mewgpu 3.7.3

//! Wrapper over a
//! [`wgpu::Pipeline`](https://docs.rs/wgpu/latest/wgpu/struct.Pipeline.html).
//!
//! See [`pipeline`] for details.


use std::{
    any::TypeId,
    marker::PhantomData,
    ops::Deref,
};
use crate::wgpu;


#[cfg(all(feature = "wgpu-29", not(feature = "wgpu-30")))]
#[doc(hidden)]
#[macro_export]
macro_rules! vertices {
    ($struct:ty, $($vertexty:ty),*) => {
        use ::std::sync::LazyLock;
        static VERTICES: LazyLock<<$struct as $crate::pipeline::MewPipeline>::VertexArray<$crate::wgpu::VertexBufferLayout<'static>>> = LazyLock::new(|| {
            #[allow(unused_imports)]
            use $crate::vertexstruct::MewVertexStruct;
            [ $( <$vertexty>::vertex_layout(), )* ]
        });
    };
}

#[cfg(feature = "wgpu-30")]
#[doc(hidden)]
#[macro_export]
macro_rules! vertices {
    ($struct:ty, $($vertexty:ty),*) => {
        use ::std::sync::LazyLock;
        static VERTICES: LazyLock<<$struct as $crate::pipeline::MewPipeline>::VertexArray<Option<$crate::wgpu::VertexBufferLayout<'static>>>> = LazyLock::new(|| {
            #[allow(unused_imports)]
            use $crate::vertexstruct::MewVertexStruct;
            [ $( Some(<$vertexty>::vertex_layout()), )* ]
        });
    };
}

#[cfg(any(feature = "wgpu-29", feature = "wgpu-30"))]
pub use vertices;


/// Define a render pipeline, with internal bind group and vertex types.
///
/// `bind_group` needs to be a numbered list of [`crate::bindgroup`] types,
/// mirrored in the shader.
///
/// `vertex_types` must be another numbered list of [`crate::vertexstruct`]s.
/// These are the allowed types of vertex formats for the shader (I'm not sure
/// why you would have multiple entries but _wgpu_ allows it so whatever).
///
/// `fragment_targets` is in the format
/// <code>[wgpu::BlendState](https://docs.rs/wgpu/latest/wgpu/struct.BlendState.html) [wgpu::ColorWrites](https://docs.rs/wgpu/latest/wgpu/struct.ColorWrites.html) as `ANY`/[wgpu::TextureFormat](https://docs.rs/wgpu/latest/wgpu/enum.TextureFormat.html)</code>.
/// The [`wgpu::ColorTargetState`](https://docs.rs/wgpu/latest/wgpu/struct.ColorTargetState.html) will be `Some` if the pipeline is built with
/// the same format specified here, or if it's `ANY` then always `Some` with
/// the format it's built with - otherwise it's a `None` entry in the slice.  
/// (tbh idk what the purpose of having multiple fragment targets is but I assume
/// it's supposed be used something like this)
///
/// `immediate_size` is the length of the
/// [immediate buffer](https://docs.rs/wgpu/latest/wgpu/struct.Features.html#associatedconstant.IMMEDIATES)
/// in the [`wgpu::PipelineLayoutDescriptor`](https://docs.rs/wgpu/latest/wgpu/struct.PipelineLayoutDescriptor.html).
///
/// `depth` is a
/// <code>[wgpu::TextureFormat](https://docs.rs/wgpu/latest/wgpu/enum.TextureFormat.html)</code>
/// to use in the [`wgpu::DepthStencilState`](https://docs.rs/wgpu/latest/wgpu/struct.DepthStencilState.html).
/// Said `DepthStencilState` comes default with `depth_write_enabled = true`,
/// <code>depth_compare = [wgpu::CompareFunction::Less](https://docs.rs/wgpu/latest/wgpu/enum.CompareFunction.html#variant.Less)</code>,
/// and default `stencil` and `bias`.
///
/// `cull` is the cull face, a <code>[wgpu::Face](https://docs.rs/wgpu/latest/wgpu/enum.Face.html)</code>.
///
/// The pipeline comes with some other defaults set (like 0 mipmaps), but there
/// are quite a few things to define, so to simplify the macro I've picked out
/// the most important things. If you really need to change them, copy the
/// source of this macro into your own struct and implement [`MewPipeline`]
/// yourself ~~you lazy bastard~~.
///
///
/// ```
/// pipeline! { Pipeline {
///     bind_groups: [
///         0 => BindGroup,
///         1 => AnotherBindGroup,
///     ],
///     vertex_types: [
///         0 => Vertex,
///     ],
///     fragment_targets: [
///         0 => ALPHA_BLENDING ALL as ANY,
///     ],
///     immediate_size: 0,
///     depth: Depth32Float,  // Omit for None
///     cull: Back,  // Omit for None
/// } }
///
/// let pipeline: Pipeline = render_context.new_pipeline(wgpu::Rgba8Unorm, shader, None, None);
///
/// render_pass.set_pipeline(&pipeline);
/// ```
#[macro_export]
macro_rules! pipeline {
    { $struct:ident { $($key:tt: $val:tt),* $(,)? } } => {
        $crate::pipeline! { @collect $struct {
            bind_groups: [],
            vertex_types: [],
            fragment_targets: [],
            immediate_size: 0,
            depth: None,
            cull: None,
        }; $({$key: $val} )* }
    };

    { @texturefmt $inputfmt:ident, ANY } => {
        Some($inputfmt)
    };
    { @texturefmt $format:ident, $fragmentfmt:ident } => {
        //Some($crate::wgpu::TextureFormat::$fragmentfmt)
        if $inputfmt == $fragmentfmt {
            Some($inputfmt)
        } else {
            None
        }
    };

    { @collect $struct:ident {
            bind_groups: $_:tt,
            vertex_types: $vertextypes:tt,
            fragment_targets: $fragmenttargets:tt,
            immediate_size: $immediate:tt,
            depth: $depth:tt,
            cull: $cull:tt,
        }; {bind_groups: $bindgroups:tt} $($rest:tt)* } => {
            $crate::pipeline! { @collect $struct {
                bind_groups: $bindgroups,
                vertex_types: $vertextypes,
                fragment_targets: $fragmenttargets,
                immediate_size: $immediate,
                depth: $depth,
                cull: $cull,
            }; $($rest)* }
    };
    { @collect $struct:ident {
            bind_groups: $bindgroups:tt,
            vertex_types: $_:tt,
            fragment_targets: $fragmenttargets:tt,
            immediate_size: $immediate:tt,
            depth: $depth:tt,
            cull: $cull:tt,
        }; {vertex_types: $vertextypes:tt} $($rest:tt)* } => {
            $crate::pipeline! { @collect $struct {
                bind_groups: $bindgroups,
                vertex_types: $vertextypes,
                fragment_targets: $fragmenttargets,
                immediate_size: $immediate,
                depth: $depth,
                cull: $cull,
            }; $($rest)* }
    };
    { @collect $struct:ident {
            bind_groups: $bindgroups:tt,
            vertex_types: $vertextypes:tt,
            fragment_targets: $_:tt,
            immediate_size: $immediate:tt,
            depth: $depth:tt,
            cull: $cull:tt,
        }; {fragment_targets: $fragmenttargets:tt} $($rest:tt)* } => {
            $crate::pipeline! { @collect $struct {
                bind_groups: $bindgroups,
                vertex_types: $vertextypes,
                fragment_targets: $fragmenttargets,
                immediate_size: $immediate,
                depth: $depth,
                cull: $cull,
            }; $($rest)* }
    };
    { @collect $struct:ident {
            bind_groups: $bindgroups:tt,
            vertex_types: $vertextypes:tt,
            fragment_targets: $fragmenttargets:tt,
            immediate_size: $_:tt,
            depth: $depth:tt,
            cull: $cull:tt,
        }; {immediate_size: $immediate:tt} $($rest:tt)* } => {
            $crate::pipeline! { @collect $struct {
                bind_groups: $bindgroups,
                vertex_types: $vertextypes,
                fragment_targets: $fragmenttargets,
                immediate_size: $immediate,
                depth: $depth,
                cull: $cull,
            }; $($rest)* }
    };
    { @collect $struct:ident {
            bind_groups: $bindgroups:tt,
            vertex_types: $vertextypes:tt,
            fragment_targets: $fragmenttargets:tt,
            immediate_size: $immediate:tt,
            depth: $_:tt,
            cull: $cull:tt,
        }; {depth: $depth:tt} $($rest:tt)* } => {
            $crate::pipeline! { @collect $struct {
                bind_groups: $bindgroups,
                vertex_types: $vertextypes,
                fragment_targets: $fragmenttargets,
                immediate_size: $immediate,
                depth: (Some($depth)),
                cull: $cull,
            }; $($rest)* }
    };
    { @collect $struct:ident {
            bind_groups: $bindgroups:tt,
            vertex_types: $vertextypes:tt,
            fragment_targets: $fragmenttargets:tt,
            immediate_size: $immediate:tt,
            depth: $depth:tt,
            cull: $_:tt,
        }; {cull: $cull:tt} $($rest:tt)* } => {
            $crate::pipeline! { @collect $struct {
                bind_groups: $bindgroups,
                vertex_types: $vertextypes,
                fragment_targets: $fragmenttargets,
                immediate_size: $immediate,
                depth: $depth,
                cull: (Some($cull)),
            }; $($rest)* }
    };

    { @collect $struct:ident {
        bind_groups: [
            $( $bindgroupnum:tt => $bindgroup:ty ),* $(,)?
        ],
        vertex_types: [
            $( $vertexnum:tt => $vertexty:ty ),* $(,)?
        ],
        fragment_targets: [
            $( $fragmentnum:tt => $blend:ident $mask:ident as $fragmentfmt:ident ),* $(,)?
        ],
        immediate_size: $immediate:expr,
        depth: $depth:expr,
        cull: $cull:expr,
    }; } => {
        #[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
        pub struct $struct {
            pipeline: $crate::wgpu::RenderPipeline,
        }

        impl ::std::ops::Deref for $struct {
            type Target = $crate::wgpu::RenderPipeline;
            fn deref(&self) -> &Self::Target {
                &self.pipeline
            }
        }

        impl $crate::pipeline::MewPipeline for $struct {
            type BindGroupSet = ( $( $bindgroup , )* );
            type BindGroupArray<T> = [T; $crate::len! { $( $bindgroupnum )* }];
            type VertexArray<T> = [T; $crate::len! { $( $vertexnum )* }];
            type FragmentArray<T> = [T; $crate::len! { $( $fragmentnum )* }];

            fn new(pipeline: $crate::wgpu::RenderPipeline) -> Self {
                Self {
                    pipeline,
                }
            }

            fn bind_group_layout_types_array() -> Self::BindGroupArray<(::std::any::TypeId, $crate::wgpu::BindGroupLayoutDescriptor<'static>)> {
                use $crate::bindgroup::MewBindGroup;
                [ $( (
                    ::std::any::TypeId::of::<$bindgroup>(),
                    <$bindgroup>::layout_desc(),
                ), )* ]
            }

            fn map_bind_group_array<'a, A: 'a, B: 'a, F: FnMut(&'a A) -> B>(array: &'a Self::BindGroupArray<A>, f: F) -> Self::BindGroupArray<B> {
                array.each_ref().map(f)
            }

            fn layout_desc<'a>(bind_group_layouts: &'a Self::BindGroupArray<Option<&$crate::wgpu::BindGroupLayout>>) -> $crate::wgpu::PipelineLayoutDescriptor<'a> {
                $crate::wgpu::PipelineLayoutDescriptor {
                    label: Some(concat!(stringify!($struct), " Layout Descriptor")),
                    bind_group_layouts,
                    immediate_size: $immediate,
                }
            }

            fn fragment_targets(surface_fmt: $crate::wgpu::TextureFormat) -> Self::FragmentArray<Option<$crate::wgpu::ColorTargetState>> {
                [ $( $crate::pipeline! { @texturefmt surface_fmt, $fragmentfmt }.map(|format| $crate::wgpu::ColorTargetState {
                    format,
                    blend: Some($crate::wgpu::BlendState::$blend),
                    write_mask: $crate::wgpu::ColorWrites::$mask,
                }), )* ]
            }

            fn pipeline_desc<'a>(
                layout: &'a $crate::pipeline::MewPipelineLayout<Self>,
                shader: &'a $crate::wgpu::ShaderModule,
                vertex_entry: Option<&'a str>,
                fragment_entry: Option<&'a str>,
                fragment_targets: &'a Self::FragmentArray<Option<$crate::wgpu::ColorTargetState>>,
            ) -> $crate::wgpu::RenderPipelineDescriptor<'a> {
                #[allow(unused_imports)]
                use $crate::wgpu::{
                    Face::*,
                    TextureFormat::*,
                };

                $crate::pipeline::vertices!($struct, $($vertexty),*);

                $crate::wgpu::RenderPipelineDescriptor {
                    label: Some(concat!(stringify!($struct), " Descriptor")),
                    layout: Some(layout),
                    vertex: $crate::wgpu::VertexState {
                        module: shader,
                        entry_point: vertex_entry,
                        compilation_options: Default::default(),
                        buffers: &*VERTICES,
                    },
                    fragment: Some($crate::wgpu::FragmentState {
                        module: shader,
                        entry_point: fragment_entry,
                        compilation_options: Default::default(),
                        targets: fragment_targets,
                    }),
                    primitive: $crate::wgpu::PrimitiveState {
                        topology: $crate::wgpu::PrimitiveTopology::TriangleList,
                        strip_index_format: None,
                        front_face: $crate::wgpu::FrontFace::Ccw,
                        cull_mode: $cull,
                        polygon_mode: $crate::wgpu::PolygonMode::Fill,
                        unclipped_depth: false,
                        conservative: false,
                    },
                    depth_stencil: $depth.map(|format| $crate::wgpu::DepthStencilState {
                        format,
                        depth_write_enabled: Some(true),
                        depth_compare: Some($crate::wgpu::CompareFunction::Less),
                        stencil: Default::default(),
                        bias: Default::default(),
                    }),
                    multisample: $crate::wgpu::MultisampleState {
                        count: 1,
                        mask: !0,
                        // Must be false for transparency to not dither
                        alpha_to_coverage_enabled: false,
                    },
                    multiview_mask: None,
                    cache: None,
                }
            }
        }
    };
}
pub use pipeline;


/// Trait for pipeline wrapper types, to get layouts and descriptors about the
/// inner pipeline.
///
/// The number of internal bind groups must be defined in the generic parameter,
/// because associated `const`s are "uNsTAbLe", apparently.
///
/// Ideally, avoid using this directly - it's horribly designed, so just look
/// away and use the [`pipeline`] macro.
pub trait MewPipeline {
    /// A tuple of the pipeline's internal bind groups (max of 4).
    type BindGroupSet;
    /// A generic array the length of the number of bind groups
    /// (literally `[T; N]`).
    type BindGroupArray<T>;
    /// A generic array the length of the number of vertex types
    /// (literally `[T; N]`).
    type VertexArray<T>;
    /// A generic array the length of the number of fragment targets
    /// (literally `[T; N]`).
    type FragmentArray<T>;

    /// Build this pipeline type from a
    /// [`wgpu::RenderPipeline`](https://docs.rs/wgpu/latest/wgpu/struct.RenderPipeline.html).
    fn new(pipeline: wgpu::RenderPipeline) -> Self;

    /// Get an array of the internal bind groups' type IDs &
    /// [`wgpu::BindGroupLayoutDescriptor`](https://docs.rs/wgpu/latest/wgpu/struct.BindGroupLayoutDescriptor.html)s.
    fn bind_group_layout_types_array() -> Self::BindGroupArray<(TypeId, wgpu::BindGroupLayoutDescriptor<'static>)>;
    /// Run a closure on each element in an array the lenth of the number of bind groups ([`Self::BindGroupArray`]).
    ///
    /// This is only necessary because of a limitation with Rust's generics in traits.
    /// Take a look at the above [`Self::BindGroupArray`], [`Self::VertexArray`], &
    /// [`Self::FragmentArray`] - the compiler has no way of knowing those are just
    /// supposed to be primitive `array`s with a generic `const` length. Ideally I'd
    /// just specify a `const usize` in the trait, but nooOOoo you're not allowed to
    /// do that, so I have to make do with this.
    ///
    /// Primitive `array`s also aren't distinguishable by any sort of trait to narrow down
    /// the type (really all I need is a [`std::iter::Map`]), but I don't want to import any
    /// bloat libraries & writing something is probably overkill for how I'm using it
    /// (purely internally).
    fn map_bind_group_array<'a, A: 'a, B: 'a, F: FnMut(&'a A) -> B>(array: &'a Self::BindGroupArray<A>, f: F) -> Self::BindGroupArray<B>;

    /// Get the [`wgpu::PipelineLayoutDescriptor`](https://docs.rs/wgpu/latest/wgpu/struct.PipelineLayoutDescriptor.html)
    /// to build the pipeline. Requires an array of references of its internal bind groups'
    /// <code>&[BindGroupLayout](https://docs.rs/wgpu/latest/wgpu/struct.BindGroupLayout.html)</code>s
    /// which are mappable from [`Self::bind_group_layout_types_array`].  
    /// Need to do it separately like this because `const fn`s in traits are "uNsTAbLe",
    /// apparently, and lifetimes exist.
    fn layout_desc<'a>(bind_group_layouts: &'a Self::BindGroupArray<Option<&wgpu::BindGroupLayout>>) -> wgpu::PipelineLayoutDescriptor<'a>;

    /// Get an array of
    /// <code>Option<[wgpu::ColorTargetState](https://docs.rs/wgpu/latest/wgpu/struct.ColorTargetState.html)></code>s.
    ///
    /// If a specific colour format was specified for this state in the macro, it will
    /// only be `Some` if the passed surface
    /// [`wgpu::TextureFormat`](https://docs.rs/wgpu/latest/wgpu/enum.TextureFormat.html)
    /// matches. If it was set to `ANY`, then for that entry it will always return
    /// `Some` with the passed-in format.
    ///
    /// tbh I'm not sure if this is how it's intended to be used but yolo
    fn fragment_targets(surface_fmt: wgpu::TextureFormat) -> Self::FragmentArray<Option<wgpu::ColorTargetState>>;

    /// Get a [`wgpu::RenderPipelineDescriptor`](https://docs.rs/wgpu/latest/wgpu/struct.RenderPipelineDescriptor.html)
    /// from a layout for this specific type of pipeline, plus a shader and the
    /// fragment targets array from [`Self::fragment_targets`].
    fn pipeline_desc<'a>(
        layout: &'a MewPipelineLayout<Self>,
        shader: &'a wgpu::ShaderModule,
        vertex_entry: Option<&'a str>,
        fragment_entry: Option<&'a str>,
        fragment_targets: &'a Self::FragmentArray<Option<wgpu::ColorTargetState>>,
    ) -> wgpu::RenderPipelineDescriptor<'a>;
}


/// Wrapper for the layout of some pipeline, so that the compiler will scream
/// at you if you mix up pipelines.
pub struct MewPipelineLayout<PIPE: ?Sized> {
    layout: wgpu::PipelineLayout,
    _marker: PhantomData<PIPE>,
}
impl<PIPE: ?Sized> Deref for MewPipelineLayout<PIPE> {
    type Target = wgpu::PipelineLayout;
    fn deref(&self) -> &Self::Target {
        &self.layout
    }
}
impl<PIPE: ?Sized> MewPipelineLayout<PIPE> {
    /// Wrap a [`wgpu::PipelineLayout`](https://docs.rs/wgpu/latest/wgpu/struct.PipelineLayout.html).
    pub fn new(layout: wgpu::PipelineLayout) -> Self {
        Self {
            layout,
            _marker: PhantomData,
        }
    }
}