Does Unity's renderer read the entire texture, or only the pixels the UVs overlap?
For example, in the following texture with the following UVs, only rows C, D, E and F are needed. Disregarding the extra storage space the rest of the texture occupies, are there any drawbacks to doing this?
Does the renderer read the entire texture or only the relevant pixels?
Unity would keep the whole texture in memory. Texture mapping is done in shaders.
That's why its recommended to try and occupy as much UV space as possible. You can even go further and use same texture for multiple objects.
Even tho this only covers opengl, it is a good resource for understanding how all of this works. https://learnopengl.com/Getting-started/Textures
Related
I have a point-cloud and a rgb texture that fit together from a depth camera. I procedurally created a mesh from a selected part of the point-cloud implementing the quickhull 3D algorithm for mesh creation.
Now, somehow I need to apply the texture that I have to that mesh. Note that there can be multiple selected parts of the point-cloud thus making multiple objects that need the texture. The texture is just a basic 720p file that should be applied to the mesh material.
Basically I have to do this: https://www.andreasjakl.com/capturing-3d-point-cloud-intel-realsense-converting-mesh-meshlab/ but inside Unity. (I'm also using a RealSense camera)
I tried with a decal shader but the result is not precise. The UV map is completely twisted from the creation process, and I'm not sure how to generate a correct one.
UV and the mesh
I only have two ideas but don't really know if they'll work/how to do them.
Try to create a correct UV and then wrap the texture around somehow
Somehow bake colors to vertices and then use vertex colors to create the desired effect.
What other things could I try?
I'm working on quite a similar problem. But in my case I just want to create a complete mesh from the point cloud. Not just a quickhull, because I don't want to lose any depth information.
I'm nearly done with the mesh algorithm (just need to do some optimizations). Quite challenging now is to match the RGB camera's texture with the depth camera sensor's point cloud, because they of course have a different viewport.
Intel RealSense provides an interesting whitepaper about this problem and as far as I know the SDK corrects these different perspectives with uv mapping and provides a red/green uv map stream for your shader.
Maybe the short report can help you out. Here's the link. I'm also very interested in what you are doing. Please keep us up to date.
Regards
I'm now struggling for weeks on a part of the game I'm making.
As a beginner in Unity and programming, I need your experience and advice to understand how can I paint on skinned mesh like this (from 1:10):
https://www.youtube.com/watch?v=grVEK1Bb6ZM
I spend a lot of time to find a solution with no result. (Decal shader to separate texture, paint on mesh with alpha, project texture, merge texture .. ). But these solutions look bad for mobile or not exactly what I need.
So If someone know a way to do that, even a little info or anything, that will drive my research, it's very welcome.
Thank you !
The example you provide limits the range of the painting with a bitmap mask (ie on the eyebrows, or on the lips), so the painting is only meant for a more enjoyable UX. If this is what you need, you should probably do something like this:
You need to know where the mouse is interacting with the model. Raycasting is expensive and requires to update the colliders every frame, since you character is skinned. If you use the masking trick of your example, this dramatically reduces the amount of computation, since you could pass a subset of the mesh containing only that specific area (maybe just the face for ex)
see https://docs.unity3d.com/ScriptReference/SkinnedMeshRenderer.BakeMesh.html
and https://answers.unity.com/questions/39490/collider-on-skinned-mesh.html
(if you can't, there could be other tricks, like rendering the character's UV into a separate float buffer/texture, and sample that buffer using the mouse position)
Once you can raycast the mesh you can fetch the UV position of the hit
https://docs.unity3d.com/ScriptReference/RaycastHit-textureCoord.html
Using those UVs you can write to a texture, or instance particles/objects on a render target etc (there are many options here).
You then need to combine that texture with the bitmap mask in the shader of the character.
I already know that if Unity is using a texture with the dimensions 250X250 it will pad the texture to 256X256 so as to make the dimensions a power of 2. If I were to have a texture of size 512X256 would it pad to 512X512 to make the texture a square or would it stay at 512X256 as each side is already a power of 2?
It should keep the 512x256 resolution. Each side needs to be a power of two, they don't have to be equal.
Note, that it's not exactly true that Unity will change the dimensions of each your texture. You can change the texture properties to legacy GUI and then you can have a pixel perfect texture. It will be wasteful or slower a bit (depending on GPU drivers), but it will work quite well.
I am making a unity 2D RTS game and I thought of using a big texture for the tiled map (instead of a lot of textures - for the memory reasons...).
The tiled map is supposed to generate randomly at runtime so I don't want to save a texture and upload it. I want the map to be generated and then build it from a set of textures resources.
so, I have a little tiles textures of grass/forest/hills etc. and after I generate the map randomly, I need to draw those little textures on my big map texture so I will use it as my map.
How can I draw a texture from my resources on other texture? I saw there is only a Get/SetPixel functions... so I can use it to copy all the pixels one by one to the big texture, but there is something easier?
Is my solution for the map is OK? (is it better from just create a lot of texture tiles side by side? There is other better solution?)
The correct way to create a large tiled map would be to compose it from smaller, approximately-screen-sized chunks. Unity will correctly not draw the chunks that are off the screen.
As for your question about copying to a texture: I have not done this before in Unity, but this process is called Blitting, and there just happens to be a method in Unity called Graphics.Blit(). It takes a source texture and copies it into a destination texture, which sounds like exactly what you're looking for. However, it requires Unity Pro :(
There is also SetPixels(), but it sounds like this function does the processing on the CPU rather than the GPU, so it's going to be extremely slow/resource-intensive.
Well, after more searching I discovered the Get/SetPixel s
Texture2D sourceTex = //get it from somewere
var pix = sourceTex.GetPixels(x, y, width, height); // get the block of pixels
var destTex = new Texture2D(width, height); // create new texture to copy the pixels to it
destTex.SetPixels(pix);
destTex.Apply(); // important to save changes
I'm working on a particle system and point sprites would be nice to use. Unfortunately I have a constraint that I pack ALL my textures in a single texture atlas. This is a huge overall speed boost to my engine as I never have to switch texture bindings. But as a result I need to be able to specify a source texture rectangle for my particles.
So my question: Is it possible to do this with point sprites? From what I've read it seems like they just try to draw the whole texture.
If not, my alternative is to pack vertex buffers, but point sprites would probably be faster.
I'm using OpenGL ES 1.1 (on the iPhone), shaders are not an option.
I guess not. From the documentation on OES_draw_texture:
(3) Doesn't ARB_point_sprite make this
extension unnecessary?
RESOLVED. No. Key differences include:
ARB_point_sprite uses the entire source texture to paint a point, i.e. its texture coordinates range from 0.0 to 1.0. This extension allows a subregion of a texture to be used as the source.