *aNode in self.children) {
if ([aNode isKindOfClass:[CC3PODResourceNode class]] ) {
for (CC3PODResourceNode *child in aNode.children) {
if (CC3BoundingBoxContainsLocation(child.globalBoundingBox, position)) {
node = aNode;
}
}
}
}
return node;
}
To conclude, in my view the mistake is in the -(BOOL)shouldMoveDirectionallywithDistance:(float)distance-method. I suppose, that something is wrong with the increase of the x- and z-values, but I couldn't figure out, what exactly is incorrect.
