I'm getting started with three.js, and I don't want to use WebGLRenderer (renderer = new THREE.WebGLRenderer();) at all. Instead I want to use renderer = new THREE.CanvasRenderer();.
I don't want to use WebGLRenderer due to lack of support.
How can I have a camera orbit without using WebGLRenderer, and use canvas only in three.js?
The three.js site has a small but effective set of Canvas samples as well. Just take a look at the source of https://threejs.org/examples/#canvas_camera_orthographic: it has an orbiting camera. It is orthographic, which you might not want, but the source should be self-explanatory on how to change it to a perspective camera.
Related
I need to post-process the scene that I rendered previously on textureA (as render target), with my custom shader and save the result to textureB (input:textureA, output:textureB). Therefore, I don't need a scene and a camera. I think it's too simple to even bother with three.js classes like EffectComposer, Shaderpass, CopyShader, TexturePass, etc.
So, how do I setup this computing-like post-processing in a simple way?
I've create for you a fiddle that shows a basic post-processing effect without EffectComposer. The idea behind this code is to work with an instance of WebGLRenderTarget.
First, you draw the scene into this render target. In the next step, you use this render target as a texture for a plane which is rendered with an orthographic camera. The code in the render loop looks like this:
renderer.clear();
renderer.render( scene, camera, renderTarget );
renderer.render( sceneFX, cameraFX );
The corresponding material of this plane is your custom shader. I've used a luminosity shader from the official repo.
Therefore, I don't need a scene and a camera.
Please do it like in the example. That's the intended way of the library.
Demo: https://jsfiddle.net/f2Lommf5/5149/
three.js R91
I'm trying to set a texture to an already existing mesh like this:
const texture = new THREE.Texture(canvas);
texture.needsUpdate = true;
(The source a HTML5 canvas and that part works ok.)
...
mesh.material[0].map = texture;
I can change the material color without any problems, but setting the texture doesn't change anything. I guess this is not how changing the texture should be done..? I'm using MeshPhongMaterial.
So, long story short: I want to be able dynamically change a texture of an mesh.
Edit:
I'm trying to set the texture to one of the materials of a Collada model that is loaded. By using dev tools I can see that the texture is there in the object, but it is just not visible. I can change the color of the same material without any problems. Sometimes I can see the texture appearing with wrong colors after a very long idle time (which is weird).
So, the scene include an earth spinning on its axis, a moon rotating around the earth, and a light source to the right that will help to simulate the effect of an eclipse. I thought it would be easy because we've done shadows and transformations before but I ran into a problem.
In our template we have the following at the top:
// For the assignment where a texture is required you should
// deactivate the Detector and use ONLY the CanvasRenderer. There are some
// issues in using waht are called Cross Domain images for textures. You
// can get more details by looking up WebGL and CORS using Google search.
// if ( Detector.webgl )
// var renderer = new THREE.WebGLRenderer();
// else
var renderer = new THREE.CanvasRenderer();
My problem is, when I leave it like that, the spotlight doesn't appear on the scene. However, as was warned, if I activate the Detector, the textures won't work.
But I need both textures and the spotlight. How do I work around this?
You are confusing yourself. Detector.webgl only checks for support of WebGL on the browser. The code below uses the WebGL renderer if the current browser supports WebGL and CanvasRenderer if there is no WebGL support.
if ( Detector.webgl )
var renderer = new THREE.WebGLRenderer();
else
var renderer = new THREE.CanvasRenderer();
With WebGL - loading textures will run into a cross domain issue. Best to then execute the code either on a web server or a local server like http://www.wampserver.com/en/ for Windows or https://www.mamp.info/en/ for Mac. Or npm-package like https://github.com/tapio/live-server.
As far as I know shadows are not supported on the CSSCanvasRender. I would ask your assignment head to clarify.
I am using CanvasRenderer to render numerous Sprite objects. I am mapping a texture (PNG image) to the Sprites. I'd like to be able to change the color of the texture programmatically.
With the WebGLRenderer, I can use ParticleSystem and ParticleSystemMaterial to achieve this. Here's a live demo of setting color to this texture (http://wxalert.info/private/dv/ball.png) with that technique: http://wxalert.info/private/dv/demo.html
But since CanvasRenderer does not support ParticleSystem, I am using Sprites instead with a SpriteBasicMaterial. Here's a live demo of this: http://wxalert.info/private/dv/demo2.html
I'd like to be able to set the color with CanvasRenderer just like with WebGLRenderer, but I'm not sure if this is possible.
One thought was perhaps to load the image to an HTML5 canvas element, apply the color there, and then load the canvas context from the material. But any other suggestions would be greatly appreciated.
UPDATE: Here's an example of kind of what I was thinking of doing if using the HTML5 canvas: http://wxalert.info/private/dv/html5canvas.html. Basically, I would do the color manipulation there and then just load the canvas from the material. But wasn't sure if there was a simpler or better way.
I'm viewing a scene using threejs and the trackball camera. I try to get the view matrix from the camera, but its matrixworldinverse isn't updating. I do call updateMatrixWorld in my render function. The matrixworld is updating, just not the inverse. Any ideas why?
You need to do it yourself:
camera.matrixWorldInverse.getInverse( camera.matrixWorld );
Make sure camera.matrixWorld is updated first. Note that by default, it is automatically updated by the renderer.
three.js r.58