I'm learning webgl, threejs and glsl shaders. The scene you see below is my attempt at working with instanced geometry. I have 3 patches of "grass". The grass is actually made of instanced cones around the central position of the mesh I'm building.
As you can see, if the central position (marked with a white wireframe cone) of the mesh is no longer in the camera view, all instances disappear.
How can I prevent this?
And to be even more specific: Are all the grass patches, or all fire instances, or all particles of the same time supposed to be instanced at once and place around the scene how we see fit? My assumption is that they should. Right?
If you are using InstancedBufferGeometry, there are two ways you can deal with frustum culling.
One way is to turn frustum culling off for the mesh:
mesh.frustumCulled = false;
The other option is to set the bounding sphere of the mesh's geometry manually, if it is known in your case:
geometry.boundingSphere = new THREE.Sphere( new THREE.Vector3(), radius );
three.js r.88
Related
I want to realize a 3D interactive globe with three.js and I wonder if there is a way to intersect over Sprites primitive with the Raycaster?
If you check the source code for RayCaster at
https://github.com/mrdoob/three.js/blob/master/src/core/Raycaster.js
it would appear that the intersectObject function only checks objects that are instances of THREE.Particle or THREE.Mesh, not THREE.Sprite. Possibly this is because sprites could be set to use screen coordinates, and so a ray that projects into your 3d scene wouldn't make sense in this situation, or if placed in the scene as the sprite image always faces the camera, it doesn't act like your standard 3d mesh.
Perhaps you could attach a PlaneGeometry or a very thin CubeGeometry to the position of your sprite, set its rotation to the rotation of the camera so that it is always parallel to the view plane of the camera like the sprite is, and then check for intersections with the mesh instead?
When using a cube camera one normally sets the envMap of the material to the cubeCamera.renderTarget, e.g.:
var myMaterial = new THREE.MeshBasicMaterial({color:0xffffff,
envMap: myCubeCamera.renderTarget,
side: THREE.DoubleSide});
This works great for meshes that are meant to reflect or refract what the cube camera sees. However, I'd like to simply create a texture and apply that to my mesh. In other words, I don't want my object to reflect or refract. I want the face normals to be ignored.
I tried using a THREE.WebGLRenderTarget, but it won't handle a cube camera. And using a single perpspective camera with WebGLRenderTarget does not give me a 360 texture, obviously.
Finally, simply assigning the cubeCamera.renderTarget to the 'map' property of the material doesn't work either.
Is it possible to do what I want?
r73.
Edit: this is not what the author of the question is looking for, I'll keep my answer below for other people
Your envmap is already a texture so there's no need to apply it as a map. Also, cubemaps and textures are structurally different, so it won't be possible to swap them, or if you succeed in doing that the result is not what you probably you might expect.
I understand from what you're asking you want a static envmap instead to be updated at each frame, if that's the case simply don't run myCubeCamera.updateCubeMap() into your render function. Instead place it at the end of your scene initialization with your desired cube camera position, your envmap will show only that frame.
See examples below:
Dynamic Cubemap Example
Static Cubemap Example
The answer is: Set the refractionRatio on the material to 1.0. Then face normals are ignored since no refraction is occurring.
In a normal situation where the Cube Camera is in the same scene as the mesh, this would be pointless because the mesh would be invisible. But in cases where the Cube Camera is looking at a different scene, then this is a useful feature.
My question is related to this article:
http://blog.wolfire.com/2009/06/how-to-project-decals/
If my understanding is correct, a mesh made from the intersection of the original mesh and a cube is added to the scene to make a decal appear.
I need to save the final texture. So I was wondering if there is a way to 'merge' the texture of the original mesh and the added decal mesh?
You'd need to do some tricky stuff to convert from the model geometry space into UV coordinate space so you could draw the new pixels into the texture map. If you want to be able to use more than one material that way, you'd also probably need to implement some kind of "material map" similar to how some deferred rendering systems work. Otherwise you're limited to at most, one material per face, which wouldn't work for detailed decals with alpha.
I guess you could copy the UV coordinates from the original mesh into the decal mesh, and the use that information to reproject the decal texture into the original texture
I'm trying to create a shadow in my orthographic scene in three.js. I'd like to have a directional light so the shadow is offset from all objects equally in the scene. I am however having problems using DirectionalLight.
My first problem is that I can't get the shado to cover the entire scene, only part of it ever has a shadow. I played with the light's frustum settings, but can't figure out how to get it to cover the scene. Ideally I'd want the frustrum to match that of the camera.
The second problem is that the shadows aren't "clean". If I use a SpotLight the shadows have nice crisp borders (but obviously not the universal directionality I want). When I use a DirectionalLight the borders are misshappen and blurry.
In the samples the tile is a simply box created with CubeGeometry.
How can I create an ortographic directional light source for my scene?
I want to realize a 3D interactive globe with three.js and I wonder if there is a way to intersect over Sprites primitive with the Raycaster?
If you check the source code for RayCaster at
https://github.com/mrdoob/three.js/blob/master/src/core/Raycaster.js
it would appear that the intersectObject function only checks objects that are instances of THREE.Particle or THREE.Mesh, not THREE.Sprite. Possibly this is because sprites could be set to use screen coordinates, and so a ray that projects into your 3d scene wouldn't make sense in this situation, or if placed in the scene as the sprite image always faces the camera, it doesn't act like your standard 3d mesh.
Perhaps you could attach a PlaneGeometry or a very thin CubeGeometry to the position of your sprite, set its rotation to the rotation of the camera so that it is always parallel to the view plane of the camera like the sprite is, and then check for intersections with the mesh instead?