ruffle/render/wgpu/src/globals.rs

//use super::utils::create_debug_label;
use bytemuck::{Pod, Zeroable};
use wgpu::util::DeviceExt;

#[derive(Debug)]
pub struct Globals {
    bind_group: wgpu::BindGroup,
    _buffer: wgpu::Buffer,
}

#[repr(C)]
#[derive(Copy, Clone, Debug, Pod, Zeroable)]
struct GlobalsUniform {
    view_matrix: [[f32; 4]; 4],
}

impl Globals {
    pub fn new(
        device: &wgpu::Device,
        layout: &wgpu::BindGroupLayout,
        viewport_width: u32,
        viewport_height: u32,
    ) -> Self {
        let temp_label = create_debug_label!("Globals buffer");
        let buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
            label: temp_label.as_deref(),
            contents: bytemuck::cast_slice(&[GlobalsUniform {
                view_matrix: [
                    [1.0 / (viewport_width as f32 / 2.0), 0.0, 0.0, 0.0],
                    [0.0, -1.0 / (viewport_height as f32 / 2.0), 0.0, 0.0],
                    [0.0, 0.0, 1.0, 0.0],
                    [-1.0, 1.0, 0.0, 1.0],
                ],
            }]),
            usage: wgpu::BufferUsages::UNIFORM,
        });

        let bind_group_label = create_debug_label!("Globals bind group");
        let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
            label: bind_group_label.as_deref(),
            layout: &layout,
            entries: &[wgpu::BindGroupEntry {
                binding: 0,
                resource: wgpu::BindingResource::Buffer(wgpu::BufferBinding {
                    buffer: &buffer,
                    offset: 0,
                    size: wgpu::BufferSize::new(std::mem::size_of::<GlobalsUniform>() as u64),
                }),
            }],
        });

        Self {
            bind_group,
            _buffer: buffer,
        }
    }

    pub fn bind_group(&self) -> &wgpu::BindGroup {
        &self.bind_group
    }
}