I am working in three.js to make terrain from the heightmap data that i have in json file. I now have a chunk of mesh which add up to make a complete terrain but since multiple chunk make multiple draw call which i believe is expensive and making my system very slow.
This is my code:
https://github.com/pravinpoudel/three.js-boilerplate/blob/main/src/client/terrain.ts
This is my terrain after i apply the heightmap and is of size 4104x1856 madeup from chunk of size (256, 256)
I checked the documentation and example of instanced rendering in three.js but all ask for same geometry but in my case i have deformed the y value of each vertex according to the heightmap data from elevation json file.
I believe that i can make it perform better with instanced rendering but i dont know how can i implement that with each geometry in the chunk have altered y value.
Moreover, is there anything more you can suggest?
I am learning a lot from this group and i believe that i can get more insight from here.
Thank you everyone for being here and helping people like me !!
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Hello I'm trying to archive the effect in the image below (that is like shine light but only on top of the raw image)
Unfortunately I can not figure out how to do it, tried some shaders and assets from the asset store, but so far no one has worked, also I dont know much about shaders.
The raw image is an ui element, and renders a render texture that is being captured by a camera.
I'm totally lost here, any kind of help will be appreciated, how to make that effect?
Fresnel shaders use the difference between the surface normal and the view vector to detect which pixels are facing the viewer and which aren't. A UI plane will always face the user, so no luck there.
Solving this with shaders can be done in two ways - either you bake a normal map of the imagined "curvature" of the outer edge (example), or you create a signed distance field (example), or some similar method which maps the distance to the edge. A normal map would probably allow for the most complex effects, and i am sure that some fresnel shaders could work with that too. It does however require you to make a model of the shape and bake the normals from that.
A signed distance field on the other hand can be generated with script from an image, so if you have a lot of images, it might be the fastest approach. Getting the edge distance in real time inside the shader would not really work since you'd have to sample a very large amount of neighboring pixels, which might make the shader 10-20 times slower depending on how thick you need the edge to be.
If you don't need the image to be that dynamic, then maybe just creating an inner glow black/white texture in Photoshop and overlaying it using an additive shader would work better for you. If you don't know how to write shaders, then maybe the two above approaches are a bit of a tall order.
I need to render a texture as a library of small parts, then copy each part to a set of different textures used in the scene. I think this is fundamental and I cannot find documentation specifically in three.js. Should I seek a solution in pure WEBGL, or is there a three.js solution?
EDIT:
One "solution" would be to set the UV coordinates of the target mesh (plane, whatever) to correspond only to the desired part of the big texture, but that would definitely be very inefficient, as it would require for each small mesh to load the whole big texture a huge waste of memory and GPU power as the whole big texture would be probably transformed multiple times(!), aside the inconvenience of setting the different UV coordinates on each mesh object.
So, I'm looking to copy and assign only a small part and occupy in memory and process only that part for each mesh.
I'm new to three.js and WebGL in general.
The sample at http://css.dzone.com/articles/threejs-render-real-world shows how to use raster GIS terrain data in three.js
Is it possible to use vector GIS data in a scene? For example, I have a series of points representing locations (including height) stored in real-world coordinates (meters). How would I go about displaying those in three.js?
The basic sample at http://threejs.org/docs/59/#Manual/Introduction/Creating_a_scene shows how to create a geometry using coordinates - could I use a similar approach with real-world coordinates such as
"x" : 339494.5,
"y" : 1294953.7,
"z": 0.75
or do I need to convert these into page units? Could I use my points to create a surface on which to drape an aerial image?
I tried modifying the simple sample but I'm not seeing anything (or any error messages): http://jsfiddle.net/slead/KpCfW/
Thanks for any suggestions on what I'm doing wrong, or whether this is indeed possible.
I did a number of things to get the JSFiddle show something.. here: http://jsfiddle.net/HxnnA/
You did not specify any faces in your geometry. In this case I just hard-coded a face with all three of your data points acting as corner. Alternatively you can look into using particles to display your data as points instead of faces.
Set material to THREE.DoubleSide. This is not usually needed or recommended, but helps debugging in early phases, when you can see both sides of a face.
Your camera was probably looking in a wrong direction. Added a lookAt() to point it to the center and made the field of view wider (this just makes it easier to find things while coding).
Your camera near and far planes were likely off-range for the camera position and terrain dimensions. So I increased the far plane distance.
Your coordinate values were quite huge, so I just modified them by hand a bit to make sense in relation to the camera, and to make sure they form a big enough triangle for it to be seen in camera. You could consider dividing your coordinates with something like 100 to make the units smaller. But adjusting the camera to account for the huge scale should be enough too.
Nothing wrong with your approach, just make sure you feed the data so that it makes sense considering the camera location, direction and near + far planes. Pay attention to how you make the faces. The parameters to Face3 is the index of each point in your vertices array. Later on you might need to take winding order, normals and uvs into account. You can study the geometry classes included in Three.js for reference.
Three.js does not specify any meaning to units. Its just floating point numbers, and you can decide yourself what a unit (1.0) represents. Whether it's 1mm, 1 inch or 1km, depends on what makes the most sense considering the application and the scale of it. Floating point numbers can bring precision problems when the actual numbers are extremely small or extremely big. My own applications typically deal with stuff in the range from a couple of centimeters to couple hundred meters, and use units in such a way that 1.0 = 1 meter, that has been working fine.
I am building quite a complex 3D environment in Three.js (FPS-a-like). For this purpose I wanted to structure the loading of textures and materials in an object oriënted way. For example; materials.wood.brownplank is a reusable material with a certain texture and other properties. Below is a simplified visualisation of the process where models uses materials and materials uses textures.
loadTextures();
loadMaterials();
loadModels();
//start doing stuff in the scene
I want to use that material on differently sized objects. However, in Three.js you can't (AFAIK) set a certain texture scale. You will have to set the repeat to scale it appropiate to your object. But I don't want to do that for every plane of every object I use.
Here is how it looks now
As you can see, the textures are not uniform in size.
Is there an easy way achieve this? So cloning the texture and/or material every time and setting the repeat according to the geometry won't do :)
I hope someone can help me.
Conclusion:
There is no real easy way to do this. I ended up changing my loading methods, where things like materials.wood.brownplank are now for example getMaterial('wood', 'brownplank') In the function new objects are instantiated
You should be able to do this by modifying your geometry UV coordinates according to the "real" dimensions of each face.
In Three.js, UV coordinates are relative to the face and texture (as in, 0.0 = one edge, 1.0 = other edge), no matter what the actual size of texture or face is. But by modifying the UVs in geometry (multiply them by some factor based on face physical size), you can use the same material and texture in different sizes (and orientations) per face.
You just need to figure out the mapping between UVs, geometry scale and your desired working units (eg. mm or m). Sorry I don't have, or know a ready algorithm to do it, but that's the approach you probably need to take. Should be quite doable with a bit of experimentation and google-fu.
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