1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170

use crate::*;

pub struct PostProcessingEffect {
    pub name: String,
    pub enabled: bool,
    pub render_texture: Texture,
    pub bind_group: wgpu::BindGroup,
    pub pipeline: wgpu::RenderPipeline,
}

impl PostProcessingEffect {
    pub fn new_with_mip(
        name: String,
        device: &wgpu::Device,
        bind_group_layouts: &[&wgpu::BindGroupLayout],
        config: &wgpu::SurfaceConfiguration,
        format: wgpu::TextureFormat,
        shader: Shader,
        mip_level_count: u32,
        blend: wgpu::BlendState,
    ) -> Self {
        let render_texture = Texture::create_scaled_mip_surface_texture(
            device,
            config,
            format,
            1.0,
            mip_level_count,
            &name,
        );

        let bind_group = device.simple_bind_group(
            &format!("{} Post Processing Bind Group", name),
            &render_texture,
            bind_group_layouts[0],
        );

        let pipeline = create_post_processing_pipeline(
            &name,
            device,
            format,
            bind_group_layouts,
            shader,
            blend,
        );

        Self { name, enabled: true, render_texture, bind_group, pipeline }
    }

    pub fn new(
        name: String,
        device: &wgpu::Device,
        bind_group_layouts: &[&wgpu::BindGroupLayout],
        config: &wgpu::SurfaceConfiguration,
        format: wgpu::TextureFormat,
        shader: Shader,
    ) -> Self {
        Self::new_with_mip(
            name,
            device,
            bind_group_layouts,
            config,
            format,
            shader,
            1,
            wgpu::BlendState::REPLACE,
        )
    }
}

pub fn create_post_processing_pipeline(
    name: &str,
    device: &wgpu::Device,
    format: wgpu::TextureFormat,
    bind_group_layouts: &[&wgpu::BindGroupLayout],
    shader: Shader,
    blend: wgpu::BlendState,
) -> wgpu::RenderPipeline {
    let shader = device.create_shader_module(shader.to_wgpu());

    let pipeline_layout =
        device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
            label: Some(&format!("{} Post Processing Pipeline Layout", name)),
            bind_group_layouts,
            push_constant_ranges: &[],
        });

    device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
        label: Some(&format!("{} Post Processing Pipeline", name)),
        layout: Some(&pipeline_layout),
        vertex: wgpu::VertexState {
            module: &shader,
            entry_point: "vs_main",
            buffers: &[],
        },
        fragment: Some(wgpu::FragmentState {
            module: &shader,
            entry_point: "fs_main",
            targets: &[Some(wgpu::ColorTargetState {
                format,
                blend: Some(blend),
                write_mask: wgpu::ColorWrites::ALL,
            })],
        }),
        primitive: wgpu::PrimitiveState {
            topology: wgpu::PrimitiveTopology::TriangleList,
            strip_index_format: None,
            front_face: wgpu::FrontFace::Ccw,
            cull_mode: None,
            unclipped_depth: false,
            polygon_mode: wgpu::PolygonMode::Fill,
            conservative: false,
        },
        depth_stencil: None,
        multisample: wgpu::MultisampleState {
            count: 1,
            mask: !0,
            alpha_to_coverage_enabled: false,
        },
        multiview: None,
    })
}

pub fn draw_post_processing_output(
    name: &str,
    encoder: &mut wgpu::CommandEncoder,
    post_processing_pipeline: &wgpu::RenderPipeline,
    post_processing_bind_group: &wgpu::BindGroup,
    lighting_params_bind_group: &wgpu::BindGroup,
    target_view: &wgpu::TextureView,
    should_clear: bool,
    blend_constant: Option<f64>,
) {
    let mut render_pass =
        encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
            label: Some(&format!("{} Post Processing Render Pass", name)),
            color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                view: target_view,
                resolve_target: None,
                ops: wgpu::Operations {
                    load: if should_clear {
                        wgpu::LoadOp::Clear(wgpu::Color {
                            r: 0.0,
                            g: 0.0,
                            b: 0.0,
                            a: 1.0,
                        })
                    } else {
                        wgpu::LoadOp::Load
                    },
                    store: true,
                },
            })],
            depth_stencil_attachment: None,
        });

    render_pass.set_pipeline(post_processing_pipeline);
    render_pass.set_bind_group(0, post_processing_bind_group, &[]);
    render_pass.set_bind_group(1, lighting_params_bind_group, &[]);

    if let Some(blend) = blend_constant {
        render_pass.set_blend_constant(wgpu::Color {
            r: blend,
            g: blend,
            b: blend,
            a: 1.0,
        });
    }

    render_pass.draw(0..3, 0..1);
}