Track stencil reference

examples/hello_triangle_c/main.c

@@ -210,7 +210,7 @@ int main() {
 
             swap_chain = wgpu_device_create_swap_chain(device, surface,
                 &(WGPUSwapChainDescriptor){
-                    .usage = WGPUTextureUsageFlags_OUTPUT_ATTACHMENT,
+                    .usage = WGPUTextureUsage_OUTPUT_ATTACHMENT,
                     .format = WGPUTextureFormat_Bgra8Unorm,
                     .width = width,
                     .height = height,

wgpu-native/src/command/render.rs

@@ -21,15 +21,24 @@ use hal::command::RawCommandBuffer;
 use std::{iter, slice};
 
 #[derive(Debug, PartialEq)]
-enum BlendColorStatus {
+enum OptionalState {
     Unused,
     Required,
     Set,
 }
 
+impl OptionalState {
+    fn require(&mut self, require: bool) {
+        if require && *self == OptionalState::Unused {
+            *self = OptionalState::Required;
+        }
+    }
+}
+
 #[derive(Debug, PartialEq)]
 enum DrawError {
     MissingBlendColor,
+    MissingStencilReference,
     IncompatibleBindGroup {
         index: u32,
         //expected: BindGroupLayoutId,
@@ -49,7 +58,8 @@ pub struct RenderPass<B: hal::Backend> {
     context: RenderPassContext,
     binder: Binder,
     trackers: TrackerSet,
-    blend_color_status: BlendColorStatus,
+    blend_color_status: OptionalState,
+    stencil_reference_status: OptionalState,
     index_state: IndexState,
 }
 
@@ -66,7 +76,8 @@ impl<B: hal::Backend> RenderPass<B> {
             context,
             binder: Binder::default(),
             trackers: TrackerSet::new(),
-            blend_color_status: BlendColorStatus::Unused,
+            blend_color_status: OptionalState::Unused,
+            stencil_reference_status: OptionalState::Unused,
             index_state,
         }
     }
@@ -80,9 +91,12 @@ impl<B: hal::Backend> RenderPass<B> {
                 index: bind_mask.trailing_zeros() as u32,
             });
         }
-        if self.blend_color_status == BlendColorStatus::Required {
+        if self.blend_color_status == OptionalState::Required {
             return Err(DrawError::MissingBlendColor);
         }
+        if self.stencil_reference_status == OptionalState::Required {
+            return Err(DrawError::MissingStencilReference);
+        }
         Ok(())
     }
 }
@@ -276,11 +290,8 @@ pub extern "C" fn wgpu_render_pass_set_pipeline(
         "The render pipeline is not compatible with the pass!"
     );
 
-    if pipeline.flags.contains(PipelineFlags::BLEND_COLOR)
-        && pass.blend_color_status == BlendColorStatus::Unused
-    {
-        pass.blend_color_status = BlendColorStatus::Required;
-    }
+    pass.blend_color_status.require(pipeline.flags.contains(PipelineFlags::BLEND_COLOR));
+    pass.stencil_reference_status.require(pipeline.flags.contains(PipelineFlags::STENCIL_REFERENCE));
 
     unsafe {
         pass.raw.bind_graphics_pipeline(&pipeline.raw);
@@ -348,7 +359,7 @@ pub extern "C" fn wgpu_render_pass_set_blend_color(pass_id: RenderPassId, color:
     let mut pass_guard = HUB.render_passes.write();
     let pass = &mut pass_guard[pass_id];
 
-    pass.blend_color_status = BlendColorStatus::Set;
+    pass.blend_color_status = OptionalState::Set;
 
     unsafe {
         pass.raw.set_blend_constants(conv::map_color(color));
@@ -360,8 +371,7 @@ pub extern "C" fn wgpu_render_pass_set_stencil_reference(pass_id: RenderPassId,
     let mut pass_guard = HUB.render_passes.write();
     let pass = &mut pass_guard[pass_id];
 
-    //TODO
-    //pass.blend_color_status = BlendColorStatus::Set;
+    pass.stencil_reference_status = OptionalState::Set;
 
     unsafe {
         pass.raw.set_stencil_reference(hal::pso::Face::all(), value);

wgpu-native/src/device.rs

@@ -1568,11 +1568,15 @@ pub fn device_create_render_pipeline(
     };
 
     let mut flags = pipeline::PipelineFlags::empty();
-    if color_states
-        .iter()
-        .any(|state| state.color_blend.uses_color() | state.alpha_blend.uses_color())
-    {
-        flags |= pipeline::PipelineFlags::BLEND_COLOR;
+    for state in color_states {
+        if state.color_blend.uses_color() | state.alpha_blend.uses_color() {
+            flags |= pipeline::PipelineFlags::BLEND_COLOR;
+        }
+    }
+    if let Some(ds) = depth_stencil_state {
+        if ds.needs_stencil_reference() {
+            flags |= pipeline::PipelineFlags::STENCIL_REFERENCE;
+        }
     }
 
     pipeline::RenderPipeline {

wgpu-native/src/pipeline.rs

@@ -122,6 +122,13 @@ pub struct DepthStencilStateDescriptor {
     pub stencil_write_mask: u32,
 }
 
+impl DepthStencilStateDescriptor {
+    pub fn needs_stencil_reference(&self) -> bool {
+        !self.stencil_front.compare.is_trivial() ||
+        !self.stencil_back.compare.is_trivial()
+    }
+}
+
 #[repr(C)]
 #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
 pub enum IndexFormat {
@@ -269,6 +276,7 @@ bitflags! {
     #[repr(transparent)]
     pub struct PipelineFlags: u32 {
         const BLEND_COLOR = 1;
+        const STENCIL_REFERENCE = 2;
     }
 }
 

wgpu-native/src/resource.rs

@@ -280,6 +280,16 @@ pub enum CompareFunction {
     Always = 7,
 }
 
+impl CompareFunction {
+    pub fn is_trivial(&self) -> bool {
+        match *self {
+            CompareFunction::Never |
+            CompareFunction::Always => true,
+            _ => false,
+        }
+    }
+}
+
 #[repr(C)]
 pub struct SamplerDescriptor {
     pub address_mode_u: AddressMode,