How to use Compute Shaders in Godot 4

Here's a quick guide on how to set up Compute Shaders in Godot 4, using a practical example by converting the score calculation from my previous video, on Splatoon's ink gun, to be run as a compute shader.
Scripts:
Shader GLSL: pastebin.com/pbGGjrE8
Test Script: pastebin.com/92cvEagc
Final Score Calculator: pastebin.com/wXCqk1nQ
Resources:
github.com/godotengine/godot-...
docs.godotengine.org/en/lates...
Check out these Sebastian lague videos to see what compute shaders can do:
• Coding Adventure: Comp...
• I Spent a Week Making ...
Chapters:
0:00 Intro
0:18 Compute Shader Intro
0:37 Minimum Compute Shader
4:40 Score Calculation GLSL
6:44 Boilerplate
7:54 Texture Uniforms
11:23 Performance Comparison
12:13 Final Script
13:00 Outro

[@Galomortalbr]

amazing video, i wish there was more content like this, Godot 4 is truly a step up from Godot 3

[@wellhellotherekyle]

Wow, you’ve quickly become one of my favorite Godot resources!

[@ZagrajmyzPszemkiem]

A wonderfull tutorial! There is so little information about any of this online, it's great to see somebody taking their time to investigate what's possible.

[@1cedragon]

Excellent tutorial! Thank you for taking the time to explain compute shaders. I wish Godot had more documentation about them because they're such a powerful tool for advanced effects.

[@leerpret3950]

This is great, thanks! Info on compute shaders are so rare, hopefully it becomes more mainstream.

[@crigz]

I hope so too! You can do some incredible things with them, it's a tool everyone should have in their belt.

[@planetbridging4249]

I dont normaly give comments to youtube videos but this one actually got me to my solution i needed and to avoid using unity. Thank you so much for helping so i can make my idea using the godot 4 with compute shaders utlizing the cpu and the gpu for my ai architecture design :D

[@Gredran]

Godot 4 tutorials are comin in!! Great video! Its a cool thing to show off that the engine can do! You definitely earned a subscriber 😊

[@binary_soup]

Turns out RGBA8 is required to use a texture in a sampler. If it doesn't have an alpha channel then the rendering device will throw an error. To fix this, you can use `image.convert(Image.FORMAT_RGBA8)` to convert its format first.

[@mezzofortestudios7342]

this was helpful, thank you

[@chriszymurgist]

I have been banging my head on this issue until I came across your comment. As an addendum the PNG also can not have mipmaps.

[@AslanSilva]

Another vid so quick! Amazing stuff.

[@RyanForresterDev]

Great video, lots of stuff learned watching this! I'm hoping to have the time at some point to try a water shader using compute shaders and use the outputs for water physics.

[@ViktorFerenczi]

Your video has been super useful and came at the exact right time for my project. Thanks! Subscribed.

[@addmix]

Thank you. You actually cared to explain what each segment of code did. I was getting very frustrated trying to understand compute shaders, but this video helped me understand it better.

[@Barnaclebeard]

Beastly content, and appreciated

[@RyanScottForReal]

This is great, thank you. Would love to see what IS a more efficient way to do it. :)

[@eigenman2571]

Super helpful! Thanks

[@arez4906]

Very dope video! You definitely deserve more attention. It would be cool to see trails (particle trails or if there are other types of trails) explained, as i just cant get them working right!

[@crigz]

Cool idea! What in particular did you struggle to get right with them?

[@arez4906]

@@crigz Somehow whenever i tried particle trails i couldnt get them to render properly. They always were a random mess of stretched triangles or whatever. Also sometimes they became super large or the actual particles didnt even render (just the trails, but those buggy)

[@crigz]

@@arez4906 is that in Godot 4.0? I had to scrap the splash particles I set up because they're currently so buggy in the beta.

[@arez4906]

@@crigz Yep it is!

[@marc.lepage]

Thinking of doing some non-game stuff in Godot 4 and this will come in very handy!

[@marc.lepage]

Just to say I have indeed been doing non-game stuff, now on Godot 4.2, and working on sharing my non-visual data (processed by compute shader) with a graphics shader without going through the CPU, so I can visualize the data but maintain framerate.

[@indieology7336]

Thank you!

[@Greebli]

This is great information thanks, but what about using the buffer in a shader to visualize the data? for example a for a fluid sim

[@giantfrogstudios839]

Nice video

[@AgnisNeZvers]

Killer video! I'm having doubts that Splatoons is used compute shaders for Wii U (Splatoon 1 in 2015) & Switch. My guess is that it's just a collision system + some approximate area calculation based on collision position.

[@farianderson168]

Do we have to use external editor for writing compute shaders?

[@nemene8585]

How do you make the fancy operators, like merging >= and ==?

[@question_mark]

lezgooooooooooooooooooooooooooo thank u so much

[@johanngambolputty5351]

Ooh, do the compute shaders support doubles? I tried to do some fractal stuff in Godot before because of the ease of setting up ui and input, but you very quickly hit precision limits... Also, can it only do compute shaders through GL? How about OpenCL (would be nice since I've already written some OCL stuff now...)

[@mezzofortestudios7342]

Currently the `RenderDevice` class uses only a Vulkan backend for compute

[@thehattedhedgehog]

I can't figure out how to clean after submitting. The memory is bulking (Godot 4.1.1.stable)

[@AbeTheApe126]

Out of interest, in the performance comparison. Is the CPU version completely single threaded? E.g. no usage of threads on the system etc? Likely you would still not get close to the gpu perf but it would make for a slightly more 'fair' comparison potentially.

[@prozacgodgamedev]

I was watching your previous splatoon tutorial and was thinking of a way to get rid of the seams. Regardless of the way the texture is unwrapped. This would only work on a compute shader because of the search space, but it should be massively parallel. I'm not 100% sure how to do this. In blender is there a way to generate a texture that matches the XYZ coordinates of a 3D surface using the same unwrap as the painting texture. This would give you a texture where paint can be splashed, and a lookup table for all splashable surfaces in 3D. In this way, we have a texture that matches the unwrapped texture, but we have XYZ coordinates for the entire level. Then when a splash happens you feed in this texture, the coordinate of the splash and the output is a texture of said splash. The way it works is ... if a 3D texture lookup triplet is inside the 3d radius of this splash sphere, it would fill in the output texture with the splash color. This should work quite flawlessly.

[@crigz]

I'll have to look into this for sure!

[@prozacgodgamedev]

@@crigz Thanks, I hope my explanation was ... adequate!

[@prozacgodgamedev]

@@crigz I was looking into this myself and quickly realized you can easily paint through walls and backfaces, so there's a technical thing there to sort out. Seems similar issues would happen in your version too.

[@crigz]

@@prozacgodgamedev Painting through walls and back-faces aren't an issue in this system, it's mostly painting over into other UV's if you don't leave enough margin, and there's not a proper wrap around on corners unless you perfectly place the UV map (not always possible). I've got a few ideas I'm experimenting with to fix this though.

[@prozacgodgamedev]

@@crigz I'm setting up to attempt to build something akin to your splatoon level and a godot fps scene to attempt a real go at it. I'm not ... that well versed in ... well anything here, I'm winging it :D It'll be fun!

[@leeuwarden20]

Did you manage to draw a triangle with RenderingDevice?

[@MACMAN2003]

would it be possible to take in an image and change the colors around a bit? like if i wanted to change color1 to color2?

[@crigz]

Yes, you can do something like that.

[@MACMAN2003]

@@crigz Do you have any idea on how to get started on doing that? Cause there's no documentation for compute shader stuff xd

[@Galomortalbr]

hey, as much as i love the computer shader solution, i can't help but to feel it's over engineered, a simpler solution would had to been to use a viewport to downscale the 2048x2048 texture to 32x32 and then calculate based on that, could be done even in the main cpu thread without much of performance impact. it's obviously not fun solution but solves the issue without having to taxs the GPU or a entire thread, i still would like more content about computer shaders.

[@savhasuvhe]

Can you do next anime shader?

[@Chevifier]

*Cuts off head to rub brain*😅

[@brettfleeman6014]

First