Image Color Data to Godot Shader

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Erich_L

I am trying to recreate this awesome solution to water flowing
(the well thought out answer below)

I have a function to create the flow map in gdscript (which is translated to just pixel by pixel colors). But I don't know how I should send this data to a shader.

I assume I try and package it all up as one image and set one of the shader's sampler2D uniforms to that image? Or maybe I set each pixel at each pixel coordinate individually?

Erich_L

XYZ's post helped me get my flow map data to the GPU. When displayed it's blurred (probably shouldn't be an issue right?) Is there a way to ... not blur it? Maybe by flooring the UVs or something?
I also noticed the image is not stretched along the y axis enough but stretching it manually of course seems wrong.
CPU solved flow velocities (right, dots). That data is transferred to the GPU (left). At the bottom of the left GPU part you can see a missing chunk. The image itself however I feel correctly reflects the CPU data shown on the right. Any tips would be much appreciated.

cybereality

Image data is just image data. It is sent to the GPU essentially uncomressed (there are GPU compression formats but they aare more or less lossless in terms of what the shader gets). You pass them in as a uniform and they can be accessed in shader code with aa sampler2d. The way you sample makes a difference. Using texture or textureLod will use the sampling type set in the editor (linear by default which is blurry). You want to use texelFetch, which samples integer coordinates in the space of the image resolution (pixel coordinates rather than texture uv coordinates). Not sure why the left is the wrong aspect raatio. It may actually be correct in memory and just displayed wrong. O you may have some incorrect uv math that would be pixeled by using pixels as mentioned above. I would start there and report back.