How to pass Subviewport output to Compute Shader

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1

Godot Version 4.4.1

Question

How do you pass a subviewport output as a uniform to a compute shader?

I think I’m only finding old info on this because the reddit comments I can find on this use functions that don’t exist anymore. I have the following code:


	var canvas_texture: Texture2D = canvas_subviewport.get_texture()
	var canvas_texture_rid = canvas_texture.get_rid()

	var canvas_sampler : RDUniform = RDUniform.new()
	canvas_sampler.uniform_type = RenderingDevice.UNIFORM_TYPE_IMAGE
	canvas_sampler.binding = 1 # As declared in the shader (binding = 1)
	canvas_sampler.add_id(canvas_texture_rid)
	uniforms.append(canvas_sampler)

Also on the compute shader side, the uniform is declared as:

layout(set = 0, binding = 1, rgba8) uniform image2D canvas;                     //CANVAS

I think the problem might be the way I’m getting the RID for the subviewport, but I’m not sure. I know the problem is not with the rest of the shader code because it works if I remove this portion.

does anyone have any idea?

2

I had a similar problem, the problem is the RID you get when calling get_rid on the texture cannot be used with the RenderingDevice. You need to call RenderingServer.texture_get_rd_texture which will give you a RID that can be used with the RDUniform.

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