rustial-renderer-wgpu 0.0.1

//! Fill-extrusion render pipeline with directional lighting and shadow mapping.

use crate::gpu::depth::DEPTH_FORMAT;
use crate::gpu::fill_extrusion_vertex::FillExtrusionVertex;
use crate::pipeline::uniforms::ViewProjUniform;

/// The fill-extrusion rendering pipeline (lit 3-D prisms with shadows).
pub struct FillExtrusionPipeline {
    /// Render pipeline configured for lit fill-extrusion drawing.
    pub pipeline: wgpu::RenderPipeline,
    /// Bind group layout for frame-global view-projection uniforms (group 0).
    pub uniform_bind_group_layout: wgpu::BindGroupLayout,
    /// Bind group layout for shadow params + shadow maps (group 1).
    pub shadow_bind_group_layout: wgpu::BindGroupLayout,
}

impl FillExtrusionPipeline {
    /// Create the fill-extrusion pipeline.
    pub fn new(device: &wgpu::Device, surface_format: wgpu::TextureFormat) -> Self {
        let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
            label: Some("fill_extrusion_shader"),
            source: wgpu::ShaderSource::Wgsl(include_str!("../shaders/fill_extrusion.wgsl").into()),
        });

        let uniform_bind_group_layout =
            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
                label: Some("fill_extrusion_uniform_bgl"),
                entries: &[wgpu::BindGroupLayoutEntry {
                    binding: 0,
                    visibility: wgpu::ShaderStages::VERTEX_FRAGMENT,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Uniform,
                        has_dynamic_offset: false,
                        min_binding_size: wgpu::BufferSize::new(
                            std::mem::size_of::<ViewProjUniform>() as u64,
                        ),
                    },
                    count: None,
                }],
            });

        let shadow_bind_group_layout = Self::shadow_bind_group_layout(device);

        let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
            label: Some("fill_extrusion_pipeline_layout"),
            bind_group_layouts: &[&uniform_bind_group_layout, &shadow_bind_group_layout],
            push_constant_ranges: &[],
        });

        let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
            label: Some("fill_extrusion_pipeline"),
            layout: Some(&pipeline_layout),
            vertex: wgpu::VertexState {
                module: &shader,
                entry_point: Some("vs_main"),
                buffers: &[FillExtrusionVertex::layout()],
                compilation_options: wgpu::PipelineCompilationOptions::default(),
            },
            fragment: Some(wgpu::FragmentState {
                module: &shader,
                entry_point: Some("fs_main"),
                targets: &[Some(wgpu::ColorTargetState {
                    format: surface_format,
                    blend: Some(wgpu::BlendState::ALPHA_BLENDING),
                    write_mask: wgpu::ColorWrites::ALL,
                })],
                compilation_options: wgpu::PipelineCompilationOptions::default(),
            }),
            primitive: wgpu::PrimitiveState {
                topology: wgpu::PrimitiveTopology::TriangleList,
                front_face: wgpu::FrontFace::Ccw,
                cull_mode: Some(wgpu::Face::Back),
                ..Default::default()
            },
            depth_stencil: Some(wgpu::DepthStencilState {
                format: DEPTH_FORMAT,
                depth_write_enabled: true,
                depth_compare: wgpu::CompareFunction::Less,
                stencil: wgpu::StencilState::default(),
                bias: wgpu::DepthBiasState::default(),
            }),
            multisample: wgpu::MultisampleState::default(),
            multiview: None,
            cache: None,
        });

        Self {
            pipeline,
            uniform_bind_group_layout,
            shadow_bind_group_layout,
        }
    }

    /// Create the shadow bind group layout shared by fill-extrusion receivers.
    ///
    /// Group 1:
    /// - binding 0: `ShadowParams` uniform (2 mat4 + 2 vec4 = 160 bytes)
    /// - binding 1: `texture_depth_2d` (cascade 0)
    /// - binding 2: `texture_depth_2d` (cascade 1)
    /// - binding 3: `sampler_comparison`
    pub fn shadow_bind_group_layout(device: &wgpu::Device) -> wgpu::BindGroupLayout {
        device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
            label: Some("fill_extrusion_shadow_bgl"),
            entries: &[
                wgpu::BindGroupLayoutEntry {
                    binding: 0,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Uniform,
                        has_dynamic_offset: false,
                        min_binding_size: wgpu::BufferSize::new(160),
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 1,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Depth,
                        view_dimension: wgpu::TextureViewDimension::D2,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 2,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Depth,
                        view_dimension: wgpu::TextureViewDimension::D2,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 3,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Comparison),
                    count: None,
                },
            ],
        })
    }
}