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

//!  Helper abstraction for per-image uniform submission.
use crate::{
    rendy::{
        command::RenderPassEncoder,
        factory::Factory,
        hal::{self, device::Device},
        memory::{MappedRange, Write},
        resource::{
            Buffer, BufferInfo, DescriptorSet, DescriptorSetLayout, Escape, Handle as RendyHandle,
        },
    },
    types::Backend,
    util,
};
use core::marker::PhantomData;
use glsl_layout::AsStd140;

/// Provides per-image abstraction for an arbitrary `DescriptorSet`.
#[derive(Debug)]
pub struct DynamicUniform<B: Backend, T: AsStd140>
where
    T::Std140: Sized,
{
    layout: RendyHandle<DescriptorSetLayout<B>>,
    per_image: Vec<PerImageDynamicUniform<B, T>>,
}

#[derive(Debug)]
struct PerImageDynamicUniform<B: Backend, T: AsStd140>
where
    T::Std140: Sized,
{
    buffer: Escape<Buffer<B>>,
    set: Escape<DescriptorSet<B>>,
    marker: PhantomData<T>,
}

impl<B: Backend, T: AsStd140> DynamicUniform<B, T>
where
    T::Std140: Sized,
{
    /// Create a new `DynamicUniform`, allocating descriptor set memory using the provided `Factory`
    /// Allocate to the supplied shader.
    pub fn new(
        factory: &Factory<B>,
        flags: hal::pso::ShaderStageFlags,
    ) -> Result<Self, failure::Error> {
        Ok(Self {
            layout: factory
                .create_descriptor_set_layout(util::set_layout_bindings(Some((
                    1,
                    hal::pso::DescriptorType::UniformBuffer,
                    flags,
                ))))?
                .into(),
            per_image: Vec::new(),
        })
    }

    /// Returns the `DescriptSetLayout` for this set.
    pub fn raw_layout(&self) -> &B::DescriptorSetLayout {
        self.layout.raw()
    }

    /// Write `T` to this descriptor set memory
    pub fn write(&mut self, factory: &Factory<B>, index: usize, item: T::Std140) -> bool {
        let mut changed = false;
        let this_image = {
            while self.per_image.len() <= index {
                self.per_image
                    .push(PerImageDynamicUniform::new(factory, &self.layout));
                changed = true;
            }
            &mut self.per_image[index]
        };

        let mut mapped = this_image.map(factory);
        let mut writer = unsafe {
            mapped
                .write::<u8>(factory.device(), 0..std::mem::size_of::<T::Std140>() as u64)
                .unwrap()
        };
        let slice = unsafe { writer.slice() };

        slice.copy_from_slice(util::slice_as_bytes(&[item]));
        changed
    }

    /// Bind this descriptor set
    #[inline]
    pub fn bind(
        &self,
        index: usize,
        pipeline_layout: &B::PipelineLayout,
        binding_id: u32,
        encoder: &mut RenderPassEncoder<'_, B>,
    ) {
        self.per_image[index].bind(pipeline_layout, binding_id, encoder);
    }
}

impl<B: Backend, T: AsStd140> PerImageDynamicUniform<B, T>
where
    T::Std140: Sized,
{
    fn new(factory: &Factory<B>, layout: &RendyHandle<DescriptorSetLayout<B>>) -> Self {
        let buffer = factory
            .create_buffer(
                BufferInfo {
                    size: std::mem::size_of::<T::Std140>() as u64,
                    usage: hal::buffer::Usage::UNIFORM,
                },
                rendy::memory::Dynamic,
            )
            .unwrap();

        let set = factory.create_descriptor_set(layout.clone()).unwrap();
        let desc = hal::pso::Descriptor::Buffer(buffer.raw(), None..None);
        unsafe {
            let set = set.raw();
            factory.write_descriptor_sets(Some(util::desc_write(set, 0, desc)));
        }
        Self {
            buffer,
            set,
            marker: PhantomData,
        }
    }

    fn map<'a>(&'a mut self, factory: &Factory<B>) -> MappedRange<'a, B> {
        let range = 0..self.buffer.size();
        self.buffer.map(factory.device(), range).unwrap()
    }

    #[inline]
    fn bind(
        &self,
        pipeline_layout: &B::PipelineLayout,
        set_id: u32,
        encoder: &mut RenderPassEncoder<'_, B>,
    ) {
        unsafe {
            encoder.bind_graphics_descriptor_sets(
                pipeline_layout,
                set_id,
                Some(self.set.raw()),
                std::iter::empty(),
            );
        }
    }
}