vert 0.1.1

The 51th Rust Game Engine, to write the 6th Game in Rust
Documentation 
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use wgpu::{PushConstantRange, ShaderStages};

use crate::{
    elements::texture::rgba_bind_group_layout,
    modules::{renderer::SURFACE_COLOR_FORMAT, GraphicsContext, Renderer},
    Dependencies, Handle, Module,
};

use super::{PostProcessingEffect, ScreenVertexShader};

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ToneMappingSettings {
    Disabled,
    Aces,
}

impl ToneMappingSettings {
    fn to_push_const(&self) -> u32 {
        match self {
            ToneMappingSettings::Disabled => 0,
            ToneMappingSettings::Aces => 1,
        }
    }
}

pub struct AcesToneMapping {
    pipeline: wgpu::RenderPipeline,
    settings: ToneMappingSettings,
    deps: Deps,
}

#[derive(Debug, Dependencies)]
pub struct Deps {
    renderer: Handle<Renderer>,
    ctx: Handle<GraphicsContext>,
}
impl Module for AcesToneMapping {
    type Config = ToneMappingSettings;
    type Dependencies = Deps;

    fn new(settings: Self::Config, deps: Self::Dependencies) -> anyhow::Result<Self> {
        let pipeline = create_pipeline(
            include_str!("tonemapping.wgsl"),
            &deps.ctx.device,
            &deps.renderer.screen_vertex_shader,
        );

        Ok(Self {
            pipeline,
            settings,
            deps,
        })
    }

    fn intialize(handle: Handle<Self>) -> anyhow::Result<()> {
        let mut renderer = handle.deps.renderer;
        renderer.register_tonemapping_effect(handle);
        Ok(())
    }
}

impl AcesToneMapping {
    pub fn settings_mut(&mut self) -> &mut ToneMappingSettings {
        &mut self.settings
    }
}

impl PostProcessingEffect for AcesToneMapping {
    fn apply<'e>(
        &'e mut self,
        encoder: &'e mut wgpu::CommandEncoder,
        input_texture: &wgpu::BindGroup,
        output_texture: &wgpu::TextureView,
    ) {
        let mut tone_mapping_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
            label: Some("AcesToneMapping"),
            color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                view: output_texture,
                resolve_target: None,
                ops: wgpu::Operations {
                    load: wgpu::LoadOp::Load,
                    store: wgpu::StoreOp::Store,
                },
            })],
            depth_stencil_attachment: None,
            occlusion_query_set: None,
            timestamp_writes: None,
        });

        tone_mapping_pass.set_pipeline(&self.pipeline);
        let tone_map = self.settings.to_push_const();
        tone_mapping_pass.set_push_constants(
            ShaderStages::FRAGMENT,
            0,
            bytemuck::cast_slice(&[tone_map]),
        );

        tone_mapping_pass.set_bind_group(0, input_texture, &[]);
        tone_mapping_pass.draw(0..3, 0..1);
    }
}

fn create_pipeline(
    shader_wgsl: &str,
    device: &wgpu::Device,
    screen_vertex_shader: &ScreenVertexShader,
) -> wgpu::RenderPipeline {
    let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
        label: Some("Tonemapping Shader"),
        source: wgpu::ShaderSource::Wgsl(std::borrow::Cow::Borrowed(shader_wgsl)),
    });
    let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
        label: None,
        bind_group_layouts: &[rgba_bind_group_layout(device)],
        push_constant_ranges: &[PushConstantRange {
            stages: ShaderStages::FRAGMENT,
            range: 0..16,
        }],
    });

    let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
        label: Some(&format!("{:?}", shader)),
        layout: Some(&pipeline_layout),
        vertex: screen_vertex_shader.vertex_state(),
        fragment: Some(wgpu::FragmentState {
            module: &shader,
            entry_point: "fs_main",
            targets: &[Some(wgpu::ColorTargetState {
                format: SURFACE_COLOR_FORMAT,
                blend: None,
                write_mask: wgpu::ColorWrites::ALL,
            })],
        }),
        primitive: wgpu::PrimitiveState {
            topology: wgpu::PrimitiveTopology::TriangleList,
            strip_index_format: None,
            front_face: wgpu::FrontFace::Ccw,
            cull_mode: Some(wgpu::Face::Back),
            polygon_mode: wgpu::PolygonMode::Fill,
            unclipped_depth: false,
            conservative: false,
        },
        depth_stencil: None,
        multisample: wgpu::MultisampleState::default(),
        multiview: None,
    });

    pipeline
}