Rotor blur similar to DCS' helicopter rotor blur.
A second camera renders the complex 3D rotor geometry into a “render texture” that is projected onto a simple shell body ("cylinder") and blurred by a custom shader.
The blur is created with following steps:
- Second orthographic camera "Capture Camera" focuses on rotor and renders only this geometry (layer "rotor") to a low res render-texture (256x256, R32G32B32A32_SFLOAT)
- Main camera renders shell body (layer "cylinder"). Vertex shader passes rotor's local mesh to fragment shader (TEXCOORD0).
- Fragment shader rotates point P1 by a given amount --> P2
- Fragment shader calculates point P2's render-texture screen space position, then sampling the render-texture at this position
- The color is weighted by sigma (see Gaussian distribution equation) and mixed to the main cameras fragment output
Depth reprojection (prior to above step)
- "Capture Camera"'s clipping planes are updated by the c# cript to be as close as possible to the rotor hub. Therefore the depth image uses its range fully to describe closer or further away parts of the rotor.
- The depth texture is scanned with the same method, described above.
- ... TBD
Shader: https://github.com/zulugithub/RotorBlur/blob/main/RotorBlur/Assets/RotationBlurShader.shader
C# script: https://github.com/zulugithub/RotorBlur/blob/main/RotorBlur/Assets/SetProjectorToShader.cs
https://forum.unity.com/threads/what-kind-of-shader-creates-this-blured-helicopter-rotor.1598373/
This software is licensed under the GPLv3 license. A copy of the license can
be found in LICENSE.txt