Start with a basic setup for rendering using the Phong shading model (or whatever model you prefer). Include texture coordinates and pass them along to the fragment shader.
There are a couple of uniform variables that define the parameters of the paint spatters:
- PaintColor: The color of the paint spatters
- Threshold: The minimum noise value where a spatter will appear
Create a noise texture with high-frequency noise.
Make your noise texture available to the fragment shader via the NoiseTex uniform sampler variable.
