Fix unsetting vertex attributes in gles backend (#3706)

Co-authored-by: Connor Fitzgerald <connor@modyfi.io>

CHANGELOG.md

@@ -185,6 +185,7 @@ By @cwfitzgerald in [#3671](https://github.com/gfx-rs/wgpu/pull/3671).
 - Reset the state of `SAMPLE_ALPHA_TO_COVERAGE` on queue reset. By @jleibs [#3589](https://github.com/gfx-rs/wgpu/pull/3589)
 - Fix `Vertex buffer is not big enough for the draw call.` for ANGLE/Web when rendering with instance attributes on a single instance. By @wumpf in [#3597](https://github.com/gfx-rs/wgpu/pull/3597)
 - Fix `copy_external_image_to_texture`, `copy_texture_to_texture` and `copy_buffer_to_texture` not taking the specified index into account if the target texture is a cube map, 2D texture array or cube map array. By @daxpedda [#3641](https://github.com/gfx-rs/wgpu/pull/3641)
+- Fix disabling of vertex attributes with non-consecutive locations [#3706](https://github.com/gfx-rs/wgpu/pull/3706)
 
 #### Metal
 

wgpu-hal/src/gles/command.rs

@@ -620,10 +620,10 @@ impl crate::CommandEncoder<super::Api> for super::CommandEncoder {
         self.state.dirty_vbuf_mask = 0;
         self.state.active_first_instance = 0;
         self.state.color_targets.clear();
-        for index in 0..self.state.vertex_attributes.len() {
+        for vat in &self.state.vertex_attributes {
             self.cmd_buffer
                 .commands
-                .push(C::UnsetVertexAttribute(index as u32));
+                .push(C::UnsetVertexAttribute(vat.location));
         }
         self.state.vertex_attributes.clear();
         self.state.primitive = super::PrimitiveState::default();
@@ -761,10 +761,10 @@ impl crate::CommandEncoder<super::Api> for super::CommandEncoder {
                 });
             }
         } else {
-            for index in 0..self.state.vertex_attributes.len() {
+            for vat in &self.state.vertex_attributes {
                 self.cmd_buffer
                     .commands
-                    .push(C::UnsetVertexAttribute(index as u32));
+                    .push(C::UnsetVertexAttribute(vat.location));
             }
             self.state.vertex_attributes.clear();
 

wgpu/tests/regression/issue_3457.rs

@@ -12,6 +12,9 @@ use wgpu::*;
 /// submit, delete the second vertex buffer and `poll(Wait)`. Because we maintained the device,
 /// the actual underlying buffer for the second vertex buffer is deleted, causing a draw call
 /// that is invalid if the second attribute is still enabled.
+///
+/// We use non-consecutive vertex attribute locations (0 and 5) in order to also test
+/// that we unset the correct locations (see PR #3706).
 #[wasm_bindgen_test]
 #[test]
 fn pass_reset_vertex_buffer() {
@@ -60,7 +63,7 @@ fn pass_reset_vertex_buffer() {
                         VertexBufferLayout {
                             array_stride: 4,
                             step_mode: VertexStepMode::Vertex,
-                            attributes: &vertex_attr_array![1 => Float32],
+                            attributes: &vertex_attr_array![5 => Float32],
                         },
                     ],
                 },

wgpu/tests/regression/issue_3457.wgsl

@@ -1,6 +1,6 @@
 struct DoubleVertexIn {
     @location(0) position: vec4<f32>,
-    @location(1) value: f32,
+    @location(5) value: f32,
 }
 
 struct DoubleVertexOut {