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.

3answers
307 views

Simulated Economic Factors Based on Supply and Demand in MMO Resource Trading Game

I'm working on a gam (naturally), and the primary activity for the player is to buy and sell commodities at various marketplaces. Each commodity has the following properties: Base Price: if all ...
1answer
254 views

Canvas isometric translations to integer coordinates

I'm creating a canvas based game with an isometric playing board. I use the following transformations to get my square tiles to render on the screen: 'applyViewportTransformation' : function() { ...
2answers
215 views

Inventory Grid Detection

I'm working on creating an inventory system for a game. The inventory system will use cells and 2D images to represent items, like Minecraft, Diablo, or WoW. I've hit a bit of a snag when trying to ...
3answers
214 views

Directional light and matrix issues

I'm trying to implement basic directional lightning in OpenGL 3.3 by emulating the logic shown in this guide: http://www.arcsynthesis.org/gltut/Illumination/Tutorial%2009.html I do not understand ...
1answer
119 views

A controlled trapezoid transformation with perspective projecton

I'm trying to implement a controlled trapezoid transformation in Adobe Flash's ActionScript using the built-in perspective projection facility. To give you an idea of how the effect looks like: ...
2answers
106 views

What effect does the amount of 0 in a stat have. [closed]

Basically I want to know if the following three characters are the same character A health 10 strength 3 defence 2 character B health 100 strength 30 defence 20 character C health 1000 ...
3answers
688 views

Getting correct angles between Vector3s

I'm working on a project where you can draw lines between points. You select one point and drag the mouse onto another point and a line is drawn between them. The line itself is a 3d object which is ...
1answer
462 views

deferred rendering and point light radius

I use a common attenuation equation for point lights: attenuation = 1 / kc + kl * d + kq * d^2. I use deferred rendering so I need to know a light radius. An example light has following intensity: ...
2answers
193 views

games logic based on closed shapes

I would like to know the math concepts behind shape based games like http://www.miniclip.com/games/fat-slice/en/ To be specific, I would like to know on how to model shapes programmatically finding ...
0answers
124 views

How to predict encounters between a ship and a body's sphere of influence in 2D

Long time listener, first time caller. I'm making a little hobby game in XNA, its about transport ships in space, analogous to container ships at sea. There are to be AI ships and player controlled ...
1answer
2k views

How to extract euler angles from transformation matrix?

I have a simple realisation of entity/component game engine. Transform component have methods to set local position, local rotation, global position and global rotation. If transform is being set new ...
2answers
167 views

Accumulating rotations for camera

It seems there are three ways to store a camera's rotation: in angles, view matrix or quaternion. I was using euler angles since when I used a matrix it had a tendency to accumulate rounding errors ...
2answers
274 views

How to build a math module and simulate a system?

For example, in the classical game SimCity: an economic model to simulate the supply and demand of the city, then calculate how many people live in each building, how many people work there. a ...
1answer
589 views

LibGDX Perspective Camera for 2D

I'm very new to LibGDX and I'm trying to use DecalBatch with PerspectiveCamera, simply to have z-coordinate for my sprites, as SpriteBatch does not offer that. However, I don't know how to calculate ...
2answers
245 views

How to implement armor? [closed]

I am a newbie in Python, I am very bad at math too and I need some help. Also close/move this post if you feel this isn't the right place for it. Hero1 = 5000 # His HP is 5k. Hero1dmg = 200 # ...
1answer
71 views

How to change Vectors due to change in it's dependent Base Vector?

PLOT : I have been developing a game where the player falls down on Y axis and the camera is a Top-Down view camera. The camera, player (main character in the game) movements etc. have all been ...
1answer
599 views

2D car physics and high speed turning

I've been looking at the following page, which has been very helpful: http://www.asawicki.info/Mirror/Car%20Physics%20for%20Games/Car%20Physics%20for%20Games.html but have come into problems with the ...
1answer
70 views

Matrix Translation Transformation Question

I've been reading a lot about computer graphics lately and because of it I'm building my own math library's for fun. I was reading about Matrix Translation and Homogeneous Coords, and was wondering ...
2answers
362 views

Defining an OpenGL unit

I have read that you can define your OpenGL unit by using glViewport. As far as I understood if you use something like glViewport(0,0,600,600) then 1 OpenGL unit = 600 pixels. Now my problem is what ...
2answers
206 views

Why does matrix multiplication lead to different result if it's done on CPU, compared to GPU(shader)?

If I'm calculating a "camera space" on the CPU, by multiplying the view with the projection matrix on the CPU , and afterwards multiplying the world to the result my vertices do not pass to the pixel ...
1answer
220 views

Get intersected volume of two planes in 3D

I'm working on AABB - AABB collision response and I'm having trouble figuring one part out. My situation is as follows (see image). I have a player AABB (blue) and an object which collides (brown). ...
3answers
328 views

How can I change the acceleration of an object to arrive at a particular time?

I'm trying to write some code to change an acceleration factor so a ball will arrive at a destination in a desired time. The problem is I don't know time (t) but I do know I want it to arrive at (t - ...
1answer
108 views

Movement constrained to the faces of a cube

The basic setup I'm working with is a cube rendered in-Engine (Panda3d, although I only am looking for a generalized solution) as well as a 2d square on one face of the cube. The eventual outcome I'm ...
1answer
350 views

What happens to data between vertex shader and pixel shader?

Short version: What can happen to the output of a vertex shader that leads to no(or very few) pixels being drawn, especially in relation to a perspective matrix. Long version: My problem refers to ...
1answer
227 views

A* for non grid network

For my specific case, I am trying to find a path finding implementation similar to what described here. I could see reference implementation for A* and HPA*, but I wonder how to extend A* to simple ...
1answer
308 views

Creating a frustum for culling in world-space glm matrices

I need to do frustum culling where the bounding boxes are in world-space to determine which entities get to be updated/drawn. I was trying to use the classic projection/view matrix plane extraction ...
5answers
1k views

how to rotate enemy to face player? [duplicate]

Okay so i havebeen rotating my enemy to face the player using float targetrotation = Math.Atan2(playerpos-enemypos); enemy.rotation = targetrotation; (<this line of code i want to change) This ...
1answer
182 views

Jump function of player [duplicate]

I'm developing game in marmalade sdk in c++. I have player in the area.and I wanna make him jump when i pressed a button.When I use this player.moveUp(5px); it just go up 5px, but he has to fall down ...
3answers
165 views

How to calculate size of object depending of its height on the screen?

I am programming a mostly 2D game on Android (with Andengine), but the player is a bouncing ball (kinda in 3D). I wanted to make the bouncing of the ball the most realistic possible, using quadrilic ...
1answer
66 views

Build a Cube/Prism from other varied Cubes/Prisms [closed]

I'm wondering, are there any algorithms or theories in existence (that aren't patented/proprietary/protected) that would take a series of 3d rectangular prisms (or cubes but a cube is a prism) and ...
2answers
189 views

Plotting entities on a radar

I'm trying to build a radar system like the one in the original X-Wing games. The way it works is that there are two circular radar systems, one for behind the ship, and one for infront. So, I've ...
8answers
2k views

Converting a 2D curve into points for data storage

I’ve created an algorithm which converts any curve i.e. path into minimum number of points so that I can save it into a file or database. The method is simple: it moves three points in equal steps ...
1answer
710 views

3D isometric depth sorting

How is it possible to depth sort tiles and objects in an isometric environments without any limitations? I've been researching this for a while now and there seems to be no publicly available answers ...
1answer
216 views

AABB of a sphere's screen space projection

What is a nice, neat way to get the AABB of a sphere's projection onto the screen? This is to determine simplified geometry for lights in deferred shading.
2answers
166 views

Distribute circles evenly on Screen - circle packing

I want to evenly distribute a random amount of circles with random diameter on the screen for. This level doesn't scroll so the users screen resolution sets the limits. Further I would like the ...
2answers
603 views

Bezier curve not drawn correctly

I'm trying to draw a bezier curve using 3 points. If I use the quadratic form: I get this result: And I believe it's correct. Now since I need to draw it with a variable number of points, ...
1answer
136 views

Physics movement prediction is way off [closed]

I'm making a simple, non-networked game. There are two players and a ball. In implementing the AI for the second player, I've run into a huge problem predicting where the ball will hit the ground. ...
4answers
236 views

A formula for point calculation based on value A's proximity to value B

I am trying to find a formula to use for my rhythm game's scoring. Basically there is a Guide entity and a Live entity. You control the Live entity and have to match it as closely as possible to a ...
2answers
751 views

How can you extract orientation from a transformation matrix?

I have a 4x4 transformation matrix M, and I want to find out the shape of a sphere when transformed by M. (Sphere is at the origin and has radius 1.) I know I can find the center by just multiplying ...
1answer
122 views

Increase restitution (bounciness) of an object in a JavaScript formula

I'm going slightly around the houses on this one. I originally started a thread over on Stack Overflow about it but then it seemed to diverge into mathematics, with no joy from the SO community over ...
2answers
343 views

How do I calculate consistent frame timings at 60fps?

I'm writing an HTML canvas game that uses requestAnimationFrame and therefore runs at 60fps, although this is more of a question about failing arithmetic than about JavaScript. If I measure the time ...
1answer
392 views

How to rotate a direction

I'm working a spotlight for my deferred renderer and I'm having trouble with matching the mesh to the visual representation of the light. Right now my mesh is a cone, the apex of the cone is at ...
1answer
276 views

How do I detect the intersection of a curve with itself?

I'm developing a game in which the player can draw a line. I want to detect if that line intersects with itself. How would I do this?
1answer
294 views

Any book about math in game design? [closed]

Game designers need math as one of their tools for designing game, unfortunately I can't find one book concentrate on this topic. I know there's math book about game programmer, but designer need ...
1answer
152 views

In a regular grid, how can I tell which tile a position is in?

I have a position on the screen, how do I calculate which grid tile that position is inside? I know the number of tiles in the grid, and the size of the screen (including how many tiles fit on it ...
2answers
214 views

How does a point squared equal the radius squared?

I am working on a simple ray tracer but I don't understand some of the formulas. One that is bugging me at the moment is this: If a sphere is centred at origin, a point p lies on a sphere of ...
2answers
242 views

2D field of view detection inverted

I'm not sure if the title matches what I'm actually facing I'm trying to test if I can see a point is in my field of view (in the context of an NPC seeing in it's direction.) I know that: cos0 = ...
1answer
477 views

Please help me with my 2D isometric tile picking [duplicate]

Possible Duplicate: How to convert mouse coordinates to isometric indexes? Okay, I apologise in advance if I make no sense here. Basically, I've got a simple application that takes in a ...
1answer
262 views

How to do perspective projection “parallax” but without changing the scale or offset of objects?

Hello everyone I have this problem that I have tried everything I could think of. The problem: I am making a 2D game with parallax effect but I am using 3d space so am not simulating the parallax but ...
2answers
429 views

Derive a algorithm to match best position

I have pieces in my game which have stats and cost assigned to them and they can only be placed at a certain location. Lets say I have 50 pieces. e.g. Piece1 = 100 stats, 10 cost, Position A. Piece2 ...