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.
5
votes
3answers
617 views
Arbitrary projection matrix from 6 arbitrary frustum planes
A projection matrix represent a tranformation from the camera view space to the rendering system clip space. In other words, it defines the transormation between a 6-sided frustum to the clip cube.
...
0
votes
1answer
747 views
as3 3D camera lookat
I'm making a 3D camera scene in Flash, draw using drawTriangles() and rotated and translated using a Matrix3D. I've got the camera to look after a specific point, but only on the Y-axis, using the x ...
3
votes
2answers
189 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 ...
2
votes
2answers
151 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 = ...
0
votes
1answer
278 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 ...
2
votes
1answer
180 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 ...
8
votes
5answers
415 views
Building (simple) stellar systems
I'm currently looking at how to easily simulate some stellar systems (meaning some central stars and then some planets with maybe satellites), in order to allow later some space based strategy game ...
1
vote
2answers
2k views
Voronoi regions of a (convex) polygon
I'm looking to add circle-polygon collisions to my Separating Axis Theorem collision detection.
The metanet software tutorial (http://www.metanetsoftware.com/technique/tutorialA.html#section3) on ...
3
votes
1answer
279 views
Drawing isometric walls
I'm having some trouble with isometric walls.
I'm drawing isometric floor tiles using the back to front rendering method, and it works fine. I also keep my floor tiles lined up properly in a nice ...
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 ...
0
votes
1answer
73 views
Find the footprint of an isometric entity
I'm working on making a 2D isometric engine in Java. I'm getting into collision detection and I've hit a bit of a problem.
Characters in-game are not restricted to movement from tile to tile - they ...
3
votes
1answer
59 views
Retrieve outer most points on a 2d graph
G'day everyone,
I have a 2d graph which has some points plotted on it.
What I need to do is get only the outer most points so that I can connect them up (isn't really relevant).
What I can't seem ...
2
votes
0answers
162 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 ...
0
votes
1answer
117 views
Y Axis inverted on vertex output
I've got my project running and somehow it seems my vertex y components are inverted. 10 in the positive on Y goes down and 10 negative on the Y axis goes up.
I can't find anything with the ...
5
votes
2answers
458 views
Manipulating a free camera
I have a camera class in my code which stores two 4x4 matrices. One for the view matrix and one for the projection matrix. Originally, I had two floats in the class for pitch and yaw and these were ...
2
votes
2answers
452 views
How can I transform a point from world space to object space?
If I have an object space described by transformation matrix that should be applied to object to transform it to world space, what I have to do to transform point (world space) to that object space.
...
1
vote
1answer
604 views
Interpolation between two 3D points?
I'm working with some splines which define a path a character follows (you can see a gameplay video here to get a better understanding of what's going on: http://www.youtube.com/watch?v=BndobjOiZ6g). ...
4
votes
1answer
161 views
Orbiting multiple objects evenly around a changing radius
I have multiple objects (circles) and I want to place them in a circle, with even distance between each one, and have them orbit the center of the screen.
If I remove one object, I want the orbit ...
2
votes
1answer
317 views
360+ degree rotation skips back to 0 degrees when using Math.Atan2(y, x)
I'm new to XNA and this is my first actual project, so forgive my noobness.
I'm using
jointAngle = System.Math.Atan2(RightStick.Y, RightStick.X);
in order to set an angle of a joint (farseer) so ...
2
votes
1answer
163 views
Min/Max of two vectors?
This seems like a simple question, but i'm having trouble searching the internet for it.
In XNA, during a collision detecting method, I would determin the minimum of some vectors.
// Get the minimum ...
2
votes
3answers
1k views
Suggest a simple Java math library for matrix operations for use with OpenGL (lwjgl) [closed]
I'm writing an OpenGL app with Java. I need to do some math for camera and frustum culling (for AABB). Could you suggest a simple and fast Java math library for that?
1
vote
1answer
279 views
Understanding math used to determine if vector is clockwise / counterclockwise from your vector
I'm reading Programming Game AI by Example by Mat Buckland. In the Math & Physics primer chapter there's a listing of the declaration of a class used to represent 2D vectors.
This class contains ...
0
votes
1answer
97 views
getting direction of x and y… north,south,east,west
I have a player in the center of the screen, where I also have my mouse position origin. (0,0) I would like to know the direction of the mouse, imagine splitting the screen with a X, so the top ...
14
votes
6answers
9k views
Best C++ Math Library for Game Engine? [closed]
I'm looking for a fast opensource C++ math-library for my game engine
with the following features:
fast (sse?)
vectors
matrices
quaternions
suitable for both opengl and directx
17
votes
6answers
5k views
What are atan and atan2 used for in games?
I am having some trouble understanding Math.tan() and Math.atan() and Math.atan2().
I have basic knowledge of trigonmetry but the usage of SIN, COS, and TAN etc for game development is very new to ...
4
votes
1answer
92 views
What OpenCL video cards (or FPGAs) features are needed for high speed multiplication?
I'm benchmarking some cryptographic related software and am looking for video cards that are better at parallel multiplication vs parallel addition.
Is there any prior work that would graph video ...
1
vote
3answers
186 views
Diamond shaped selection on a staggered iso map
I have a staggered isometric tile map and want to do a selection that aligns with the diamond shape of the tiles.
This is what I mean:
So I got two points on screen and their map cell coordinates. ...
-1
votes
3answers
323 views
Scale a normalized 2D vector always to the same length
For any normalized 2D vector, except for ( 0, 0 ), how would I scale the vector to always be the same length?
For example:
int length = 10;
vector v = vector( 0.1, 0.5 );
vector v2 = vector( 0.3, ...
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 ...
1
vote
2answers
183 views
convert orientation vec3 to a rotation matrix
I've got a normalized vec3 that represents an orientation.
Each frame of animation, an object's orientation changes slightly, so I add a delta vector to the orientation vector and then normalize to ...
3
votes
1answer
282 views
2D Smooth Turning in a Tile-Based Game
I am working on a 2D top-view grid-based game. A ball that rolls on the grid made up of different tiles. The tiles interact with the ball in a variety of ways.
I am having difficulty cleanly ...
2
votes
1answer
173 views
Vector vs Scalar velocity?
I am revamping an engine I have been working on and off on for the last few weeks to use a directional vector to dictate direction; this way I can dictate the displacement based on a direction. ...
2
votes
1answer
131 views
How do I draw a dotted or dashed line?
I'm trying to draw a dashed or dotted line by placing individual segments(dashes) along a path and then separating them. The only algorithm I could come up with for this gave me a dash length that was ...
2
votes
2answers
104 views
Getting to math applications gradually
I'm currently getting a formal degree related to computation, in particular my current focus is numerical programming, scientific computing and machine learning. I'd love to apply that knowledge in ...
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
3answers
2k views
Getting isometric grid coordinates from standard X,Y coordinates
I'm currently trying to add sprites to an isometric Tiled TMX map using Objects in cocos2d. The problem is the X and Y metadata from TMX object are in standard 2d format (pixels x, pixels y), instead ...
1
vote
0answers
89 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...
...
3
votes
1answer
256 views
Spherical to Cartesian Coordinates
Well I'm reading the Frank's Luna DirectX10 book and, while I'm trying to understand the first demo, I found something that's not very clear at least for me. In the updateScene method, when I press A, ...
1
vote
2answers
607 views
Line Intersection from parametric equation
I'm sure this question has been asked before. However, I'm trying to connect the dots by translating an equation on paper into an actual function. I thought It would be interesting to ask here instead ...
6
votes
4answers
2k views
Calculating velocity needed to hit target in parabolic arc
If I have a point which I want to hit at the end or during a parabolic arc, how would I calculate the needed x and y velocity?
12
votes
1answer
198 views
Orthographic unit translation mismatch on grid (e.g. 64 pixels translates incorrectly)
I am looking for some insight into a small problem with unit translations on a grid.
Update and Solved
I solved my own issue. See below for details. Everything in this part of the post turned out to ...
0
votes
1answer
106 views
Build a view frustum from angles
I have 4 angles, left, right, top & bottom. These angles are in degrees. They define the angle between the forward vector and the corresponding side. I am trying to use these to calculate the ...
0
votes
1answer
101 views
Rotate/Translate object in local space
I am just trying to create a movementcontroller class for game entities. These class should transform the entity affected by the mouse and keyboard input. I am able to calculate the changed rotation ...
4
votes
1answer
117 views
How to transform mesh components?
I am attempting to transform the components of a mesh directly using a 4x4 matrix. This is working for the vertex positions, but it is not working for the normals (and probably not the tangents ...
-2
votes
1answer
155 views
Move projectile in direction the gun is facing [duplicate]
Possible Duplicate:
Move sprite in the direction it is facing?
I am attempting to have a projectile follow the direction a gun is facing. When using the following code I am unable to make ...
1
vote
1answer
812 views
Optimized algorithm for line-sphere intersection in GLSL
Well, hello then!
I need to find intersection between line and sphere in GLSL. Right now my solution is based on Paul Bourke's page and was ported to GLSL this way:
// The line passes through p1 and ...
0
votes
1answer
89 views
Using NumPy arrays as 2D mathematical vectors?
Right now I'm using lists as position, velocity, and acceleration vectors in my game. Is that a better option than using NumPy's arrays (not the standard library's) as vectors (with float data ...
15
votes
7answers
520 views
Do I need a Point and a Vector object? Or just using a Vector object to represent a Point is ok?
Structuring the components of an engine that I am developing along with a friend (learning purposes), I came to this doubt.
Initially we had a Point constructor, like the following:
var Point = ...
4
votes
1answer
447 views
Re-create 2D side-on wave effect from Worms game
I'm trying to recreate the waves/water effect from Worms ( see here http://youtu.be/S6lrRqst9Z4?t=31s ) From what I understand its not actually a sprite, its procedurally generated by something like a ...
1
vote
2answers
95 views
Logarithmic spacing of FFT subbands
I'm trying to do the examples within the GameDev.net Beat Detection article ( http://archive.gamedev.net/archive/reference/programming/features/beatdetection/index.html ) I have no issue with ...
