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

// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

use std::error;
use std::fmt;
use std::sync::Arc;

use buffer::BufferAccess;
use format::Format;
use pipeline::vertex::VertexMemberTy;
use vk;
use SafeDeref;

/// Trait for types that describe the definition of the vertex input used by a graphics pipeline.
pub unsafe trait VertexDefinition<I>:
    VertexSource<Vec<Arc<dyn BufferAccess + Send + Sync>>>
{
    /// Iterator that returns the offset, the stride (in bytes) and input rate of each buffer.
    type BuffersIter: ExactSizeIterator<Item = (u32, usize, InputRate)>;
    /// Iterator that returns the attribute location, buffer id, and infos.
    type AttribsIter: ExactSizeIterator<Item = (u32, u32, AttributeInfo)>;

    /// Builds the vertex definition to use to link this definition to a vertex shader's input
    /// interface.
    fn definition(
        &self,
        interface: &I,
    ) -> Result<(Self::BuffersIter, Self::AttribsIter), IncompatibleVertexDefinitionError>;
}

unsafe impl<I, T> VertexDefinition<I> for T
where
    T: SafeDeref,
    T::Target: VertexDefinition<I>,
{
    type BuffersIter = <T::Target as VertexDefinition<I>>::BuffersIter;
    type AttribsIter = <T::Target as VertexDefinition<I>>::AttribsIter;

    #[inline]
    fn definition(
        &self,
        interface: &I,
    ) -> Result<(Self::BuffersIter, Self::AttribsIter), IncompatibleVertexDefinitionError> {
        (**self).definition(interface)
    }
}

/// How the vertex source should be unrolled.
#[derive(Copy, Clone, Debug)]
#[repr(u32)]
pub enum InputRate {
    /// Each element of the source corresponds to a vertex.
    Vertex = vk::VERTEX_INPUT_RATE_VERTEX,
    /// Each element of the source corresponds to an instance.
    Instance = vk::VERTEX_INPUT_RATE_INSTANCE,
}

/// Information about a single attribute within a vertex.
/// TODO: change that API
#[derive(Copy, Clone, Debug)]
pub struct AttributeInfo {
    /// Number of bytes between the start of a vertex and the location of attribute.
    pub offset: usize,
    /// VertexMember type of the attribute.
    pub format: Format,
}

/// Error that can happen when the vertex definition doesn't match the input of the vertex shader.
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum IncompatibleVertexDefinitionError {
    /// An attribute of the vertex shader is missing in the vertex source.
    MissingAttribute {
        /// Name of the missing attribute.
        attribute: String,
    },

    /// The format of an attribute does not match.
    FormatMismatch {
        /// Name of the attribute.
        attribute: String,
        /// The format in the vertex shader.
        shader: (Format, usize),
        /// The format in the vertex definition.
        definition: (VertexMemberTy, usize),
    },
}

impl error::Error for IncompatibleVertexDefinitionError {}

impl fmt::Display for IncompatibleVertexDefinitionError {
    #[inline]
    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        write!(
            fmt,
            "{}",
            match *self {
                IncompatibleVertexDefinitionError::MissingAttribute { .. } =>
                    "an attribute is missing",
                IncompatibleVertexDefinitionError::FormatMismatch { .. } => {
                    "the format of an attribute does not match"
                }
            }
        )
    }
}

/// Extension trait of `VertexDefinition`. The `L` parameter is an acceptable vertex source for this
/// vertex definition.
pub unsafe trait VertexSource<L> {
    /// Checks and returns the list of buffers with offsets, number of vertices and number of instances.
    // TODO: return error if problem
    // TODO: better than a Vec
    // TODO: return a struct instead
    fn decode(&self, L) -> (Vec<Box<dyn BufferAccess + Send + Sync>>, usize, usize);
}

unsafe impl<L, T> VertexSource<L> for T
where
    T: SafeDeref,
    T::Target: VertexSource<L>,
{
    #[inline]
    fn decode(&self, list: L) -> (Vec<Box<dyn BufferAccess + Send + Sync>>, usize, usize) {
        (**self).decode(list)
    }
}