Transformation in game development is usually refers to linear algebra operations on points, vectors and matrices.
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8answers
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Why do we move the world instead of the camera?
I heard that in an OpenGL game what we do to let the player move is not to move the camera but to move the whole world around.
For example here is an extract of this tutorial: OpenGL View matrix
...
10
votes
1answer
418 views
Special relativity shader in GLSL
I'm trying to implement a GLSL shader which helps understanding special relativity Lorentz Transformation.
Let's take two axis-aligned inertial observer O and O' . The observer O' is in motion w.r.t ...
6
votes
3answers
377 views
Transforming a primitive tetrahedron into a primitive icosahedron?
I've created a tetrahedron by creating a BoundingBox and building the faces of the tetrahedron within the bounding box as follows (see image as well):
VertexPositionNormalTexture[] vertices = new ...
6
votes
2answers
320 views
How can you extract orientation from a transformation matrix?
I have a 4x4 transformation matrix M, and I want to find out the shape of a sphere when transformed by M. (Sphere is at the origin and has radius 1.)
I know I can find the center by just multiplying ...
6
votes
1answer
244 views
How can I attach a model to the bone of another model?
I am trying to attach one animated model to one of the bones of another animated model in an XNA game.
I've found a few questions/forum posts/articles online which explain how to attach a weapon ...
3
votes
2answers
248 views
How is the gimbal locked problem solved using accumulative matrix transformations
I am reading the online "Learning Modern 3D Graphics Programming" book by Jason L. McKesson
As of now, I am up to the gimbal lock problem and how to solve it using quaternions.
However right here, ...
3
votes
2answers
106 views
Calculating transform of arrow model pointing at some point in 3D space
I'm working on a 3D flight game and I'd like to implement a simple "navigation arrow" pointing at the next waypoint in world which the player has to fly to.
I have position of both airplane (=camera) ...
3
votes
1answer
111 views
Extract derived 3D scaling from a 3D Sprite to set to a 2D billboard
I am trying to get the derived position and scaling of a 3D Sprite and set them to a 2D Sprite.
I have managed to do the first part like this:
var p:Point = sprite3d.local3DToGlobal(new ...
3
votes
1answer
99 views
Calibration of a 6 DOF tracking device
Setting: In our facility we have a 3D laboratory with 3 large displays (two edge-to-edge on orthogonal walls, one on the ground, also edge-to-edge). Its primary use-case is exploring 3D virtual ...
2
votes
1answer
87 views
transformations of matrices
I'm in the process of reading up on 3d matrices and trying to following this powerpoint and had a few questions as to how to exactly determine the type of transformation from a matrix.
If I have a ...
2
votes
1answer
62 views
Translating Viewmatrix is inverted, why?
So I've defined a Projectionmatrix, Viewmatrix and a Modelmatrix using OpenGL (LWJGL).
But when I translate my Viewmatrix to +X it moves my object to the right (hence my camera is moving to the ...
2
votes
1answer
373 views
OpenGL: Move camera regardless of rotation
For a 2D board game I'd like to move and rotate an orthogonal camera in coordinates given in a reference system (window space), but simply can't get it to work.
The idea is that the user can drag the ...
2
votes
1answer
160 views
Scaling along an arbitrary axis (Dealing with non-uniform scale)
I'm trying to build my own little engine to get more familiar with the concepts of 3D programming.
I have a transform class that on each frame it creates a Scaling Matrix (S), a Rotation Matrix from ...
2
votes
1answer
50 views
How to transform a subset of a vertex in a vertex buffer?
float linePos[6]={0.0f,5.0f,0.0f,0.0f,30.0f,0.0f};
...
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(float)*3*2, linePos, ...
2
votes
1answer
213 views
Transform 3D vectors between coordinate systems
I've got 6 points in 3D space: A,B,C,D,E,F, that represent 4 vectors. AB is perpendicular to AC and DE is perpendicular to DF.
I need to find a transformation matrix M, that transforms AB to DE and ...
2
votes
2answers
199 views
how to transform child elements position into a world position
I'm making a 2d space game in Javascript with canvas. In this game there's a bunch of spaceships, positioned in world space, with turrets, positioned relative to their parent ships. These objects also ...
2
votes
2answers
93 views
Realtime fisheye to cubic or spherical panorama transformations with OpenGL or pixelshaders
I'd like to transform a sequence of circular fisheye-images to cubic or spherical panorama images to be used in a panorama-viewer based on OpenGL. The viewer-part is nemas problemas but the transform ...
2
votes
1answer
297 views
How can I create a 2D camera with upscaling and translation?
I've computed a Viewport that is fair in size (a proper aspect ratio to the given device) and then I calculate my ScaleMatrix like so:
scaleMatrix = Matrix.CreateScale(
(float) ...
1
vote
2answers
185 views
Transforming bounding spheres
When testing bounding spheres as part of the collision detection process, I'm using this method:
public static BoundingSphere TransformBoundingSphere(Matrix m, BoundingSphere b)
{
var ...
1
vote
3answers
219 views
Inverting matrix then decomposing gives different quaternion than decomposing then inverting the quat
I'm getting different signs when I convert a matrix to quaternion and invert that, versus when I invert a matrix and then get the quaternion from it:
Quaternion a = Quaternion.Invert(getRotation(m));
...
1
vote
3answers
492 views
In Maya how do I convert trans, rot, scale data to a 4 x 4 transformation matrix?
I have been given the following Maya camera data:
trans X: 1.542
trans y: 3.319
trans z: -1.821
rot X: 117.882
rot Y: 2.189
rot Z: 154.074
scale X: 1
scale Y: 1
scale Z: 1
What is the ...
1
vote
1answer
273 views
How to do geometric projection shadows?
I have decided that since my game world is mostly flat I don't need better shadows than geometric projections - at least for now.
The only problem is I don't even know how to do those properly - that ...
1
vote
1answer
100 views
Deformation of Sphere using Transformations
I have a graphic related question. I need to have a transformation matrix that I have no idea about what it is. The problem is to create right image from the right sphere. I created those images in ...
1
vote
1answer
177 views
Transformation matrix that maps a window
I'm currently learning OpenGL at uni, and they give us questions to help us learn (these are not worth anything), however I'm stuck on this one question and would have to travel over an hour and a ...
1
vote
1answer
52 views
changing coordinate system
I'm currently trying to transform a system by scaling it on x and y axis and have some uncertainty. I have the general concept that scaling works as such:
My original box has corners at (0, 0) and ...
1
vote
2answers
200 views
Render rotated rectangle inside other rectangle bounds using Libgdx
I have this code to generate a red rectangle inside a grey rectangle:
new Rectangle(grey_rectangle_position_x, Game.SCREEN_HEIGHT/2-Rectangle.height/2,0);
This code makes the following:
Now, I ...
1
vote
1answer
225 views
Translate along local axis
I have an object with a position matrix and a rotation matrix (derived from a quaternion, but I digress). I'm able to translate this object along world-relative vectors, but I'm trying to figure out ...
1
vote
1answer
588 views
Translating local to global coordinates in ARToolkit / OpenGL
Ok, so I've tried reading over the other questions and something's just not clicking for me. I am working on an augmented reality application using ARToolkit, however it should just be straight ...
1
vote
1answer
102 views
Canvas isometric translations to integer coordinates
I'm creating a canvas based game with an isometric playing board. I use the following transformations to get my square tiles to render on the screen:
'applyViewportTransformation' : function() {
...
1
vote
1answer
93 views
Proper approach to handle transformation matrix and extract its components
Basically I have a Transformation component object with following structure(pseudo):
TransformComponent{
Vec3 position;
Vec3 rotation; //in euler angles
Vec3 scale;
Mat4 worldMatrix; ...
1
vote
1answer
99 views
SimpleOpenNI: Check if user hand is in specific area on image
Concerning our Microsoft Kinect project, we need some help.
We control a robot with our movements tracked by the Kinect sensor. We display the depth image of the Kinect sensor on our screen, so we ...
1
vote
1answer
156 views
Bullet Physic: Transform body after adding
I would like to transform a rigidbody after adding it to the btDiscreteDynamicsWorld.
When I use the CF_KINEMATIC_OBJECT flag I am able to transform it but it's static (no collision response/gravity). ...
1
vote
1answer
132 views
Orthogonal projection and world transform
I'm reading about projection matrix. Needs of perspective projection is obvious, but I'm not sure about orthogonal projection. Because orthogonal projection effect looks possible with only world ...
1
vote
1answer
398 views
Transform 3d viewport vector to 2d vector
I am playing around with 3d transformations and came along an issue.
I have a 3d vector already within the viewport and need to transform it to a 2d vector. (let's say my screen is 10x10)
Does that ...
1
vote
1answer
183 views
How do I draw shape distortion with a Texture2D in XNA?
Say I have a rectangular Texture2D object in XNA, and I draw it on the screen.
How can I animate it so it slowly changes to a trapezoid shape, and then to a pentagon, etc.
I have no idea what this ...
1
vote
1answer
169 views
2D Matrix Transformation (with a Player and Ground)
I have a simple game that I'm trying to do for learning purposes, but Matrices are a bit hard, especially in DirectX.
I currently have a tilesystem that renders tiles at the screen and a character ...
1
vote
0answers
56 views
How to work with edge Texture
Im not sure if i use the right terms, but im not able to find something to start with.
Im trying to develop a little HTML5 game. I have a ground with a texture and now I want to make a surrounding ...
1
vote
1answer
322 views
importing animations in Blender, weird rotations/locations
This is for the Blender 2.6 API.
There are two problems:
1. When I import a single animation frame from my animation file to Blender, all bones look fine.
But when I import multiple (all of the ...
0
votes
2answers
174 views
OpenGL: Transformations
I'm not sure if I correctly understand 3D transformations in OpenGL. Let's assume I'm using the typical matrix stack.
It seems like you move the world X units over, drop in a bag of verts (a mesh) ...
0
votes
1answer
74 views
coordinate transformation
I have two coordinate systems, like so
How can I transform a point on the one of the coordinate system to other ?
Pxyz = M . Px'y'z' what is M ?
0
votes
2answers
363 views
How can I reflect a point with respect to the plane?
How can I reflect a point with respect to a plane?
Example:
I have three points (0,0,2), (4,0,0) and (0,8,0). And I have a point (x,y,z). From these, I want derive a composite transformation matrix. ...
0
votes
1answer
127 views
Rotation of Rectangle along Y-axis transformed to parallelogram
After the rotation of a rectangular view along the Y-axis, about its center, transformed into parallelogram, how do I get the rotated parallelogram coordinates?
By Y-axis, I mean perpendicular to the ...
0
votes
1answer
181 views
Optimizing hierarchical transform
I'm transforming objects in 3D space by transforming each vector with the object's 4x4 transform matrix. In order to achieve hierarchical transform, I transform the child by its own matrix, and then ...
0
votes
2answers
48 views
Transform translation relative to world space
What is common algorithm for translating a transform matrix relative to world space axis?
E.g. Matrix M is representing some local space.
When I want to translate M relative to it's own local axis, I ...
0
votes
1answer
136 views
Interpolating a player between two 2D points?
I would like a player to be able to move in a direction smoothly, whilst sticking to a fixed grid. Much like in Pokemon, how the player can move, but when the key is pressed and released quickly, they ...
0
votes
1answer
290 views
How to extract euler angles from transformation matrix?
I have a simple realisation of entity/component game engine.
Transform component have methods to set local position, local rotation, global position and global rotation.
If transform is being set new ...
0
votes
1answer
65 views
How to change Vectors due to change in it's dependent Base Vector?
PLOT :
I have been developing a game where the player falls down on Y axis and the camera is a Top-Down view camera. The camera, player (main character in the game) movements etc. have all been ...
0
votes
2answers
290 views
getting bone base and tip positions from a transform matrix?
I need this for a Blender3d script, but you don't really need to know Blender to answer this.
I need to get bone head and tip positions from a transform matrix read from a file.
The position of base ...
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 ...
0
votes
1answer
156 views
Apply bone tranforms when importing FBX in XNA
Preconditions: I have some models, that does only contain some meshes and one texture. There is no animation within the model. An example: a model of a table.
I want to draw the Model with a custom ...
