SVG: orbit items around point and keep them oriented vertically - animation

I have a series of logos I am trying to rotate in a circle around a center point. Like a ferris wheel.
I can do the rotation fine, but I am trying to have the logos (i.e. the ferris wheel cabins) stay right-side up as the circle goes around.
Is there any way to do this in SVG?

Related

MapLibre GL JS with terrain layer: How to pin a horizontal plane to a specific altitude?

I based some code on the "Add a 3D model" example at maplibre.org in order to draw only a horizontal plane on a map which uses setTerrain to add a terrain layer.
My intention is to draw a couple of semitransparent layers at a given heights above sea level and have them intersect with mountains, somewhat similar to contour lines.
In my first test I just created a 1km-wide square at altitude 0.
I am somewhat confused by the behavior, since altitude 0 turns out to be the height of the terrain in the center of the visible map area. When I then drag the map and release the mouse, altitude 0 gets somehow reset again to the new altitude 0 of the terrain at the center, making the plane change its relative altitude.
The following animated GIF illustrates the problem:
The GIF has a mountain range to the right and the elevation is greatly exaggerated, in order to better illustrate the issue.
What do I need to do in order to be able to specify the height of the plane in meters above sea level and have it appear to be fixed at that height when dragging the map?
I think I need to get the height of the terrain at the center and then add/substract it from the plane's z-position in order for it to stay put at the height relative to given landmarks, but I have got no idea on how to do this inside of a custom layer's render function.

ThreeJS Flashing/Shooting Star

I am looking at this link https://www.igoodi.eu/home and wondering how they are doing that "flashing" / "shooting" stars. Is it a sphere that's being scaled down/up or zoom in/out? But when I tried to do that the star is deformed with respect to x,y,z position. I want it to be perfect sphere shaped when it is scaled/zoomed up.

Raytracing animated object

Is in any way possible to get intersection of a ray and an animated skin?
I'm trying to highlight animated characters and other objects in my game on mouse over, rather accurately.
I've set up an example of this with my current approach, so you can see the problem:
http://jsfiddle.net/Eskel/k44960Lp/1/
The model is rigged with a single bone and the bone animated to translate from side to side. Raytracing intersection turns it red. You can find the interaction in the middle, where I suppose it interacts with the static geometry.
I'm using Three.Raycaster
raycaster.intersectObject mesh

Three.js How to draw multiple spheres every 30deg for a clock

Good evening,
I was using EaselJS and now I'm trying to figure out how to use ThreeJS.
In EaselJS, you can set the rotation point of an element on the canvas before rotating it, .but it seems impossible to do the same thing in ThreeJS.
So, how can I draw a Sphere very 30deg to form a circle, like a clock.
A sphere at 12, at 1 o'clock, 2 o'clock, 3 o'clock...
I can rotate my sphere (which is useless) and position it, but I don't know how to calculate the coordinates.
Can't wait to hear back from one of you,
Jay
You need to translate then rotate each sphere.
so translate each circle by the radius of the clock,
circle.translateZ(10);
then rotate it into place by rotating around the clock center. In this case around the y axis,
circle.rotateOnAxis(new THREE.Vector3(0.0, 1.0, 0.0), THREE.Math.degToRad(30*i));
Do that for each circle.
Both libraries are based on a hierarchy scene with matrix rotations and translations. But one is 3D. Also the API is kinda different.

SIMPLE Ruby library for drawing shapes and managing clicks

I am looking for simple library for Ruby that could help me drawing things on the screen. I am not developing a game, I just want to display some graphs, so I need to
draw circles on a certain position,
put a label on these circles,
being notified that circle XYZ has been selected (I want to know the circle, not the coords),
draw lines connecting circles' borders,
change the color of the these circles,
(optional) animate moving a circle from position (x1,y1) to (x2,y2) in X seconds,
(even more optional) zoom on part of this scene.
Do you know anything that could help me with this?
Check out the green_shoes gem. Here's an example of some code to get you started, too!

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