Questions tagged [geometry]

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

Filter by
Sorted by
Tagged with
21 votes
2 answers
7k views

What is a "normal" in game development

I'm new in Game development and probably this is a silly question. I had a look online but haven't found a clear answer, I did it bit quick but enough to evaluate that this is a confusing topic ...
Federico Baù's user avatar
0 votes
1 answer
75 views

How can I correctly pass 2 vertices instead of all 4 for a quad to a vertex shader?

If I am rendering quads, but all the quads will be axis-aligned (that is, their plane is always parallel to either the X Y or Z plane), I thought I could cut vertex video memory usage in half by ...
user16217248's user avatar
9 votes
3 answers
8k views

How do game engines avoid recalculating normals upon mesh rotation?

Assume that a face of a mesh is defined by vertices A, B, C and that the normal of the face ...
Carpetfizz's user avatar
2 votes
0 answers
53 views

Aligning vector by rotation around non-orthogonal axis

This is almost more a geometry/mathematics question than a game dev one, but I think I'll have a better chance actually understanding the answer if I ask here. Rather than try to explain it- because ...
Keith Stein's user avatar
3 votes
0 answers
71 views

How to test for intersection of a cone with infinite camera frustum (no near/far plane)?

I have a given infinite camera frustum defined by four planes, each defined by a normal (left, right, bottom, top). From those planes we can also easily get the camera position and the view direction. ...
Lukas Kalbertodt's user avatar
1 vote
1 answer
57 views

Vertex Shader Sphere Projection and CPU Distance Calculation

I have multiple planes whose vertices are transformed to a position on a sphere in the vertex shader. The GLSL function called pointToSphere transforms a point <...
Miguel Myers's user avatar
0 votes
1 answer
55 views

How to calculate angular momentum of two colliding bodies about their shared center of mass in 2D?

I'm following this guide to implementing collisions in 2D physics. It shows this diagram, but I don't understand how to calculate the values of Da and ...
noodle_run's user avatar
0 votes
0 answers
74 views

Generating tris for concave polygon 2D

I have an arbitrary array of points that describe vertices of the polygon 2D, they ar in order. To generate plane mesh for that, I need to generate tris. For something like circle/hexagon/square it is ...
Kirikan's user avatar
1 vote
0 answers
20 views

Move a non-convex polygon's outline inwards?

The polygons are small 3D parts of a quasi sphere centered in the origin and a solution that works in the plane can easily be made to work in this world. I tried to move the outline inwards by using ...
August2323's user avatar
2 votes
2 answers
100 views

Finding the closest point on a circle to end of a ray in 3D

I have a circle in 3D space, so we have center C with radius r, and the normal of plane the circle lies on, N. There is also a normalized vector V that I am modifying to go far past the circle's ...
A well-rested dog's user avatar
3 votes
2 answers
115 views

How to check if player actually went through a trigger area and didn't just touch it?

I'm trying to make a racing game that measures your distance from the center-line of the road. To do this I need to check on which part of the road the player is, so the calculation is correct. (If it ...
SirResnick2's user avatar
0 votes
1 answer
70 views

Discontinuous Normals on a Normalized Cube Mesh with Displacement Texture

In my project, I have created a normalized cube using six plane meshes. To improve its visual quality, I added a displacement texture and calculated the normals for that texture to ensure proper ...
Memory1's user avatar
0 votes
1 answer
45 views

Rotating around 3D cube Camera Controller for Unity

I am Unity game developer with more than 2 years experience. I am working in a personal project, a mobile game for Android in Unity. I am trying to make a camera controller for a 3D Cube Game in Unity....
DamagedCyborg's user avatar
0 votes
1 answer
36 views

How to correctly position a set of cuboids based on a direction property in MonoGame

I am trying to create a map for my game using a list of cuboid sections that are defined like this: ...
Maxim Gershkovich's user avatar
0 votes
0 answers
18 views

Two moving and rotating bodies, how to approximate hitbox of a trajectory of a point on one body in the coordinate system of other

The game is in 2D. Let's say I have two bodies: A and B, each with position, angle, velocity vector, and angular velocity (I'm not sure yet if I should be using angles, or rotation matrices). Given a ...
HolyBlackCat's user avatar
  • 1,998
0 votes
2 answers
160 views

How to get area of 2D shape bounded by vertical and horizontal line segments?

I am making a game similar to Volfied using Unity: The player outlines an area using straight lines, either horizontal or vertical. I am stuck at the algorithm to decompose the area into rectangles ...
nicklowkc's user avatar
0 votes
2 answers
102 views

How do I detect collisions with a circle sector against basic geometry?

For the 2D game that I'm building, I want some entities to be able to use areas of attack, such as a wedge/circle sector area of attack. In this case, the circle sector is a pie-slice shaped section ...
WulffHunter's user avatar
0 votes
1 answer
78 views

What is the point of Geometry2D.make_atlas()?

I'm completely bewildered by the Geometry2D.make_atlas() method. I believe it has to do with texture atlases based on its name and comment on its source code but am ...
Javlin Joslin's user avatar
0 votes
1 answer
294 views

Two methods of finding angle between vectors give different answers!

Ok, am I misunderstanding how Unity quaternions work, or is there a bad (about 2 degrees difference!) floating point error? The TLDR is I use a quaternion r to rotate vector v and put the result in w. ...
user1895149's user avatar
0 votes
1 answer
199 views

How to create an octahedron for sphere subdivision?

I have vertices that generate the first out of two pyramids. However, I want to have the second pyramid facing downwards as to make an octahedron. What are the correct vertices to use, because I've ...
Chillzy's user avatar
  • 47
0 votes
1 answer
91 views

Help understanding the math to position sphere vertices by latitude and longitude

For a project of mine, I need to render spheres without loading a pre-made model or using built-in functions. I found this bit of code on the internet that seems to work but I really want to ...
Chillzy's user avatar
  • 47
0 votes
1 answer
67 views

Align two meshes given 2 faces

I have two meshes (A and B) and I know that a triangle in A has the same size and same angles as a triangle in B. For simplicity, suppose A is an octahedron and B is a tetrahedron. And suppose the ...
nkint's user avatar
  • 951
0 votes
1 answer
117 views

GameObject mesh.vertices array is empty

I've an Icosphere GameObject: I want to iterate over each of the faces and change the material based on their distance from the center, however I don't seem to be able to retrieve the list of ...
TomSelleck's user avatar
0 votes
0 answers
44 views

Wheel position on surface

I have a bicycle with suspension and need to find the contact point of the wheel on the "road". If the front fork was pointing straight down, it would be as easy as doing a raycast down the ...
Charl Cillie's user avatar
1 vote
1 answer
106 views

Given a quad in 3D space with two diagonally opposite points and normal, how would I find the other two points?

Image attached below for clarification: So here we have a plane with a random rotation in 3D space, and we have the values for P1, P2, and the plane normal. How do I find the points X1 and X2? This ...
Pooper's user avatar
  • 23
1 vote
1 answer
56 views

Add and Removing Elements on the Circumference of a Circle

I am trying to spawn entities on the circumference of a circle. These entities may be removed at any time, including all of them being removed. Periodically I would like to add an element on the ...
stats's user avatar
  • 135
0 votes
1 answer
62 views

Finding point along vector to maintain distance to an arbitrary point

I'm currently working on a particular project where orthographic and perspective projections are both used interchangeably. To keep the transition between both projection modes somewhat seamless, I ...
JJJohan's user avatar
0 votes
1 answer
120 views

How to spread circles evenly around a point?

In my game there's a part where a bunch of circles need to evenly spread around a point. Like in this demo below: ...
Ryan Peschel's user avatar
2 votes
0 answers
56 views

Audio emission from a polygon instead of a point

I'm developing a 2D game in Godot. The engine doesn't matter in this case. Given a polygon, convex or concave, and a listener (camera) location, what 2D position should an audio emitter be placed at ...
Anixias's user avatar
  • 23
2 votes
1 answer
406 views

Efficiently find all points within a circle

I am writing code that requires me to find all points within circle on certain parts of the screen hundreds of times per frame. I wrote a quadtree for this and have 1 method called query_circle that ...
Aayush's user avatar
  • 47
0 votes
0 answers
165 views

How can I move an object on a non flat surface in vulkan?

I am writing a small "game" in vulkan, in which a car can move in an environment that is not flat, like a desert with valleys. I am able to translate my car and follow it with the camera on ...
Luca Venturini's user avatar
0 votes
1 answer
70 views

Tangent Space View Direction based factor value remap

I'm trying to setup a mask similar to what Fresnel produces. Unfortunately Fresnel gives pretty bad results at grazing angles so I ended up using this : ...
MaT's user avatar
  • 1,045
0 votes
2 answers
175 views

Finding the position of a point based on a relative point inside a quad

I'm trying to get the relative point position on a quad using a [0,1] Vector2, like in the picture below: The red dots are relative positions. What I'm trying to make is a function that takes the A,B,...
Paulo Vinícius Bettio's user avatar
1 vote
1 answer
462 views

Find closest open space in grid of rectangles?

I'm making a builder game where you snap arbitrarily sized rectangles into a 2D grid. I want the player to be able to drag and drop these rectangles anywhere on the grid, but prevent collisions (i.e., ...
Andrew's user avatar
  • 13
3 votes
0 answers
696 views

Wall sliding collision resolution with multiple objects

TLDR My collision resolution algorithm with wall sliding works perfect for multiple walls but it fails when the angle of the corner of two walls is less than 90 degrees. (acute angles) and the player ...
Ciberman's user avatar
  • 135
0 votes
1 answer
140 views

Find out (general) orientation of cube faces with rotated and translated camera

I have the following problem. I have a camera that is initially looking at a cube. The cube is with center at (0, 0, 0). The camera that is initially on (0, 0, 60). The camera can rotate and translate ...
Teodor Dyakov's user avatar
0 votes
0 answers
71 views

Finger (Sensor) Shaking Detection

I want to make the user be able to shake a certain object through the phone's sensor. I have drag&drop mechanics now, and I want this shake to be directly related to that mechanics. How would that ...
ArtemiZ Studio's user avatar
0 votes
2 answers
71 views

Changing Model's rotation to keep its left side toward the pivot as it goes in a circle

I wrote a little script for my scene that allows my ship to circle an island, and it seems to work alright. Now I am trying to get the ship model to stay broadside to a pivot point in the center of ...
Doug Ray's user avatar
  • 143
2 votes
0 answers
17 views

Create a quad that faces a given normal [duplicate]

Let's imagine that we have a given normal, (it could be done with source and destination points but let's say that source is 0 0 0 and the destination has been already normalized) What could be the ...
Frank Escobar's user avatar
0 votes
1 answer
74 views

writing a custom Quaternion.FromTo

I'm using the new Unity.Mathematics library. I'm trying to to replace Quaternion.FromTo(Vector3 from, Vector3 to) which returns a quaternion with what it would take ...
Charly's user avatar
  • 742
0 votes
1 answer
262 views

How do I adjust the start diameter of a spotlight in Unity?

To clarify, I'm an experienced 3D modeller, but there are hiccups here and there getting used to Unity's interface. I'm working with an adjustable spotlight for a game; it can be mounted and directed ...
Michael Macha's user avatar
1 vote
0 answers
49 views

how to efficiently raytrace a rectangle side in 8bits without mul and div?

Imagine you are on a hardware that is 8bits like the nes or the game boy, NO mul no div, only add and shift. Given a rectangle or integer size nk*mk, where k is the size of the underlying grid, and P ...
user29244's user avatar
  • 327
2 votes
1 answer
78 views

How do I get the consistent time it would take for two points to reach each other in circular motion?

I'm making a 2D game. It involves the player swinging around a grapple hook in perfect circular motion, however, I want to make the cooldown for this ability based on predicted end position for the ...
Andrew M's user avatar
1 vote
1 answer
302 views

Optimal way to find the closest entity to player with a restricted set of functions

The scripting engine of Skyrim (and Fallout 4) has an interesting function called FindClosestActor(x,y,z,radius). If you call it with x,y,z center coordinates and a radius, it returns the closest ...
Bálint Juhász's user avatar
0 votes
1 answer
63 views

Needs help on actually making the trigonometric function work as intended

...
random person's user avatar
-1 votes
1 answer
183 views

Extracting cell center and corner points from rasterized Voronoi diagram

I currently have this code which I copied from Rosetta code: ...
random person's user avatar
1 vote
1 answer
548 views

Deriving shadow position from a 2D heightmap

I have a 2D heightmap with discrete values. Based on these values they should cast a fixed position shadow (constant angle respective to the "sun"). I can figure out how to cast it on a flat ...
KayleMaster's user avatar
3 votes
0 answers
869 views

How to project 3D meshes onto a 2D plane producing a 2D polygon silhouette?

I would like to project a number of separate 3D meshes onto a 2D plane and create a 2D polygon representing the outline of all the meshes. I would also like to to create multiple 2D polygons if the ...
Path's user avatar
  • 31
0 votes
1 answer
54 views

Arranging points in a 2D grid so that successively added points approximate a square shape

So, I ran into a problem with placing points in a grid while always trying to fit them into a square. Here are some examples (the numbers represent the order of placement): Placing 1 point: ...
thzoid's user avatar
  • 3
0 votes
0 answers
61 views

How to find the center of mass from CapsuleCast in unity

Is there an easy way to find the center of mass from a CapsuleCast, or should I find the geometric center of it?
RhinoPak's user avatar

1
2 3 4 5
11