How do I create a three.js material/geometry which uses part of a texture?
I am first rendering a scene to a texture. This texture is used for a Mesh with a CubeGeometry and a MeshLambertMaterial. What I would like to do now is have only a part of the texture displayed on the cube face (like a window into the texture).
I've done this before using OpenGL ES directly, with shaders, but I don't see what parameters might make it possible using the standard three.js library.
That is what texture coordinates are for. See this question and answer:
http://stackoverflow.com/questions/19366991/drawing-part-of-open-gl-texture/19367844#19367844
Related
I want to render a cube similar to .
My problem is how to render the face projections.
I tried using Reflector, but it is tricky to size and position so it captures just the face that I want, and also shows the sides.
I also saw I can use a separate canvas to render (I imagine using an orthographic camera), but I wish for everything to be in the same canvas. I saw an example with multiple views, but it seems that they can't be positioned behind.
So, is there a way to achieve this?
One possible approach to solve the issue:
Setup an orthographic camera such that its frustum encloses the cube. You can then position the camera in front of each side of the cube, use lookAt( cube.position ) to orient it properly and then render the scene into a render target. You need one render target per side. You can then use it as a texture for the respective plane mesh.
There is an official live example that demonstrates how RTT (render-to-texture) is done with three.js. Try to use it as a code template for your own app.
https://threejs.org/examples/#webgl_rtt
Is there any way to apply simple image texture to bufferGeometry created using new ObjectLoader? Earlier we use to create MeshBasicMaterial with map to apply texture to any Geometry, but that doesnt seems to be working directly with bufferGeometry. Can someone provide an example to apply any image texture on any BufferGeometry? Or any kind of Util library that will make life easy with bufferGeometry textures?
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 want to render a 2D scene using opengl es 2.0. In this scene i want to have a set of sprites (quads) to be rendered. I'm using orthographic projection. I want each sprite to have some z-value which will determine if it appears on front or back. But I want to render sprites not in z-value order. So how can I still achieve z-ordering is kept?
Despite the fact that you render using an ortographic projection, the 3rd dimension is still there. Just make sure that the nearz and farz values contain your objects, and remember to enable depth testing. Then you substitute all your 2D coordinates with appropriate 3D coordinates.
glEnable(GL_DEPTH_TEST); and you are good.