The circular movement of an object around a specific axis.

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1answer
55 views

Rotating a vector around a vector in 3D space

I am trying to rotate a moon around a planet (the planet is also rotating around an axis) but I am having trouble doing so. I tried to make the model move through space like so: @Override public ...
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0answers
60 views

what are the rules of wrapping angles [closed]

I would like to know the rules of wrapping an angle and when should I wrap?. I've seen so far two ranges for wrapping namely [-pi,pi] and [0,2pi]. I have no idea which one should I use. My project is ...
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2answers
96 views

Why do we say things are rotated around the z-axis in a space graph?

I've embarked on a journey of game development. I need to learn lots of 3D terminology, since I want to make 3D games. I learned that X is to the right, Y is up, and Z is towards you. Then why when a ...
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0answers
16 views

PhysX - Revolute joint around unit vector

I'm using a right-handed coordinate system with (0,0,-1) = forward, (1,0,0) = right and (0,1,0) = up. PhysX version is 3.3.0. I have a unit vector which represents the axis around which my actor is ...
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vote
1answer
26 views

Error in plane transformation

I have a bunch of coplanar points, who sit on plane P. I want to translate the plane to Q with the points upon. Here is what I do: I take three points from P, say a, b, c. Their centroid is denoted ...
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1answer
30 views

Rotation with XMMatrix to Rotation with XMFLOAT3

I'm rotating a Direction Light around a fixed object, so the light only contains a XMFLOAT3 to determine it's direction that it is facing. I have another object rotation using the variable Rotation ...
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1answer
22 views

Get 3D quad rotation matrix from points

I have 4 3D points which represent a even quad in space. (So 3 points are sufficient) I need to get all the individual transformations (translation, rotation, dimensions) so that I can build that quad ...
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2answers
207 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 ...
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0answers
30 views

Unity 2D angular velocity center

I try to add angular velocity to my GameObject with this command: rigidbody2D.angularVelocity = Random.value * tumble; All works, but I want center of velocity be in the center of my rigidbody, but ...
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0answers
35 views

Three.js camera turning leftside right

In Three.js I am trying to implement an orbiting camera can be rotated around the x and the y axis. I am using these two functions: function rotateX(rot) { var x = camera.position.x, ...
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0answers
43 views

Camera movement in Super Hexagon

I do realize there is no camera in OpenGL ES 2, but from my understanding you can simulate one using view and projection matrices. I'm using Android, by the way. Here's a video of the game, in case ...
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1answer
71 views

3d rotation of a Gunner unit to shoot the target

I'm developing a scenario to shoot incoming targets by a specific gunner unit, however I'm confused to actual logic of shooting an object with a gun. I'm working in 3D environment. I'v target's ...
2
votes
2answers
54 views

What are “local” and “global” rotations?

Each node in jME3 has local and global rotations, which can be expressed in quaternions. What are they? Documentation has no clues, about in which state rotations are zero?
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1answer
38 views

XNA 3D cube rotation problem

I am new to game programming and still trying to clear up my basics. I am stuck with a problem and unable to resolve on my own knowledge. I am trying to rotate a 3d cube in MonoGame (Similar to XNA) ...
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1answer
58 views

Libgdx Do a fixed rotation for orthographic camera

Im trying to rotate my orthographic camera in the render loop to a fixed angle, but I can only make the camera spin with the code I got: in the create OrthographicCamera camera = new ...
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2answers
76 views

Do I need to store a generic rotation point/radius for rotating around a point other than the origin for object transforms?

I'm having trouble implementing a non-origin point rotation. I have a class Transform that stores each component separately in three 3D vectors for position, scale, and rotation. This is fine for ...
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vote
3answers
79 views

Rotation matrix for a 3D vector

I have a direction vector on which I have to apply some rotation to align it to positive z-axis. To use Matrix.CreateRotationX(angle) of XNA, I need the angle for which I'd have to compute cos or tan ...
0
votes
1answer
50 views

Repelling a rigidbody in the direction an object is rotating

Working in Unity, I have a game object which I rotate each frame, like so: void Update() { transform.Rotate(new Vector3(0, 1, 0) * speed * Time.deltaTime); } However, I'm running into problems ...
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vote
1answer
102 views

libgdx rotation (animation, arrays) issues and help needed

well i am a noob at java and libgdx. i got the homing bullet working with the help of someone. now i am smashing my head as to how i can make it rotate so it faces the ball (which is the main ...
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2answers
53 views

what's wrong with my lookAt and move forward code?

so am still in the process of getting familiar with libGdx and one of the fun things i love to do is to make basics method for reusability on future projects, and for now am stacked on getting a ...
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0answers
21 views

How to rotate a trigger actor in UDK?

Working on a project and I need a trigger actor to detect a custom projectile type I've made. I would use a KActor with a TakeDamage event, but KActors despawn my projectiles. The issue is that I ...
4
votes
3answers
401 views

How to rotate a set of points on z = 0 plane in 3-D, preserving pairwise distances?

I have a set of points double n[] on the plane z = 0. And I have another set of points double[] m on the plane ax + by + cz + d = 0. Length of n is equal to length of m. Also, euclidean distance ...
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0answers
47 views

Issue with turntable rotation openGL

I am trying to implement turn table like rotation in my openGL app. In turn-table like rotation, z-axis is not supposed to roll. But in my app z-axis rolls like anything when I try to rotate the ...
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votes
1answer
58 views

Can I have a fixed-angle sprite with a non-fixed-angle CircleCollider2D?

In Unity2D, can I have a fixed-angle sprite with a non-fixed-angle CircleCollider2D? I would like to move my character using the circle physics (without fixed-angle), but display him always as if he ...
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2answers
66 views

How can I find the difference between rotations represented as angles in [0, 360]?

What is the easiest way to find the difference between two 2D rotations/directions? I want to test if one rotation is within 10° of another. I would just subtract, but there are some problems ...
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1answer
184 views

LibGdx sprite rotation vs Box2D physics rotation problem

LibGdx sprite rotation vs Box2D physics rotation problem Tearing my hair out on this one. I am an experienced software developer, but very new to LibGdx and Box2D development. I am writing a game ...
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0answers
22 views

Why the rotation matrix of X(θ1)Y(θ2)Z(θ3) can be viewed as extrinsic rotation of order ZYX and intrinsic order of XYZ?

As title, from wiki and OpenGL red book(7e) I found the expression v' = R_x * R_y * R_z * v can be viewed as Rotate vector v about local x axis, and y axis, finally z axis. Rotate vector v about ...
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1answer
54 views

Incomplete mesh using DrawIndexedPrimitives after rotating mesh

Through help on this site I was able to draw the triangles of an unrotated, nonscaled nontransformed mesh created in Blender and exported to OBJ, accurately imported through Assimp and rendered in XNA ...
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vote
1answer
130 views

Bullets won't shoot out of barrel in top-down shooter

So I am working on a top down shoot and have been stumped on why my bullets refuse to come out of the barrel of the gun. I know about the rotation equation which is x2 = x * cos(theta) - y * ...
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0answers
80 views

Unity crashes completely when I rotate my objects

I've started my first tiny Unity project and after 20 minutes I run into a brick wall. My goal was to create a Android 2D game with falling polygons, that you have to click and they disappear. ...
3
votes
3answers
136 views

How do I disassemble a 3x3 transformation matrix into rotation and scaling matrices?

I have a transformation matrix that rotates and scales. Is there any easy way to disassemble it into the original rotation and scaling matrices? For instance: M = R * S; // I need f and h such that ...
2
votes
1answer
76 views

Unity - Quaternion - Rotate / Unrotate Error

I'm trying to unrotate a quaternion, aligning it with the axis, and then rotate it back to where it was originally. But with every iteration it seems to lose precision and just after 20 iterations the ...
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vote
1answer
128 views

Matrix rotation wrong orientation LibGDX

I'm having a problem with matrix rotation in libgdx. I rotate it using the method matrix.rotate(Vector3 axis, float angle) but the rotation happens in the model orientation and I need it happens in ...
0
votes
1answer
79 views

Camera rotation around point, but without centering

Let's say i have the following: Point somewhere in space Camera with position and orientation (up, right, forward) I want to rotate camera around the point, but also keep this point in same place ...
2
votes
0answers
88 views

Quaternion - rotating rigidBody to particular angle over time

Using Bullet Physics. There's a rigid body that is rotated. For some delta-time I need to rotate that body to have rotation of (0, y, 0) - keep the old y value rotation but reset x and z. The ...
0
votes
0answers
54 views

How do I get a sprite's angle after collision?

I'm using Cocos2d (version 3) and I want my hero sprite to be jostled around by incoming enemy sprites. The Chipmunk-based physics work, but I need some way to track the rotation of the sprite after a ...
0
votes
0answers
62 views

rotating sprite with quaternion in scenegraph

I have been trying to set up a scenegraph in XNA, which I then use to draw sprites in the correct places. It uses matrix transformations to accomplish this. So far, I got position and scale working ...
0
votes
0answers
29 views

XNA 2D Stencil Buffer Rotation

I am currently working on a 2d game related to planets and am trying to get a stencil buffer working with rotation. I currently have a stencil buffer found from another related answer but it refuses ...
0
votes
0answers
27 views

How to find optimal perpendicular axis of rotation vector to draw arrows?

I am drawing lines on the screen. Each line has a point (x,y,z) and a direction (u,v,w). I want to draw arrow heads on these lines, like two lines that start from (x,y,z) and leave at a 15 degree ...
0
votes
0answers
45 views

GLM Rotating Combining Multiple Quaternions?

I have a camera which I want to control with my mouse. I want the mouse to control the pitch and yaw of the camera but not the roll. To avoid loss of significance, I am storing the quaternions for ...
0
votes
3answers
128 views

OpenGL: glRotatef cause performance drop while rotating -x and -y

I have made a rotating cube and I got some performance drops while using two glRotatef calls. So basically this code is giving me 80FPS: //code 1 GLrotate_x += 0.4f; GLrotate_y += 0.4f; ...
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vote
1answer
192 views

How can I restrict the rotation of an object to a subset of axes using quaternions?

I've got a question about quaternions in my WebGL application. How can I rotate an object only around two axes? For example, how can I exclude/nullify rotation about the Y axis? The problem is that ...
1
vote
1answer
234 views

Unity objects not rotating around pivot point

Suddenly, for some reason, objects in the unity editor started rotating around their center of gravity (at least that's what I think is going on) instead of their pivot point. I tried placing the ...
1
vote
1answer
153 views

How to translate swipe gestures into rotations?

I am making a snake game. I want to rotate my snake in the direction specified by swiping on the screen, the directions are limited to orthogonals (90 degree increments). It's an android game. Can ...
1
vote
1answer
273 views

Movement and rotation of bodies in top down game

We are developing a 2D top down game with libgdx using the included box2d as physics engine. We don't want our bodies to accelerate but to instantly move with the wanted velocity. The bodies are ...
0
votes
0answers
66 views

libgdx get rotated sprite coords points

I would like to get the position of each edge of a sprite when he has been rotated. I have no idea how to do it, I made a image to explain it. I would like to get the X and Y position of each Red ...
1
vote
1answer
93 views

JavaScript: Rotating a canvas around its center for a 2D sidescroller

I've been making a 2D sidescrolling game using JavaScript and HTML. The game is set in space, where the player character can fly around (Up, Down, Left and Right keys) and rotate the world around him ...
1
vote
0answers
72 views

Rotating SpriteBatch clockwise

I have developed a 2D game that looks great on the Android. Now I want to make it cross-platform. For this I need to literally rotate everything when it is on desktop. I tried to do that by rotating ...
0
votes
1answer
51 views

Rotating image around a given point

Im trying to simulate shadows in a 2d RPG, So far I can make the shadows but i cant blit them properly, Im trying to rotate them according to where the "sun" is (just a position) I have looked at ...
2
votes
0answers
27 views

Xna 4 Model Rotation with inertia not working as expected with variable updates

I am trying to rotate a model with inertia damping with the keyboard. The code works great with a fixed time step but it doesn't behave the same with a variable update frequency. Update method: ...