Fix 2d_shapes and general 2D mesh instancing (bevyengine#10051)

# Objective

- Fix bevyengine#10050 

## Solution

- Push constants needed to be defined in the pipeline layout and
`bevy_sprite` needed to have a `webgl` feature.

crates/bevy_internal/Cargo.toml

@@ -73,7 +73,7 @@ x11 = ["bevy_winit/x11"]
 subpixel_glyph_atlas = ["bevy_text/subpixel_glyph_atlas"]
 
 # Optimise for WebGL2
-webgl = ["bevy_core_pipeline?/webgl", "bevy_pbr?/webgl", "bevy_render?/webgl", "bevy_gizmos?/webgl"]
+webgl = ["bevy_core_pipeline?/webgl", "bevy_pbr?/webgl", "bevy_render?/webgl", "bevy_gizmos?/webgl", "bevy_sprite?/webgl"]
 
 # enable systems that allow for automated testing on CI
 bevy_ci_testing = ["bevy_app/bevy_ci_testing", "bevy_time/bevy_ci_testing", "bevy_render?/bevy_ci_testing", "bevy_render?/ci_limits"]

crates/bevy_sprite/Cargo.toml

@@ -8,6 +8,9 @@ repository = "https://github.com/bevyengine/bevy"
 license = "MIT OR Apache-2.0"
 keywords = ["bevy"]
 
+[features]
+webgl = []
+
 [dependencies]
 # bevy
 bevy_app = { path = "../bevy_app", version = "0.12.0-dev" }

crates/bevy_sprite/src/mesh2d/mesh.rs

@@ -536,6 +536,13 @@ impl SpecializedMeshPipeline for Mesh2dPipeline {
             true => ViewTarget::TEXTURE_FORMAT_HDR,
             false => TextureFormat::bevy_default(),
         };
+        let mut push_constant_ranges = Vec::with_capacity(1);
+        if cfg!(all(feature = "webgl", target_arch = "wasm32")) {
+            push_constant_ranges.push(PushConstantRange {
+                stages: ShaderStages::VERTEX,
+                range: 0..4,
+            });
+        }
 
         Ok(RenderPipelineDescriptor {
             vertex: VertexState {
@@ -555,7 +562,7 @@ impl SpecializedMeshPipeline for Mesh2dPipeline {
                 })],
             }),
             layout: vec![self.view_layout.clone(), self.mesh_layout.clone()],
-            push_constant_ranges: Vec::new(),
+            push_constant_ranges,
             primitive: PrimitiveState {
                 front_face: FrontFace::Ccw,
                 cull_mode: None,