CC Simple Wire Removal: Frame Offset takes the strip from the previous or next frame (#533)

crates/gpu/src/fx_pixel2.rs

@@ -476,6 +476,10 @@ fn wire_removal(e: &mut Enc, ctx: &EffectCtx, b: GBuf) -> Option<GBuf> {
     if half <= 0.0 {
         return Some(b);
     }
+    // Frame Offset reads another frame from the effect host: that renders on the CPU.
+    if ctx.params.e("removalStyle") == 1 && ctx.params.f("frameOffset").round() != 0.0 && ctx.env.host.is_some() {
+        return None;
+    }
     let slope = (ctx.params.f("slope") / 100.0).clamp(0.0, 1.0) as f32;
     let mirror = (ctx.params.f("mirrorBlend") / 100.0).clamp(0.0, 1.0) as f32;
     let a = b.to_px(ctx.params.v2("pointA"));

crates/gpu/src/tests_fx_pixel2.rs

@@ -243,6 +243,7 @@ fn keys_and_3d() {
     effect_case("ec.key.ccsimplewireremoval", &[]);
     effect_case("ec.key.ccsimplewireremoval", &[("removalStyle", e(0)), ("thickness", n(8.0)), ("slope", n(50.0))]);
     effect_case("ec.key.ccsimplewireremoval", &[("removalStyle", e(1)), ("mirrorBlend", n(60.0)), ("pointB", pt(60.0, 10.0))]);
+    effect_case("ec.key.ccsimplewireremoval", &[("removalStyle", e(1)), ("frameOffset", n(-2.0)), ("thickness", n(6.0))]);
     effect_case("ec.key.ccsimplewireremoval", &[("removalStyle", e(3)), ("mirrorBlend", n(30.0)), ("slope", n(20.0))]);
     effect_case("ec.obsolete.basic3d", &[("swivel", n(25.0))]);
     effect_case("ec.obsolete.basic3d", &[("tilt", n(-30.0)), ("swivel", n(10.0)), ("specularHighlight", on())]);