A branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space.

learn more… | top users | synonyms

1
vote
1answer
584 views

Geometry shader and triangle adjacency

I'm currently trying to change my project to use GL_TRIANGLE_ADJACENCY instead of GL_TRIANGLES. Following this question, I have managed to construct my index buffer fine, but when it comes to the ...
2
votes
2answers
29 views

Detect collision that happen between frames, between slices of moving, rotating circles?

To detect a collision between two circles, we check if the distance between their centers is smaller than the sum of their radii. To detect a collision between a slice (in this case half) of a circle ...
0
votes
1answer
48 views

Is there a way of moving the transform of an object relative to it's geometry

I have a number of objects (mostly prefabs) that have their transform origin in inconvienient places such as about 1 unit to the left of the actual geometry or somewhere inside an object where it's ...
0
votes
1answer
67 views

Outline of plane slice of arbitrary object

How would you extract the outline of a shape from slicing a plane through an arbitrary object? Note: This is related to my Unity Answers question, but not exactly the same.
1
vote
1answer
54 views

How can I mask this CanvasRenderer?

I'm creating a text box that allows for selectable text, based off of Unity's InputField. An issue I am now facing is that the selection highlight does not respond to masks (The parent has a mask, but ...
-1
votes
1answer
49 views

Why is this unity camera moving in weird directions?

I have the following script public class CameraScript : MonoBehaviour { public bool AllowZoom; public float zoom; public float Speed; Transform board; void Start(){ ...
0
votes
1answer
34 views

Maya 2015 Collada mesh transforms not applied

I am trying to load a dae (Collada) model into my 3d engine. The problem is they export the vertices and transforms seperately. So in Maya 2015 it looks like this In the game engine I have it simply ...
0
votes
2answers
3k views

How do I add an image inside a rectangle or a circle in JavaFX?

Suppose we have a rectangle called r Rectangle r = new Rectangle(40, 20); and an image called image Image image = new Image("...src for image"); How do I fit the image inside the rectangle? ...
0
votes
2answers
49 views

Calculate land center on grid

I have a grid based game. The main map is 2d array with land ids, something like this (here are 2 lands on the map, one formed where the 1's are and one formed by where the 2's are): [ 1 , 2 , 2 ] [ ...
1
vote
0answers
51 views

Taking a 2D slice of a 3D volume

I have a regular 3D polygon and I'd like to display 2D slices of it. What is the best way to achieve this? (Preferrably in OpenGL, but a general algorithm/tecnique would be good as well). I've ...
8
votes
2answers
2k views

Geometry System of Populous: The Beginning [closed]

I want to to develop a game like Populous: The Beginning with my friend. But we could not find out what type of geometry they have used for the world. We know that - all tiles have the same size - ...
0
votes
2answers
138 views

which quarter of a triangle the point is in

I've got a world made out of squares. The square are devided in four triangles like this: The corners have their heights stored in a 2D array and the center height is the average of the corners. To ...
1
vote
1answer
45 views

Ortho projection of 3D points with a vector

I have 3D points and I need to make an 2D orthographic projection of them onto a plane that is defined by the origin and a normal n. The meaning of this is basically looking at the points from the top ...
4
votes
1answer
85 views

Suboptimal A* Pathfinding Solution Example using Manhattan Distance Heuristic

I believe using an overestimating heuristic with A* is not guaranteed to find the shortest path. Assuming an agent can travel as a bird using euclidean distances, the manhattan distance provides just ...
32
votes
9answers
6k views

How can I quantify a drawn line's straightness?

I'm working on a game which requires players to draw a line from a point A(x1,y1) to the other point B(x2,y2) on the screen of an Android device. I want to find how well that drawing fits to a ...
14
votes
4answers
648 views

How do you calculate the nearest point on 2 curves?

Given the points of a line and a quadratic bezier curve, how do you calculate their nearest point? .... Similarly, given the points of 2 curves, how do you get the nearest point?
0
votes
1answer
153 views

Rotate Object Towards Direction in 2D

For my RTS game's physics engine, I'm trying to find out a clever way to make a unit face the direction it's moving in. Given a Vector2d direction of movement (its normalized velocity), how can I ...
2
votes
1answer
147 views

Get quaternion between two objects on sphere

In a planetary gravity environment objects are represented in the following way: struct object { struct quaternion quat; // quaternion to represent the rotation between the object and the center ...
0
votes
2answers
88 views

Moving OBB vs. triangle intersection test

Requirements: to write a test function that, given a moving OBB (oriented bounding box) and a triangle, returns true whenever the OBB hits the triangle. The OBB is described by its half extents (h1, ...
2
votes
1answer
53 views

Mapping Coplanar Vertices in 3D space on to a 2D Plane

Say I have a plane specified by a normal vector and point on the plane. I want to specify a 2-D co-ordinate system that lies 'across' the plane, and then use that to find the 2-dimensional distance ...
5
votes
2answers
1k views

What is a good way to determine if a vector is between two other vectors in 2D?

I could operate with the angles, but I do not have the angles calculated yet (and would like to avoid having to do that). It would be possible to calculate and cache the local-coordinate-frame angles, ...
0
votes
0answers
32 views

Rotating between two coordinate frames

I have two coordinate frames, A and B. I want to create the rotation matrix RAB which takes you from A to B. A is a right-handed system, and B is a left-handed system. Furthermore, after moving from a ...
0
votes
1answer
103 views

Collision Detection algorithm using Line Detection

For a 2D physics sandbox I am working on, I need a way of detecting detecting a collision using lines. This sandbox uses a class called Particle, which has a x and a y (stored as a struct called ...
0
votes
1answer
65 views
1
vote
2answers
1k 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 asegment and a cylinder? The segment is defined by ...
16
votes
2answers
4k views

How do I test if a circle and concave polygon intersect?

I have a polygon (sometimes convex, but often concave), and a bunch of circles with different radii. How can I find out if a circle is intersecting/overlapping with the polygon? I could split my ...
0
votes
0answers
51 views

Fat geometry shader

I've seen this video: all the geometry seems to grow and become fat. Nice effect. I'm just approaching the shader matter, and I'm still have to learn a lot about how to change geometry via shaders. ...
11
votes
3answers
4k views

Are the Minecraft animations hardcoded into the game? [closed]

I would like to know how the animation system works in minecraft. I get a feeling that all the mobs are hardcoded into the game. Did notch really sit there and create the matrices for all the ...
0
votes
0answers
22 views

How does collision detection work? [duplicate]

I was curious on how hit collision works in games. I know there is a simple method that gives every object in a 2D or 3D world a recengular hitbox that makes it easy to detect a collision, but when ...
12
votes
6answers
2k views

What's the fastest way checking if two moving AABBs intersect?

I have two AABBs that are moving, what's the fastest way to check if they will intersect under a frame? By moving I mean not just to check with the usual rectangle intersection method, I mean some ...
5
votes
5answers
3k views

How can I test whether points are within a polygon?

I have 2D-points, which boundaries depict a polygon. The points are at integer positions (no fractions possible). Now I want to build an enumerator in C# that returns all points that are inside the ...
31
votes
6answers
3k views

Hexagon collision detection for fast moving objects?

A object has a position and a speed vector. Usually only the position is used to check if two objects collide, this is problematic for very fast moving objects as it can happen that the object moves ...
1
vote
3answers
245 views

How do I interpret the dot product of non-normalized vectors?

I know that if you take the dot-product of two normalized vectors, you get the cosine of the angle between them. But if I take the dot-product of two non-normalized vectors (or one normalized, one ...
12
votes
2answers
13k views

How can I convert a mouse click to a ray?

I have a perspective projection. When the user clicks on the screen, I want to compute the ray between the near and far planes that projects from the mouse point, so I can do some ray intersection ...
3
votes
2answers
1k views

Decomposing a concave mesh into a set of convex meshes

I'd like to be able to decompose a concave mesh into a set of convex meshes for 2 reasons: Transparent rendering Physics shapes Is there an algorithm that takes a set of triangles (concave) as ...
0
votes
1answer
416 views

Issues with Sine Wave Generation and Rotation

I'm working on generating objects in sine wave that lets you specify parameters that are start x, end x, start y, and end y position. Below is the method that I used to generate the debris void ...
1
vote
0answers
50 views

How can I keep vertex order the same on every Instantiate()?

While trying to resolve another question, I have discovered that if I Instantiate() from a prefab, the order of the mesh vertices (and therefore triangles) is inconsistent between instances. This is ...
1
vote
1answer
53 views

Algorithm that cover one mesh by another mesh

Suppose I have two meshes (Let call me first MeshShirt and second - MeshBody) Meshes are aligned (if i render both MeshShirt "covers" MeshBody). But some parts of the body are not "under" the ...
0
votes
1answer
145 views

Formula to measure uv-mapping distortion

Does anyone know a simple way of calculating (offline) the amount a texture is distorted when mapped to a triangle like the following? Vertex Position UV Coordinates A (Ax, Ay, Az) ...
1
vote
1answer
113 views

Chamfered cube geometry generator

I'm trying to create a geometry generator for a "Chamfered Cube". I've got the vertices working, but I'm stuck with creating the faces. I don't really know how I could re-arrange my algorithm to ...
0
votes
0answers
57 views

Calculation technique for 2D inertia tensors?

Just wondering what the techniques are out there. It's only 2D so I figured there'd be a good chance for there to be a "one size fits all" solution out there that's essentially an analytical solution. ...
0
votes
1answer
139 views

Given seams, how do I unfold a mesh?

If a user marks a seam on a mesh, how do 3D modelling programs (like Blender or Maya) unfold the mesh on to a 2D surface? I can only find papers trying to automate the seaming for you. Given ...
2
votes
1answer
2k views

How do I find the circumcenter of a triangle in 3D?

I want to find the circumcenter of a triangle. Wolfram only shows how to find the circumcircle of a triangle in R2. How can I find the circumcenter of a triangle in R3?
1
vote
2answers
115 views

How to find the points of intersection of two OBBs

In my game I need to be able to find the points of intersection between two OBBs. I'm using Separate Axis Theorem to check if there's an intersection and get the penetration vector if there is one. ...
1
vote
1answer
223 views

How to access Maya Bonus Tools 2012 in Maya 2014

I have been trying to use the paint geometry tool for Maya 2014 but it isnt showing up. I downloaded Bonus Tools 2012 and installed it. Where can I find this tool in Maya 2014?
0
votes
1answer
308 views

How to determine the distance between a point and a rotated rectangle

This question is very similar to How do I calculate distance from a point to a rectangle?. But that question assumes that the rectangle is axis-alligned, or not rotated. So just like in that ...
1
vote
1answer
243 views

In a TPS, how to aim bullets to the direction the camera is pointing, but make the shooting from the player?

(In C#/XNA.) I mean, I can't find an answer nowhere. I'm trying to learn how to make a Third Person Shooter, especially like the one I found in a game called "M.A.R.S.", from Epic Games. I don't want ...
2
votes
1answer
71 views

Distort a quad with a World Matrix

Is it possible to distort a quad multiplying its vertices by a specific world matrix? See the picture to understand what kind of distortion I need: Please note, that the quad is in 3d space and I ...
2
votes
2answers
47 views

Calculating angle a segment forms with a ray

I am given a point C and a ray r starting there. I know the coordinates (xc, yc) of the point C and the angle theta the ray r forms with the horizontal, theta in (-pi, pi]. I am also given another ...
0
votes
3answers
72 views

Calculating the center of a turning circle

I'm trying to understand how to calculate the midpoint of a turning circle. In the attached picture, my unit is at location U. I want to compute the trajectory of the unit as it turns toward the ...