I am a newbie in both OpenGL as well as Three.js, I am working on a streaming based "on-line" viewer which uses websockets to transmit points (with surface normals) from one system application to a remote web interface. Long story short, I have modified BufferGeometry and use THREE.PointsMaterial to visualize incoming data with points.
Since I already am sending points locations [xyz], color [rgb] and normals [abc] so I would love to use technique such as surface-splatting Splatting. Unfortunately due to my limited knowledge and lack of internet resources can any one guide me to implement a very basic surface splatting technique using three.js?
Question: How to draw elliptical surfaces instead of points in three.js
Any help will be highly appreciated.
it would probably work using points if you compute the point-size per point such that the whole ellipsis fits in there and use the fragment-shader to compute the area of the ellipsis based on the viewing-angle (i suppose this is what you want to do, right?).
Alternatively, you can use instancing based on a simple quad and use instance-attributes for position and orientation of the quads. In this case, you just need to render a circle into each of the quads.
Related
Does Three.JS have a function or capability of AI( Artificial intelligence )? Specifically let's say a FPS game. I want enemies to look for me and try to kill me, is it possible in three.js? Do they have a functionality or a system of such?
Webgl
create buffer
bind buffer
allocate data
set up state
issue draw call
run GLSL shaders
three.js
create a 3d context using WebGL
create 3 dimensional objects
create a scene graph
create primitives like spheres, cubes, toruses
move objects around, rotate them scale them
test for intersections between rays, triangles, planes, spheres, etc.
create 'materials' (rather than shaders)
javascript
write algorithms
I want enemies to look for me and try to kill me
Yes, three.js is capable of doing this, you just have to write an algorithm using three's classes. Your enemies would be 3d objects, casting rays, intersecting with other objects, etc.
You would be building a game engine, and you could use three.js as your rendering framework within that engine. Rendering is just one part of it. Think of a 2d shooter, you could make it using a 2d context, but you could also enhance it and make it 2.5d, by working with a 3d context. Everything else can stay the same.
any webgl engine that might have it ? or is it just not a webgl thing
Unity probably has everything you can possibly think of. Unity is capable of outputting WebGL, so it could be considered a 'webgl engine'.
Bablyon.js is more engine like.
Three Js is the best and most powerfull WebGL 3d engine that has no equal on the market , and its missing out on such an ability
Three.js isn't exactly a 3d engine. Wikipedia says:
Three.js is a lightweight cross-browser JavaScript library/API used to
create and display animated 3D computer graphics on a Web browser.
Three.js uses WebGL.
so if i need to just draw a car, or a spinning logo, i don't need them to come looking for me, or try to shoot me. I just need them to stay in one place, and rotate.
For a graphics demo you don't even need this - with a few draw instructions, you could render a full screen quad with a very elaborate pixel shader. Three gives you a ton of options, especially if you consider all the featured examples.
It works both ways, while you can expand three.js anyway you want, you can strip it down for just a very specific purpose.
If you need to build an app that needs to do image processing, and feature no '3d' graphics, you could still leverage webgl with three.js.
You don't need any vector, matrix, ray , geometry classes.
If you don't have vector3, you probably cant keep planeGeometry, but you would use bufferGeometry, and manually construct a plane. No transformations need to happen, so no need for matrix classes. You'd use shaders, and textures, and perhaps something like the EffectsComposer.
I’m afraid not. Three.js is just a engine for displaying 3d content.
Using it to create games only is one possibility. However few websites raise with pre-coded stuff like AI (among other things) to attract game creators, but using them is more restrictive than writing the exact code you need
Three.js itself doesn't however https://mugen87.github.io/yuka/ is a great AI engine that can work in collaboration with three to create AI.
They do a line if sight and a shooting game logic, as well as car logic which I've been playing around with recently, a React Three Fiber example here: https://codesandbox.io/s/loving-tdd-u1fs9o
I'm trying and failing to work out how to achieve a quad-tree of materials (images) on a single plane, much like a Google Maps-style zoomable tile that gets more accurate the closer you get.
In short, I want to be able to have a 1x1 image texture (covering a plane that is 256 units wide and tall) that can then be replaced with a 2x2 texture, that can then be replaced with a 4x4 texture, and so on.
Like the image example below…
Ideally, I want to avoid having to create a different plane for each zoom level / number of segments. A perfect solution would allow me to break a single plane into 8x8 segments (highest zoom) and update the number of textures on the fly. So it would start with a 1x1 texture across all 64 (8x8) segments, then change into a 2x2 texture with each texture covering 4x4 segments, and so on.
Unfortunately, I can't work out how to do this. I explored setting the materialIndex for each face but you aren't able to update those after the first render so that wouldn't work. I've tried looking into UV coordinates but I don't understand how it would work in this situation, nor how to actually implement that in Three.js – there is little in the way of documentation / examples for this specific case.
A vertex shader is another option that came up in research, but again I don't know enough to understand how to construct that.
I'd appreciate any and all help with this, it will be a technique that proves valuable for other Three.js users I'm sure.
Not 100% sure what you are trying to do, whether you are talking about texture atlasing (looking up and different textures based on current setting/zooms) but if you are looking for quad-tree based texturing that increases in detail as you zoom in then this is essentially what mipmaping is and does.
(It can be also be used to do all sorts of weird things because of that, but that's another adventure entirely)
Generally mipmapping is automatic based on the filtering you use - however it sounds like you need more control over it.
I created an example hidden away in the three.js source tree which may help:
http://mrdoob.github.com/three.js/examples/webgl_materials_texture_manualmipmap.html
Which shows you how to load each mipmap level in manually, rather than have it just be automatically generated.
HTH
I am working on a project where I am to use the Kinect to track facial expressions and animate a 3D model (.ply) accordingly.
So far I have managed to track a human face with a finite number of key-points on the face. I am able to get the coordinates of each key-point at every frame.
I am not very adept with animating techniques and general concepts of Mesh deformation and would really appreciate if one could provide a library which provides a high-level API so as to do said animation using x,y coordinates of key-points.
I am aware of CUBICA but unsure whether it can be used for what I want. Please excuse me as I am not very adept with this and would appreciate any help.
I too am looking for something that would do this (with .NET if possible), so I could hook Kinect up, set the position of each joint and see the character animate - without needing to set the position and angle of each bone which quickly gets very complex when you take into account the X,Y and Z positions.
So far my research has lead me to believe I will need a 3D engine that supports inverse kinematics - if anyone else had any better advice I'd be keen to hear it.
I have a photos that is taken by 360 degree lance now does anyone know how to create 360 degree photo viewer ?
please don't send the link of already developed softwares , it would be better if someone has
the road map / example code / articles.
Preferred Technologies Could be
Java/Flash/Flex/HTML 5 / javascript
Well I haven't done it myself yet but it basically boils down to projecting the photos you have to some camera surrounding primitive.
Easiest would be a cube but this will probably result in not so good results especially at the edges and corners. Better would be a sphere on which the images are projected.
But basically, adding 3D-primitives and mapping textures on it should easily be capable with Java or Flash. If you try to program it for browsers, have a look at WebGL. This would be a more future-oriented approach that doesn't need Flash... And it already provides good methods for texture mapping on surfaces.
If by 360° you only mean the horizontal plane you could also use a cylinder, which makes it much easier than projecting on spheres. You'll just need a wide panorama photo that goes around completely and map it to the cylinder.
So basically no matter which primitive you choose you'll need to position your camera within this primitive, project the photos to the primitive and implement some controls that allow the user to rotate the camera freely.
Can you provide any example photos? This would make it easier to find a way to solve your problem and find a good way of projecting the texture...
Hope that helps... if not, keep asking...
I need the fastest sphere mapping algorithm. Something like Bresenham's line drawing one.
Something like the implementation that I saw in Star Control 2 (rotating planets).
Are there any already invented and/or implemented techniques for this?
I really don't want to reinvent the bicycle. Please, help...
Description of the problem.
I have a place on the 2D surface where the sphere has to appear. Sphere (let it be an Earth) has to be textured with fine map and has to have an ability to scale and rotate freely. I want to implement it with a map or some simple transformation function of coordinates: each pixel on the 2D image of the sphere is defined as a number of pixels from the cylindrical map of the sphere. This gives me an ability to implement the antialiasing of the resulting image. Also I think about using mipmaps to implement mapping if one pixel on resulting picture is corresponding to more than one pixel on the original map (for example, close to poles of the sphere). Deeply inside I feel that this can be implemented with some trivial math. But all these thoughts are just my thoughts.
This question is a little bit related to this one: Textured spheres without strong distortion, but there were no answers available on my question.
UPD: I suppose that I have no hardware support. I want to have an cross-platform solution.
The standard way to do this kind of mapping is a cube map: the sphere is projected onto the 6 sides of a cube. Modern graphics cards support this kind of texture at the hardware level, including full texture filtering; I believe mipmapping is also supported.
An alternative method (which is not explicitly supported by hardware, but which can be implemented with reasonable performance by procedural shaders) is parabolic mapping, which projects the sphere onto two opposing parabolas (each of which is mapped to a circle in the middle of a square texture). The parabolic projection is not a projective transformation, so you'll need to handle the math "by hand".
In both cases, the distortion is strictly limited. Due to the hardware support, I recommend the cube map.
There is a nice new way to do this: HEALPix.
Advantages over any other mapping:
The bitmap can be divided into equal parts (very little distortion)
Very simple, recursive geometry of the sphere with arbitrary precision.
Example image.
Did you take a look at Jim Blinn's articles "How to draw a sphere" ? I do not have access to the full articles, but it looks like what you need.
I'm a big fan of StarconII, but unfortunately I don't remember the details of what the planet drawing looked like...
The first option is triangulating the sphere and drawing it with standard 3D polygons. This has definite weaknesses as far as versimilitude is concerned, but it uses the available hardware acceleration and can be made to look reasonably good.
If you want to roll your own, you can rasterize it yourself. Foley, van Dam et al's Computer Graphics -- Principles and Practice has a chapter on Bresenham-style algorithms; you want the section on "Scan Converting Ellipses".
For the point cloud idea I suggested in earlier comments: you could avoid runtime parameterization questions by preselecting and storing the (x,y,z) coordinates of surface points instead of a 2D map. I was thinking of partially randomizing the point locations on the sphere, so that they wouldn't cause structured aliasing when transformed (forwards, backwards, whatever 8^) onto the screen. On the downside, you'd have to deal with the "fill" factor -- summing up the colors as you draw them, and dividing by the number of points. Er, also, you'd have the problem of what to do if there are no points; e.g., if you want to zoom in with extreme magnification, you'll need to do something like look for the nearest point in that case.