learn-wgpu/code/beginner/tutorial8-depth/src/texture.rs

use image::GenericImageView;


pub struct Texture {
    pub texture: wgpu::Texture,
    pub view: wgpu::TextureView,
    pub sampler: wgpu::Sampler,
}

impl Texture {
    pub const DEPTH_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Depth32Float;

    pub fn create_depth_texture(device: &wgpu::Device, sc_desc: &wgpu::SwapChainDescriptor) -> Self {
        let desc = wgpu::TextureDescriptor {
            format: Self::DEPTH_FORMAT,
            usage: wgpu::TextureUsage::OUTPUT_ATTACHMENT,
            ..sc_desc.to_texture_desc()
        };
        let texture = device.create_texture(&desc);

        let view = texture.create_default_view();
        let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
            address_mode_u: wgpu::AddressMode::ClampToEdge,
            address_mode_v: wgpu::AddressMode::ClampToEdge,
            address_mode_w: wgpu::AddressMode::ClampToEdge,
            mag_filter: wgpu::FilterMode::Linear,
            min_filter: wgpu::FilterMode::Nearest,
            mipmap_filter: wgpu::FilterMode::Nearest,
            lod_min_clamp: -100.0,
            lod_max_clamp: 100.0,
            compare_function: wgpu::CompareFunction::Always,
        });

        Self { texture, view, sampler }
    }

    pub fn from_bytes(device: &wgpu::Device, bytes: &[u8]) -> Result<(Self, wgpu::CommandBuffer), failure::Error> {
        let img = image::load_from_memory(bytes)?;
        Self::from_image(device, &img)
    }

    pub fn from_image(device: &wgpu::Device, img: &image::DynamicImage) -> Result<(Self, wgpu::CommandBuffer), failure::Error> {
        let rgba = img.as_rgba8().unwrap();
        let dimensions = img.dimensions();

        let size = wgpu::Extent3d {
            width: dimensions.0,
            height: dimensions.1,
            depth: 1,
        };
        let texture = device.create_texture(&wgpu::TextureDescriptor {
            size,
            array_layer_count: 1,
            mip_level_count: 1,
            sample_count: 1,
            dimension: wgpu::TextureDimension::D2,
            format: wgpu::TextureFormat::Rgba8UnormSrgb,
            usage: wgpu::TextureUsage::SAMPLED | wgpu::TextureUsage::COPY_DST,
        });

        let buffer = device
            .create_buffer_mapped(rgba.len(), wgpu::BufferUsage::COPY_SRC)
            .fill_from_slice(&rgba);

        let mut encoder = device.create_command_encoder(&Default::default());

        encoder.copy_buffer_to_texture(
            wgpu::BufferCopyView {
                buffer: &buffer,
                offset: 0,
                row_pitch: 4 * dimensions.0,
                image_height: dimensions.1,
            }, 
            wgpu::TextureCopyView {
                texture: &texture,
                mip_level: 0,
                array_layer: 0,
                origin: wgpu::Origin3d::ZERO,
            }, 
            size,
        );

        let cmd_buffer = encoder.finish();

        let view = texture.create_default_view();
        let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
            address_mode_u: wgpu::AddressMode::ClampToEdge,
            address_mode_v: wgpu::AddressMode::ClampToEdge,
            address_mode_w: wgpu::AddressMode::ClampToEdge,
            mag_filter: wgpu::FilterMode::Linear,
            min_filter: wgpu::FilterMode::Nearest,
            mipmap_filter: wgpu::FilterMode::Nearest,
            lod_min_clamp: -100.0,
            lod_max_clamp: 100.0,
            compare_function: wgpu::CompareFunction::Always,
        });
        
        Ok((Self { texture, view, sampler }, cmd_buffer))
    }
}