1
vote
1answer
36 views

Compute billboard rotation

I'm trying to compute a matrix to have object always facing the camera. For the moment, my result look pretty good, the problem is that my original billboard scale isn't preserved (Every billboard ...
2
votes
2answers
211 views

How can I simplify this code to compute the shortest rotation between two angles?

The following code will find the shortest rotation (in radians) (from pi to -pi) that I need to apply to from to leave me with to. Scalar rotationBetween(Scalar from, Scalar to) { Scalar fromMod ...
3
votes
1answer
89 views

What are the performance and size tradeoffs of Eigen::Transform versus Eigen::Matrix4f?

We finished migrating from DirectXMath to the Eigen math libraries for our 3D-Game Engine last week for portability reasons. After implementing transformations with matrices as we know them, we found ...
6
votes
2answers
199 views

How do I avoid interpolation artefacts when scaling up a heightmap?

I am using a bicubic interpolation algorithm in order to upscale a height map, and I am noticing some artifacts around the pixels boundaries. However, these artifacts don't seem to appear when I use a ...
1
vote
2answers
403 views

OpenGL position from depth is wrong

My engine is currently implemented using a deferred rendering technique, and today I decided to change it up a bit. First I was storing 5 textures as so: DEPTH24_STENCIL8 - Depth and stencil ...
0
votes
1answer
431 views

Box2d making a body follow the mouse accurately

I am trying to make a box2d b2Body follow my mouse position. This is the code I am using at the moment but it is not performing very well: deltaPos = mousePos - body->GetPosition(); deltaPos *= k; ...
3
votes
0answers
229 views

Use quaterions to move the camera direction according to mouse movement

I am trying to use quaterions to move the camera direction vector in the following way. This code is perfectly working glm::quat temp1 = glm::normalize( glm::quat((GLfloat)( ...
-1
votes
2answers
332 views

Shooting many bullets toward the mouse position

I try to shoot a bullet toward the mouse position by this code. float deltaX = mousePosition.x - (aircraft.getPosition().x + aircraft.getLocalBounds().width / 2); float deltaY = mousePosition.y - ...
0
votes
1answer
188 views

Issues calculating frame independent movement

I'm developing a Breakout style game in C++ using SDL. The problem so far is that the ball slows down and speeds up for no particular reason. The slowdowns usually last a few seconds. EDIT : When ...
1
vote
0answers
169 views

Rotate a point in 3D space with sine and cosine

I got my camera controlled by the mouse. Now I want a sphere to be always in the center of my view(just for testing). I tried that by assigning the sine of the Y rotation of the camera times 10 as the ...
0
votes
0answers
235 views

Space Strategy Ship Movement Math

This is similar to a question I asked a while ago, but I phrased it so terribly so might as well start over. I am trying to implement ship movement in 3D space, but confined to a 2D plane at y=0 (see ...
0
votes
1answer
178 views

Trying to convert as3 Matrix to C++ glm matrix

I am trying to convert a library called DragonBones to C++ Opengl which allows you to use Flash based skeletal animation. I'm almost done but I am running into a problem. I am trying to transform the ...
1
vote
2answers
738 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 ...
-1
votes
3answers
257 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 ...
0
votes
2answers
199 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 ...
4
votes
2answers
482 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 ...
2
votes
1answer
243 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). ...
0
votes
1answer
317 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 ...
2
votes
2answers
660 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, ...
2
votes
1answer
370 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 ...
3
votes
1answer
732 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, ...
3
votes
3answers
170 views

Determining a point that reached another point

I have two points, one is moving and one is stationary. I would like to know if the moving point has reached that point or not. I tried to calculate the distance between two vectors and the distance ...
1
vote
2answers
250 views

Billboarding + aligning with velocity direction

I'm working on a particle system where I'm orientating the billboard using the inverted orientation matrix of my camera. This works quite well and my quad are rotated correctly towards the camera. ...
0
votes
1answer
220 views

Getting Center and Radius of Irregural Object

I have drawn an asteroid object manually , and would like to get its center/radius by a specific equation. I think I can get them by calculated and hard-coded values. The code to draw the asteroid: ...
3
votes
2answers
424 views

Explaining Asteroids Movement code

I'm writing an Asteroids Atari clone, and I want to figure out how the AI for the asteroids is done. I have came across that piece of code, but I can't get what it does 100% if ...
1
vote
0answers
62 views

obb vs obb and resolve/response for 2d space game [duplicate]

Possible Duplicate: OBB vs OBB Collision Detection How can i detect if an rotated obb intersects another rotated obb and resolve it so both obb objects dont go further into each other. I ...
0
votes
1answer
294 views

Why is std::atan2 returning -0.0?

Really? Negative zero?! double Vector2D::GetFacingAngle(const Vector2D& target, const Vector2D& source) { a2de::Vector2D facingVec(Vector2D(source) - Vector2D(target)); //Negating ...
2
votes
2answers
574 views

Rotating an object smoothly

I'm trying to rotate a ship in an asteroid game. What I'm doing is creating a float angle variable and at each time I press left or right buttons, I increase and decrease it, and in the drawing ...
1
vote
2answers
410 views

Aligning bullet's position in Asteroid Game

I'm writing an asteroid game and I would like to align the bullets on the ship's tip. I also want when the ship fires, the bullet gets the same orientation(angle, direction) of the ship and also be ...
1
vote
2answers
792 views

Rotating a polygon around it's center

I have drawn a ship using three lines, and would like to rotate the ship around its axis in opengl, I have tried the following, but the ship translates while rotation!. void Ship::Draw( ) { ...
-1
votes
1answer
185 views

Camera not working

I made a camera in DX9. To move forward I press the Up arrow. To rotate on the Y axis I use the mouse. When I perform these movements on their own the camera moves at the speed I want. However, if I ...
2
votes
1answer
775 views

Is it possible to billboard a sprite using a transformation matrix?

None of the current topics on billboarding seemed to answer this question. But, given a sprite (or quad) that has it's own 4x4 transformation matrix a camera with a view matrix (a standard 4x4 ...
0
votes
2answers
387 views

Camera target point based on angles

I'm working on a test project to learn some basic OpenGL. Right now I'm trying to work on a "camera" with gluLookAt. My camera object is really simple, I have two vectors, one for the position and the ...
-1
votes
1answer
379 views

Rotating points on a circle

I have drawn a 2D circle in X,Y,Z. I wanted to draw something on specific vertices of that circle and I managed to do it. When I wanted to move the circle, I wanted the vertices to get the updated ...
0
votes
1answer
799 views

Camera Rotation (for mouse look) with LookAt does not work as expected (Local/Global)

My code for rotating my 3D fps camera isn't working as expected. I expect that the X-axis does rotate with the Y-axis, but it ain't so. I made some pictures to explain it better, I think its doing ...
-1
votes
2answers
201 views

How to make sure that a Point A moving in the direction V reaches at Point B?

Let say I have, Point A(X1,Y1) moving in the direction V(W, H). I need to make sure that it reaches B(X2,Y2). I think I need to subtract some value in Point A(X1, X2). But not know what? I also sure ...
2
votes
1answer
192 views

Calculate the direction, From Outer Polygon Point to Inner Polygon inside Point

I was able to find the co-ordinates of inner Polygon using this trick. Need the co-ordinates of innerPolygon But, I have some problem in getting the direction from Outer Polygon Point to Inner ...
3
votes
2answers
94 views

Need the co-ordinates of innerPolygon

Let say I have this diagram, Given that i have all the co-ordinates of outer polygon and the distance between inner and outer polygon is d is also given. How to calculate the inner polygon ...
5
votes
2answers
2k views

I am looking to create realistic car movement using vectors

I have goggled how to do this and found this http://www.helixsoft.nl/articles/circle/sincos.htm I have had a go at it but most of the functions that were showed didn't work I just got errors because ...
4
votes
3answers
2k views

Random Vector within a cone [duplicate]

I'm looking to create a random vector within a cone given the radius (base). It feels like I've been traversing through many pages on the internet and still I'm no further forward to getting an ...
3
votes
3answers
1k views

How do I find the angle required to point to another object?

I am making an air combat game, where you can fly a ship in a 3D space. There is an opponent that flies around as well. When the opponent is not on screen, I want to display an arrow pointing in the ...
3
votes
3answers
373 views

How do I approach this collision model?

This is the game level prototype I have already implemented. It has few objects per room to allow me to finally add some collision detection/response code into it. VIDEO As you can probably see, ...
6
votes
1answer
840 views

AABB - AABB Collision, which face do I hit?

To allow my objects to slide when they collide, I need to : Know which face of the AABB they collide with. Calculate the normal to that face. Return the normal and calculate the impulse that to ...
2
votes
2answers
470 views

3D Translation using only distance and angles

So I'm starting to foray into 3D game programming, but I've hit something of a snag. I have an object I want to move around. It should always move either forward or backward relative to its local Z ...
3
votes
3answers
2k views

How do I shoot bullets towards the mouse in a top down shooter?

I have a formula for pointing my main character of the game towards the mouse, and it gets the angle he needs to be turned to point towards the mouse. But how do I get the bullets from the gun to use ...
2
votes
3answers
1k views

simplest way of making a sphere roll in a realistic way

rather than just moving a sphere across a plane, I want to make it roll like a ball. What is the simplest way of doing this? I assume it will have something to do with the circumference of the ball ...
1
vote
2answers
355 views

Should SIMD be used by people who are new to game development?

I have been learning game development, using C++ and OpenGL, for about 4-5 months. Before that I used to program in C# and the .NET platform(about a year). So, I consider myself new to game ...
4
votes
4answers
316 views

What should be taken into consideration when choosing a math library for games?

I'm currently selecting a C++ math library to use for a project. There are several questions here and on SO concerning the 'best' library available and many answers with different suggestions, but I ...
2
votes
1answer
331 views

How do I build a matrix to translate one set of points to another?

I've got 3 points in space that define a triangle. I've also got a vertex buffer made up of three vertices, that also represent a triangle that I will refer to as a "model". How can I can I find the ...
9
votes
1answer
3k views

Circle-Line Collision Detection Problem

I am currently developing a breakout clone and I have hit a roadblock in getting collision detection between a ball (circle) and a brick (convex polygon) working correctly. I am using a Circle-Line ...