Controlling refraction with MeshStandardMaterial - three.js

So I have very basic setup:
var cubeCamera = new THREE.CubeCamera (1, 1000, 1024);
cubeCamera.renderTarget.texture.minFilter = THREE.LinearMipMapLinearFilter;
cubeCamera.renderTarget.texture.mapping = THREE.CubeRefractionMapping;
cubeCamera.updateCubeMap (renderer, scene);
var matte = new THREE.MeshStandardMaterial({
envMap: cubeCamera.renderTarget.texture,
metalness: 0.5,
roughness: 0.4
});
and this creates correctly blurred refraction. However, driving metalness to 0 makes it vanish almost completely, making the material seem fully opaque. What is correct way to set up matte refractive material?

You are trying to use MeshStandardMaterial to create a translucent and refractive non-metallic material. You are setting metalness to zero, or near zero.
Non-metals typically have a low specular reflectance. That means the specular reflections from the environment are minimal — certainly compared to metals. Consequently, MeshStandardMaterial has been designed to have similar properties.
You have two options.
The first option is to compensate by increasing material.envMapIntensity, which defaults to 1. This simulates a brighter environment.
A second option is to use the more feature-rich MeshPhysicalMaterial, instead.
MeshPhysicalMaterial has an additional material.reflectivity property which controls the specular reflectance for non-metals. For physically-based materials, setting this property to 1 is a reasonable maximum value, but you can increase it further if you want.
three.js r.86

Related

Why transparency doesn't work on my mesh?

I have two meshes on my scene. One cylinder and one classic plane in the middle.
I applied a png texture on my cylinder so we can see through. It seems to work for the cylinder.
On this screenshot you'll easily see my issue : I don't understand why my image is not visible behind my cylinder.
The code I used for my cylinder :
myCylinderMesh.material.transparent = true;
myCylinderMesh.material.side = THREE.DoubleSide;
How can I manage to see the part of the image hidden behind the cylinder ?
EDIT 1 :
I added the code that #ScieCode sent me :
myCylinderMesh.material.alphaTest = 0.5;
Here's the result :
It works better : now I can see the part missing of my image. But there's one thing missing : the opacity of my cylinder. I'm supposed to see my image behind the letters too.
Currently I have this opacity :
myCylinderMesh.material.opacity = 0.7;
Do you know what I am missing ? Thanks
EDIT 2 :
Here's the code for my two meshes :
Cylinder :
geoCylinder = new THREE.CylinderBufferGeometry( 0.4, 0.4, 2*Math.PI*0.4/(2048/128), 64, 1, true );
matCylinder = new THREE.MeshBasicMaterial( { map:texture, transparent:true, color:0x000000, alphaTest: 0.5, opacity: 0.6, side: THREE.DoubleSide } );
meshCylinder = new THREE.Mesh( geoCylinder, matCylinder );
Plane :
geoPlane = new THREE.PlaneBufferGeometry( 0.8, 0.8 );
matPlane = new THREE.MeshBasicMaterial( { map: texturePlane, transparent:true} );
meshPlane = new THREE.Mesh( geoPlane, matPlane );
This behavior happens because of how transparency rendering works internally. Transparent objects need to be sorted/rendered separately from opaque objects. This assures that objects will render as expected on the final image. (not always, though)
The problem here is that your plane geometry is inside the cylinder geometry, when sorting it will either be rendered first or later. Which, in turn, causes these artifacts you are experiencing here. The whole transparency render is a lot more complex than what I'm making it to be.
Since your plane object doesn't need to be translucent, you can simply set the alphaTest property of its material. Which will only render the fragment pixels with alpha greater than this value. This will also prevent that object from being considered transparent and it will always be rendered first, fixing the artifacts in your scene.
JSFiddle
Additional info: When using a transparent material with DoubleSide, you might experience self transparency problems. This happens for the same reason I just explained, but between faces of the same object. A possible solution for this problem is to set depthWrite = false, this prevent the object from writing to the depth buffer. So every face will get rendered, disregarding if another face occludes it.

In three.js, when we need PointCloud.sortParticles enabled?

I found some of the examples enable this property, but there're not enough comments to make me understand what it matters.
Could you please tell me what's the best practice of this property?
EDIT: PointCloud is now Points, and the .sortParticles property has been removed. That means the points are rendererd in the order they exist in the buffer. The answer below is outdated. three.js r.73
This is a perfect example of why it is important to understand at least the basic concepts of webGL if you are using three.js. (See this SO post.)
You need to set PointCloud.sortParticles = true if the rendering order matters.
Here is an example where the rendering order matters:
var material = new THREE.PointCloudMaterial( {
map: texture, // has transparent areas
transparent: true
} );
var pointCloud = new THREE.PointCloud( geometry, material );
pointCloud.sortParticles = true; // the default is false
In this case, the renderer will sort the points by depth, so points further from the camera are rendered first, and show through the transparent areas of the closer ones.
Here is an example where rendering order does not matter:
var material = new THREE.PointCloudMaterial( {
map: texture,
blending: THREE.AdditiveBlending,
depthTest: false,
transparent: true
} );
// point cloud
var pointCloud = new THREE.PointCloud( geometry, material );
Since sorting occurs on the CPU-side, it is best to choose your material settings wisely, so you can avoid the overhead -- especially for large systems.
I suggest you build a testbed and experiment. There are many, many possible cases to consider.
three.js r.69

Three.js lightMap causes an error WebGLRenderingContext: GL ERROR :GL_INVALID_OPERATION

I'm loading a jpeg file for light map
var texture = new THREE.ImageUtils.loadTexture("textures/metal.jpg");
Then I apply the texture to THREE.MeshPhongMaterial
var frontMaterial = new THREE.MeshPhongMaterial( {
color: 0xfade7e,
specular: 0xffffff,
ambient: 0xaa0000,
lightMap:texture
} )
Full error message is WebGLRenderingContext: GL ERROR :GL_INVALID_OPERATION : glDrawElements: attempt to access out of range vertices in attribute 2
Is here something wrong? An error occures in all browsers. Three.js r.56
As explained by #alteredq in this thread, a LightMap requires a second set of UVs.
The point of lightmaps is that they can live independently of other textures, thus giving other textures chance to be much higher detail. Lightmaps use their own set of UV coordinates (usually auto-generated by some light baking solution, as opposed to artist-created primary UV set).
Using lightmaps with the same UVs as everything else doesn't make much sense, as then you could achieve basically the same result for less texture cost simply by baking light map together with color map (this is e.g. what Rage uses, it looks fantastic but needs boatload of textures).
Also lightmaps should be multiplicative, not additive. Big use case for lightmaps are pre-baked shadows and ambient occlusion, so you need to be able to darken things.
So the answer to your question is that geometry.faceVertexUvs[0] contains the usual set of UVs; you need to add to your geometry geometry.faceVertexUvs[1].
three.js r.56
This error become because the Three.js buffers are outdated. When your add some textures (map,bumpMap ...) to a Mesh, you must recompose the buffers and update UVs like this :
ob is THREE.Mesh, mt is a Material, tex is a texture.
tex.needsUpdate = true;
mt.map = tex;
ob.material = mt;
ob.geometry.buffersNeedUpdate = true;
ob.geometry.uvsNeedUpdate = true;
mt.needsUpdate = true;
That's all folks !
Hope it's help.
Regards.
Sayris

Opacity maps for THREE.js?

Are there any opacity maps for THREE.js ? Like:
so that I can use it on a map like
MeshBasicMaterial, MeshLambertMaterial, MeshPhongMaterial and MeshStandardMaterial support an alphaMap.
Alternatively, you could bake the transparency into your color texture's alpha channel.
In either case, you need to set material.transparent = true.
EDIT: If you are implementing a cut-out (alpha is either 0 or 1), then instead of setting material.transparent = true, you can just set material.alphaTest = 0.5.
three.js r.87

Three.js custom objLoader geometry lighting

I have this object I'm loading with THREE.objLoader and then create a mesh with it like so:
mesh = new THREE.SceneUtils.createMultiMaterialObject(
geometry,
[
new THREE.MeshBasicMaterial({color: 0xFEC1EA}),
new THREE.MeshBasicMaterial({
color: 0x999999,
wireframe: true,
transparent: true,
opacity: 0.85
})
]
);
In my scene I then add a DirectionalLight, it works and I can see my object, however it's like the DirectionalLight was an ambient one. No face is getting darker or lighter as it should be.
The object is filled with the color, but no lighting is applied to it.
If someone can help me with that it would be much appreciated :)
What could I be missing ?
Jsfiddle here: http://jsfiddle.net/5hcDs/
Ok folks, thanks to Maël Nison and mr doob I was able to understand the few things I was missing, being the total 3d noob that I am... I believe people starting to get into the 3d may find useful a little recap:
Basic 3d concepts
A 3d Face is made of some points (Vertex), and a vector called a normal, indicating the direction of the face (which side is the front and which one is the backside).
Not having normals can be really bad, because lighting is applied on the frontside only by default. Hence the black model when trying to apply a LambertMaterial or PhongMaterial.
An OBJ file is a way to describe 3D information. Want more info on this? Read this wikipedia article (en). Also, the french page provides a cube example which can be useful for testing.
Three.js tips and tricks
When normals are not present, the lighting can't be applied, hence the black model render. Three.js can actually compute vertex and face normals with geometry.computeVertexNormals() and/or geometry.computeFaceNormals() depending on what's missing
When you do so, there's a chance Three.js' normal calculation will be wrong and your normals will be flipped, to fix this you can simply loop through your geometry's faces array like so:
/* Compute normals */
geometry.computeFaceNormals();
geometry.computeVertexNormals();
/* Next 3 lines seems not to be mandatory */
mesh.geometry.dynamic = true
mesh.geometry.__dirtyVertices = true;
mesh.geometry.__dirtyNormals = true;
mesh.flipSided = true;
mesh.doubleSided = true;
/* Flip normals*/
for(var i = 0; i<mesh.geometry.faces.length; i++) {
mesh.geometry.faces[i].normal.x = -1*mesh.geometry.faces[i].normal.x;
mesh.geometry.faces[i].normal.y = -1*mesh.geometry.faces[i].normal.y;
mesh.geometry.faces[i].normal.z = -1*mesh.geometry.faces[i].normal.z;
}
You have to use a MeshPhongMaterial. MeshBasicMaterial does not take light in account when computing fragment color.
However, when using a MeshPhongMaterial, your mesh becomes black. I've never used the OBJ loader, but are you sure your model normales are right ?
Btw : you probably want to use a PointLight instead. And its position should probably be set to the camera position (light.position = camera.position should do the trick, as it will allow the light to be moved when the camera position will be edited by the Controls).

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