# Tagged Questions

79 views

### Gun Bobbing Algorithm Math Explanation

I stumbled across this really neat algorithm which I don't fully understand. It simulates a camera's bobbing effect commonly witnessed in first person shooters while running/walking. I'm mainly unsure ...
241 views

### RPG like hit points growth algorithms help

I am currently making an XNA game in C#. I want to increase health as the player level up. I am currently using this equation. MaxHealth = Convert.ToInt32(100 * Math.Pow(1.17, level - 1)); Its ...
60 views

### What is the optimal way to handle matrix internal data storage for interop with native graphics apis?

I'm writing a managed (c#) game engine and have stumbled on a bit of a crossroads in design/implementation regarding matrix types. Matrix types need to be optimized for marshaling to native graphics ...
163 views

### How do I create a knockback-movement?

I am a web developer new to game development, and with limited math knowledge. I am writing a character movement controller in Unity. The game has an isometric Diablo-like camera. The character moves ...
76 views

### Predicted target location [duplicate]

I'm having an issue with calculating the predicted linear angle a projectile needs to move in to intersect a moving enemy ship for my 2D game. I've tried following the document here, but what I've ...
34 views

### Predicted target location

I'm having an issue with calculating the predicted linear angle a projectile needs to move in to intersect a moving enemy ship for my 2D game. I've tried following the document here, but what I've ...
140 views

### Calculating ball trajectory in Pong

I'm making a Pong game and I'm just looking for a simple way to calculate a straight travelling path for the ball based on the angle of the ball. How would I go about implementing something like this? ...
113 views

### Projecting a light onto a quad

I need to project the light onto the quad and use its value for translating the vertices. I'm currently having 6 vertices, two quads, The points are A X C B Y D Point X, Y are coming from two ...
371 views

### Intelligently move aircraft using curves

I am trying to code a script to move an aircraft entity from point A to point B and at some point in the middle of moving have the aircraft forward vector face Point C (to fire a missile at an enemy ...
297 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 ...
138 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. ...
155 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 ...
218 views

### How do I find two points at an angle on opposite sides of a circle?

With reference to my previous question: I'm using micklh's answer, which works perfectly. However, it calculates the gradient based on two points, a starting point and an ending point. I want to ...
423 views

### Day and Night Cycles and Skybox Blending

I've been working on adding day/night cycles and random weather to my project using the Neoaxis engine. The day/night cycles itself is pretty simple, just rotating the "sun" light around the Y axis. ...
249 views

### Code to generate a color gradient within a texture using a diagonal line

I want to generate a color gradient between two colors from x1,y1 to x2,y2. I'm unsure how to do this though. I can use Color.Lerp to get all of the color steps, but the problem is that I don't ...
98 views

### margin of error trying to check if a point lays on line

Working with floating point values it is as easy as breathing to run on approximation errors by comparing quantities which should be the same. I want to know if there is a way built in some MSDN (or ...
53 views

### Percentages for different platform generation [duplicate]

I have a level manager, which creates levels and levels create platforms. Levels can contain a variety of platforms. I dont really understand how I can say: I want a 10% of one platform being ...
372 views

### Slerping rotation mirrors

I rotate my game character to watch at the target using the following code: transform.rotation = Quaternion.Slerp(startQuaternion, lookQuaternion, turningNormalizer*turningSpeed/10f) ...
121 views

### Velocity deacceleration working incorrectly

Basicly, I've tried to code velocity into my game, which works sort of. The deaccelaration works sort of, but not correctly. The problem is, that the positive values, decreases just fine and dandy to ...
320 views

### Rotate around the centre of the screen

I want my camera to rotate around the centre of screen and I'm not sure how to achieve that. I have a rotation in the camera but I'm not sure what its rotating around. (I think it might be rotating ...
150 views

### Rotating sprite 180 deg

I should say first, that I have the rotation down. Its just that I want my square to rotate exactly 180 degrees. Currently, it will rotate but it will rotate but by less each jump. So after several ...
286 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 ...
1k 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 ...
345 views

### Unproject mouse position to tile — extremely jumpy 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... ...
1k views

### Simulating a sine wave/oscillating pattern for enemies

I'm creating a simple top down shooter, right now I have an enemy which simply follows the player. I'd like to change things up and have the enemies move towards the player but in a wave like motion. ...
264 views

### How to offset particles from point of origin

Hi I'm having troubles off setting particles from a point of origin. I want my particles to spread out after a certain radius from a the point of origin. For example, this is what I have right now: ...
406 views

### Calculating the correct particle angle in an outwards explosion

I'm creating a simple particle explosion but am stuck in finding the correct angle to rotate my particle. The effect I'm going for is similar to this: Where each particle is going outwards from the ...
594 views

### Breakout… Getting the ball reflection X angle when htitting paddle / bricks [duplicate]

Im currently creating a breakout clone for my first ever C# / XNA game. Currently Ive had little trouble creating the paddle object, ball object, and all the bricks. The issue im currently having is ...
397 views

### Finding closest object to a location within a specific perpendicular distance to direction vector

I have a location and a direction vector indicating facing, I want to find the closest object to that location that is within some tolerance distance (perpendicular distance) to the ray formed by the ...
938 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). ...
380 views

I am creating a quad that starts as a single quad, then divides itself multiple times (from 1 -> 4 -> 16 -> 64 -> 256 etc) but I have encounted an issue. When I get to 64 sub divisions only 16 quads ...
388 views

### Confused about order of operation when using a Matrix in XNA, C#

Here are two different pieces of code This is what I started with Vector2 hold = Vector2.Transform(pos1, mat1); Matrix inv = Matrix.Invert(mat2); Vector2 pos2 = Vector2.Transform(hold, inv); And ...
318 views

### Moving two objects proportionally

I'm trying to move two objects away from each other at a proportional distance, but on different scales. I'm not quite sure how to do this. Object A can go from position 0.1 to 1. Object B has no ...
1k views

### Line segment / circle intersection - X value seems wrong?

Major Edit I'm making a Breakout clone, and having difficulty with collision detection between a circle and line segment. Apologies, my earlier question was a result of frustration and no sleep :) ...
7k views

### Get position of point on circumference of circle, given an angle?

I would like to know how to get a specific point on the circumference of a circle, given an angle. The diameter of the circle is 1, and the center point of the circle is { X: 0.5, Y: 0.5 }.
4k views

### Getting the angle between two objects?

I have a set of boxes which create a sort of path, they don't intersect very smoothy and to help that process I'm trying ot find a way to get an angle between them that can make it easier to generate ...
179 views

### An ellipse outside two points?

I am trying to generate an ellipse outside two points (two-dimensional vectors). Is there a formular for that, or a cool way of doing that in C# XNA? What I am trying to do is have a particle circle ...
527 views

### Vary speed of enemy smoothly

Hey. I'm trying to create an enemy that travels at a speed s on screen but I'm having trouble with trying to make the speed vary in a smooth motion. Basically, I can get the enemy to move at a ...
1k views

### Rotate object to face player

This is probably a simple vector question, but I'm not sure how to do it. I have an object at vector position (ox,oy). Potentially every update, the user walks around the screen, and will be at ...
1k views

### Adding air drag to a golf ball trajectory equation

I'm developing a 2D golf game in VB.NET 2005, but I am stuck on how to implement air or wind drag that should affect the ball. Already I have these equations for projectile: Vo ...
499 views

### Calculating camera zoom value (top-down)

I need some help in 'camera maths'. I have a birds eye view of two characters. One character is static and the other can move. I would like the camera to always show both characters in full and, in ...
920 views

### Arrays for a heightmap tile-based map

I'm making a game that uses a map which have tiles, corners and borders. Here's a graphical representation: I've managed to store tiles and corners in memory but I'm having troubles to get ...
1k views

### Restrict movement within a radius

I asked a similar question recently but now I think I know more about what I really want to know. I can answer my own question if I get to understand this bit. I have a situation where a sprite's ...
1k views

### snapping an angle to the closest cardinal direction

I'm developing a 2D sprite-based game, and I'm finding that I'm having trouble with making the sprites rotate correctly. In a nutshell, I've got spritesheets for each of 5 directions (the other 3 come ...
269 views

### Correct Blitting 2 surface problem

this is a graphics/math problem. Consider this 2 sprite / surface As you can see they are a tank and his gun turret. Now, i manage the turret rotation, and it works, and, also, the rotation of ...