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Question by seltonnn · May 07, 2018 at 02:50 PM · shader texture rendertexture draw paint

How to paint on a 3D object without raycast in Unity (from shader)?

I have spent weeks to find a way to paint on a 3D Object with a brush in Unity. I have find solutions with raycasting and RenderTexrures, but it's not fast enough.

Currently I am passing the cameras MVP matrix to my shader to create a circle on the 3D object's surface, but I am unable to "burn it" on the texture from the shader, since there is no way(?) to make actual changes from a shader.

I have also tried to do something with ZBuffer, but it only works if nothing moves. As soon as I move something, the draw will "flow".

I am not an expert in shader coding, but I see no option for drawing anything from there.

Please if you have any suggestions, do not hesitate to share with me.

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