Lib.rs

提供两个宏，blend_formula! 和 blend_equation!，用于将任意公式评估为其等效的GPU混合模式。如果不存在，则为编译时错误。

通过功能标志 wgpu 提供相应的 wgpu 类型的转换特征。

示例

use blend_formula::*;

 // Formulae:
assert_eq!(blend_formula!(src*src.a + dst*(1 - src.a)), BlendFormula {
    src_factor: BlendFactor::SrcAlpha,
    dst_factor: BlendFactor::OneMinusSrcAlpha,
    operation: BlendOperation::Add
});
assert_eq!(blend_formula!(-src), BlendFormula {
    src_factor: BlendFactor::One,
    dst_factor: BlendFactor::Zero,
    operation: BlendOperation::RevSub
});
assert_eq!(blend_formula!(dst < src*c), BlendFormula {
    src_factor: BlendFactor::Constant,
    dst_factor: BlendFactor::One,
    operation: BlendOperation::Min
});

 // Equations:
assert_eq!(blend_equation!(src + dst*(1-src.a)), 
    BlendEquation::PREMULTIPLIED_ALPHA_BLENDING
);
assert_eq!(blend_equation!((dst+(src-dst)*src.a).rgb, (dst+src-dst*src).a),
    BlendEquation::ALPHA_BLENDING
);

 // Shortcuts:
assert_eq!(blend_formula!(+), blend_formula!(src+dst));
assert_eq!(blend_formula!(*), blend_formula!(src*dst));
assert_eq!(blend_equation!(-, dst.a), BlendEquation {
    color: blend_formula!(src-dst),
    alpha: blend_formula!(dst),
});