use std::mem::size_of;
use bytemuck::{Pod, Zeroable};
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub struct InstanceId(pub(crate) usize);
#[repr(C)]
#[derive(Copy, Clone, Debug, PartialEq, Pod, Zeroable)]
pub struct Instance {
/// Position on the screen
pub position: [f32; 2],
/// Relative size
pub size: [f32; 2],
/// The location of the texture in the texture atlas
pub texture_coordinates: [f32; 2],
/// The size of the sprite's texture
pub texture_size: [f32; 2],
/// The index of the texture atlas to use
pub texture_atlas_index: u32,
/// Rotation, in radians
pub rotation: f32,
/// z-index
pub z_index: u32,
}
impl Default for Instance {
fn default() -> Self {
Self {
position: [0.0; 2],
size: [1.0; 2],
rotation: 0.0,
z_index: 0,
texture_coordinates: [0.0; 2],
texture_size: [1.0; 2],
texture_atlas_index: 0,
}
}
}
impl Instance {
// whenever this is updated, please also update `sprite.wgsl`
const ATTRIBUTES: [wgpu::VertexAttribute; 7] = wgpu::vertex_attr_array![
1 => Float32x2, 2 => Float32x2, 3 => Float32x2, 4 => Float32x2,
5 => Uint32, 6 => Float32, 7 => Uint32
];
pub(crate) fn desc<'a>() -> wgpu::VertexBufferLayout<'a> {
// make sure these two don't conflict
debug_assert_eq!(
Self::ATTRIBUTES[0].shader_location as usize,
crate::Vertex::ATTRIBUTES.len()
);
wgpu::VertexBufferLayout {
array_stride: size_of::<Self>() as wgpu::BufferAddress,
step_mode: wgpu::VertexStepMode::Instance,
attributes: &Self::ATTRIBUTES,
}
}
}
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