The point or points at which two or more shapes cross or overlap one another.

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2
votes
0answers
43 views

Minimum number of vertex moves to un-intersect a polygon with itself [migrated]

In my game, I have n points that form a self-intersecting polygon. The points can be moved by dragging them. How can I form a non-intersecting polygon this way, in the minimum number of moves?
1
vote
0answers
43 views

Precalculating timespan of bullet collision on cubic bezier curve circles?

I'm fairly new to game logics, C#/XNA (The language/library of choice) and bezier curves in general, and is stuck in my current project. I'm going to try to explain as thoroughly as I can what the ...
0
votes
1answer
95 views

Is this the correct way to detect ray-sphere intersection?

I have this java function that should return a true or false for any sphere passed to it if they intersect. However it seems to end being true a lot of the time when it shouldn't and false sometimes ...
0
votes
2answers
162 views

Thick Ray interaction with AABB

I would like to intersect a thick ray (actually a cylinder) with an AABB. The current code to perform intersection with the ray is the following. template <class RealT> bool ...
2
votes
1answer
91 views

How do I compute the point of a triangle-ray intersection?

I have a line (the direction vector of the player) and a triangle representing the face of a model (so composed of 3 points). I can't find the mathematical operation to check if that vector is ...
2
votes
2answers
148 views

How can I compute the common points when spheres intersect?

When two spheres intersect they should share one or two points. I want to know how to compute those points? I was thinking of something like this: -check if the spheres intersect -calculate ...
0
votes
1answer
80 views

Tennis game algorithm and maths

Tennis courts are real dimensions and game is 3D Ball has position (x,y,z), speed(vx,vy,vz) and acceleration (ax,ay,az) Game has 30 fps and on each update (1/30sec) it has these properties vx +=ax; ...
2
votes
1answer
327 views

Finding Z given X & Y coordinates on terrain?

I need to know the most efficient way of finding Z given X & Y coordinates on terrain. My terrain is set up as a grid, each grid block consisting of two triangles which may be flipped in any ...
0
votes
1answer
196 views

Performing intersection testing in world's or object's space?

Am adding basic ray casting and collision detection for my game, also adding bounding volumes/collision mesh. Given that the ray is cast in world space and each mesh's node can track world ...
2
votes
2answers
111 views

Intersection of a point and rectangle

I have a mouse cordinates in 2D game (x and y) and a rectangle (x,y, width,height). How to find if the point is in the rectangle? I do not have any code to post here. I'm just searching for help.
1
vote
2answers
122 views

XNA Calculate two points of triangle with given Z

I want to calculate the two points of a 3D triangle that have a specified Z coordinate. I guess the way to do this would be to somehow create a plane which is perfectly flat with my given Z coordinate ...
0
votes
0answers
53 views

XNA inverted matrix acting strange

First of all, I am trying to calculate the two points of a triangle that have a given z position. I have figured out what I think to be quite a good method. First of all I move the triangle to be ...
1
vote
1answer
108 views

What does Rectangle.Intersect means/do?

Ok I have two rectangles one is the ball and other is the paddle. 1. if(ball.rectangle.intersects(paddle.rectangle)) y = -Math.Abs(y); and 2. ...
3
votes
1answer
107 views

Moller Tri Tri intersection

I'm done implementing Moller's tri-tri intersection routine. It gives you the location of where each triangle edge intersects the line of intersection between the 2 triangle planes: Really you get ...
1
vote
1answer
154 views

Wrong intersection: Bounding Sphere and Ray

I've got a huge problem with BoundingSpheres and Rays in XNA and I really don't know how to solve it. The problem: foreach (BoundingSphere s1 in GetCollisionHullBoundingSpheres()) if ...
1
vote
0answers
90 views

XNA C# Rectangle Intersect Ball on a Square [closed]

I made a Game like Peggle Deluxe using C# and XNA for lerning. I have 2 rectangles a ball and a square field. The ball gets shoot out with a cannon and if the Ball hits the Square the Square ...
0
votes
1answer
324 views

How can I remove the view and projection matrix from ray position to get only the ray model?

I've got a little problem with my picking module and I need your help. I have a method to project a ray from the camera to a fixed point when I click somewhere. The computed ray looks good, it go to ...
4
votes
3answers
433 views

Fast method of detecting whether point is inside mesh

I'm trying to construct a 3d object from a large number of particles. I think this is called BVH (Bounding volume hierarchy). I figured the best way is to draw the particles inside the mesh, then let ...
-2
votes
1answer
101 views

How to use D3DXIntersectTri function to find intersected point?

How to calculate direction for D3DXIntersectTri function to find intersected point? And after getting the result in Distance how to get that coordinate(XYZ)?
1
vote
0answers
158 views

Sketchy results from ray-plane intersection code

I've set up a demo with simple first-person controls using C++ and OpenGL, and it seems to work reasonably well. My goal is this: when the player looks at a plane and clicks the left mouse button, ...
2
votes
2answers
115 views

Calculate intersection of a line with a plane

I was reading something about: “Intersection of a line with a plane”. But I don’t fully understand how to calculate it on their way. The goal is to calculate where the plane and the line will ...
3
votes
1answer
123 views

What to do after detecting OBB-OBB intersection

I'm using this code to detect intersections between two OBBs. The problem is that i don't know what to do after detecting it. I tried using a simple algorithm: if (collision detected) { ...
1
vote
2answers
1k views

Line Intersection from parametric equation

I'm sure this question has been asked before. However, I'm trying to connect the dots by translating an equation on paper into an actual function. I thought It would be interesting to ask here instead ...
3
votes
2answers
199 views

how to calculate intersection time and place of multiple moving arcs

I have rocks orbiting moons, moons orbiting planets, planets orbiting suns, and suns orbiting black holes, and the current system could have many many layers of orbitage. the position of any object ...
0
votes
2answers
381 views

ray polygon intersection

Hi, I am looking for an elegant way to do ray and polygon intersections in 2d. I don't care about languages. Now what I'm doing is taking a line that lies on the ray (with a screen length) and ...
1
vote
2answers
589 views

Segment-Cylinder intersection

What is the complete code (C#, pseudo, does not matter) for calculating the resulting segment (or its absence) for the intersection of the segment and the cylinder? The segment is defined by ...
2
votes
2answers
257 views

What is a technique for 2D ray-box intersection that is suitable for old console hardware?

I'm working on a Sega Genesis homebrew game (it has a 7mhz 68000 CPU). I'm looking for a way to find the intersection between a particle sprite and a background tile. Particles are represented as a ...
3
votes
4answers
158 views

Ray Triangle Intersection issue

I'm trying to perform ray triangle intersection on a mesh made of triangles. The below code seems to work fine but only about 50% of the time. The ray often gets into positions where no intersection ...
4
votes
1answer
2k views

How to Calculate the Contact Point between Ray and Plane

Is there any quick way to find the intersection point between Plane and Ray?
4
votes
1answer
864 views

Closest point on an ellipsoid

I need to know how to get the closest point on the surface of an ellipsoid to another point. I had an idea, but apparently i was wrong, and oversimplfying. What i did was squash the ellipsoid and ...
4
votes
1answer
679 views

Ellipsoid v. Box collision detection

I'm trying to write some collision detection code. ATM i have the code properly resolving Ellipsoid v. Ellipsoid collisions, and Box v. Box collisions, but Ellipsoid v. Box collisions doesnt work. ...
2
votes
2answers
1k views

Find meeting point of 2 objects in 2D, knowing (constant) speed and slope

I have a gun which fires a projectile that has to hit an enemy. The problem is that the gun has to be automatic, i.e. - choose the angle in which it has to shoot, so that the projectile hits the enemy ...
3
votes
3answers
3k views

Triangle - Rectangle Intersection in 2D

I had previously asked this for 3D but now I changed my strategy and would like to do the intersection in 2D. The Rectangle is axis aligned and will always be in a fixed position, and has a constant ...
3
votes
1answer
2k views

Triangle-Plane intersection in 3D space

I would like to clip a triangle if its bounds lie partially out of a cube for this I guess I would need some kind of Triangle Plane intersection code, I'm not well versed with math but I do have the ...
7
votes
5answers
1k views

How to determine which cells in a grid intersect with a given triangle?

I'm currently writing a 2D AI simulation, but I'm not completely certain how to check whether the position of an agent is within the field of view of another. Currently, my world partitioning is ...