bevy/bevy_render/src/mesh.rs

321 lines
11 KiB
Rust

use crate::{
pipeline::{
state_descriptors::{IndexFormat, PrimitiveTopology},
VertexBufferDescriptor, VertexFormat,
},
render_resource::AssetBatchers,
Renderable, Vertex,
};
use bevy_asset::{Asset, Handle};
use glam::*;
use legion::prelude::*;
use std::borrow::Cow;
use thiserror::Error;
use zerocopy::AsBytes;
pub const VERTEX_BUFFER_ASSET_INDEX: usize = 0;
pub const INDEX_BUFFER_ASSET_INDEX: usize = 1;
#[derive(Clone, Debug)]
pub enum VertexAttributeValues {
Float(Vec<f32>),
Float2(Vec<[f32; 2]>),
Float3(Vec<[f32; 3]>),
Float4(Vec<[f32; 4]>),
}
impl VertexAttributeValues {
pub fn len(&self) -> usize {
match *self {
VertexAttributeValues::Float(ref values) => values.len(),
VertexAttributeValues::Float2(ref values) => values.len(),
VertexAttributeValues::Float3(ref values) => values.len(),
VertexAttributeValues::Float4(ref values) => values.len(),
}
}
// TODO: add vertex format as parameter here and perform type conversions
pub fn get_bytes(&self) -> &[u8] {
match *self {
VertexAttributeValues::Float(ref values) => values.as_bytes(),
VertexAttributeValues::Float2(ref values) => values.as_bytes(),
VertexAttributeValues::Float3(ref values) => values.as_bytes(),
VertexAttributeValues::Float4(ref values) => values.as_bytes(),
}
}
}
impl From<&VertexAttributeValues> for VertexFormat {
fn from(values: &VertexAttributeValues) -> Self {
match values {
VertexAttributeValues::Float(_) => VertexFormat::Float,
VertexAttributeValues::Float2(_) => VertexFormat::Float2,
VertexAttributeValues::Float3(_) => VertexFormat::Float3,
VertexAttributeValues::Float4(_) => VertexFormat::Float4,
}
}
}
#[derive(Debug)]
pub struct VertexAttribute {
pub name: Cow<'static, str>,
pub values: VertexAttributeValues,
}
impl VertexAttribute {
pub const POSITION: &'static str = "position";
pub const NORMAL: &'static str = "normal";
pub const UV: &'static str = "uv";
pub fn position(positions: Vec<[f32; 3]>) -> Self {
VertexAttribute {
name: Self::POSITION.into(),
values: VertexAttributeValues::Float3(positions),
}
}
pub fn normal(normals: Vec<[f32; 3]>) -> Self {
VertexAttribute {
name: Self::NORMAL.into(),
values: VertexAttributeValues::Float3(normals),
}
}
pub fn uv(uvs: Vec<[f32; 2]>) -> Self {
VertexAttribute {
name: Self::UV.into(),
values: VertexAttributeValues::Float2(uvs),
}
}
}
#[derive(Error, Debug)]
pub enum MeshToVertexBufferError {
#[error("VertexBufferDescriptor requires a VertexBufferAttribute this Mesh does not contain.")]
MissingVertexAttribute { attribute_name: Cow<'static, str> },
#[error("Mesh VertexAttribute VertexFormat is incompatible with VertexBufferDescriptor VertexAttribute VertexFormat.")]
IncompatibleVertexAttributeFormat {
attribute_name: Cow<'static, str>,
descriptor_format: VertexFormat,
mesh_format: VertexFormat,
},
}
#[derive(Debug)]
pub struct Mesh {
pub primitive_topology: PrimitiveTopology,
pub attributes: Vec<VertexAttribute>,
pub indices: Option<Vec<u32>>,
}
impl Mesh {
pub fn new(primitive_topology: PrimitiveTopology) -> Self {
Mesh {
primitive_topology,
attributes: Vec::new(),
indices: None,
}
}
pub fn get_vertex_buffer_bytes(
&self,
vertex_buffer_descriptor: &VertexBufferDescriptor,
) -> Result<Vec<u8>, MeshToVertexBufferError> {
let length = self.attributes.first().map(|a| a.values.len()).unwrap_or(0);
let mut bytes = vec![0; vertex_buffer_descriptor.stride as usize * length];
for vertex_attribute in vertex_buffer_descriptor.attributes.iter() {
match self
.attributes
.iter()
.find(|a| VertexFormat::from(&a.values) == vertex_attribute.format)
{
Some(mesh_attribute) => {
let attribute_bytes = mesh_attribute.values.get_bytes();
let attribute_size = vertex_attribute.format.get_size() as usize;
for (i, vertex_slice) in attribute_bytes.chunks(attribute_size).enumerate() {
let vertex_offset = vertex_buffer_descriptor.stride as usize * i;
let attribute_offset = vertex_offset + vertex_attribute.offset as usize;
bytes[attribute_offset..attribute_offset + attribute_size]
.copy_from_slice(vertex_slice);
}
}
None => {
return Err(MeshToVertexBufferError::MissingVertexAttribute {
attribute_name: vertex_attribute.name.clone(),
})
}
}
}
Ok(bytes)
}
pub fn get_index_buffer_bytes(&self, index_format: IndexFormat) -> Option<Vec<u8>> {
self.indices.as_ref().map(|indices| match index_format {
IndexFormat::Uint16 => indices
.iter()
.map(|i| *i as u16)
.collect::<Vec<u16>>()
.as_bytes()
.to_vec(),
IndexFormat::Uint32 => indices.as_bytes().to_vec(),
})
}
}
pub mod shape {
use super::{Mesh, VertexAttribute};
use crate::pipeline::state_descriptors::PrimitiveTopology;
use glam::*;
pub struct Cube;
impl From<Cube> for Mesh {
fn from(_: Cube) -> Self {
let vertices = &[
// top (0., 0., 1.)
([-1., -1., 1.], [0., 0., 1.], [0., 0.]),
([1., -1., 1.], [0., 0., 1.], [1., 0.]),
([1., 1., 1.], [0., 0., 1.], [1., 1.]),
([-1., 1., 1.], [0., 0., 1.], [0., 1.]),
// bottom (0., 0., -1.)
([-1., 1., -1.], [0., 0., -1.], [1., 0.]),
([1., 1., -1.], [0., 0., -1.], [0., 0.]),
([1., -1., -1.], [0., 0., -1.], [0., 1.]),
([-1., -1., -1.], [0., 0., -1.], [1., 1.]),
// right (1., 0., 0.)
([1., -1., -1.], [1., 0., 0.], [0., 0.]),
([1., 1., -1.], [1., 0., 0.], [1., 0.]),
([1., 1., 1.], [1., 0., 0.], [1., 1.]),
([1., -1., 1.], [1., 0., 0.], [0., 1.]),
// left (-1., 0., 0.)
([-1., -1., 1.], [-1., 0., 0.], [1., 0.]),
([-1., 1., 1.], [-1., 0., 0.], [0., 0.]),
([-1., 1., -1.], [-1., 0., 0.], [0., 1.]),
([-1., -1., -1.], [-1., 0., 0.], [1., 1.]),
// front (0., 1., 0.)
([1., 1., -1.], [0., 1., 0.], [1., 0.]),
([-1., 1., -1.], [0., 1., 0.], [0., 0.]),
([-1., 1., 1.], [0., 1., 0.], [0., 1.]),
([1., 1., 1.], [0., 1., 0.], [1., 1.]),
// back (0., -1., 0.)
([1., -1., 1.], [0., -1., 0.], [0., 0.]),
([-1., -1., 1.], [0., -1., 0.], [1., 0.]),
([-1., -1., -1.], [0., -1., 0.], [1., 1.]),
([1., -1., -1.], [0., -1., 0.], [0., 1.]),
];
let mut positions = Vec::new();
let mut normals = Vec::new();
let mut uvs = Vec::new();
for (position, normal, uv) in vertices.iter() {
positions.push(position.clone());
normals.push(normal.clone());
uvs.push(uv.clone());
}
let indices = vec![
0, 1, 2, 2, 3, 0, // top
4, 5, 6, 6, 7, 4, // bottom
8, 9, 10, 10, 11, 8, // right
12, 13, 14, 14, 15, 12, // left
16, 17, 18, 18, 19, 16, // front
20, 21, 22, 22, 23, 20, // back
];
Mesh {
primitive_topology: PrimitiveTopology::TriangleStrip,
attributes: vec![
VertexAttribute::position(positions),
VertexAttribute::normal(normals),
VertexAttribute::uv(uvs),
],
indices: Some(indices),
}
}
}
pub struct Quad {
pub size: Vec2,
}
impl From<Quad> for Mesh {
fn from(quad: Quad) -> Self {
let extent_x = quad.size.x() / 2.0;
let extent_y = quad.size.y() / 2.0;
let north_west = vec2(-extent_x, extent_y);
let north_east = vec2(extent_x, extent_y);
let south_west = vec2(-extent_x, -extent_y);
let south_east = vec2(extent_x, -extent_y);
let vertices = &[
(
[south_west.x(), south_west.y(), 0.0],
[0.0, 0.0, 1.0],
[0.0, 1.0],
),
(
[north_west.x(), north_west.y(), 0.0],
[0.0, 0.0, 1.0],
[0.0, 0.0],
),
(
[north_east.x(), north_east.y(), 0.0],
[0.0, 0.0, 1.0],
[1.0, 0.0],
),
(
[south_east.x(), south_east.y(), 0.0],
[0.0, 0.0, 1.0],
[1.0, 1.0],
),
];
let indices = vec![0, 2, 1, 0, 3, 2];
let mut positions = Vec::new();
let mut normals = Vec::new();
let mut uvs = Vec::new();
for (position, normal, uv) in vertices.iter() {
positions.push(position.clone());
normals.push(normal.clone());
uvs.push(uv.clone());
}
Mesh {
primitive_topology: PrimitiveTopology::TriangleStrip,
attributes: vec![
VertexAttribute::position(positions),
VertexAttribute::normal(normals),
VertexAttribute::uv(uvs),
],
indices: Some(indices),
}
}
}
pub struct Plane {
pub size: f32,
}
impl From<Plane> for Mesh {
fn from(plane: Plane) -> Self {
Quad {
size: Vec2::new(plane.size, plane.size)
}.into()
}
}
}
pub fn mesh_batcher_system() -> Box<dyn Schedulable> {
SystemBuilder::new("mesh_batcher")
.write_resource::<AssetBatchers>()
.with_query(
<(Read<Handle<Mesh>>, Read<Renderable>)>::query().filter(changed::<Handle<Mesh>>()),
)
.build(|_, world, asset_batchers, query| {
for (entity, (mesh_handle, _renderable)) in query.iter_entities(world) {
asset_batchers.set_entity_handle(entity, *mesh_handle);
}
})
}