Numeric representation of the location of an entity in the game space. There are multiple forms of coordinate systems to cater to a variety of methods to map position.

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6
votes
1answer
238 views

BRDF and Spherical coordinate in ray tracing

I developed a ray tracer that use standard phong/blinn phong lighting model. Now I'm modifying it to support physically based rendering, so I'm implementing various BRDF models. At the moment I'm ...
2
votes
1answer
622 views

Why AnchorPoint doesn't affect `CCLayer` Positioning?

I think there is a difference between CCLayer and CCNode behavior when I change their AnchorPoint. I will describe what I mean and please somebody explain it ? Scenario: I start with CCNode CCNode ...
1
vote
1answer
92 views

Using glm to rotate the modelview matrix based on the cursor position

I am rendering a 3D model of an object, and I want the user to be able to rotate around that object by dragging the mouse. To do this, I want to use the cursor position to continually update the ...
1
vote
1answer
136 views

Isometric Tile Selection with rectangular bounding boxes

I am having problems trying to determine which tile I have selected with the mouse. Currently it selects two tiles, rather than one. Producing the following results: My tiles height, is half their ...
0
votes
1answer
32 views

Box2d Coordinate System

In the game I'm trying to code I got to have two bodies. One StaticBody and one DynamicBody. I want to have the DynamicBody on top of the StaticBody. Somehow all I get is this: Is it possible that ...
0
votes
1answer
253 views

Mouse coordinate conversion Libgdx

I have a camera: //Map is a my object that wrapper of TiledMap class In the create method: this.renderer=new OrthogonalTiledMapRenderer(this.map.getMap(); this.camera=new OrthographicCamera(); ...
1
vote
0answers
25 views

Explanation of the parameters in the line intersection code

I am trying to understand a C code that moves the mesh nodes for each time step and i am totally struck on the parameters t1 and t2 please help me sorting this out. So here is what the function gets ...
1
vote
0answers
42 views

Getting screen coordinates of actor

I'm trying to tell if an actor exists at a screen position so I can do something if the actor is clicked on. To do this, I first need to get the screen coordinates of the actor so I can compare it to ...
1
vote
0answers
22 views

Proper way to wrap sprite for Z dimension

I am using SFML, but I need to add some emulation of 3D by wrapping the sprite with a Z component. When sprites are drawed (or when objects moved?), their X and Y will change depending on Z. My ...
1
vote
0answers
68 views

Matrix transform from one coordinate system to another

I have been beating my head against the wall for weeks on this and it is time I just break down and ask for help. I need to move a 3D camera from an in house system into Unreal 4. The two use ...
1
vote
0answers
34 views

Can I “Pre-rotate” VBOs while loading them in LWJGL?

It is possible to flip VBOs horizontally and vertically by swapping around destination coordinates. Is it possible to rotate an image by any angle, such as 45 degrees, using different destination ...
1
vote
0answers
153 views

Storing rigid body collision shapes in local or world coordinates

I'm writing the beginnings of a lightweight 2d rigid body engine (in javascript, as a hobby project), and i'm debating whether to store collision shapes in local or in (updated as needed) world ...
1
vote
0answers
164 views

How can I convert between float3 and float2 in HLSL?

I want to offload some 3D calculations to the GPU without raising my requirements to DX10. Specifically, I am generating densities in 64x64x64 3D blocks, which fit nicely into 512x512 2D textures. I ...
1
vote
0answers
131 views

Rotate view matrix based on touch coordinates

I'm working on an Android game where I need to rotate the camera around the origin based on the user dragging their finger. My view matrix has initial position of sitting on the negative z and facing ...
1
vote
0answers
120 views

Rotate Points with Object in world space

I posted this in the original stack overflow then realized that a game-dev specific one exists. I am working on personal project that requires me to have 4 points surrounding an object (1 at each of ...
1
vote
0answers
500 views

Converting motionevent.getx and motionevent.gety to pixel or Object coordinates in the view

I am trying to draw buttons using OpenGL I have added a Gesture Listener for the GLSurface View now i have motionevent when ever the user touches. My question is how can i convert motionevent.getx and ...
0
votes
0answers
25 views

Converting Transformation Matrices from OpenCV to Unity

I am working on an AR project, which uses OpenCV and Unity 3D. OpenCV uses Right Handed Coordinate system (different from OpenGL, because OpenCV camera looks along positive Z axis), while Unity has ...
0
votes
0answers
29 views

Platformer Tile Map Collision Help

I've been working on a small platformer as a simple project but, I'm having troubles with my collision detection. What I want is that as the player falls due to gravity, it will stop when it touches ...
0
votes
0answers
18 views

How do I generated cubic UV coordinates for a mesh?

I'm trying to add a utility function to my game engine that generates cubic texture coordinates for a specified mesh. I've attempted to come up with my own algorithm but I can't get it to work ...
0
votes
0answers
18 views

Screen coordinates to letterboxed view

So I have letter boxing working properly (it's not really important but I'll post that bit of code too), but I'm trying to figure out the point/vector arithmetic for translating (projecting) screen ...
0
votes
0answers
89 views

Coordinate system in OGLdev tutorials

Working with OGLdev tutorials http://ogldev.atspace.co.uk/ I found that this code uses coordinate system, which doesn't look like in most other samples. Positive x-axis direction is left, and not ...
0
votes
0answers
124 views

Pre- or post-multiplication for rotation between coordinate frames

I have three 3D coordinate frames: O, A and B, as shown below. I want to know the rotation matrix RAB between A and B, that is the rotation that is required, with respect to the frame A, to move ...
0
votes
0answers
35 views

Rotating between two coordinate frames

I have two coordinate frames, A and B. I want to create the rotation matrix RAB which takes you from A to B. A is a right-handed system, and B is a left-handed system. Furthermore, after moving from a ...
0
votes
0answers
141 views

How to get a position from a radial distance and angles?

I have a radius and the 2 angles for northSouth and eastWest rotations in degrees. I need a Spherical position or a cartesian position (I have code translate one to the other) Where a position is ...
0
votes
0answers
74 views

Transformations between coordinate systems

In a graphics engine, I have three three-dimensional orthogonal coordinate systems, O, A and B. A and B are the result of two different transformations from O. I now want to calculate the ...
0
votes
0answers
267 views

How do I find the rotation point given a touch anchor, new position and new rotation?

I've got an Cocos2d layer which anchorPoint, position and rotation (according to http://www.qcmat.com/understanding-anchorpoint-in-cocos2d/) vary when the pinch zoom gestures. Everything works fine. ...