Better naming of things to help diagnose #3242

crates/re_renderer/src/transform.rs

@@ -36,7 +36,7 @@ pub fn ndc_from_pixel(pixel_coord: glam::Vec2, screen_extent: glam::UVec2) -> gl
 
 /// Defines a transformation from a rectangular region of interest into a rectangular target region.
 ///
-/// Transforms map the range of `region_of_interest` to the range of `region`.
+/// Transforms the range of `region_of_interest` to the range of `region`.
 #[derive(Clone, Debug)]
 pub struct RectTransform {
     pub region_of_interest: RectF32,

crates/re_renderer/src/view_builder.rs

@@ -152,6 +152,7 @@ impl Default for AutoSizeConfig {
 pub struct TargetConfiguration {
     pub name: DebugLabel,
 
+    /// The viewport resolution in physical pixels.
     pub resolution_in_pixel: [u32; 2],
     pub view_from_world: macaw::IsoTransform,
     pub projection_from_view: Projection,

crates/re_space_view_spatial/src/ui_2d.rs

@@ -389,16 +389,16 @@ pub fn view_2d(
 }
 
 fn setup_target_config(
-    painter: &egui::Painter,
+    egui_painter: &egui::Painter,
     canvas_from_ui: RectTransform,
     space_name: &str,
     auto_size_config: re_renderer::AutoSizeConfig,
     any_outlines: bool,
     pinhole: Option<Pinhole>,
 ) -> anyhow::Result<TargetConfiguration> {
-    let pixels_from_points = painter.ctx().pixels_per_point();
+    let pixels_from_points = egui_painter.ctx().pixels_per_point();
     let resolution_in_pixel =
-        gpu_bridge::viewport_resolution_in_pixels(painter.clip_rect(), pixels_from_points);
+        gpu_bridge::viewport_resolution_in_pixels(egui_painter.clip_rect(), pixels_from_points);
     anyhow::ensure!(resolution_in_pixel[0] > 0 && resolution_in_pixel[1] > 0);
 
     // TODO(#1988):
@@ -457,8 +457,8 @@ fn setup_target_config(
 
     // Cut to the portion of the currently visible ui area.
     let mut viewport_transformation = re_renderer::RectTransform {
-        region_of_interest: egui_rect_to_re_renderer(painter.clip_rect()),
-        region: egui_rect_to_re_renderer(*canvas_from_ui.from()),
+        region_of_interest: re_render_rect_from_egui_rect(egui_painter.clip_rect()),
+        region: re_render_rect_from_egui_rect(*canvas_from_ui.from()),
     };
 
     // The principal point might not be quite centered.
@@ -478,12 +478,12 @@ fn setup_target_config(
             viewport_transformation,
             pixels_from_point: pixels_from_points,
             auto_size_config,
-            outline_config: any_outlines.then(|| outline_config(painter.ctx())),
+            outline_config: any_outlines.then(|| outline_config(egui_painter.ctx())),
         }
     })
 }
 
-fn egui_rect_to_re_renderer(rect: egui::Rect) -> re_renderer::RectF32 {
+fn re_render_rect_from_egui_rect(rect: egui::Rect) -> re_renderer::RectF32 {
     re_renderer::RectF32 {
         min: glam::vec2(rect.left(), rect.top()),
         extent: glam::vec2(rect.width(), rect.height()),

crates/re_viewer_context/src/gpu_bridge/mod.rs

@@ -117,7 +117,7 @@ pub fn get_or_create_texture<'a>(
 /// Render the given image, respecting the clip rectangle of the given painter.
 pub fn render_image(
     render_ctx: &mut re_renderer::RenderContext,
-    painter: &egui::Painter,
+    egui_painter: &egui::Painter,
     image_rect_on_screen: egui::Rect,
     colormapped_texture: ColormappedTexture,
     texture_options: egui::TextureOptions,
@@ -127,12 +127,13 @@ pub fn render_image(
 
     use re_renderer::renderer::{TextureFilterMag, TextureFilterMin};
 
-    let clip_rect = painter.clip_rect().intersect(image_rect_on_screen);
-    if !clip_rect.is_positive() {
+    let viewport = egui_painter.clip_rect().intersect(image_rect_on_screen);
+    if !viewport.is_positive() {
         return Ok(());
     }
 
     // Where in "world space" to paint the image.
+    // This is an arbitrary selection.
     let space_rect = egui::Rect::from_min_size(egui::Pos2::ZERO, image_rect_on_screen.size());
 
     let textured_rectangle = re_renderer::renderer::TexturedRect {
@@ -156,19 +157,20 @@ pub fn render_image(
 
     // ------------------------------------------------------------------------
 
-    let pixels_from_points = painter.ctx().pixels_per_point();
+    let pixels_from_points = egui_painter.ctx().pixels_per_point();
     let ui_from_space = egui::emath::RectTransform::from_to(space_rect, image_rect_on_screen);
     let space_from_ui = ui_from_space.inverse();
     let space_from_points = space_from_ui.scale().y;
-    let points_from_pixels = 1.0 / painter.ctx().pixels_per_point();
+    let points_from_pixels = 1.0 / egui_painter.ctx().pixels_per_point();
     let space_from_pixel = space_from_points * points_from_pixels;
 
-    let resolution_in_pixel = viewport_resolution_in_pixels(clip_rect, pixels_from_points);
+    let resolution_in_pixel = viewport_resolution_in_pixels(viewport, pixels_from_points);
     anyhow::ensure!(resolution_in_pixel[0] > 0 && resolution_in_pixel[1] > 0);
 
-    let camera_position_space = space_from_ui.transform_pos(clip_rect.min);
+    let camera_position_space = space_from_ui.transform_pos(viewport.min);
 
     let top_left_position = glam::vec2(camera_position_space.x, camera_position_space.y);
+
     let target_config = re_renderer::view_builder::TargetConfiguration {
         name: debug_name.into(),
         resolution_in_pixel,
@@ -191,10 +193,10 @@ pub fn render_image(
         &[textured_rectangle],
     )?);
 
-    painter.add(new_renderer_callback(
+    egui_painter.add(new_renderer_callback(
         render_ctx,
         view_builder,
-        clip_rect,
+        viewport,
         re_renderer::Rgba::TRANSPARENT,
     ));
 

crates/re_viewer_context/src/gpu_bridge/re_renderer_callback.rs

@@ -5,7 +5,7 @@ type ViewBuilderMap = slotmap::SlotMap<ViewBuilderHandle, Option<re_renderer::Vi
 pub fn new_renderer_callback(
     render_ctx: &mut re_renderer::RenderContext,
     view_builder: re_renderer::ViewBuilder,
-    clip_rect: egui::Rect,
+    viewport: egui::Rect,
     clear_color: re_renderer::Rgba,
 ) -> egui::PaintCallback {
     let composition_view_builder_map = render_ctx
@@ -16,7 +16,7 @@ pub fn new_renderer_callback(
     let view_builder_handle = composition_view_builder_map.insert(Some(view_builder));
 
     egui_wgpu::Callback::new_paint_callback(
-        clip_rect,
+        viewport,
         ReRendererCallback {
             view_builder: view_builder_handle,
             clear_color,