Depth offset for lines & points (#2052)

* depth offset for lines & points

* fix comment typo, rename padding variable

crates/re_renderer/examples/2d.rs

@@ -174,16 +174,48 @@ impl framework::Example for Render2D {
             std::iter::repeat(re_renderer::PickingLayerInstanceId::default()),
         );
 
-        // Pile stuff to test for overlap handling
+        // Pile stuff to test for overlap handling.
+        // Do in individual batches to test depth offset.
         {
-            let mut batch = line_strip_builder.batch("overlapping objects");
-            for i in 0..10 {
-                let x = 5.0 * i as f32 + 20.0;
+            let num_lines = 20_i16;
+            let y_range = 700.0..780.0;
+
+            // Cycle through which line is on top.
+            let top_line = ((time.seconds_since_startup() * 6.0) as i16 % (num_lines * 2 - 1)
+                - num_lines)
+                .abs();
+            for i in 0..num_lines {
+                let depth_offset = if i < top_line { i } else { top_line * 2 - i };
+                let mut batch = line_strip_builder
+                    .batch(format!("overlapping objects {i}"))
+                    .depth_offset(depth_offset);
+
+                let x = 15.0 * i as f32 + 20.0;
                 batch
-                    .add_segment_2d(glam::vec2(x, 700.0), glam::vec2(x, 780.0))
-                    .color(Hsva::new(10.0 / i as f32, 1.0, 0.5, 1.0).into())
-                    .radius(Size::new_points(10.0));
+                    .add_segment_2d(glam::vec2(x, y_range.start), glam::vec2(x, y_range.end))
+                    .color(Hsva::new(0.25 / num_lines as f32 * i as f32, 1.0, 0.5, 1.0).into())
+                    .radius(Size::new_points(10.0))
+                    .flags(LineStripFlags::FLAG_COLOR_GRADIENT);
             }
+
+            let num_points = 8;
+            let size = Size::new_points(3.0);
+            point_cloud_builder
+                .batch("points overlapping with lines")
+                .depth_offset(5)
+                .add_points_2d(
+                    num_points,
+                    (0..num_points).map(|i| {
+                        glam::vec2(
+                            30.0 * i as f32 + 20.0,
+                            y_range.start
+                                + (y_range.end - y_range.start) / num_points as f32 * i as f32,
+                        )
+                    }),
+                    std::iter::repeat(size),
+                    std::iter::repeat(Color32::WHITE),
+                    std::iter::repeat(re_renderer::PickingLayerInstanceId::default()),
+                );
         }
 
         let line_strip_draw_data = line_strip_builder.to_draw_data(re_ctx).unwrap();

crates/re_renderer/shader/lines.wgsl

@@ -5,6 +5,7 @@
 #import <./utils/flags.wgsl>
 #import <./utils/size.wgsl>
 #import <./utils/srgb.wgsl>
+#import <./utils/depth_offset.wgsl>
 
 @group(1) @binding(0)
 var line_strip_texture: texture_2d<f32>;
@@ -28,6 +29,7 @@ struct BatchUniformBuffer {
     world_from_obj: Mat4,
     outline_mask_ids: UVec2,
     picking_layer_object_id: UVec2,
+    depth_offset: f32,
 };
 @group(2) @binding(0)
 var<uniform> batch: BatchUniformBuffer;
@@ -262,7 +264,7 @@ fn vs_main(@builtin(vertex_index) vertex_idx: u32) -> VertexOut {
 
     // Output, transform to projection space and done.
     var out: VertexOut;
-    out.position = frame.projection_from_world * Vec4(pos, 1.0);
+    out.position = apply_depth_offset(frame.projection_from_world * Vec4(pos, 1.0), batch.depth_offset);
     out.position_world = pos;
     out.center_position = center_position;
     out.round_cap_circle_center = round_cap_circle_center;

crates/re_renderer/shader/point_cloud.wgsl

@@ -4,6 +4,7 @@
 #import <./utils/flags.wgsl>
 #import <./utils/size.wgsl>
 #import <./utils/sphere_quad.wgsl>
+#import <./utils/depth_offset.wgsl>
 
 @group(1) @binding(0)
 var position_data_texture: texture_2d<f32>;
@@ -26,7 +27,8 @@ var<uniform> draw_data: DrawDataUniformBuffer;
 struct BatchUniformBuffer {
     world_from_obj: Mat4,
     flags: u32,
-    _padding: UVec2, // UVec3 would take its own 4xf32 row, UVec2 is on the same as flags
+    depth_offset: f32,
+    _padding: UVec2,
     outline_mask: UVec2,
     picking_layer_object_id: UVec2,
 };
@@ -101,7 +103,7 @@ fn vs_main(@builtin(vertex_index) vertex_idx: u32) -> VertexOut {
 
     // Output, transform to projection space and done.
     var out: VertexOut;
-    out.position = frame.projection_from_world * Vec4(quad.pos_in_world, 1.0);
+    out.position = apply_depth_offset(frame.projection_from_world * Vec4(quad.pos_in_world, 1.0), batch.depth_offset);
     out.color = point_data.color;
     out.radius = quad.point_resolved_radius;
     out.world_position = quad.pos_in_world;

crates/re_renderer/src/line_strip_builder.rs

@@ -5,8 +5,8 @@ use crate::{
     renderer::{
         LineBatchInfo, LineDrawData, LineDrawDataError, LineStripFlags, LineStripInfo, LineVertex,
     },
-    Color32, DebugLabel, OutlineMaskPreference, PickingLayerInstanceId, PickingLayerObjectId,
-    RenderContext, Size,
+    Color32, DebugLabel, DepthOffset, OutlineMaskPreference, PickingLayerInstanceId,
+    PickingLayerObjectId, RenderContext, Size,
 };
 
 /// Builder for a vector of line strips, making it easy to create [`crate::renderer::LineDrawData`].
@@ -70,6 +70,7 @@ impl LineStripSeriesBuilder {
             overall_outline_mask_ids: OutlineMaskPreference::NONE,
             additional_outline_mask_ids_vertex_ranges: Vec::new(),
             picking_object_id: PickingLayerObjectId::default(),
+            depth_offset: 0,
         });
 
         LineBatchBuilder(self)
@@ -163,6 +164,13 @@ impl<'a> LineBatchBuilder<'a> {
         self
     }
 
+    /// Sets the depth offset for the entire batch.
+    #[inline]
+    pub fn depth_offset(mut self, depth_offset: DepthOffset) -> Self {
+        self.batch_mut().depth_offset = depth_offset;
+        self
+    }
+
     /// Adds a 3D series of line connected points.
     pub fn add_strip(&mut self, points: impl Iterator<Item = glam::Vec3>) -> LineStripBuilder<'_> {
         let old_strip_count = self.0.strips.len();

crates/re_renderer/src/point_cloud_builder.rs

@@ -5,7 +5,8 @@ use crate::{
         PointCloudBatchFlags, PointCloudBatchInfo, PointCloudDrawData, PointCloudDrawDataError,
         PointCloudVertex,
     },
-    Color32, DebugLabel, OutlineMaskPreference, PickingLayerInstanceId, RenderContext, Size,
+    Color32, DebugLabel, DepthOffset, OutlineMaskPreference, PickingLayerInstanceId, RenderContext,
+    Size,
 };
 
 /// Builder for point clouds, making it easy to create [`crate::renderer::PointCloudDrawData`].
@@ -69,6 +70,7 @@ impl PointCloudBuilder {
             overall_outline_mask_ids: OutlineMaskPreference::NONE,
             additional_outline_mask_ids_vertex_ranges: Vec::new(),
             picking_object_id: Default::default(),
+            depth_offset: 0,
         });
 
         PointCloudBatchBuilder(self)
@@ -140,6 +142,13 @@ impl<'a> PointCloudBatchBuilder<'a> {
         self
     }
 
+    /// Sets the depth offset for the entire batch.
+    #[inline]
+    pub fn depth_offset(mut self, depth_offset: DepthOffset) -> Self {
+        self.batch_mut().depth_offset = depth_offset;
+        self
+    }
+
     /// Add several 3D points
     ///
     /// Returns a `PointBuilder` which can be used to set the colors, radii, and user-data for the points.

crates/re_renderer/src/renderer/lines.rs

@@ -121,8 +121,8 @@ use crate::{
         BindGroupDesc, BindGroupEntry, BindGroupLayoutDesc, GpuBindGroup, GpuBindGroupLayoutHandle,
         GpuRenderPipelineHandle, PipelineLayoutDesc, PoolError, RenderPipelineDesc, TextureDesc,
     },
-    Color32, DebugLabel, LineStripSeriesBuilder, OutlineMaskPreference, PickingLayerObjectId,
-    PickingLayerProcessor,
+    Color32, DebugLabel, DepthOffset, LineStripSeriesBuilder, OutlineMaskPreference,
+    PickingLayerObjectId, PickingLayerProcessor,
 };
 
 use super::{
@@ -174,7 +174,9 @@ pub mod gpu_data {
         pub outline_mask_ids: wgpu_buffer_types::UVec2,
         pub picking_object_id: PickingLayerObjectId,
 
-        pub end_padding: [wgpu_buffer_types::PaddingRow; 16 - 5],
+        pub depth_offset: wgpu_buffer_types::F32RowPadded,
+
+        pub end_padding: [wgpu_buffer_types::PaddingRow; 16 - 6],
     }
 }
 
@@ -272,6 +274,9 @@ pub struct LineBatchInfo {
 
     /// Picking object id that applies for the entire batch.
     pub picking_object_id: PickingLayerObjectId,
+
+    /// Depth offset applied after projection.
+    pub depth_offset: DepthOffset,
 }
 
 /// Style information for a line strip.
@@ -368,6 +373,7 @@ impl LineDrawData {
                 overall_outline_mask_ids: OutlineMaskPreference::NONE,
                 picking_object_id: PickingLayerObjectId::default(),
                 additional_outline_mask_ids_vertex_ranges: Vec::new(),
+                depth_offset: 0,
             }]
         } else {
             batches
@@ -620,6 +626,7 @@ impl LineDrawData {
                             .unwrap_or_default()
                             .into(),
                         picking_object_id: batch_info.picking_object_id,
+                        depth_offset: (batch_info.depth_offset as f32).into(),
                         end_padding: Default::default(),
                     }),
             );
@@ -640,6 +647,7 @@ impl LineDrawData {
                                     world_from_obj: batch_info.world_from_obj.into(),
                                     outline_mask_ids: mask.0.unwrap_or_default().into(),
                                     picking_object_id: batch_info.picking_object_id,
+                                    depth_offset: (batch_info.depth_offset as f32).into(),
                                     end_padding: Default::default(),
                                 })
                         })

crates/re_renderer/src/renderer/point_cloud.rs

@@ -18,7 +18,7 @@ use std::{num::NonZeroU64, ops::Range};
 use crate::{
     allocator::create_and_fill_uniform_buffer_batch,
     draw_phases::{DrawPhase, OutlineMaskProcessor, PickingLayerObjectId, PickingLayerProcessor},
-    include_shader_module, DebugLabel, OutlineMaskPreference, PointCloudBuilder,
+    include_shader_module, DebugLabel, DepthOffset, OutlineMaskPreference, PointCloudBuilder,
 };
 use bitflags::bitflags;
 use bytemuck::Zeroable as _;
@@ -80,7 +80,11 @@ mod gpu_data {
     #[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable)]
     pub struct BatchUniformBuffer {
         pub world_from_obj: wgpu_buffer_types::Mat4,
-        pub flags: wgpu_buffer_types::U32RowPadded, // PointCloudBatchFlags
+
+        pub flags: u32, // PointCloudBatchFlags
+        pub depth_offset: f32,
+        pub _row_padding: [f32; 2],
+
         pub outline_mask_ids: wgpu_buffer_types::UVec2,
         pub picking_object_id: PickingLayerObjectId,
 
@@ -141,6 +145,9 @@ pub struct PointCloudBatchInfo {
 
     /// Picking object id that applies for the entire batch.
     pub picking_object_id: PickingLayerObjectId,
+
+    /// Depth offset applied after projection.
+    pub depth_offset: DepthOffset,
 }
 
 /// Description of a point cloud.
@@ -209,6 +216,7 @@ impl PointCloudDrawData {
             overall_outline_mask_ids: OutlineMaskPreference::NONE,
             additional_outline_mask_ids_vertex_ranges: Vec::new(),
             picking_object_id: Default::default(),
+            depth_offset: 0,
         }];
         let batches = if batches.is_empty() {
             &fallback_batches
@@ -400,14 +408,17 @@ impl PointCloudDrawData {
                     .iter()
                     .map(|batch_info| gpu_data::BatchUniformBuffer {
                         world_from_obj: batch_info.world_from_obj.into(),
-                        flags: batch_info.flags.bits.into(),
+                        flags: batch_info.flags.bits,
                         outline_mask_ids: batch_info
                             .overall_outline_mask_ids
                             .0
                             .unwrap_or_default()
                             .into(),
-                        end_padding: Default::default(),
                         picking_object_id: batch_info.picking_object_id,
+                        depth_offset: batch_info.depth_offset as f32,
+
+                        _row_padding: [0.0, 0.0],
+                        end_padding: Default::default(),
                     }),
             );
 
@@ -425,10 +436,13 @@ impl PointCloudDrawData {
                                 .iter()
                                 .map(|(_, mask)| gpu_data::BatchUniformBuffer {
                                     world_from_obj: batch_info.world_from_obj.into(),
-                                    flags: batch_info.flags.bits.into(),
+                                    flags: batch_info.flags.bits,
                                     outline_mask_ids: mask.0.unwrap_or_default().into(),
-                                    end_padding: Default::default(),
                                     picking_object_id: batch_info.picking_object_id,
+                                    depth_offset: batch_info.depth_offset as f32,
+
+                                    _row_padding: [0.0, 0.0],
+                                    end_padding: Default::default(),
                                 })
                         })
                         .collect::<Vec<_>>()