bevy/crates/bevy_text/src/draw.rs
Carter Anderson ccb31bc949
Optimize Text rendering / SharedBuffers (#972)
optimize Text rendering / SharedBuffers
2020-12-02 12:38:20 -08:00

122 lines
4.1 KiB
Rust

use bevy_math::{Mat4, Vec3};
use bevy_render::{
color::Color,
draw::{Draw, DrawContext, DrawError, Drawable},
mesh,
pipeline::{PipelineSpecialization, VertexBufferDescriptor},
prelude::Msaa,
renderer::{AssetRenderResourceBindings, BindGroup, RenderResourceBindings, RenderResourceId},
};
use bevy_sprite::TextureAtlasSprite;
use glyph_brush_layout::{HorizontalAlign, VerticalAlign};
use crate::PositionedGlyph;
#[derive(Debug, Clone, Copy)]
pub struct TextAlignment {
pub vertical: VerticalAlign,
pub horizontal: HorizontalAlign,
}
impl Default for TextAlignment {
fn default() -> Self {
TextAlignment {
vertical: VerticalAlign::Top,
horizontal: HorizontalAlign::Left,
}
}
}
#[derive(Clone, Debug)]
pub struct TextStyle {
pub font_size: f32,
pub color: Color,
pub alignment: TextAlignment,
}
impl Default for TextStyle {
fn default() -> Self {
Self {
color: Color::WHITE,
font_size: 12.0,
alignment: TextAlignment::default(),
}
}
}
pub struct DrawableText<'a> {
pub render_resource_bindings: &'a mut RenderResourceBindings,
pub asset_render_resource_bindings: &'a mut AssetRenderResourceBindings,
pub position: Vec3,
pub style: &'a TextStyle,
pub text_glyphs: &'a Vec<PositionedGlyph>,
pub msaa: &'a Msaa,
pub font_quad_vertex_descriptor: &'a VertexBufferDescriptor,
}
impl<'a> Drawable for DrawableText<'a> {
fn draw(&mut self, draw: &mut Draw, context: &mut DrawContext) -> Result<(), DrawError> {
context.set_pipeline(
draw,
&bevy_sprite::SPRITE_SHEET_PIPELINE_HANDLE,
&PipelineSpecialization {
sample_count: self.msaa.samples,
vertex_buffer_descriptor: self.font_quad_vertex_descriptor.clone(),
..Default::default()
},
)?;
let render_resource_context = &**context.render_resource_context;
if let Some(RenderResourceId::Buffer(vertex_attribute_buffer_id)) = render_resource_context
.get_asset_resource(&bevy_sprite::QUAD_HANDLE, mesh::VERTEX_ATTRIBUTE_BUFFER_ID)
{
draw.set_vertex_buffer(0, vertex_attribute_buffer_id, 0);
} else {
println!("Could not find vertex buffer for `bevy_sprite::QUAD_HANDLE`.")
}
let mut indices = 0..0;
if let Some(RenderResourceId::Buffer(quad_index_buffer)) = render_resource_context
.get_asset_resource(&bevy_sprite::QUAD_HANDLE, mesh::INDEX_BUFFER_ASSET_INDEX)
{
draw.set_index_buffer(quad_index_buffer, 0);
if let Some(buffer_info) = render_resource_context.get_buffer_info(quad_index_buffer) {
indices = 0..(buffer_info.size / 4) as u32;
} else {
panic!("Expected buffer type.");
}
}
// set global bindings
context.set_bind_groups_from_bindings(draw, &mut [self.render_resource_bindings])?;
for tv in self.text_glyphs {
let atlas_render_resource_bindings = self
.asset_render_resource_bindings
.get_mut(&tv.atlas_info.texture_atlas)
.unwrap();
context.set_bind_groups_from_bindings(draw, &mut [atlas_render_resource_bindings])?;
let sprite = TextureAtlasSprite {
index: tv.atlas_info.glyph_index,
color: self.style.color,
};
let transform = Mat4::from_translation(self.position + tv.position.extend(0.));
let transform_buffer = context.get_uniform_buffer(&transform).unwrap();
let sprite_buffer = context.get_uniform_buffer(&sprite).unwrap();
let sprite_bind_group = BindGroup::build()
.add_binding(0, transform_buffer)
.add_binding(1, sprite_buffer)
.finish();
context.create_bind_group_resource(2, &sprite_bind_group)?;
draw.set_bind_group(2, &sprite_bind_group);
draw.draw_indexed(indices.clone(), 0, 0..1);
}
Ok(())
}
}