Grymskvll / Godot-SmearFrame3D-shader

Disclaimer

At the time of writing, Godot does not have a reasonable way to add shader effects to meshes/materials. The process of adding this smear effect to an existing material is tedious and likely destructive. Use in production at your own peril.

Simple Free-Look Camera (used in the demo) is by Adam Viola: https://github.com/adamviola/simple-free-look-camera

Usage

Adding smear

1. Go here and give this issue a thumbs up: godotengine/godot-proposals#1779
   1. Cry because Godot doesn't have a practical way to add shader effects to existing materials
2. To proceed, your mesh must use a ShaderMaterial with a (text) Shader:
   • If your mesh uses a SpatialMaterial, convert it to a (text) ShaderMaterial
   • If your mesh uses a VisualShader, convert it to a (text) Shader
   • Warning: There's no way to convert it back!
   • Tip: if you're going to instance the mesh (or it's parent) multiple times, turn on Local To Scene for the material
3. Copy the contents of SmearFrame3D.shader into the generated shader:
   • uniforms at the top
   • Replace (or merge with) the vertex function
   • Keep things in the same order
4. Add a SmearFrame3D node as a child of your MeshInstance
5. Configure the SmearFrame3D node (see below)

Configuring smear

Next, you can tune the smear (select the SmearFrame3D node):

• Enabled: toggle smear on/off
• Smear Amount: overall smear length (Smear Amount: 1: vertices will at most move back to their position on previous frame (unless there's noise))
• Front Smear Factor: how much smear to add ahead of motion
• Rear Smear Factor: how much smear to add behind motion
• Front Normal Bias: front-facing normals are better aligned with our motion (prevents pinching especially with low noise)
• Rear Normal Bias: rear-facing normals are better aligned against our motion (prevents pinching especially with low noise)
• Noise Factor: how much noise to add to smear
• Noise Max: how far the noise spikes extend from the mesh
• Noise Min: how far the noise spikes extend into the mesh
• Tuned To Fps: the framerate that the smear is tuned to (for consistent smear regardless of fps)
• Smear Speed Min: the minimum speed (actually distance travelled since last frame) before smear appears
• Smear Speed Ease: the additional speed (actually additional distance travelled since last frame) before smear reaches maximum length
• Noise Tex Width: width of the noise texture
• Noise Tex Height: height of the noise texture