Mathematics questions deal with the arithmetic, geometry, calculus, formulae and other calculations used in the development of a game.
2
votes
1answer
786 views
Converting time of day into a smooth day/night variable?
I'm trying to make a smooth day/night cycle for a game project that I've been working on. I've already set up a clock that adds deltaTime to seconds, wraps seconds to gameMinutes, etc. The issue that ...
2
votes
1answer
18 views
Libgdx : point that scrolls on the edge of a circle
I'm not very familiar with libgdx vectors. I want to create my own joystick-controller and I want to know how can I find the coordinates of B by using Vectors. I can calculate the radius and I have ...
0
votes
2answers
42 views
Getting neighbors of hex tiles in 3D space
I have a hex tiled model like attached below. Each of the hex tiles are separate objects meaning I can access each of the hex tiles individually inside Unity
Now in my program I want to be able to ...
0
votes
1answer
93 views
Finding a vector perpendicular to a current vector
Assume, that we have a player that has a vector direction. We have an enemy, that is shooting a player. And the task is to find out from which side the enemy is shooting. I know the algorithm, how to ...
4
votes
2answers
181 views
Can someone explain dual contouring?
I've been trying to understand voxel rendering and have been looking at dual contouring (DC).
So far I understand this much:
Run a density function for a set of grid points (i.e noise function)
...
2
votes
0answers
25 views
Calculate required resolution
Lets say I have a rectangle with width x and height y. Then there is transformation matrix T.
Now, how using only those data can I estimate minimal resolution of texture (that is its width and ...
3
votes
3answers
115 views
2 component unit vector
Is it possible to store a 3d unit length vector with only 2 components, for example as coordinates on a unit sphere? It seems possible but I have never seen anyone do this. Would this be at all ...
1
vote
1answer
57 views
Usage of math.Atan2 in a 3D coordinate system with Unity
I have a simple question on usage of math.Atan2 function with Unity in a 3D environment.
I found this code on Unity's documentation for Math.Atan2. I changed it a bit to fit my
needs.
Vector3 ...
0
votes
1answer
83 views
Gun Bobbing Algorithm Math Explanation
I stumbled across this really neat algorithm which I don't fully understand. It simulates a camera's bobbing effect commonly witnessed in first person shooters while running/walking. I'm mainly unsure ...
1
vote
0answers
64 views
How to rotate enemies on 2D radar and clip them to circle shape? [duplicate]
I've been working on implementing a 2D radar for a 3D game lately, it's working fine in a very basic version. This is what is looks like:
It works by transforming the 3D coordinates of the enemies ...
1
vote
1answer
50 views
Scale around a point
I am trying to create an image editing application for the purpose of generating UV maps in my own format. I am currently working on scaling the image for the purpose of zooming. I can get the image ...
2
votes
1answer
75 views
Screen coordinates to isometric coordinates?
I know this has been discussed here before, but I couldn't find an easy solution for my particular problem. I have a tile system and I'd like to convert screen coordinates into isometric tile ...
1
vote
3answers
123 views
How do I generate solar systems for a 2d universe map, but still look random
I need to generate 64 systems separated into 16 sectors, each with 4 systems. Each system must have another system within 10 units in it's own sector, but no closer than 3. One system in a sector ...
1
vote
1answer
17 views
Camera world matrix to view matrix
I've been working on a game engine and I model every object in my scene graph as an "entity" this includes my camera.
My camera therefore has a position and rotation in world space and at the moment ...
0
votes
1answer
42 views
Computing Field-of-View from window dimensions
I'm looking into computing the vertical Field-of-View (FOVy) based on the projection parameters of my camera. From this source, I've found an equation that seems to work.
float ...
0
votes
1answer
54 views
Is the rendering of distorted point clouds more complex?
I have two point clouds of n points:
A dense ball-shape point cloud with many points inside
A spherical point cloud with points on its surface.
Is there (really) any difference between rendering ...
3
votes
4answers
247 views
RPG like hit points growth algorithms help
I am currently making an XNA game in C#. I want to increase health as the player level up. I am currently using this equation.
MaxHealth = Convert.ToInt32(100 * Math.Pow(1.17, level - 1));
Its ...
2
votes
1answer
58 views
Impact of object's statistics on the rendering
Consider two 3D objects with n points and n triangles. One of the objects has a smooth surface such as a ball or a box, and the other object is like a fuzzy onion-layered object with large ...
1
vote
1answer
46 views
Rotating a square rendered on a Bitmap
I'm writing a Software Renderer for fun/learning. Basically, it's just a giant array of integers which contain hexadecimal values (representing colour) that are rendered to the screen....
int ...
1
vote
1answer
46 views
Compute billboard rotation
I'm trying to compute a matrix to have object always facing the camera. For the moment, my result look pretty good, the problem is that my original billboard scale isn't preserved (Every billboard ...
2
votes
1answer
66 views
AABB implementation
I have seen in some texts and tutorials on the web where an AABB is implemented as a position vector and then half-width and half-height vectors. What is the advantage in using the half-width and ...
1
vote
1answer
76 views
How can I test if an oriented rectangle contains another oriented rectangle?
I have the following situation:
To detect whether is the red rectangle is inside orange area I use this function:
- (BOOL)isTile:(CGPoint)tile insideCustomAreaMin:(CGPoint)min max:(CGPoint)max {
...
0
votes
1answer
36 views
Find normal based on rotation?
Given the XYZ rotation of an object, e.g. (90,0,0), how can I find the object's normal assuming the object is pointing along it's local Z axis?
In the above example the desired result is (0,1,0).
...
0
votes
0answers
29 views
Parabolic throw with set Height and range (libgdx) [duplicate]
Currently i'm working on a minigame for android where you have a rotating ball in the center of the display which jumps when touched in the direction of his current angle. I'm simply using a gravity ...
4
votes
2answers
167 views
How can I manually construct a right-handed orthographic projection matrix?
I need the formula to create a orthographic projection matrix. I am using GLM math libary and DirectX11. The reason I cannot use GLM to create it is because the NDC spaces are different between DX11 ...
0
votes
2answers
34 views
Converting A 3D Rotational Vector Into A 3D Forward Heading Vector
I need to do a raycast which accepts a Vector3D StartPos and a Vector3D EndPos.
I have available to me the characters position and the cameras rotation in 3D vectors.
I need to somehow compute a ...
-1
votes
3answers
94 views
Shooting based off mouse position [duplicate]
I'm trying to shoot bullets where the mouse is aiming using one image as a test. I'm trying to get the mechanics like this
I have some kind of algorithm to handle that but the results arn't too ...
0
votes
0answers
34 views
Calculating co-ordinates of a line/ray that's increasing in height with a known slope/radians. Height increase is also known
basically in my game I'm firing a line. The line's anchor point is at the very bottom of it, and half of its width.
When I fire the line, its rotation gets set to face where we want it to go. Then, ...
4
votes
1answer
87 views
Determining a sensible gear-like hierarchy for a series of connected objects
I would like a series of objects to behave in similar manner to a series of connected gears.
This means that each black object in the diagram below will rotate at a speed based on the ratio of their ...
-1
votes
1answer
85 views
Code explanation
Can someone please explain whats going on in this code written by Paul Irish
I did not understand the draw().
function draw() {
var time = new Date().getTime() * 0.002;
var x = Math.sin( ...
0
votes
1answer
60 views
What is the optimal way to handle matrix internal data storage for interop with native graphics apis?
I'm writing a managed (c#) game engine and have stumbled on a bit of a crossroads in design/implementation regarding matrix types.
Matrix types need to be optimized for marshaling to native graphics ...
0
votes
1answer
76 views
Rotating a vector around a vector in 3D space
I am trying to rotate a moon around a planet (the planet is also rotating around an axis) but I am having trouble doing so.
I tried to make the model move through space like so:
@Override
public ...
0
votes
3answers
84 views
Bridge made out of blocks at an angle
I want the player to select 2 points (vectors). With these 2 points a floor should be created. When these points are parallel to the x-axis it's easy, just calculate the amount of blocks needed by a ...
0
votes
0answers
24 views
Map to Screen Coordinates for isometric style map with tile height of 71 and width of 110
I am aware of the coordinates to convert map to screen coordinates and back with isometric tiles with a height and width ratio of 2:1. What I need is the same for tile width of 110 and height of 71, I ...
0
votes
2answers
169 views
How do I create a knockback-movement?
I am a web developer new to game development, and with limited math knowledge. I am writing a character movement controller in Unity. The game has an isometric Diablo-like camera. The character moves ...
2
votes
2answers
49 views
How to use “weighted average easing” correctly with variable framerate?
I often use a weighted average for smoothly animating numerical values to a target value, like so:
frame(dt) {
value = ((value*someFactor) + targetValue) / (someFactor+1)
}
As you can see dt ...
1
vote
1answer
44 views
Fit a bounding box in the scene modifying FOV
Suppose I have a radius for a spherical bounding box around a mesh.
My goal is to render the scene such as when the camera moves, the bounding box whose centre the camera look at, occupies always ...
0
votes
0answers
61 views
Closest distance from 3D point to vector line
First let's have a look at my little drawing:
I have an origin point p1 defined by x, y and z co-ordinates, and a vector v given by x, y and z magnitude.
I also have an arbitrary point, p2, given ...
6
votes
4answers
505 views
How do I convert from the global coordinate space to a local space?
Given an entity named EntityA, I want to define a local coordinate space, where the position of EntityA is the origin, its heading vector is the X axis, and the normal of the heading vector is the Y ...
1
vote
2answers
103 views
Find point in 3D plane
I have four points in a 3D space, example:
(0,0,1)
(1,0,1)
(1,0,2)
(0,0,2)
Then I have a 2D position on that square plane:
x = 0.5
y = 0.5
I need to find out the 3D space point of that position in ...
1
vote
1answer
55 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
37 views
Scaling entity by screen height (simulating depth on orthographic camera)
i want my entities to be at 100% scaling (for example 128x128 pixels) when they are at 40% of the screen height (for example 480 pixels at 100%), so when they are at 41%, they are at 99% scaling ...
3
votes
1answer
272 views
Explain this line segment intersection code
I've been reading this article on pathfinding over polygon meshes using line-of-sight, and in the article are several code snippets. One of them, the one I'm trying to understand, is a simple function ...
2
votes
2answers
201 views
How to make a projectile align correctly with the entity that shot it
I'm developing a 2D game. In the game, all entities can rotate 360 degrees. Each entity holds an angle value, and every frame it is drawn rotated around it's center by it's current angle value. For ...
2
votes
2answers
221 views
How can I simplify this code to compute the shortest rotation between two angles?
The following code will find the shortest rotation (in radians) (from pi to -pi) that I need to apply to from to leave me with to.
Scalar rotationBetween(Scalar from, Scalar to)
{
Scalar fromMod ...
1
vote
1answer
40 views
XY Location scaling with varying density screens
I have a phone with resolution H=1280,W=720,Density=2
I have a tablet with resolution H=1216,W=800,Density=1.331
I drew a rectangle on my phone with corners Left,Top (-1.6,1.55), Right,Bottom ...
1
vote
1answer
71 views
How do you change movement to strafe
Right now my player can move forward and backward using
case 'a':case 'A':
speed.x = lx * 0.1;
speed.z = lz * 0.1;
break;
case 'b':case 'B':
speed.x = -(lx * 0.1);
speed.z = ...
1
vote
2answers
69 views
How to get the normal that points *out* of a polygon
In 2D, each vector (x, y) has two normals: (-y, x) and (y, -x), pointing in opposite directions.
Say I have a polygon and for each of it's edges I need to get the normal pointing outwards. In the ...
1
vote
0answers
51 views
Resolving penentration after collision using Separating Axis Thereom
I implemented collision detection in my game using SAT. The detection works, but I'm trying to use the algorithm to figure out the penetration vector of the two OBBs and push them apart (before doing ...
3
votes
1answer
105 views
How can I find the tangent and normal at an interpolated point on a Catmull-Rom/Hermite spline?
I have an implementation of a simple Catmull-Rom spline. It works, but I'm trying my hardest to be able to place vertices at extrusions along the curve. For this I need the normal (and tangent in the ...
