# Tagged Questions

Arithmetic, geometry, calculus, and all else which resolves the number-crunching necessary in a game. Math questions are those that deal with the formulae and calculations used by the game in various parts.

124 views

### Precalculate the position of a rotating Aircraft

To start honestly, this question is probably mostly handling math. But thats only the road I tried to go and failed miserably, so maybe theres a much more simple way to do. Ok the game situation is ...
180 views

### Transforms in Box2D

I'm attempting to implement a camera in my game. I had it working for regular objects, but I began using Box2D and obviously things changed a bit. I have a Body object that I want to draw at the ...
74 views

### Need transform matrix to translate the center of the view to a custom position within the target texture

My problem is as follows: I want to use a single render target texture for drawing 16 viewports where I want to display the 16 different combinations of the marching squares algorithm with my 3D ...
101 views

### Stereo 3D: drawing 2D elements at apparent screen depth

I'm developing an application making use of DirectX11's stereoscopic features. At such I am not relying on nVidia's automatic implementation. That means I have to replicate a way to render 2d elements ...
116 views

### Determining explosion radius damage - Circle to Rectangle 2D

One of the Cocos2D games I am working on has circular explosion effects. These explosion effects need to deal a percentage of their set maximum damage to all game characters (represented by ...
65 views

### Surface normal to screen angle

I've been struggling to get this working. I simply wish to take a surface normal and convert it to a screen angle. As an example, assuming we're working with the highlighted surface on the sphere ...
325 views

### Modular spaceship control

I am developing a physics based game with spaceships. A spaceship is constructed from circles connected by joints. Some of the circles have engines attached. Engines can rotate around the center ...
182 views

### Matrix multiplication - Scene Graphs

I wrote a MatrixStack class in C# to use in a SceneGraph. So, to get the world matrix for an object I am suposed to use: WorldMatrix = ParentWorld * LocalTransform But, in fact, it only works as ...
406 views

### Procedural dungeon generation. No corridors, color key doors

I am curious how dungeons like the one in Runescape dungeoneering skill are generated. They basicaly have a 10x10 grid. So theres 100 rooms total. There's starting room and exit room. And each one are ...
98 views

### Which is the right way to build a OpenGL Projection Matrix

This time I'm trying to learn the core of matrix transformations. I dont like the idea to using a Math library and dont understand what is hapening on background, because this I'm having some ...
199 views

### Making Ball Fling in a Curve Direction

I was wondering how to figuring out how to slice a ball (banana kick) by flinging it curve-ways. However, according to the LibGDX's gesture listener, the method for flinging only focuses on a straight ...
121 views

### Quaternion to direction vector - flipping

I've kinda solved this myself by adapting the Camera::setDirection code from OGRE to work for my need: Now I have the following code: Vector3 boneDir = getBoneWorldOrientation(mEntity, mHips) * ...
39 views

### How do I fire a projectile at where an object will be located in the future? [duplicate]

I'm making a tower defense game where the towers are shooting projectiles at enemies. I do not want to make the projectiles homing, and I want to make sure that when a tower fires a projectile, it ...
164 views

### Is this Rotation Matrix correct?

I'm having heavly troubles with setting up a View Matrix and a Projection Matrix. It simply doesnt work. So I think my problem is related to my rotationMatrix function. I'm using this tutorial to ...
315 views

### How can I remove the view and projection matrix from ray position to get only the ray model?

I've got a little problem with my picking module and I need your help. I have a method to project a ray from the camera to a fixed point when I click somewhere. The computed ray looks good, it go to ...
124 views

### How do I derive the angular movement for a craft

I have the regular (linear) motion implemented like this: class Craft{ ... Vector location, velocity, acceleration, angularVelocity, angularAcceleration; ... //the move class responsible for linear ...
83 views

### Getting half plane direction relative from cam position

Im implementing certain Camera movements in my turn based games. I'm able to place and rotate the camera between two units that attack each other. However it will always move to the same "side". Which ...
337 views

### Generate equal regions in a hex map

Taking for example large (X by Y) hex map, how can I divide the map into N regions of connected hexes to simulate countries? The goal is to generate a hex map that looks like a real life map with ...
135 views

### How good do I have to be at Math to create a 3D game using three.js? [closed]

A question I've often had, how good at Math do I need to be to create 3 dimensional games? I get along with 2d games just fine. I understand everything I'm doing without problems after practise. ...
226 views

### How to account for acceleration when aiming projectiles?

How do I aim a constant speed projectile to hit a target if there is a constant acceleration vector acting on it? (For example, the wind and gravity from Worms.)
93 views

### Move from point a, to point b, and determine the accuracy

Let's say I have a circle at point a (0,0), and I wish to move it to point b (23,58), whatever, how can I accurately do this with a speed variation if I wanted. (I'm doing this in javascript). Every ...
393 views

### Calculate object coordinates from window coordinates using inverse projection matrix

What I am trying to to is placing 3D Objects (A Sphere) in the world when I click there. I am using a perspective projection so the first step after calculating the canonical clip coordinates from ...
92 views

### Opengl 3.2 Flickering after smooth animation?

Okay I am new to OpenGL I am getting an odd issue. I am performing rotation on a bunch of triangles on a scene graph. The rotation starts off really smooth everything is animating then much later you ...
235 views

### Drawing the same scene with perspective then orthographic projections

I have a scene that I'm rendering first with a perspective matrix. I then want to rerender it in a different viewport using an orthographic matrix for a top-down 2D view of the scene. I think I may be ...
443 views

### make a sphere rolling on a roulette mesh stop at predetermined place

I have a roulette and a ball(sphere) placed on it. When the game begins the roulette spins. The spinning of the roulette and gravitational forces on the ball makes it roll along the 3d roulette mesh. ...
212 views

### Matrix represents same rotation with different euler angles

I have Transform component storing it's rotation as Quaternion. Transform has set/getEulerAngles (rotation order oy, ox, oz). I want to rotate object in any direction but while testing I get ...
196 views

### Heightmap implementation in javascript question, a 2D water heightmap

I have a height map function from GPU Gems 2 Chapter 18, where they're generating a set of B/W pixels from this equation: H(x,y,t) = Σi=0N h ( Axi x + Bxi,  Ayi y + Byi,  Ati x + ...
542 views

### Picking 3D with OpenGL ES 2

I'm trying to implement picking in my framework but I don't understand how I can do this. I'm working with: OpenGL ES 2. GLM mathematic library. What I have understand, picking can be made with ...
92 views

### adding space between each bricks in breakOut [closed]

i am trying to create breakout. code below loop though my 2d array(map) and creates bricks. the problem is that i want to add 10 pixels space between each bricks. i was thinking to add ...
101 views

### Should I negate a variable or use absolute value? [closed]

this is how i was chaning ball postion if(...) //if ball goes to left of screen dx = -dx if(...) //if ball goes right of screen dx = -dx; i found some people using math.abs to move ball ...
115 views

### How to make healthbar size relative to hp

Like in most games with healthbars, the units in my game have a hp_bar object which is a frame, with a slightly smaller rectangle inside which should get smaller (and change color) as a unit loses hp, ...
247 views

### Need help with a complex 3d scene (using Ogre and bullet)

In my setup there is a box with a hole on one side, and a freely movable "stick" (or bar, tube). This stick can be inserted/moved through the hole into the box. This hole is exactly as wide as the ...
154 views

### What kind of projection is ScreenX=X/Z, ScreenY=Y/Z?

I have an existing class which transforms 3D vectors and projects them on a 2D plane (Camera). The code is all written in C without help from an external library. To project a single vector (X,Y,Z) ...
256 views

### Negative scale in Matrix 4x4

After some rotations and to from quaternion conversions I get negative scale from Matrix 4x4, is it possible? I need that scale to draw sprite on screen so I get sprite flipped, how to deal with this ...
129 views

### Keeping raycast on the same level

I want my raycast to end at certain height(red line). But as the game is 3D and the camera rotates I can't use a fixed magnitude. What I thought was a stroke of genius, I figured I'd project the ...
365 views

### Drone targeting

Imagine a "drone" and a target point on a 2d plane. There are eight parameters: P = my position Q = target position V = my velocity I = my moment of inertia w = my angular velocity s = my angular ...
111 views

### Rotation independent rotation

I came up with some cube rotating, but I could not make it smooth and easy to use because as the cube turned - the keys that handle the turning changed their purpose. Link to demo. The demo rotation ...
206 views

### Getting an angle in degrees from north

This may have been asked already, but I was unable to find it, because I don't really know what I'm looking for. I drew a picture: I need theta. I've seen various solutions using Vector.Dot, and ...
296 views

### What algorithm to use to fill a KenKen square board with cages?

I am working on recreating KenKen, a popular math puzzle involving a blank grid that is divided into "cages". Each cage is just a collection of adjacent squares and has a clue which is generally a ...
57 views

### Going from point a to b through a curve using “gravity” [duplicate]

I have enemies and when they die they spawn an energy ball with a given velocity. I want to move this ball to the player using "gravity" to create a curved path. I have a version of the function but ...
192 views

### 1D functions and shapes

I have a set of numbers I normalize ( so the converted number is between 0 and 1 ) which I want to pass trough a function, which in return gives me a different number between 0 and 1 based on the ...
414 views

### Fast method of detecting whether point is inside mesh

I'm trying to construct a 3d object from a large number of particles. I think this is called BVH (Bounding volume hierarchy). I figured the best way is to draw the particles inside the mesh, then let ...
63 views

### Math concepts from the ground up; practical uses in game design? [duplicate]

I recently went back to school and chose to start learning math from the ground up, to ensure proper footing in higher level courses. I was always interested in game design and took a computer science ...
269 views

### Discover x,y coordinates given set arc distance and rotation

I have a turn-based car simulation. My vehicles have a maximum speed they can travel in a round, as well as a maximum amount they can change their heading over the course of a round. Say, 20 meters ...
233 views

### RGB to xyY color space conversion and luminance

The luminance calculated by following GLSL functions (fragment shaders - tonemap) has different value: float GetLuminance (vec3 rgb) { return (0.2126 * rgb.x) + (0.7152 * rgb.y) + (0.0722 * ...
556 views

### How to simulate early politics? [duplicate]

I'm making a historically accurate game where the player can interact with past times and shape the future. The entire game is scientifically generated with math and real physics. (no, it won't have ...
583 views

### Quaternion Look At with Up vector

I have implemented a "look at" method for my screen elements and it almost works how I want it to work. The ScreenElement class uses a R3 Vector and a Quaternion to determine the position and ...
71 views

### Different types of smooth object movement

In a game I have a specific object and two positions the object will move from and to. I already have the function for calculating current position in specific time. It works like this: Inputting 0 ...