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.
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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.
I'm trying to add clouds to my scene using the approach in https://codepen.io/teolitto/pen/KwOVvL, which is to make a large number of plane objects at random positions that each rotate continuously around their z axes.
But I would like to be able to move my camera, change its target, etc., and still have the cloud planes look right.
What I need to do is rotate the planes so that as the camera moves and changes target, the cloud planes stay perpendicular to the camera's axis. And I need to do this without changing the planes' rotation around their own z-axis, because otherwise that would break the cloudlike appearance.
I've tried cloudplane.lookAt(camera.position) but of course that doesn't work. It aims all of the planes at the camera, instead of making them all perpendicular to the camera axis. It also sets the object's z-axis, so the clouds don't evolve.
Any advice is appreciated. (I'm new to three.js, so if I have some of the terminology wrong, I apologize for that.)
Edit:
Setting the cloudplane's rotation.x and rotation.y to match the camera's rotation.x and rotation.y seems to get me pretty close, but it doesn't quite get there - its still possible to orbit the camera to a position where the clouds are all invisible because they're all parallel to the camera.
I'm working on a driving simulation in Three.js using height map data from the planet Venus.
GitHub repo here: https://github.com/hypothete/venus-walk
Here's how the simulation works so far:
In a hidden scene, a camera called the globeCamera moves at a fixed height over a sphere textured with the Venus height map. You can see this happening in the lower left viewport in my picture. The globeCamera renders its view to a WebGLRenderTarget to be used as a local height map. The result is in the second viewport in the middle left.
In the visible scene, a plane mesh called the terrainMesh has its vertices displaced up and down in correspondence with the values from the local height map. This gives the illusion that a vehicle placed in the center of the plane is moving across a surface when actually we're just updating the plane's vertices from the movement of the globeCamera.
Since I know the rotation of the globeCamera, I can pass that value to my fragment shader to rotate the terrainMesh's rock texture with the height map.
How can I offset the rock texture's position so that texture units translate with the terrain as well? I've tried tracking the globeCamera's offset as a 2D vector and adding that to the rotated UV in the fragment shader, but my results were inconsistent. Thanks for your help.
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.
Using a basic THREE.PlaneGeometry and Orbit and Pan controls.. for some reason when I look at the underside of the plane, the plane vanishes from the scene. Is there some way that I could look at the underside of the PlaneGeometry?