Prevent premultiplication on image import

Author: cwfitzgerald

wgpu-hal/src/gles/queue.rs

@@ -388,11 +388,12 @@ impl super::Queue {
                 const UNPACK_PREMULTIPLY_ALPHA_WEBGL: u32 = 0x9241;
 
                 unsafe {
-                    gl.pixel_store_i32(UNPACK_FLIP_Y_WEBGL, src.flip_y as i32);
-                    gl.pixel_store_i32(
-                        UNPACK_PREMULTIPLY_ALPHA_WEBGL,
-                        dst_premultiplication as i32,
-                    );
+                    if src.flip_y {
+                        gl.pixel_store_bool(UNPACK_FLIP_Y_WEBGL, true);
+                    }
+                    if dst_premultiplication {
+                        gl.pixel_store_bool(UNPACK_PREMULTIPLY_ALPHA_WEBGL, true);
+                    }
                 }
 
                 unsafe { gl.bind_texture(dst_target, Some(dst)) };
@@ -492,8 +493,12 @@ impl super::Queue {
                 }
 
                 unsafe {
-                    gl.pixel_store_i32(UNPACK_FLIP_Y_WEBGL, 0);
-                    gl.pixel_store_i32(UNPACK_PREMULTIPLY_ALPHA_WEBGL, 0);
+                    if src.flip_y {
+                        gl.pixel_store_bool(UNPACK_FLIP_Y_WEBGL, false);
+                    }
+                    if dst_premultiplication {
+                        gl.pixel_store_bool(UNPACK_PREMULTIPLY_ALPHA_WEBGL, false);
+                    }
                 }
             }
             C::CopyTextureToTexture {

wgpu/tests/external_texture.rs

@@ -18,9 +18,24 @@ async fn image_bitmap_import() {
     let blob = web_sys::Blob::new_with_u8_array_sequence(&array).unwrap();
 
     // Parse the image from the blob
-    let image_bitmap_promise = web_sys::window()
+    let image_bitmap_function: js_sys::Function = web_sys::window()
         .unwrap()
-        .create_image_bitmap_with_blob(&blob)
+        .get("createImageBitmap")
+        .unwrap()
+        .dyn_into()
+        .unwrap();
+
+    let options_arg = js_sys::Object::new();
+    js_sys::Reflect::set(
+        &options_arg,
+        &wasm_bindgen::JsValue::from_str("premultiplyAlpha"),
+        &wasm_bindgen::JsValue::from_str("none"),
+    )
+    .unwrap();
+    let image_bitmap_promise: js_sys::Promise = image_bitmap_function
+        .call2(&wasm_bindgen::JsValue::UNDEFINED, &blob, &options_arg)
+        .unwrap()
+        .dyn_into()
         .unwrap();
 
     // Wait for the parsing to be done