2D Texture drawing/painting on iOS/Android (fast)?

I have previously written an app before in Unity that allows the user to draw onto a ‘wall’ - but in this instance I need a more responsive solution with larger textures (for a drawing game for Android where the user creates the game objects - similar to Drawn to Life - 2D game).

… so I was just wondering if anyone has done something similar with good results (am currently developing in Java on Android but being able to use Unity will speed things up x2).

Appreciate any hints/suggestions,

Use a camera with ClearFlags “Don’t Clear” to draw to a RenderTexture, then you instance a sprite as a brush.

Make it follow the mouse(finger) and appear/disappear on press/release. This is the fastest way to draw to a texture afaik.

Setting pixels or blitting through code are not performant enough for mobile devices.

You will most likely need to do some shader work in order to implement an eraser and solve transparency issues, but I couldn’t find another way around that personally.