HACK(eddyb): avoid push constants on wasm/WebGPU.

EmbarkStudios · Apr 15, 2023 · 3ef6ae0 · 3ef6ae0
1 parent 8f1d75b
commit 3ef6ae0
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Showing 2 changed files with 22 additions and 17 deletions.
diff --git a/examples/runners/wgpu/src/graphics.rs b/examples/runners/wgpu/src/graphics.rs
@@ -170,6 +170,10 @@ 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,
@@ -305,11 +309,14 @@ 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/shaders/sky-shader/src/lib.rs b/examples/shaders/sky-shader/src/lib.rs
@@ -130,10 +130,8 @@ fn get_ray_dir(uv: Vec2, pos: Vec3, look_at_pos: Vec3) -> Vec3 {
     (forward + uv.x * right + uv.y * up).normalize()
 }
 
-pub fn fs(constants: &ShaderConstants, frag_coord: Vec2) -> Vec4 {
-    let mut uv = (frag_coord - 0.5 * vec2(constants.width as f32, constants.height as f32))
-        / constants.height as f32;
-    uv.y = -uv.y;
+pub fn fs(uv: Vec2) -> Vec4 {
+    let uv = uv - 0.5;
 
     // hard-code information because we can't bind buffers at the moment
     let eye_pos = vec3(0.0, 0.0997, 0.2);
@@ -150,23 +148,23 @@ pub fn fs(constants: &ShaderConstants, frag_coord: Vec2) -> Vec4 {
 }
 
 #[spirv(fragment)]
-pub fn main_fs(
-    #[spirv(frag_coord)] in_frag_coord: Vec4,
-    #[spirv(push_constant)] constants: &ShaderConstants,
-    output: &mut Vec4,
-) {
-    let frag_coord = vec2(in_frag_coord.x, in_frag_coord.y);
-    *output = fs(constants, frag_coord);
+pub fn main_fs(uv: Vec2, output: &mut Vec4) {
+    *output = fs(uv);
 }
 
 #[spirv(vertex)]
-pub fn main_vs(#[spirv(vertex_index)] vert_idx: i32, #[spirv(position)] builtin_pos: &mut Vec4) {
+pub fn main_vs(
+    #[spirv(vertex_index)] vert_idx: i32,
+    #[spirv(position)] builtin_pos: &mut Vec4,
+    out_uv: &mut Vec2,
+) {
     // Create a "full screen triangle" by mapping the vertex index.
     // ported from https://www.saschawillems.de/blog/2016/08/13/vulkan-tutorial-on-rendering-a-fullscreen-quad-without-buffers/
     let uv = vec2(((vert_idx << 1) & 2) as f32, (vert_idx & 2) as f32);
     let pos = 2.0 * uv - Vec2::ONE;
 
     *builtin_pos = pos.extend(0.0).extend(1.0);
+    *out_uv = uv;
 }
 
 #[cfg(test)]