uv mapping in Metal
- SwiftUI + Metal – Create special effects by building your own shaders - YouTube at 26:07
- What is UV mapping?
- Essentially UV Mapping is altering the position calculations from absolute pixel values to relative ratio values.
Case study
// Called in SwiftUI using .colorEffect()
[[ stitchable ]] float2 wave(
float2 position, float time, float2 rect) {
float2 uv = position / rect; // 👈🏼
pos.y += sin(time * 5 + position.y / 20) * 5;
return position;
}
)| Width | X | UV |
|---|---|---|
| 100 | 0 | 0 |
| 100 | 50 | 0.5 |
| 200 | 50 | 0.25 |