Fix video errors having black rectangle around them

crates/viewer/re_renderer/src/renderer/rectangles.rs

@@ -204,6 +204,11 @@ pub struct RectangleOptions {
     /// Tint that is multiplied to the rect, supports pre-multiplied alpha.
     pub multiplicative_tint: Rgba,
 
+    /// Force drawing the rectangle with alpha blending enabled even if `multiplicative_tint` is opaque.
+    /// (Note that we'll draw without pre-multiplied alpha here, assuming all alpha is unmultiplied)
+    /// TODO(#12223): This is only really needed if you know you have a texture that you know has a meaningful alpha channel.
+    pub force_draw_with_transparency: bool,
+
     pub depth_offset: DepthOffset,
 
     /// Optional outline mask.
@@ -216,6 +221,7 @@ impl Default for RectangleOptions {
             texture_filter_magnification: TextureFilterMag::Nearest,
             texture_filter_minification: TextureFilterMin::Linear,
             multiplicative_tint: Rgba::WHITE,
+            force_draw_with_transparency: false,
             depth_offset: 0,
             outline_mask: OutlineMaskPreference::NONE,
         }
@@ -332,6 +338,7 @@ mod gpu_data {
                 multiplicative_tint,
                 depth_offset,
                 outline_mask,
+                force_draw_with_transparency: _,
             } = options;
 
             let sample_type = match texture_format.sample_type(None, None) {
@@ -535,7 +542,8 @@ impl RectangleDrawData {
                     },
                 ),
                 draw_outline_mask: rectangle.options.outline_mask.is_some(),
-                has_transparency: rectangle.options.multiplicative_tint.a() < 1.0, // TODO(#12223): what about textures with alpha?
+                has_transparency: rectangle.options.multiplicative_tint.a() < 1.0
+                    || rectangle.options.force_draw_with_transparency, // TODO(#12223): what about textures with alpha?
             });
         }
 

crates/viewer/re_view_spatial/src/visualizers/utilities/textured_rect.rs

@@ -63,6 +63,7 @@ pub fn textured_rect_from_image(
                 texture_filter_magnification,
                 texture_filter_minification,
                 multiplicative_tint,
+                force_draw_with_transparency: false,
                 depth_offset: ent_context.depth_offset,
                 outline_mask: ent_context.highlight.overall,
             },

crates/viewer/re_view_spatial/src/visualizers/video/mod.rs

@@ -82,6 +82,7 @@ fn visualize_video_frame_texture(
                 outline_mask: highlight.overall,
                 depth_offset,
                 multiplicative_tint,
+                force_draw_with_transparency: false,
             },
         };
         visualizer_data.add_pickable_rect(
@@ -237,6 +238,7 @@ fn show_video_playback_issue(
                 outline_mask: highlight.overall,
                 #[expect(clippy::disallowed_methods)] // Ok to just dim it
                 multiplicative_tint: egui::Rgba::from_gray(0.5),
+            force_draw_with_transparency: true,
                 ..Default::default()
             },
     };

crates/viewer/re_view_spatial/tests/video.rs

@@ -10,7 +10,7 @@ use re_test_context::external::egui_kittest::SnapshotOptions;
 use re_test_viewport::TestContextExt as _;
 use re_video::{VideoCodec, VideoDataDescription};
 use re_viewer_context::{TimeControlCommand, ViewClass as _};
-use re_viewport_blueprint::ViewBlueprint;
+use re_viewport_blueprint::{ViewBlueprint, ViewProperty};
 
 fn workspace_dir() -> std::path::PathBuf {
     std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
@@ -266,10 +266,27 @@ fn test_video(video_type: VideoType, codec: VideoCodec) {
         }
     }
 
-    let view_id = test_context.setup_viewport_blueprint(|_ctx, blueprint| {
-        blueprint.add_view_at_root(ViewBlueprint::new_with_root_wildcard(
+    let view_id = test_context.setup_viewport_blueprint(|ctx, blueprint| {
+        let view_id = blueprint.add_view_at_root(ViewBlueprint::new_with_root_wildcard(
             re_view_spatial::SpatialView2D::identifier(),
-        ))
+        ));
+
+        // Set a background color other than black so we can see the effect of transparency on errors & lack thereof on the video.
+        let property = ViewProperty::from_archetype::<
+            re_sdk_types::blueprint::archetypes::Background,
+        >(ctx.blueprint_db(), ctx.blueprint_query, view_id);
+        property.save_blueprint_component(
+            ctx,
+            &re_sdk_types::blueprint::archetypes::Background::descriptor_kind(),
+            &re_sdk_types::blueprint::components::BackgroundKind::SolidColor,
+        );
+        property.save_blueprint_component(
+            ctx,
+            &re_sdk_types::blueprint::archetypes::Background::descriptor_color(),
+            &re_sdk_types::components::Color::from_rgb(200, 100, 200),
+        );
+
+        view_id
     });
 
     // Decoding videos can take quite a while!