Initial pipeline abstraction

Source/Render/Pipeline/StencilState.rs

@@ -0,0 +1,37 @@
+use super::StencilFaceState;
+use serde::{Deserialize, Serialize};
+
+/// State of the stencil operation (fixed-pipeline stage).
+#[repr(C)]
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq, Serialize, Deserialize)]
+pub struct StencilState {
+    /// Front face mode.
+    pub front: StencilFaceState,
+
+    /// Back face mode.
+    pub back: StencilFaceState,
+
+    /// Stencil values are AND'd with this mask when reading and writing from the stencil buffer. Only low 8 bits are used.
+    pub read_mask: u32,
+
+    /// Stencil values are AND'd with this mask when writing to the stencil buffer. Only low 8 bits are used.
+    pub write_mask: u32,
+}
+
+impl StencilState {
+    /// Returns true if the stencil test is enabled.
+    pub fn IsEnabled(&self) -> bool {
+        (self.front != StencilFaceState::IGNORE || self.back != StencilFaceState::IGNORE)
+            && (self.read_mask != 0 || self.write_mask != 0)
+    }
+
+    /// Returns true if the state doesn't mutate the target values.
+    pub fn IsReadOnly(&self) -> bool {
+        self.write_mask == 0
+    }
+
+    /// Returns true if the stencil state uses the reference value for testing.
+    pub fn NeedsReferenceValue(&self) -> bool {
+        self.front.NeedsReferenceValue() || self.back.NeedsReferenceValue()
+    }
+}