WebGL Custom Shader Fluid on Image - three.js

I am currently trying to dive into the topic of WebGL shaders with THREE.js. I would appreciate if someone could give me some starting points for the following scenario:
I would like to create a fluid-like material, which either interacts with the users mouse or «flows» on it's on.
a little like this
http://cake23.de/turing-fluid.html
I would like to pass a background image to it, which serves as a starting point in terms of which colors are shown in the «liquid sauce» and where they are at the beginning. so to say: I define the initial image which is then transformed by a self initiated liquid flowing and also by the users interaction.
How I would proceed, with my limited knowledge:
I create a plane with the wanted image as a texture.
On top (between the image and the camera) I create a new mesh (plane too?) and this mesh has some custom vertex and fragment shaders applied.
Those shaders should somehow take the color from behind (from the image) and then move those vertices around following some physical rules...
I realize that the given example above has unminified code, but still it is so much, that I can't really break it down to simpler terms, which I fully understand. So I would really appreciate if someone could give me some simpler concepts which serve as a starting point for me.
more pages addressing things like this:
http://www.ibiblio.org/e-notes/webgl/gpu/fluid.htm
https://29a.ch/sandbox/2012/fluidwebgl/
https://haxiomic.github.io/GPU-Fluid-Experiments/html5/
Well, anyway thanks for every link or reference, for every basic concept or anything you'd like to share.
Cheers
Edit:
Getting a similar result (visually) like this image would be great:

I'm trying to accomplish a similar thing. I am being surfing the web a lot. Looking for any hint I can use. so far, my conclusions are:
Try to support yourself using three.js
The magic are really in the shaders, mostly in the fragments shaders it could be a good thing start understanding how to write them and how they work. This link is a good start. shader tutorial
understand the dynamic (natural/real)behavior of fluid could be valuable. (equations)
maybe, this can help you a bit too. Raindrop simulation
If you have found something more around that, let me know.
I found this shaders already created. Maybe, any of them can help you without forcing you to learn a plenty of stuff. splash shaders
good luck

Related

Creating frosted glass three webgl

I'm having trouble to find how to create a material with the look of frosted glass. I haven't found anything on the web that looks what I want to do.
I've tried a lot of settings for the material.
In this link you can see what I'm trying to get..
Does anybody have an idea how to solve this?
Regards
Rikard
One way I've encountered that worked well for me in the past performed a Blit on the portion of the framebuffer you want frosted with the blur algo or normal pattern of your choice. A stencil mask as part of the glass shader is used to determine which portion should be affected and which should not.
This article has a nice writeup on glass refraction which, when used with a blur will give a good effect.
https://beclamide.medium.com/advanced-realtime-glass-refraction-simulation-with-webgl-71bdce7ab825
I know It's not WebGL per se, but I've used the below Unity frosted glass shader before, to great effect. You may be able to extract the pertinent pieces from it and use that knowledge to assemble a WebGL version. https://github.com/andydbc/unity-frosted-glass
I'm about to undertake this myself, and will update this answer with actual code 'if' I succeed.

Threejs edge helper

I'm new to Threejs and I have been using the EdgesHelper which achieves the look I want for now. But I have two questions...
What is the default edge width/how is it calculated?
Can the edge width be changed...
I have searched around and I'm pretty sure that due to some limitation (not of threejs of Windows I believe) that there is no simple method to change the thickness of the edges (?). Alot of the examples I found that have thicker edges would only work on a particular geometry (e.g. doesn't seem universal).
Perhaps I am wrong but I would have thought that this would be a very common requirement? Rather then spend hours/days/weeks trying to get what i want myself (which I'm not even sure I personally would be able to do), does anyone know of a way to have control over the edge thickness, an existing example or a library that someone has already done that can work on any shape (any imported obj for example)
Many thanks
Coming back to this as Wilt mentioned there are other threads on this. Basically you cannot change the thickness due to a limitation in ANGLE, there are some work around like the THREE.MeshLine (also mentioned in the link Wilt stated) but i found most work aroudns had some limitations for what I wanted
https://mattdesl.svbtle.com/drawing-lines-is-hard explains what is difficult to it in lines.
He also has a library called https://github.com/mattdesl/three-line-2d which should make lines easier to use.

Which concepts should be used to render road lighting from a vehicle point of view using Blender?

I have never used Blender except for quick trials when I installed in Linux, but I wonder if I can used to solve a very specific problem.
I want to render some images showing a vehicle projecting light in a road with some objects (people, posts, signs). I need a bird's eye (superior, orthogonal) view, and the view from inside the vehicle (perspective, first-person) that is the image that would be seen by the driver or rider.
My question is: "Which CONCEPTS should I look for when searching Blender tutorials, in order to:
Select and use the proper rendering algorithm;
Modeling a scene with surfaces, materials, light sources and cameras;
Adding photorealistic behavior regarding light diffusion, reflection, etc.
Sorry if that is too obvious or too basic, but I am not even sure if Blender is able to model such a thing with an acceptable degree of photorealism (not super-realistic, that is not my intention).
Also, if there is another more appropriate StackExchange site to post this quesion, please let me know.
A nice First-Person viewport would be similar to this (without contour lines):
And a nice bird's eye viewport (witout color-mapping) would be this:
Cycles is blender's newer render engine that is fully raytraced and can easily create realistic results. On the other hand the older blender internal renderer can give you more control over lights, like length and angle from source but also the ability to subtract light from areas, it also supports volumetric rendering (if you want a foggy lit area) which is being worked on for cycles. This may be a key to the results you want. As you want to have control over the area that is lit I would run a couple of tests with lights over a plane to see whether cycles or blender internal can easily give the results your after.
As for the final render you can set the camera to perspective with control over focal length or orthographic and adjust scale as well as the option of a panoramic camera to get the final image you want.
Blender includes a ruler and protractor feature, there are also a couple of addons that may help. The scene settings offer metric or imperial display of measurements within blender.
For concepts, it sounds like your final scene would be fairly simple and any basic modelling and texturing would help. Blendswap could be a good resource for free models to help get you started.
For tutorials Blender Cookie is a great site for tutorials on specific tasks and has a good introduction to blender tutorial, while Blenderguru tutorials focus more on the final image.
Blender has also had it's own stackexchange site blender.stackexchange.com for a few months now.

creating a translucent plastic material

I would like to create a plastic material using three.js, something like the lighter fuel container here:
http://wiki.blender.org/index.php/Doc:2.4/Tutorials/Render/Import/SolidWorks
I would be glad if I could get a reasonably simple example to start working from.
I am actually not rendering an image but visualizing a mathematical problem (cellular automata). I need a set of interlocking surfaces (something like sheets of plastic foil) with as much visual information as possible, so I can distinguish between them. Therefore I was looking for: translucency, reflections, rotating an object with a fixed light source, visible edges. Later I will add some animated color coding, but for now I need a good material.
Here is the current status of my code:
https://github.com/jeras/three.js/tree/master/pyca
Here is how this networks look for 1D CA, but I would like to handle a 2D problem:
http://rattus.info/al/files/conference.pdf
Thanks,
Iztok Jeras
Well if you are looking for some examples to start working from , you should go to this three.js tutorials site : http://stemkoski.github.io/Three.js .
There is a lot of examples and the ones you might be interested of are :
the tranlucence
the reflection
the refraction
some bubble effect
Hope this helps

Inverse kinematic animation

I'm trying to find or create a working example of inverse kinematic posing in three.js. Ideally I would like to export human models from Makehuman via their Collada exporter, load them with THREE.ColladaLoader and set them into different poses in three.js programmatically or through some dat.GUI interface. A bit like an artist doll implementation - I don't need animation, but real-time feedback when tweaking the pose would be nice, and inverse kinematic style posing would be highly preferred.
I've been studying and searching information for days. This http://www.youtube.com/watch?v=6om9xy6rnc0 is very close, but I was unable to find any example code or downloads. The closest working example I've found is this: http://mrdoob.github.com/three.js/examples/webgl_animation_skinning.html However that appears to use predefined animation frames, which in turn appears to manipulate the bones in forward kinematics manner so that was not much help either.
I couldn't even find a model for testing, as I don't know what to look for when searching something with IK rigs/skinning/bones compatible with Three.js. Makehuman does seem to have plenty of rigging export options, I don't know if any of those are usable.
Is there a usable IK system in Three.js, and if so, are there any working examples, working human models, or any hints on which exact rigging system/workflow should study to accomplish this? If direct Collada support is not possible, creating the characters in Blender and exporting them is an option too..
EDIT: found this live demo http://www.akjava.com/demo/poseeditor/ but the code is totally unreadable.
I don’t feel competent enough to answer your question, but I’ll post three links which may put you on the right track.
wylieconlon/kinematics
– a great demo of 2D inverse kinematics animation. The code is totally readable.
https://www.khanacademy.org/computer-programming/inverse-kinematics/1191743453
– another demo, this time less flexible but more terse.
How to calculate inverse kinematics
– a rabbit hole of links. Just in case you’d want to dive right into the thing.
This seems promising.
Fullik : javascript fast iterative solver for Inverse Kinematics on three.js
is a conversion from java to Caliko 3D libs
Caliko library is an implementation of the FABRIK inverse kinematics (IK) algorithm
https://github.com/lo-th/fullik

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