Mathematics questions deal with the arithmetic, geometry, calculus, formulae and other calculations used in the development of a game.
-1
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0answers
37 views
Problem math game Gamemaker
Umm for some reason Gamemaker doesn't see certain parts of my code. I am not so good at programming so can someone please help?
So I am making a cash register game, and for some reason some of the ...
0
votes
0answers
19 views
What is the actual formula to find the vertices of an animation frame in using a BVH file?
I've read this tutorial and tried many formulas to build the skeleton. I am able to build it without the rotations, but those break everything. This, for example, is a simplified code for one of my ...
0
votes
0answers
17 views
Cone Lighting formula for 2D projection space?
There is a good formula for a 3d cone lighting:
float angleCos = dot(lightVector.rgb, lightDirection.rgb);
attenuation = saturate((angleCos-coneCos)*coneCos);
What if I want to compute whether my ...
2
votes
1answer
99 views
3D Camera Rotation
Please, forgive me, but I need help and I've been stuck on this for a few weeks now, I'm making no progress and everywhere I go and I see a different answer, everything I try doesn't work. I've had ...
7
votes
1answer
430 views
How can I project a 3D point onto a 3D line?
Let's say I have a line defined by two points, A and B, both in the form (x, y, z). These points represent a line in 3D space.
I also have a point P, defined in the same format, that isn't on the ...
0
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0answers
27 views
Forgot about an commonly used letter for angle s in trigonometry [on hold]
I had to draw it on GIMP in order to search it on Google image search, but it did not throw any desirable results.
What letter does this symbol represent? Perhaps the correct version is horizontally ...
2
votes
1answer
100 views
What is Vector Projection and what is it's use in games?
Couldn't find a clear enough answer on Google.
I know what vectors are. But what does it mean to project a vector onto another, and what is it used for in games?
2
votes
1answer
69 views
C# - Separating Overlapping Rectangles
I'm trying to separate an arbitrary number of randomly sized rectangles, while still keeping them snapped to the grid, and somewhat packed together nicely. The goal is to start with something like ...
1
vote
1answer
55 views
The correct way to transform a ray with a matrix?
Playing with XNA Triangle Picking Sample I found out that it does not work well if you scale the world matrix of the objects you want to pick. When I dug into the implementation I found this comment ...
0
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0answers
6 views
Using morton codes to compress data - how? [migrated]
I've been reading something about morton codes and I got that locality is preserved in the sequence of generated numbers.
What I don't understand is how this information can be used to compress data ...
10
votes
3answers
331 views
How do I lerp between values that loop (such as hue or rotation)?
View Demo
I'm trying to make the joint rotate smoothly around the center of the canvas, toward the angle of mouse pointer. What I have works, but I want it to animate the shortest distance possible ...
0
votes
2answers
27 views
Compute cone angle (cos) given side and hypotenuse vectors at time 0 and world matrix at time 1
I need a formula for the cosine of a cone, given normalized side vector, normalized hypotenuse vector at time 0 and world matrix at time 1. This is needed to implement custom spotlights in a level ...
0
votes
0answers
28 views
libgdx get rotated sprite coords points
I would like to get the position of each edge of a sprite when he has been rotated.
I have no idea how to do it, I made a image to explain it.
I would like to get the X and Y position of each Red ...
3
votes
1answer
53 views
Field of view determination with partially opaque cells
I'm currently implementing the field of view of a player in a 2D-grid based game. I've chosen a standard ray tracing algorithm because he really fits the features needed in my game.
However, the ...
3
votes
2answers
86 views
How simulate the return effect of the wheel of fortune needle
I am trying to create a spinning wheel which slows down after a specific time.
I managed to simulate the slowdown of the wheel but I need also to put a needle which go up and down with an angle of ...
3
votes
1answer
67 views
What is an axis aligned integer bounding box?
In this paper, in the Distance field computation section, it says that an axis aligned integer bounding box of a Prism has to be calculated. Can someone explain what an axis aligned integer bounding ...
0
votes
0answers
25 views
Calculating intersection of line segment with view frustum
I want to calculate the intersection of a line segment with the view frustum.
Here's what I tried so far. The code works perfectly when the look direction vector is orthogonal to the line. E.g. ...
0
votes
0answers
30 views
HTML5 Canvas: Get rect coords after rotation (relative to screen)
update: function(delta) {
for (var i = 0; i < this.bullets.length; i++) {
this.bullets[i].velocity = this.bullets[i].speed * delta;
this.bullets[i].contextX += ...
2
votes
1answer
73 views
Converting between Spiral Honeycomb Mosaic and axial hex coordinates
There seems to be quite a lot of logic in dealing with hexagonal grids using a system of axial coordinates like the one described here.
In doing some reading about hex grids, though, I ran across the ...
0
votes
1answer
31 views
Rotating image around a given point
Im trying to simulate shadows in a 2d RPG, So far I can make the shadows but i cant blit them properly, Im trying to rotate them according to where the "sun" is (just a position)
I have looked at ...
0
votes
0answers
41 views
how to do picking in 2d lwjgl
I searched the whole internet, but I couldn't find something useful.
How to do picking (like ray picking) in lwjgl in orthographic mode (2d)?
I think this is less confusing than picking in 3d, but I ...
4
votes
1answer
344 views
Algorithm for randomly generating reachable platforms
I want to randomly generate reachable platforms on the fly for a 2D game. Right now, I am just creating platforms at random x,y positions. Only 4 platforms can exist at once, so once the 5th one is ...
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votes
0answers
37 views
Segment-Segment continuous collision detection
I'm implementing a continuous collision detection system and need to check if the edges of two triangles will collide. One segment is stationary, while the other moves with constant velocity. The ...
0
votes
1answer
42 views
Getting the position of a directional light w.r.t. a moving object.
I have a forward vector of my object, which is a bike, and its position, and I have a directional light direction.
I would like to know where the light is with regards to the bike ...
1
vote
1answer
85 views
Calculating How To Intercept a Moving Object [duplicate]
So I have two objects, Target and Interceptor. Target's position, direction of movement and movement speed are known, and Interceptor's position and movement speed are also known. Both movement speeds ...
8
votes
4answers
341 views
Modify random distribution functions :: Make it less likely to get multiple similar values in a sequence
I want to generate a sequence of numbers for procedurally generating planets in a galaxy sector. Each planet should be placed randomly, however it should be very unlikely that two planets are directly ...
0
votes
1answer
34 views
Best method for selecting points from a point set - path distance
having a big set of points and a polygonal path what is the best way to select a set of points that are at a certain distance or smaller from the path?
Or do I need to iterate thru all points on each ...
1
vote
2answers
79 views
How can I fix my sprite being rotated 90 degrees more than toward the mouse?
I am trying to get a Sprite in LibGDX to look at the player's mouse. Here's the code I have (mind you, I am using JRuby):
target = mouse_position.sub(spatial.position)
rotation = ...
1
vote
1answer
79 views
How can make an object orbit a sphere in a random direction?
How can I move an object on a random orbital path around a sphere?
I've created some objects at an initial position that is essentially a random point on the sphere offset by some distance (say, ...
0
votes
0answers
43 views
Java Angle Math: Calculate how near the player looks to an entity [duplicate]
I am programming a Minecraft Bukkit plugin and need a way to calculate an input number from 0 to 360 for displaying a custom compass / radar. So if the player directly looks at the object (shouldn't ...
1
vote
2answers
75 views
matrix to rotate a vector to a known arbitrary axis
Let's say I have a vector V (v.x,v.y,v.z) which is normalized and points somewhere in 3d space. And that I have another vector Z of (0,0,1). Knowing only these two things I'm looking for a ...
6
votes
1answer
173 views
Square Grid Polygonal Terrain Query algorithm?
I have a square, fixed-grid terrain with one terrain type per grid unit in my game, and I want to do an arbitrary polygonal terrain query which returns all of the grid units enclosed/intersected by ...
0
votes
0answers
86 views
Alter a model-view-projection matrix
I have a model-view-projection matrix created based upon my camera. Is it possible to make alterations to it after it was computed to affect the corners of the resulting camera frustrum? For example, ...
0
votes
1answer
90 views
What are the correct angles in the Top-down perspective?
In the following picture it says that in the Top-down perspective the angles are 90°, but if it would be 90° then you shouldn't see the front of the building and the roof at the same time...
So what ...
6
votes
2answers
135 views
How do I avoid interpolation artefacts when scaling up a heightmap?
I am using a bicubic interpolation algorithm in order to upscale a height map, and I am noticing some artifacts around the pixels boundaries. However, these artifacts don't seem to appear when I use a ...
0
votes
1answer
64 views
Trying to make sprite float up and down [closed]
Using LibGDX + Box2D and my understanding of the answer posted from this question: Here
I apply the following impulse:
// modify sprite's Box2d Body object
int a = 8; // amplitude
int f = 1; // ...
-1
votes
1answer
45 views
lerp z rotation towards mousepointer
I am trying to get transform.rotation.z to chase the mouse pointer at a rotation speed. But I get a very weird results and can't figure out what I am doing wrong.
var mp = Input.mousePosition;
...
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votes
1answer
72 views
Lerp speed or lerp time [closed]
Am I right about the fact that lerping can be done over a set period of time or at a speed which will continue until the target is reached?
How are the formulas for the two? Is it something like ...
0
votes
0answers
54 views
How to convert bones skeleton into joints skeleton?
I'm exploring skeletal animation and taking Half-Life SMD format as example. It has skeleton rigged as hierarchy of joints. Each joint has a parent and offset + rotation to it.
Now I'm importing ...
8
votes
3answers
435 views
Can I jump from A to B?
I'm making some rudimentary AI for my side-scroller and I need to know whether an AI unit can reach point B from point A simply by taking a jump.
Flight trajectory of my characters is a bit unusal as ...
0
votes
0answers
46 views
Implementing ClearPath (crowd pathfinding)
This is the academic article:
http://gamma.cs.unc.edu/CA/ClearPath.pdf
Here is the confusing part (marked in red):
The first part is the path in which the object will move.
The first part of ...
1
vote
1answer
71 views
Area of surface contained in pixel
Let's say I have some surface rasterized and stored to a texture. How do I calculate the actual surface area that is visible in one of the rasterized pixels, from some other location?
So far, I'm ...
1
vote
0answers
40 views
Calculating Friction due to rotation from ball bounce? [duplicate]
In this question asked by codemonkey, The rotation will depend upon:
upon impact, on:
Initial Speed of the ball hitting the surface (magnitude of ball velocity vector)
Friction co-efficient of ball ...
7
votes
1answer
277 views
RK4, Derivatives, Understanding Game Physics
Gafferon Games has a great article on RK4 Integration for building physics simulations which can be found here: Integration Basics
Personally my mathematics and physics knowledge could use ...
-2
votes
2answers
81 views
Convert atan2 value to standard 360-degree-system value [duplicate]
Lets say I'm using atan2 to get the angle between two vectors.
atan2 gives a value in radians. I convert it to degrees using a built in function in Java. This gives me a value between 0 and 180 ...
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votes
1answer
74 views
How does atan2 work when getting angle of a vector?
I know that atan2 gives me the absolute angle of any vector. But it doesn't give a value from 0 to 360 degrees. Instead, it gives a value (if I'm not mistaken), between 0 and 180, or between 0 and ...
1
vote
1answer
77 views
How to adjust a font to fit inside a speech bubble?
I'm creating a game that contains a speech bubble for dialog. The idea of this function is to allow one call to set new text in a speech bubble. The speech bubble will adjust in size of the new font ...
0
votes
1answer
120 views
Using atan2 to calculate angle between two vectors
I understand that:
atan2(vector.y, vector.x) = the angle between the vector and the X axis.
But I wanted to know how to get the angle between two vectors using atan2. So I came across this solution:
...
0
votes
3answers
74 views
How to apply logarithmic type formula for speed?
I want my character's speed to ramp up using somewhat of a logarithmic formula. I am confused about how specifically I would implement this. I want the character to move fast with a little movement as ...
4
votes
2answers
374 views
How do I use the dot product to get an angle between two vectors?
I am learning to use normalized vectors in my games.
I've learned that in order to know the angle between two vectors, I can use the dot product. This gives me a value between -1 and 1, where
1 ...
