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.

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2
votes
2answers
252 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 ...
3
votes
1answer
849 views

Opengl-es picking object

I saw a lot of picking code opengl-es, but nothing worked. Can someone give me what am I missing? My code is (from tutorials/forums) Vec3 far = Camera.getPosition(); Vec3 near = ...
0
votes
1answer
39 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 ...
0
votes
1answer
53 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 ...
0
votes
1answer
257 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 ...
0
votes
1answer
112 views

Camera lookAt target changes when rotating parent node

have the following issue.I have a camera with lookAt method which works fine.I have a parent node to which I parent the camera.If I rotate the parent node while keeping the camera lookAt the target , ...
0
votes
1answer
162 views

Normalizing the direction to check if able to move

i have a a room with 4 walls along the x and z axis respectively. My player who is in first person (therefore the camera) should have collision detection with these walls. I'm relatively new to this ...
0
votes
1answer
355 views

rotate opengl mesh relative to camera

I have a cube in opengl. It's position is determined by multiplying it's specific model matrix, the view matrix, and the projection matrix and then passing that to the shader as per this tutorial ...
-1
votes
1answer
148 views

How to implement cue-stick animation for a pool game?

Hello I am developing a Pool game, and I've been scratching my head about what formula is needed to implement an animation for the cue stick. The animation of the cue stick should look as if it's ...
-5
votes
1answer
118 views

is object facing another object or facing it in opposite direction?

In 2d, in degrees, negative degrees possible. What I want is to rotate the player to face the same direction as the door before opening it, but when I'll do the same again now from the opposite side, ...
4
votes
0answers
250 views

Isometric - precise screen coordinates to isometric

I'm trying to translate mouse coords to precise isometric coords (I can already find the tile the mouse is over, but I want it to be more precise). I've tried several different methods but I seem to ...
2
votes
0answers
161 views

Catmull Rom Spline - Constant Speed

Given the equations found in the answer here: Determine arc-length of a Catmull-Rom spline How would one A) Apply this to a 3D Catmull-Rom Spline, and B) write A out programmatically (for the math ...
2
votes
0answers
99 views

Typical Applications of Linear System Solver in Game Developemnt

I am going to write a custom solver for linear system. I would like to survey the typical problems involved the linear system solving in games. So that I can custom optimization on these problems ...
2
votes
0answers
135 views

Portal View/Projection Matrix near plane

For RenderToTexture/Camera based portal rendering, the basics seems simple enough. However, with a free camera, most of the time it is going to be looking at such portals at an angle: Now a ...
2
votes
0answers
82 views

Constrained/penalized distance function

Assume a character is located on a n by n grid and has to reach a certain entry on that grid. Its current position is (x1,y1). Also on the same grid is an enemy with coordinates (x2,y2). Each step ...
1
vote
0answers
150 views

How do I implement a physics gun?

I'm currently trying to implement a physics gun for my game. What I want is for the entity to stay in the same position on the screen no matter how I wiggle the camera about, what is the correct way ...
1
vote
0answers
87 views

Numerically stable(ish) method of getting Y-intercept of mouse position?

I'm trying to unproject the mouse position to get the position on the X-Z plane of a ray cast from the mouse. The camera is fully controllable by the user. Right now, the algorithm I'm using is... ...
1
vote
0answers
657 views

Orthographic Camera Zooming

In XNA I am using a spritebatch to render a board. I have created a camera class which can provide me a view and projection matrix. Currently I am supplying the view matrix to my sprite batch when I ...
1
vote
0answers
116 views

Issues with Spherical Coords and gluLookAt

I am currently developing a game set in a planet(A sphere), in which my camera mostly works though some issues arise from this method: ...
1
vote
0answers
541 views

Rotation deforming mesh (Opengl ES 2.0)

I'm trying to render a rotating cube on Opengl ES 2.0, using some math classes I wrote (based on a lot of online and offline info) for quaternions, matrixes and the like. As far as I know all the math ...
0
votes
0answers
14 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 ...
0
votes
0answers
52 views

Uses for vector projection?

My previous question was solved by vector projection. Thus I spent some time studying it (Few helpful links: Interactive projection, short video and a longer video.). There were plenty of sites that ...
0
votes
0answers
98 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 ...
0
votes
0answers
39 views

Cascaded Shadow Maps left handed to right handed coord system

Im trying to port the Directx SDK (june 2010) sample (CascadedShadowMaps11) into a right handed version (to later implement in my engine) but i can't figure out the math, so far i got it partially ...
0
votes
0answers
57 views

Calculating the position of an object with regards to current position using OpenGL like matrices

i have a 1st person camera that collides with walls, i also have a small sphere in front of my camera denoted by the camera position plus the distance ahead. I cannot get the postion of the sphere but ...
0
votes
0answers
125 views

way to do if(x > x2) x = x2 with rotation?

Alright, so I got this walking code, and some collision detection, now the collision detection returns a Vector3f of the closest point on the triangle that the projected position is at (pos + move), ...
0
votes
0answers
94 views

What is the connection between an isometric angle and scale

I am trying to work out an isometric projection matrix for a custom angle. In the engine I'm using there's a projection matrix defined like so: projection.rotate(45 * (Math.PI / 180) ); scale = ...