From abc31ac2b214dadba48de1e3203f294136c7c6fe Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <eddyb@lyken.rs>
Date: Thu, 23 Mar 2023 06:30:25 +0200
Subject: [PATCH] HACK(eddyb): avoid push constants on wasm/WebGPU.

---
 examples/runners/wgpu/src/graphics.rs | 17 ++++++++++++-----
 examples/runners/wgpu/src/lib.rs      |  7 ++++++-
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/examples/runners/wgpu/src/graphics.rs b/examples/runners/wgpu/src/graphics.rs
index a98e06d2e0..8fe72d67fd 100644
--- a/examples/runners/wgpu/src/graphics.rs
+++ b/examples/runners/wgpu/src/graphics.rs
@@ -164,6 +164,10 @@ async fn run(
     let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
         label: None,
         bind_group_layouts: &[],
+        // HACK(eddyb) disabling push constants to test WebGPU.
+        #[cfg(target_arch = "wasm32")]
+        push_constant_ranges: &[],
+        #[cfg(not(target_arch = "wasm32"))]
         push_constant_ranges: &[wgpu::PushConstantRange {
             stages: wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
             range: 0..std::mem::size_of::<ShaderConstants>() as u32,
@@ -298,11 +302,14 @@ async fn run(
                         };
 
                         rpass.set_pipeline(render_pipeline);
-                        rpass.set_push_constants(
-                            wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
-                            0,
-                            bytemuck::bytes_of(&push_constants),
-                        );
+                        // HACK(eddyb) disabling push constants to test WebGPU.
+                        if cfg!(not(target_arch = "wasm32")) {
+                            rpass.set_push_constants(
+                                wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
+                                0,
+                                bytemuck::bytes_of(&push_constants),
+                            );
+                        }
                         rpass.draw(0..3, 0..1);
                     }
 
diff --git a/examples/runners/wgpu/src/lib.rs b/examples/runners/wgpu/src/lib.rs
index 4bdb7cd9cc..bd8420b8d6 100644
--- a/examples/runners/wgpu/src/lib.rs
+++ b/examples/runners/wgpu/src/lib.rs
@@ -161,13 +161,18 @@ pub struct Options {
 pub fn main(
     #[cfg(target_os = "android")] android_app: winit::platform::android::activity::AndroidApp,
 ) {
-    let options: Options = Options::from_args();
+    let mut options: Options = Options::from_args();
 
     #[cfg(not(any(target_os = "android", target_arch = "wasm32")))]
     if options.shader == RustGPUShader::Compute {
         return compute::start(&options);
     }
 
+    // HACK(eddyb) forcing a shader w/o push constants to test WebGPU.
+    if cfg!(target_arch = "wasm32") {
+        options.shader = RustGPUShader::Simplest;
+    }
+
     graphics::start(
         #[cfg(target_os = "android")]
         android_app,