From 00c4499419300d75a41401b5396a29498b5c2a53 Mon Sep 17 00:00:00 2001
From: Andreas Reich <andreas@rerun.io>
Date: Tue, 13 Jun 2023 19:19:32 +0200
Subject: [PATCH] Fix WebGL crash due to rectangle shader returning arrays
 (#2413)

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### What

Works around  https://github.com/gfx-rs/naga/issues/2380

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)


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PR Build Summary: https://build.rerun.io/pr/2413

<!-- pr-link-docs:start -->
Docs preview: https://rerun.io/preview/26e3636/docs
Examples preview: https://rerun.io/preview/26e3636/examples
<!-- pr-link-docs:end -->
---
 crates/re_renderer/shader/rectangle_fs.wgsl | 37 +++++++--------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/crates/re_renderer/shader/rectangle_fs.wgsl b/crates/re_renderer/shader/rectangle_fs.wgsl
index 706b66977f23..58d84196e819 100644
--- a/crates/re_renderer/shader/rectangle_fs.wgsl
+++ b/crates/re_renderer/shader/rectangle_fs.wgsl
@@ -46,16 +46,6 @@ fn clamp_to_edge_nearest_neighbor(coord: Vec2, texture_dimension: Vec2) -> IVec2
     return IVec2(clamp(floor(coord), Vec2(0.0), texture_dimension - Vec2(1.0)));
 }
 
-/// Takes a floating point texel coordinate and outputs the four integer texel coordinates that are used for bilinear filtering.
-/// All four samples are clamped to the texture edge.
-fn clamp_to_edge_bilinear_samples(coord: Vec2, texture_dimension: Vec2) -> array<IVec2, 4> {
-    let v00 = clamp_to_edge_nearest_neighbor(coord + vec2(-0.5, -0.5), texture_dimension);
-    let v01 = clamp_to_edge_nearest_neighbor(coord + vec2(-0.5,  0.5), texture_dimension);
-    let v10 = clamp_to_edge_nearest_neighbor(coord + vec2( 0.5, -0.5), texture_dimension);
-    let v11 = clamp_to_edge_nearest_neighbor(coord + vec2( 0.5,  0.5), texture_dimension);
-    return array<IVec2, 4>(IVec2(v00), IVec2(v01), IVec2(v10), IVec2(v11));
-}
-
 fn filter_bilinear(coord: Vec2, v00: Vec4, v01: Vec4, v10: Vec4, v11: Vec4) -> Vec4 {
     let top = mix(v00, v10, fract(coord.x - 0.5));
     let bottom = mix(v01, v11, fract(coord.x - 0.5));
@@ -75,11 +65,10 @@ fn fs_main(in: VertexOut) -> @location(0) Vec4 {
                 clamp_to_edge_nearest_neighbor(coord, texture_dimensions), 0));
         } else {
             // bilinear
-            let sample_positions = clamp_to_edge_bilinear_samples(coord, texture_dimensions);
-            let v00 = decode_color(textureLoad(texture_float, sample_positions[0], 0));
-            let v01 = decode_color(textureLoad(texture_float, sample_positions[1], 0));
-            let v10 = decode_color(textureLoad(texture_float, sample_positions[2], 0));
-            let v11 = decode_color(textureLoad(texture_float, sample_positions[3], 0));
+            let v00 = decode_color(textureLoad(texture_float, clamp_to_edge_nearest_neighbor(coord + vec2(-0.5, -0.5), texture_dimensions), 0));
+            let v01 = decode_color(textureLoad(texture_float, clamp_to_edge_nearest_neighbor(coord + vec2(-0.5,  0.5), texture_dimensions), 0));
+            let v10 = decode_color(textureLoad(texture_float, clamp_to_edge_nearest_neighbor(coord + vec2( 0.5, -0.5), texture_dimensions), 0));
+            let v11 = decode_color(textureLoad(texture_float, clamp_to_edge_nearest_neighbor(coord + vec2( 0.5,  0.5), texture_dimensions), 0));
             normalized_value = filter_bilinear(coord, v00, v01, v10, v11);
         }
     } else if rect_info.sample_type == SAMPLE_TYPE_SINT {
@@ -91,11 +80,10 @@ fn fs_main(in: VertexOut) -> @location(0) Vec4 {
                 clamp_to_edge_nearest_neighbor(coord, texture_dimensions), 0)));
         } else {
             // bilinear
-            let sample_positions = clamp_to_edge_bilinear_samples(coord, texture_dimensions);
-            let v00 = decode_color(Vec4(textureLoad(texture_sint, sample_positions[0], 0)));
-            let v01 = decode_color(Vec4(textureLoad(texture_sint, sample_positions[1], 0)));
-            let v10 = decode_color(Vec4(textureLoad(texture_sint, sample_positions[2], 0)));
-            let v11 = decode_color(Vec4(textureLoad(texture_sint, sample_positions[3], 0)));
+            let v00 = decode_color(Vec4(textureLoad(texture_sint, clamp_to_edge_nearest_neighbor(coord + vec2(-0.5, -0.5), texture_dimensions), 0)));
+            let v01 = decode_color(Vec4(textureLoad(texture_sint, clamp_to_edge_nearest_neighbor(coord + vec2(-0.5,  0.5), texture_dimensions), 0)));
+            let v10 = decode_color(Vec4(textureLoad(texture_sint, clamp_to_edge_nearest_neighbor(coord + vec2( 0.5, -0.5), texture_dimensions), 0)));
+            let v11 = decode_color(Vec4(textureLoad(texture_sint, clamp_to_edge_nearest_neighbor(coord + vec2( 0.5,  0.5), texture_dimensions), 0)));
             normalized_value = filter_bilinear(coord, v00, v01, v10, v11);
         }
     } else if rect_info.sample_type == SAMPLE_TYPE_UINT {
@@ -107,11 +95,10 @@ fn fs_main(in: VertexOut) -> @location(0) Vec4 {
                 clamp_to_edge_nearest_neighbor(coord, texture_dimensions), 0)));
         } else {
             // bilinear
-            let sample_positions = clamp_to_edge_bilinear_samples(coord, texture_dimensions);
-            let v00 = decode_color(Vec4(textureLoad(texture_uint, sample_positions[0], 0)));
-            let v01 = decode_color(Vec4(textureLoad(texture_uint, sample_positions[1], 0)));
-            let v10 = decode_color(Vec4(textureLoad(texture_uint, sample_positions[2], 0)));
-            let v11 = decode_color(Vec4(textureLoad(texture_uint, sample_positions[3], 0)));
+            let v00 = decode_color(Vec4(textureLoad(texture_uint, clamp_to_edge_nearest_neighbor(coord + vec2(-0.5, -0.5), texture_dimensions), 0)));
+            let v01 = decode_color(Vec4(textureLoad(texture_uint, clamp_to_edge_nearest_neighbor(coord + vec2(-0.5,  0.5), texture_dimensions), 0)));
+            let v10 = decode_color(Vec4(textureLoad(texture_uint, clamp_to_edge_nearest_neighbor(coord + vec2( 0.5, -0.5), texture_dimensions), 0)));
+            let v11 = decode_color(Vec4(textureLoad(texture_uint, clamp_to_edge_nearest_neighbor(coord + vec2( 0.5,  0.5), texture_dimensions), 0)));
             normalized_value = filter_bilinear(coord, v00, v01, v10, v11);
         }
     } else {