Introduce dynamic `opacity` support for `Image` and `Svg`

1 files changed, 7 insertions, 4 deletions

diff --git a/wgpu/src/shader/image.wgsl b/wgpu/src/shader/image.wgsl
index 71bf939c..accefc17 100644
--- a/wgpu/src/shader/image.wgsl
+++ b/wgpu/src/shader/image.wgsl
@@ -12,15 +12,17 @@ struct VertexInput {
     @location(1) center: vec2<f32>,
     @location(2) scale: vec2<f32>,
     @location(3) rotation: f32,
-    @location(4) atlas_pos: vec2<f32>,
-    @location(5) atlas_scale: vec2<f32>,
-    @location(6) layer: i32,
+    @location(4) opacity: f32,
+    @location(5) atlas_pos: vec2<f32>,
+    @location(6) atlas_scale: vec2<f32>,
+    @location(7) layer: i32,
 }
 
 struct VertexOutput {
     @builtin(position) position: vec4<f32>,
     @location(0) uv: vec2<f32>,
     @location(1) layer: f32, // this should be an i32, but naga currently reads that as requiring interpolation.
+    @location(2) opacity: f32,
 }
 
 @vertex
@@ -33,6 +35,7 @@ fn vs_main(input: VertexInput) -> VertexOutput {
     // Map the vertex position to the atlas texture.
     out.uv = vec2<f32>(v_pos * input.atlas_scale + input.atlas_pos);
     out.layer = f32(input.layer);
+    out.opacity = input.opacity;
 
     // Calculate the vertex position and move the center to the origin
     v_pos = input.pos + v_pos * input.scale - input.center;
@@ -56,5 +59,5 @@ fn vs_main(input: VertexInput) -> VertexOutput {
 @fragment
 fn fs_main(input: VertexOutput) -> @location(0) vec4<f32> {
     // Sample the texture at the given UV coordinate and layer.
-    return textureSample(u_texture, u_sampler, input.uv, i32(input.layer));
+    return textureSample(u_texture, u_sampler, input.uv, i32(input.layer)) * vec4<f32>(1.0, 1.0, 1.0, input.opacity);
 }