wgpu-renderer/Source/Render/Pipeline/StencilFaceState.rs

use super::{CompareFunction, StencilOperation};
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 StencilFaceState {
    /// Comparison function that determines if the fail_op or pass_op is used on the stencil buffer.
    pub compare: CompareFunction,

    /// Operation that is preformed when stencil test fails.
    pub fail_op: StencilOperation,

    /// Operation that is performed when depth test fails but stencil test succeeds.
    pub depth_fail_op: StencilOperation,

    /// Operation that is performed when stencil test success.
    pub pass_op: StencilOperation,
}

impl StencilFaceState {
    /// Ignore the stencil state for the face.
    pub const IGNORE: Self = StencilFaceState {
        compare: CompareFunction::Always,
        fail_op: StencilOperation::Keep,
        depth_fail_op: StencilOperation::Keep,
        pass_op: StencilOperation::Keep,
    };

    /// Returns true if the face state uses the reference value for testing or operation.
    pub fn NeedsReferenceValue(&self) -> bool {
        self.compare.NeedsReferenceValue()
            || self.fail_op == StencilOperation::Replace
            || self.depth_fail_op == StencilOperation::Replace
            || self.pass_op == StencilOperation::Replace
    }
}

impl Default for StencilFaceState {
    fn default() -> Self {
        Self::IGNORE
    }
}