Show previews of colormaps when selecting them (#1846)

* Make infallible version of get_or_create_texture

* Show colormap previews in UI

* Spelling

crates/re_viewer/src/gpu_bridge/mod.rs

@@ -52,7 +52,7 @@ pub fn viewport_resolution_in_pixels(clip_rect: egui::Rect, pixels_from_point: f
     [resolution.x as u32, resolution.y as u32]
 }
 
-pub fn get_or_create_texture<'a, Err>(
+pub fn try_get_or_create_texture<'a, Err>(
     render_ctx: &mut RenderContext,
     texture_key: u64,
     try_create_texture_desc: impl FnOnce() -> Result<Texture2DCreationDesc<'a>, Err>,
@@ -64,6 +64,23 @@ pub fn get_or_create_texture<'a, Err>(
     )
 }
 
+pub fn get_or_create_texture<'a>(
+    render_ctx: &mut RenderContext,
+    texture_key: u64,
+    create_texture_desc: impl FnOnce() -> Texture2DCreationDesc<'a>,
+) -> GpuTexture2DHandle {
+    enum Never {}
+    let result: Result<GpuTexture2DHandle, Never> = render_ctx
+        .texture_manager_2d
+        .get_or_create_with(texture_key, &mut render_ctx.gpu_resources.textures, || {
+            Ok(create_texture_desc())
+        });
+    match result {
+        Ok(handle) => handle,
+        Err(never) => match never {},
+    }
+}
+
 /// Render a `re_render` view using the given clip rectangle.
 pub fn renderer_paint_callback(
     render_ctx: &mut re_renderer::RenderContext,
@@ -132,6 +149,11 @@ 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() {
+        return Ok(());
+    }
+
     // Where in "world space" to paint the image.
     let space_rect = egui::Rect::from_min_size(egui::Pos2::ZERO, image_rect_on_screen.size());
 
@@ -163,10 +185,10 @@ pub fn render_image(
     let space_from_pixel = space_from_points * points_from_pixels;
 
     let resolution_in_pixel =
-        crate::gpu_bridge::viewport_resolution_in_pixels(painter.clip_rect(), pixels_from_points);
+        crate::gpu_bridge::viewport_resolution_in_pixels(clip_rect, pixels_from_points);
     anyhow::ensure!(resolution_in_pixel[0] > 0 && resolution_in_pixel[1] > 0);
 
-    let camera_position_space = space_from_ui.transform_pos(painter.clip_rect().min);
+    let camera_position_space = space_from_ui.transform_pos(clip_rect.min);
 
     let top_left_position = glam::vec2(camera_position_space.x, camera_position_space.y);
     let target_config = re_renderer::view_builder::TargetConfiguration {
@@ -196,7 +218,7 @@ pub fn render_image(
         render_ctx,
         command_buffer,
         view_builder,
-        painter.clip_rect(),
+        clip_rect,
         painter.ctx().pixels_per_point(),
     ));
 

crates/re_viewer/src/gpu_bridge/tensor_to_gpu.rs

@@ -13,9 +13,9 @@ use re_renderer::{
     RenderContext,
 };
 
-use crate::misc::caches::TensorStats;
+use crate::{gpu_bridge::get_or_create_texture, misc::caches::TensorStats};
 
-use super::get_or_create_texture;
+use super::try_get_or_create_texture;
 
 // ----------------------------------------------------------------------------
 
@@ -63,7 +63,7 @@ fn color_tensor_to_gpu(
     tensor: &Tensor,
     tensor_stats: &TensorStats,
 ) -> anyhow::Result<ColormappedTexture> {
-    let texture_handle = get_or_create_texture(render_ctx, hash(tensor.id()), || {
+    let texture_handle = try_get_or_create_texture(render_ctx, hash(tensor.id()), || {
         let [height, width, depth] = height_width_depth(tensor)?;
         let (data, format) = match (depth, &tensor.data) {
             // Use R8Unorm and R8Snorm to get filtering on the GPU:
@@ -161,10 +161,8 @@ fn class_id_tensor_to_gpu(
     let colormap_width = 256;
     let colormap_height = (max as usize + colormap_width - 1) / colormap_width;
 
-    let colormap_texture_handle = get_or_create_texture(
-        render_ctx,
-        hash(annotations.row_id),
-        || -> anyhow::Result<_> {
+    let colormap_texture_handle =
+        get_or_create_texture(render_ctx, hash(annotations.row_id), || {
             let data: Vec<u8> = (0..(colormap_width * colormap_height))
                 .flat_map(|id| {
                     let color = annotations
@@ -175,17 +173,16 @@ fn class_id_tensor_to_gpu(
                 })
                 .collect();
 
-            Ok(Texture2DCreationDesc {
+            Texture2DCreationDesc {
                 label: "class_id_colormap".into(),
                 data: data.into(),
                 format: TextureFormat::Rgba8UnormSrgb,
                 width: colormap_width as u32,
                 height: colormap_height as u32,
-            })
-        },
-    )?;
+            }
+        });
 
-    let main_texture_handle = get_or_create_texture(render_ctx, hash(tensor.id()), || {
+    let main_texture_handle = try_get_or_create_texture(render_ctx, hash(tensor.id()), || {
         general_texture_creation_desc_from_tensor(debug_name, tensor)
     })?;
 
@@ -214,7 +211,7 @@ fn depth_tensor_to_gpu(
     );
     let (min, max) = depth_tensor_range(tensor, tensor_stats)?;
 
-    let texture = get_or_create_texture(render_ctx, hash(tensor.id()), || {
+    let texture = try_get_or_create_texture(render_ctx, hash(tensor.id()), || {
         general_texture_creation_desc_from_tensor(debug_name, tensor)
     })?;
 

crates/re_viewer/src/ui/view_tensor/tensor_slice_to_gpu.rs

@@ -56,7 +56,7 @@ fn upload_texture_slice_to_gpu(
 ) -> Result<re_renderer::resource_managers::GpuTexture2DHandle, TensorUploadError> {
     let id = egui::util::hash((tensor.id(), slice_selection));
 
-    crate::gpu_bridge::get_or_create_texture(render_ctx, id, || {
+    crate::gpu_bridge::try_get_or_create_texture(render_ctx, id, || {
         texture_desc_from_tensor(tensor, slice_selection)
     })
 }

crates/re_viewer/src/ui/view_tensor/ui.rs

@@ -78,7 +78,7 @@ impl ViewTensorState {
                     Some(ctx.cache.tensor_stats(tensor)),
                 );
                 self.texture_settings.ui(ctx.re_ui, ui);
-                self.color_mapping.ui(ctx.re_ui, ui);
+                self.color_mapping.ui(ctx.render_ctx, ctx.re_ui, ui);
             });
 
         ui.separator();
@@ -245,17 +245,29 @@ impl Default for ColorMapping {
 }
 
 impl ColorMapping {
-    fn ui(&mut self, re_ui: &re_ui::ReUi, ui: &mut egui::Ui) {
+    fn ui(
+        &mut self,
+        render_ctx: &mut re_renderer::RenderContext,
+        re_ui: &re_ui::ReUi,
+        ui: &mut egui::Ui,
+    ) {
         let ColorMapping { map, gamma } = self;
 
         re_ui.grid_left_hand_label(ui, "Color map");
         egui::ComboBox::from_id_source("color map select")
             .selected_text(map.to_string())
             .show_ui(ui, |ui| {
                 ui.style_mut().wrap = Some(false);
-                for option in Colormap::ALL {
-                    ui.selectable_value(map, option, option.to_string());
-                }
+
+                egui::Grid::new("colormap_selector")
+                    .num_columns(2)
+                    .show(ui, |ui| {
+                        for option in Colormap::ALL {
+                            ui.selectable_value(map, option, option.to_string());
+                            colormap_preview_ui(render_ctx, ui, option);
+                            ui.end_row();
+                        }
+                    });
             });
         ui.end_row();
 
@@ -267,6 +279,71 @@ impl ColorMapping {
     }
 }
 
+/// Show the given colormap as a horizontal bar.
+fn colormap_preview_ui(
+    render_ctx: &mut re_renderer::RenderContext,
+    ui: &mut egui::Ui,
+    colormap: Colormap,
+) -> egui::Response {
+    crate::profile_function!();
+
+    let desired_size = egui::vec2(128.0, 16.0);
+    let (rect, response) = ui.allocate_exact_size(desired_size, egui::Sense::hover());
+
+    if ui.is_rect_visible(rect) {
+        if let Err(err) = paint_colormap_gradient(render_ctx, colormap, ui, rect) {
+            re_log::error_once!("Failed to paint colormap preview: {err}");
+        }
+    }
+
+    response
+}
+
+fn paint_colormap_gradient(
+    render_ctx: &mut re_renderer::RenderContext,
+    colormap: Colormap,
+    ui: &mut egui::Ui,
+    rect: egui::Rect,
+) -> anyhow::Result<()> {
+    let horizontal_gradient_id = egui::util::hash("horizontal_gradient");
+    let horizontal_gradient =
+        crate::gpu_bridge::get_or_create_texture(render_ctx, horizontal_gradient_id, || {
+            let width = 256;
+            let height = 1;
+            let data: Vec<u8> = (0..width)
+                .flat_map(|x| {
+                    let t = x as f32 / (width as f32 - 1.0);
+                    half::f16::from_f32(t).to_le_bytes()
+                })
+                .collect();
+
+            re_renderer::resource_managers::Texture2DCreationDesc {
+                label: "horizontal_gradient".into(),
+                data: data.into(),
+                format: wgpu::TextureFormat::R16Float,
+                width,
+                height,
+            }
+        });
+
+    let colormapped_texture = re_renderer::renderer::ColormappedTexture {
+        texture: horizontal_gradient,
+        range: [0.0, 1.0],
+        gamma: 1.0,
+        color_mapper: Some(re_renderer::renderer::ColorMapper::Function(colormap)),
+    };
+
+    let debug_name = format!("colormap_{colormap}");
+    crate::gpu_bridge::render_image(
+        render_ctx,
+        ui.painter(),
+        rect,
+        colormapped_texture,
+        egui::TextureOptions::LINEAR,
+        &debug_name,
+    )
+}
+
 // ----------------------------------------------------------------------------
 
 /// Should we scale the rendered texture, and if so, how?