84 lines
3.3 KiB
Rust
84 lines
3.3 KiB
Rust
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use enum_map::Enum;
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use swf::BlendMode;
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#[derive(Enum, Debug, Copy, Clone)]
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pub enum ComplexBlend {
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Multiply, // Can't be trivial, 0 alpha is special case
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Screen, // Can't be trivial. (dst + src) - (dst * src)
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Lighten, // Might be trivial but I can't reproduce the right colors
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Darken, // Might be trivial but I can't reproduce the right colors
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Difference, // Can't be trivial, relies on abs operation
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Invert, // May be trivial using a constant? Hard because it's without premultiplied alpha
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Alpha, // Can't be trivial, requires layer tracking
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Erase, // Can't be trivial, requires layer tracking
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Overlay, // Can't be trivial, big math expression
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HardLight, // Can't be trivial, big math expression
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}
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#[derive(Debug, Copy, Clone)]
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pub enum BlendType {
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/// Trivial blends can be expressed with just a "draw bitmap" with blend states
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Trivial(TrivialBlend),
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/// Complex blends require a shader to express, so they are separated out into their own render
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Complex(ComplexBlend),
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}
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impl BlendType {
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pub fn from(mode: BlendMode) -> BlendType {
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match mode {
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BlendMode::Normal => BlendType::Trivial(TrivialBlend::Normal),
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BlendMode::Layer => BlendType::Trivial(TrivialBlend::Normal),
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BlendMode::Multiply => BlendType::Complex(ComplexBlend::Multiply),
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BlendMode::Screen => BlendType::Complex(ComplexBlend::Screen),
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BlendMode::Lighten => BlendType::Complex(ComplexBlend::Lighten),
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BlendMode::Darken => BlendType::Complex(ComplexBlend::Darken),
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BlendMode::Difference => BlendType::Complex(ComplexBlend::Difference),
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BlendMode::Add => BlendType::Trivial(TrivialBlend::Add),
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BlendMode::Subtract => BlendType::Trivial(TrivialBlend::Subtract),
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BlendMode::Invert => BlendType::Complex(ComplexBlend::Invert),
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BlendMode::Alpha => BlendType::Complex(ComplexBlend::Alpha),
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BlendMode::Erase => BlendType::Complex(ComplexBlend::Erase),
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BlendMode::Overlay => BlendType::Complex(ComplexBlend::Overlay),
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BlendMode::HardLight => BlendType::Complex(ComplexBlend::HardLight),
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}
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}
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pub fn default_color(&self) -> wgpu::Color {
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wgpu::Color::TRANSPARENT
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}
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}
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#[derive(Enum, Debug, Copy, Clone)]
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pub enum TrivialBlend {
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Normal,
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Add,
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Subtract,
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}
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impl TrivialBlend {
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pub fn blend_state(self) -> wgpu::BlendState {
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// out = <src_factor> * src <operation> <dst_factor> * dst
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match self {
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TrivialBlend::Normal => wgpu::BlendState::PREMULTIPLIED_ALPHA_BLENDING,
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TrivialBlend::Add => wgpu::BlendState {
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color: wgpu::BlendComponent {
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src_factor: wgpu::BlendFactor::One,
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dst_factor: wgpu::BlendFactor::One,
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operation: wgpu::BlendOperation::Add,
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},
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alpha: wgpu::BlendComponent::OVER,
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},
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TrivialBlend::Subtract => wgpu::BlendState {
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color: wgpu::BlendComponent {
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src_factor: wgpu::BlendFactor::One,
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dst_factor: wgpu::BlendFactor::One,
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operation: wgpu::BlendOperation::ReverseSubtract,
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},
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alpha: wgpu::BlendComponent::OVER,
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},
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}
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}
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}
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