I'm trying to get a blender model that I've exported to display properly, but it appears as though the texture for the leaves isn't being blended correctly as an alpha ( though the trunk itself work fine ). Here's what I'm seeing:
Notice how the leaves aren't aliased through correctly ( i.e. it should look like a tree with leaves, not with gray sheets of paper ).
In Blender the tree looks fine, but I've had a few people tell me that it looks like my alpha is inverted ( I'm not totally sure what that means ). My guess is that, with a bit of file tweaking and conversion, I could get the attached images to work fine. Here are the image resources I've got:
I don't think it's necessary, but in case you want to see the exported JSON, I've dumped it here:
https://gist.github.com/funnylookinhat/5062061
I'm pretty sure that the issue is the black and white image of the oak leaves - given that it's the only difference between the two packed textures. Is there a way I can work with it or convert it so that it applies correctly to the layers of leaves?
UPDATE
I'm able to get something that looks mostly right ( minus some weird transparency layering issues ) - but I'm pretty sure that it isn't being done correctly... any help would still be much appreciated.
I added in transparency on the white/black and green images resulting in these:
Which resulted in the following:
Then I flipped the references to the two of them in the JSON - which resulted in this:
I'm 99% sure this isn't working as intended, it appears as though the Diffuse map isn't working correctly... any suggestions?
Three.js has no mask textures (the black and white texture), so you need to bake it into the alpha channel of the diffuse texture (so use .png format as .jpg does not support alpha - as you are currently doing).
Your update is on the right track although the diffuse alpha is poorly done (holes in leaves). This can be done right e.g. in Gimp by decomposing the diffuse color channels and then recomposing with the added mask layer as alpha (note however that white is assumed to be opaque and black transparent so inversion might be needed).
In the material, don't use the mask texture at all. There might also be problems with leaves overlapping each other which is a difficult problem to solve as transparency in general is quite the PITA. You can try disabling the material's depthWrite and/or playing with alphaTest values (e.g. setting it to 0.1) to get different kind of artifacts.
Related
I worked with a freelancer to create a few 3D models and I'm now trying to apply materials to them in Xcode, but some of the models are behaving weirdly. When I import the .dae file, instead of the default gray color models usually have, they are part green, part black, and part transparent. When I try to apply a material, the material only applies to the green parts, and any color seems to blend with the green.
The freelancer is at a loss because he says there shouldn't be anything different about the models that are working and the ones that aren't.
I've attached a screenshot of one of the broken models and one of the working ones, both with the same material applied.
Any help would be much appreciated!
I tried playing around with different material settings and searching for materials that were secretly applied to broken model, but to no avail.
I fixed this issue by removing a Colors item that was in Geometry Sources. I'm still not sure exactly what it is (I'm a SceneKit noob), but removing it did the trick.
This answer is just to illustrate the issue you might have with the texture coordinates. If you use one single color and not textures, you'll be good. But if you plan to add some texturing, you might want to unwrap your model in a different way. the following images should illustrate that.
This model shows texture coordinates that looks like a perspective projection and you loose a lot of space. It cannot be textured in a good manner. it should be unwrapped differently (illustration from Blender).
This model here is perfectly unwrapped with non overlapping textures and alomst every free space on the image texture is used for anything (illustration from Blender).
hope I could help in some manner.
I am struggling with the common transparency sorting issue. I know there are ways around it (like manually sorting the objects or order-independent transparency) but all that can become quite fiddly. I'd be ok if there was a way to have objects that are partly opaque and partly 100% transparent and have them intersect correctly.
In theory this should be possible. Opaque pixels would be rendered to color buffer and z buffer in the standard way and transparent pixels are just left out.
What I'm looking for is something like indexed transparency as it was used with gif files, for instance that all pixels of an object that have the color #FF00FF are not rendered.
I just don't know if and how this would be possible using three.js. Also, I want to be able to use it with custom shaders.
EDIT: Thanks for your comments so far and sorry for the confusion. This is more of a conceptional thing than a specific problem with my code. It's just that I am often faced with the issue that parts of transparent objects cut out parts of other transparent objects which should be in front of them. Also, transparent objects do not intersect correctly, it's always that one covers another. I understand why this happens and that it is a problem which is inherent to the way transparency is treated. But often I only need parts of an object completely transparent, no partial-shine-through-alpha transparency. Which could be possible if there was a way to leave out certain pixels of objects and render the rest like a normal opaque object.
Let's assume I want to have a metal chain and each segment is a PlaneGeometry thing with a texture that shows the shape of an O (and the rest transparent). Now the chain should be shown with correct interlinkage so to say.
Any help welcome!
Cheers!
If you are rendering a three.js scene, and your texture maps contain no partially-transparent pixels -- that is, each pixel is either 100% opaque or 100% transparent, then you can achieve a proper rendering by setting
material.alphaTest = 0.5;
//material.transparent = true; // likely not needed
The same holds true if you are using a binary alpha-map.
If you are writing a custom shader, then you can achieve the same effect by using a pattern like the following in your fragment shader:
if ( texelColor.a < 0.5 ) discard;
three.js r.84
I'm currently rendering a skybox to a THREE.CubeCamera target and am then using that target as the environment map on a material. The idea being that I want to have the colour of a cube affected by the colour of the sky around it, though not fully reflecting it (like how a white matte cube would look in the real world).
For example, here is what I have so far applying the environment map to a THREE.LambertMaterial or THREE.PhongMaterial with reflectivity set to 0.7 (same results):
Notice in the first image that the horizon line is clearly visible (this is at sunset when it's most obvious) and that the material is very reflective. The second image shows the same visible horizon line, which moves with the camera as you orbit. The third image shows the box at midday with blue sky above it (notice how the blue is reflected very strongly).
The effect I'm trying to aim for is a duller, perhaps blurred representation of what we can already see working here. I want the sky to affect the cube but I don't want to fully reflect it, instead I want each side of the cube to have a much more subtle effect without a visible horizon line.
I've experimented with the reflection property of the materials without much luck. Yes, it reduces the reflection effect but it also removes most of the colouring taken from the skybox. I've also tried the shininess property of THREE.PhongMaterial but that didn't seem to do much, if anything.
I understand that environment maps are meant to be reflections, however my hope is that there is a way to achieve what I'm after. I want a reflection of the sky, I just need it to be much less precise and instead more blurred / matte.
What could I do to achieve this?
I achieve this writing my own custom shader based on physically based rendering shading model.
I use cook-torrance model that consider roughness of the material for specular contribution. It's not an easy argument that I can talk in this answer, you can find great references here http://graphicrants.blogspot.it/ at the specular BRDF article.
In this question you can find how I achieve the blurry reflection depending on material roughness.
Hope it can help.
I solved this by passing a different set of textures that were blurred to be the cubemap for the object.
I loaded a mesh in three.js and loaded a grey texture with already baked in illuminations into a THREE.MeshBasicMaterial. Then I loaded a black and white Environment map with THREE.ImageUtils.loadTextureCube, set reflectivity to 0.4 and mix it with THREE.MixOperation.
The problem is now, that the black parts of the environment map make the mesh darker, which is not what i want. I want only the reflection of the white parts, like in an additive blending or like a specular (but still from the environment map).
I can fake that by changing the black to a grey, but then the model becomes rather flat.
I tried to do it with some render passes like in this tutorial (http://bkcore.com/blog/3d/webgl-three-js-animated-selective-glow.html ), but then I get some anti aliasing gaps in some small geometry lines which i also have.
Any suggestions?
That's currently not supported...
Do you mind posting it here as a feature request?
https://github.com/mrdoob/three.js/issues
I am working on a simple painting app using LibGDX, and I am having trouble getting it to "paint" properly with the setup I am using. The way I am trying to do this is to draw with sprites, and add these individual sprites into a background texture, using LibGDX's FBO commands, when it is appropriate.
The problem I am having is something relating to blending, in that when the sprites are added to this texture that I am building, any transparent pixels of the sprite that are on top of pixels that have been drawn to previous will be brightened up substantially, which obviously doesn't look very good. The following is what the result looks like, using a circle with a green>red gradient as the "brush". The top row is part of the background texture now, while the bottom one is still in its purely sprite drawn form.
http://i238.photobucket.com/albums/ff307/Muriako/hmm.png
Basically, the transparent areas of each sprite are brightening anything below them, and I need to make them completely transparent. I have messed around with many different blending mode combinations and couldn't find one that was any better. GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA for example did not have this problem, but instead the transparent pixels of each sprite seem to be lowered in alpha and even take on some of the color from the layer below, which seemed even more annoying.
I will be happy to post any code snippets on request, but my code has become a bit of mess since I started trying to fix these problems, so I would rather only put up the necessary bits as necessary.
What order are you drawing the sprites in? Alpha blending only works with respect to pixels already in the target, so you have to draw all alpha-containing things (and everything "behind" them) in Z order to get the right result. I'm using .glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);