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

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3
votes
2answers
128 views

Most efficient way to get the world position of the 8 vertexes of a Box Collider (C#)

What I am looking for is the most efficient way to get the world position of the 8 vertexes of the Box Collider of a freely rotated Gameobject. I cannot use collider.bounds since object is rotated, ...
5
votes
1answer
147 views

Finding new position after collision with multiple colliders

What is the most accurate way to find the correct position to where a moving character should be re-positioned as a collision-resolution, after it has collided with multiple colliders? The figure ...
8
votes
4answers
806 views

How do I efficiently check if a point is inside a rotated rectangle?

Part for the sake of optimization, part for learning purposes, I will dare to ask: How can I most efficiently check whether a 2D point P is inside a 2D rotated rectangle XYZW, using C# or C++? ...
13
votes
3answers
769 views

Are the first three values that describe a 3D plane actually a 3D vector?

A 3d plane is typically defined as a,b,c,d. Are a,b,c actually the x,y,z coordinates of a 3d vector, with d defining the rotation of the plane, something like axis-angle rotation data?
19
votes
5answers
1k views

How can I tell whether an object is moving CW or CCW around a connected path?

Lets say we have a jagged shape: And two creatures moving along it's outline. Then we smooth the shape completely by pulling the corners out. We get this: It is easy to see now that Orange is ...
1
vote
1answer
627 views

How do I calculate the distance between a point and a rotated rectangle?

This question is similar to another one about axis-aligned rectangles. However, I specifically want to calculate this for rotated rectangles. I have a rectangle with a (cx, cy) for the center ...
16
votes
6answers
7k views

How do I calculate distance between a point and an axis-aligned rectangle?

I have a 2D rectangle with x, y position, height and width, and a randomly positioned point nearby. Is there a way to check if this point might collide with the rectangle if it is closer than a ...
6
votes
4answers
2k views

How do I restrict the movement of a point to within a radius of another?

I have a situation where a sprite's center point needs to be constrained within a certain boundary in 2D space. The boundary is circular, so the sprite is constrained within a radius. This radius is ...
2
votes
1answer
115 views

Realistic angular velocity for rolling sphere in Unity 5.1

I'm trying to make a small 2D game with a rolling ball/sphere using Unity 5.1, but if find the angular velocity of the ball weird. On this first image (http://imgur.com/8wBoGms), you can see the ...
5
votes
2answers
776 views

Is there an efficient way to identify in which run-time generated room a character is, in a non-grid 3D environment? How?

Here is what I am trying to implement. I wrote a script that allows the player to place walls during run-time, in non grid-based 3D environment (walls can be diagonal with rotation increasing/...
1
vote
0answers
41 views

Detecting the two Vector3 that determine the bottom-edge of the side of a box-collider that had collision (with C#)

So, I understand that plenty of questions have been posted on how to detect which side of a Box Collider had collision. However, what I am trying to achieve is a little different. I want to find out, ...
1
vote
0answers
140 views

Calculating Minimum Translation Vector in Separating Axis Theorem based algorithm

In the 2D SAT collision determination algorithm, you project the convex polygons onto each potential separating axis. Supposing the polygons intersect, from what I understand, the axis for which the ...
0
votes
2answers
108 views

Optimal way to find point D that lays at the perpendicular line between point A and line BC

I am trying to write a script in C# to find the position of point D in 2D space in a specific scenario. I know the (X,Y) position of point A, which never happens to be on the line that contains the ...
0
votes
2answers
128 views

Rotate coordinates back after rotating game context (geometry)

To achieve something similar to the image below using HTML5 canvas one can simply write the following: var TO_RADIANS = 0.0174532925; context.translate(30, 20); context.rotate(30 * TO_RADIANS); ...
1
vote
3answers
139 views

What's the most efficient way to find the position of a point in relation to corners of a rectangle despite rectangle's scale

I am struggling to achieve the following with C# (in Unity). I need to find the position of the points that lay at a given distance (let's say 1m) from the corners of a rectangle, in a way that the ...
1
vote
1answer
957 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 ...
4
votes
2answers
467 views

How to properly rotate towards a local point in Unity C#? (a local LookAt)

I am having a nightmare trying to make a child object rotate towards a given point of its parent object, similar to what is possible at the world level when using LookAt. The problem is that most ...
2
votes
0answers
101 views

Rotate perspective camera to align screen width to procedural object's width (Unity, C#)

I give up. After much trying and searching, I have to say I was unable to achieve the following task, for which I must call for your wise advice. In my current Unity 5 application (using C#), there ...
0
votes
0answers
31 views

Drawing shapes within a rectangle area

I am working on a Objective-c project where I need to draw multiple rectangle shapes inside a rectangle area like the attached image. Basically calculating CGPoints inside the CGRect. Thanks in ...
0
votes
2answers
203 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.
9
votes
4answers
235 views

How do I interpolate around a rectangle?

I want to make a fancy animation where a point travels around a rectangle. I want to find the point's position at a time t. The rectangle is given by X, Y, Width and Height. Is there an algorithm ...
0
votes
1answer
93 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 ...
1
vote
1answer
47 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 ...
1
vote
1answer
139 views

Sliding DOOM style collision resolution against arbitrary 2D geometry

I've been working on a HTML5 canvas raycasting engine for the web browser, with the end goal of making a simple FPS game in the style of the early 90s. The engine sits somewhere between Wolfenstein 3D ...
0
votes
0answers
41 views

boost/geometry replacement in Java/for the JVM (Destructable Box2D terrain)

I'd like to reimplement https://github.com/seemk/DestructibleBox2D in Java. The main problem is finding an adequate replacement for the boost/geometry library. Any ideas?
0
votes
0answers
40 views

3D Picking: Doesn't Work Consistently

I'm trying to implement a 3D picking function that at the moment simply calculates the ray being sent from the camera after the user clicks the mouse on the window. It kind of works well when the ...
2
votes
2answers
98 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 ...
-1
votes
1answer
105 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
2answers
69 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 ] [ ...
0
votes
0answers
273 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
186 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
95 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
155 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 ...
36
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 ...
15
votes
4answers
798 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
371 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
184 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
319 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
168 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
2k 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
37 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
201 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
68 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 Vector3(x,y,z)...
18
votes
2answers
5k 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
63 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. ...
12
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
25 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 ...