Passing player's position into visual shader?

Question

I need to make a visual shader material that would turn partially transparent (ie lower the alpha) when the mesh is between the player and the camera. I can get the camera position, and I can do the calculations ("if object is between player's position and camera position, lower alpha") -- how do I pass in the player's position?

Answer 1

Use uniforms:
https://docs.godotengine.org/en/3.0/tutorials/shading/shading_language.html#uniforms

They also work in visual shaders, just like in scripted ones. You add them as any other node.

Comments

Thank you! Yeah I was looking at that. So do I just give it a reference with an absolute path to the player? And (assuming every object with this shader on it is updating the player's position every frame) is that a problem for performance?

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I'd create a Vector3 uniform and have it be updated with the player's position in a process function of a scene which has access to the shader. Don't think performance will be an issue, but it depends in the complexity of the shader.

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I'll try that. Thank you!

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Working! The key to this was making sure that my uniform was a vec3, not a xform, so that when I passed in the translation it accepted it correctly. Thank you so much!!

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No problem! Glad to help. Good luck!