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Draft end-to-end support for the new algorithm. Not working yet.

This commit is contained in:
Patrick Walton 2017-01-24 15:30:14 -08:00
parent 1cd3a1e6bd
commit 50ad78db2a
6 changed files with 230 additions and 96 deletions
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4
examples/generate-atlas.rs
View File

@ -66,8 +66,8 @@ fn main() {
}
}
let glyph_buffers = glyph_buffer_builder.finish(&rasterizer.device).unwrap();
let batch = batch_builder.finish(&rasterizer.device).unwrap();
let glyph_buffers = glyph_buffer_builder.finish().unwrap();
let batch = batch_builder.finish(&glyph_buffer_builder).unwrap();
let atlas_size = Size2D::new(WIDTH, HEIGHT);
let coverage_buffer = CoverageBuffer::new(&rasterizer.device, &atlas_size).unwrap();

24
resources/shaders/draw.vs.glsl
View File

@ -19,14 +19,14 @@ layout(std140) struct GlyphDescriptor {
ivec4 extents;
// The number of units per em in this glyph.
uint unitsPerEm;
// The number of points in this glyph.
uint pointCount;
// The index of the first point.
// The index of the first point in the VBO.
uint startPoint;
// The index of the first element in the IBO.
uint startIndex;
};
// Information about the position of each glyph in the atlas.
layout(std140) struct ImageInfo {
layout(std140) struct ImageDescriptor {
// The left/top/right/bottom positions of the glyph in the atlas.
uvec4 atlasRect;
// The font size in pixels.
@ -42,17 +42,17 @@ layout(std140) uniform ubGlyphDescriptors {
GlyphDescriptor uGlyphs[MAX_GLYPHS];
};
layout(std140) uniform ubImageInfo {
ImageInfo uImageInfo[MAX_GLYPHS];
layout(std140) uniform ubImageDescriptors {
ImageDescriptor uImages[MAX_GLYPHS];
};
// The position of each vertex in glyph space.
in ivec2 aPosition;
// Which image the vertex belongs to.
// Which glyph the vertex belongs to.
//
// TODO(pcwalton): See if this is faster as a binary search on the vertex ID.
in uint aImageIndex;
in uint aGlyphIndex;
// The vertex ID, passed along onto the TCS.
flat out uint vVertexID;
@ -60,13 +60,13 @@ flat out uint vVertexID;
void main() {
vVertexID = gl_VertexID;
ImageInfo imageInfo = uImageInfo[aImageIndex];
GlyphDescriptor glyph = uGlyphs[imageInfo.glyphIndex];
ImageDescriptor image = uImages[aGlyphIndex];
GlyphDescriptor glyph = uGlyphs[aGlyphIndex];
float emsPerUnit = 1.0f / float(glyph.unitsPerEm);
vec2 glyphPos = vec2(aPosition.x - glyphInfo.extents.x, glyphInfo.extents.w - aPosition.y);
vec2 atlasPos = glyphPos * emsPerUnit * imageInfo.pointSize + vec2(imageInfo.atlasRect.xy);
vec2 glyphPos = vec2(aPosition.x - glyph.extents.x, glyph.extents.w - aPosition.y);
vec2 atlasPos = glyphPos * emsPerUnit * image.pointSize + vec2(image.atlasRect.xy);
gl_Position = vec4(atlasPos, 0.0f, 1.0f);
}

95
src/batch.rs
View File

@ -9,18 +9,17 @@
// except according to those terms.
use atlas::Atlas;
use compute_shader::buffer::{Buffer, BufferData, HostAllocatedData, Protection};
use compute_shader::device::Device;
use gl::types::{GLsizei, GLsizeiptr, GLuint};
use gl;
use glyph_buffer::GlyphBufferBuilder;
use std::mem;
use std::os::raw::c_void;
use std::u16;
const POINTS_PER_SEGMENT: u32 = 32;
pub struct BatchBuilder {
pub atlas: Atlas,
pub indices: Vec<u32>,
pub images: Vec<ImageDescriptor>,
pub point_count: u32,
pub glyph_indices: Vec<u32>,
}
impl BatchBuilder {
@ -29,12 +28,12 @@ impl BatchBuilder {
pub fn new(available_width: u32, shelf_height: u32) -> BatchBuilder {
BatchBuilder {
atlas: Atlas::new(available_width, shelf_height),
indices: vec![],
images: vec![],
point_count: 0,
glyph_indices: vec![],
}
}
/// FIXME(pcwalton): Support the same glyph drawn at multiple point sizes.
pub fn add_glyph(&mut self,
glyph_buffer_builder: &GlyphBufferBuilder,
glyph_index: u32,
@ -47,35 +46,83 @@ impl BatchBuilder {
let pixel_size = descriptor.pixel_rect(point_size).size.ceil().cast().unwrap();
let atlas_origin = try!(self.atlas.place(&pixel_size));
self.images.push(ImageDescriptor {
while self.images.len() < glyph_index as usize + 1 {
self.images.push(ImageDescriptor::default())
}
self.images[glyph_index as usize] = ImageDescriptor {
atlas_x: atlas_origin.x,
atlas_y: atlas_origin.y,
point_size: point_size,
glyph_index: glyph_index,
start_point_in_batch: self.point_count,
point_count: descriptor.point_count as u32,
});
};
self.point_count += descriptor.point_count as u32;
self.glyph_indices.push(glyph_index);
Ok(())
}
pub fn finish(&mut self, device: &Device) -> Result<Batch, ()> {
let indices = BufferData::HostAllocated(HostAllocatedData::new(&self.indices));
let images = BufferData::HostAllocated(HostAllocatedData::new(&self.images));
pub fn finish(&mut self, glyph_buffer_builder: &GlyphBufferBuilder) -> Result<Batch, ()> {
self.glyph_indices.sort();
let (mut current_range, mut counts, mut start_indices) = (None, vec![], vec![]);
for &glyph_index in &self.glyph_indices {
let first_index = glyph_buffer_builder.descriptors[glyph_index as usize].start_index as
usize;
let last_index = match glyph_buffer_builder.descriptors.get(glyph_index as usize + 1) {
Some(ref descriptor) => descriptor.start_index as usize,
None => glyph_buffer_builder.indices.len(),
};
match current_range {
Some((current_first, current_last)) if first_index == current_last => {
current_range = Some((current_first, last_index))
}
Some((current_first, current_last)) => {
counts.push((current_last - current_first) as GLsizei);
start_indices.push(current_first);
current_range = Some((first_index, last_index))
}
None => current_range = Some((first_index, last_index)),
}
}
if let Some((current_first, current_last)) = current_range {
counts.push((current_last - current_first) as GLsizei);
start_indices.push(current_first);
}
// TODO(pcwalton): Try using `glMapBuffer` here.
unsafe {
let mut images = 0;
gl::GenBuffers(1, &mut images);
gl::BindBuffer(gl::UNIFORM_BUFFER, images);
gl::BufferData(gl::UNIFORM_BUFFER,
(self.images.len() * mem::size_of::<ImageDescriptor>()) as GLsizeiptr,
self.images.as_ptr() as *const ImageDescriptor as *const c_void,
gl::DYNAMIC_DRAW);
Ok(Batch {
indices: try!(device.create_buffer(Protection::ReadOnly, indices).map_err(drop)),
images: try!(device.create_buffer(Protection::ReadOnly, images).map_err(drop)),
point_count: self.point_count,
start_indices: start_indices,
counts: counts,
images: images,
})
}
}
}
pub struct Batch {
pub indices: Buffer,
pub images: Buffer,
pub point_count: u32,
pub start_indices: Vec<usize>,
pub counts: Vec<GLsizei>,
pub images: GLuint,
}
impl Drop for Batch {
fn drop(&mut self) {
unsafe {
gl::DeleteBuffers(1, &mut self.images);
}
}
}
#[derive(Clone, Copy, Debug)]
@ -116,13 +163,11 @@ impl Iterator for GlyphRangeIter {
}
#[repr(C)]
#[derive(Clone, Copy, Debug)]
#[derive(Clone, Copy, Default, Debug)]
pub struct ImageDescriptor {
atlas_x: u32,
atlas_y: u32,
point_size: f32,
glyph_index: u32,
start_point_in_batch: u32,
point_count: u32,
}

1
src/coverage.rs
View File

@ -14,7 +14,6 @@ use compute_shader::texture::{ExternalTexture, Format, Texture};
use euclid::size::Size2D;
use gl::types::{GLint, GLuint};
use gl;
use std::mem;
pub struct CoverageBuffer {
pub texture: Texture,

104
src/glyph_buffer.rs
View File

@ -8,8 +8,6 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use compute_shader::buffer::{Buffer, BufferData, HostAllocatedData, Protection};
use compute_shader::device::Device;
use euclid::{Point2D, Rect, Size2D};
use gl::types::{GLsizeiptr, GLuint};
use gl;
@ -19,14 +17,15 @@ use otf::loca::LocaTable;
use std::mem;
use std::os::raw::c_void;
static DUMMY_VERTEX: Vertex = Vertex {
x: 0,
y: 0,
glyph_index: 0,
};
pub struct GlyphBufferBuilder {
pub coordinates: Vec<(i16, i16)>,
/// TODO(pcwalton): Try omitting this and binary search the glyph descriptors in the vertex
/// shader. Might or might not help.
pub glyph_indices: Vec<u16>,
pub operations: Vec<u8>,
pub vertices: Vec<Vertex>,
pub indices: Vec<u32>,
pub descriptors: Vec<GlyphDescriptor>,
}
@ -34,9 +33,8 @@ impl GlyphBufferBuilder {
#[inline]
pub fn new() -> GlyphBufferBuilder {
GlyphBufferBuilder {
coordinates: vec![],
glyph_indices: vec![],
operations: vec![],
vertices: vec![DUMMY_VERTEX],
indices: vec![],
descriptors: vec![],
}
}
@ -49,38 +47,31 @@ impl GlyphBufferBuilder {
-> Result<(), ()> {
let glyph_index = self.descriptors.len() as u16;
let mut point_index = self.coordinates.len() / 2;
let mut point_index = self.vertices.len() as u32;
let start_index = self.indices.len() as u32;
let start_point = point_index;
let mut operations = if point_index % 4 == 0 {
0
} else {
self.operations.pop().unwrap()
};
let mut last_point_on_curve = true;
try!(glyf_table.for_each_point(loca_table, glyph_id, |point| {
self.coordinates.push((point.position.x, point.position.y));
self.glyph_indices.push(glyph_index);
self.vertices.push(Vertex {
x: point.position.x,
y: point.position.y,
glyph_index: glyph_index,
});
let operation = if point.first_point_in_contour {
0
} else if point.on_curve {
1
if !point.first_point_in_contour && point.on_curve {
let indices = if last_point_on_curve {
[point_index - 2, 0, point_index - 1]
} else {
2
[point_index - 3, point_index - 2, point_index - 1]
};
operations |= operation << (point_index % 4 * 2);
self.indices.extend(indices.iter().cloned());
}
point_index += 1;
if point_index % 4 == 0 {
self.operations.push(operation)
}
last_point_on_curve = point.on_curve
}));
if point_index % 4 != 0 {
self.operations.push(operations)
}
// Add a glyph descriptor.
let bounding_rect = try!(glyf_table.bounding_rect(loca_table, glyph_id));
self.descriptors.push(GlyphDescriptor {
@ -89,26 +80,33 @@ impl GlyphBufferBuilder {
right: bounding_rect.max_x() as i32,
top: bounding_rect.max_y() as i32,
units_per_em: head_table.units_per_em as u32,
point_count: (point_index - start_point) as u32,
start_point: start_point as u32,
start_index: start_index,
pad: 0,
});
Ok(())
}
pub fn finish(&self, device: &Device) -> Result<GlyphBuffers, ()> {
// TODO(pcwalton): Try using `glMapBuffer` here. Requires precomputing contours.
pub fn finish(&self) -> Result<GlyphBuffers, ()> {
// TODO(pcwalton): Try using `glMapBuffer` here. Requires precomputing contour types and
// counts.
unsafe {
let (mut coordinates, mut descriptors) = (0, 0);
gl::GenBuffers(1, &mut coordinates);
let (mut vertices, mut indices, mut descriptors) = (0, 0, 0);
gl::GenBuffers(1, &mut vertices);
gl::GenBuffers(1, &mut indices);
gl::GenBuffers(1, &mut descriptors);
let length = self.coordinates.len() * mem::size_of::<(i16, i16)>();
gl::BindBuffer(gl::ARRAY_BUFFER, coordinates);
gl::BindBuffer(gl::ARRAY_BUFFER, vertices);
gl::BufferData(gl::ARRAY_BUFFER,
length as GLsizeiptr,
self.coordinates.as_ptr() as *const (i16, i16) as *const c_void,
(self.vertices.len() * mem::size_of::<Vertex>()) as GLsizeiptr,
self.vertices.as_ptr() as *const Vertex as *const c_void,
gl::STATIC_DRAW);
gl::BindBuffer(gl::ELEMENT_ARRAY_BUFFER, indices);
gl::BufferData(gl::ELEMENT_ARRAY_BUFFER,
(self.indices.len() * mem::size_of::<u32>()) as GLsizeiptr,
self.indices.as_ptr() as *const u32 as *const c_void,
gl::STATIC_DRAW);
let length = self.descriptors.len() * mem::size_of::<GlyphDescriptor>();
@ -119,7 +117,8 @@ impl GlyphBufferBuilder {
gl::STATIC_DRAW);
Ok(GlyphBuffers {
coordinates: coordinates,
vertices: vertices,
indices: indices,
descriptors: descriptors,
})
}
@ -127,7 +126,8 @@ impl GlyphBufferBuilder {
}
pub struct GlyphBuffers {
pub coordinates: GLuint,
pub vertices: GLuint,
pub indices: GLuint,
pub descriptors: GLuint,
}
@ -139,8 +139,8 @@ pub struct GlyphDescriptor {
pub right: i32,
pub top: i32,
pub units_per_em: u32,
pub point_count: u32,
pub start_point: u32,
pub start_index: u32,
pub pad: u32,
}
@ -150,7 +150,17 @@ impl GlyphDescriptor {
let pixels_per_unit = point_size / self.units_per_em as f32;
Rect::new(Point2D::new(self.left as f32, self.bottom as f32),
Size2D::new((self.right - self.left) as f32,
(self.bottom - self.top) as f32)) * pixels_per_unit
(self.top - self.bottom) as f32)) * pixels_per_unit
}
}
#[derive(Copy, Clone)]
#[repr(C)]
pub struct Vertex {
x: i16,
y: i16,
/// TODO(pcwalton): Try omitting this and binary search the glyph descriptors in the vertex
/// shader. Might or might not help.
glyph_index: u16,
}

90
src/rasterizer.rs
View File

@ -16,9 +16,10 @@ use compute_shader::queue::{Queue, Uniform};
use compute_shader::texture::Texture;
use coverage::CoverageBuffer;
use euclid::rect::Rect;
use gl::types::{GLchar, GLenum, GLint, GLsizei, GLuint};
use gl::types::{GLchar, GLenum, GLint, GLsizei, GLuint, GLvoid};
use gl;
use glyph_buffer::GlyphBuffers;
use glyph_buffer::{GlyphBuffers, Vertex};
use std::mem;
use std::ptr;
// TODO(pcwalton): Don't force that these be compiled in.
@ -36,11 +37,19 @@ pub struct Rasterizer {
pub queue: Queue,
draw_program: GLuint,
accum_program: Program,
draw_vertex_array: GLuint,
draw_position_attribute: GLint,
draw_image_index_attribute: GLint,
draw_atlas_size_uniform: GLint,
draw_glyph_descriptors_uniform: GLuint,
draw_image_info_uniform: GLuint,
}
impl Rasterizer {
pub fn new(device: Device, queue: Queue) -> Result<Rasterizer, ()> {
let draw_program;
let (draw_program, draw_position_attribute, draw_image_index_attribute);
let (draw_atlas_size_uniform, draw_glyph_descriptors_uniform, draw_image_info_uniform);
let mut draw_vertex_array = 0;
unsafe {
let shaders = [
try!(compile_gl_shader(gl::VERTEX_SHADER,
@ -68,7 +77,22 @@ impl Rasterizer {
gl::LINK_STATUS,
"Program",
gl::GetProgramiv,
gl::GetProgramInfoLog))
gl::GetProgramInfoLog));
gl::GenVertexArrays(1, &mut draw_vertex_array);
draw_position_attribute =
gl::GetAttribLocation(draw_program, b"aPosition\0".as_ptr() as *const GLchar);
draw_image_index_attribute =
gl::GetAttribLocation(draw_program, b"aImageIndex\0".as_ptr() as *const GLchar);
draw_atlas_size_uniform =
gl::GetUniformLocation(draw_program, b"uAtlasSize\0".as_ptr() as *const GLchar);
draw_glyph_descriptors_uniform =
gl::GetUniformBlockIndex(draw_program,
b"ubGlyphDescriptors\0".as_ptr() as *const GLchar);
draw_image_info_uniform =
gl::GetUniformBlockIndex(draw_program, b"ubImageInfo\0".as_ptr() as *const GLchar);
}
// FIXME(pcwalton): Don't panic if this fails to compile; just return an error.
@ -79,6 +103,12 @@ impl Rasterizer {
queue: queue,
draw_program: draw_program,
accum_program: accum_program,
draw_vertex_array: draw_vertex_array,
draw_position_attribute: draw_position_attribute,
draw_image_index_attribute: draw_image_index_attribute,
draw_atlas_size_uniform: draw_atlas_size_uniform,
draw_glyph_descriptors_uniform: draw_glyph_descriptors_uniform,
draw_image_info_uniform: draw_image_info_uniform,
})
}
@ -90,7 +120,57 @@ impl Rasterizer {
coverage_buffer: &CoverageBuffer,
texture: &Texture)
-> Result<Event, ()> {
// TODO(pcwalton)
unsafe {
gl::UseProgram(self.draw_program);
gl::BindVertexArray(self.draw_vertex_array);
// Set up the buffer layout.
gl::BindBuffer(gl::ARRAY_BUFFER, glyph_buffers.vertices);
gl::VertexAttribIPointer(self.draw_position_attribute as GLuint,
2,
gl::SHORT,
mem::size_of::<Vertex>() as GLint,
0 as *const GLvoid);
gl::VertexAttribIPointer(self.draw_image_index_attribute as GLuint,
1,
gl::UNSIGNED_SHORT,
mem::size_of::<Vertex>() as GLint,
mem::size_of::<(i16, i16)>() as *const GLvoid);
gl::EnableVertexAttribArray(self.draw_position_attribute as GLuint);
gl::EnableVertexAttribArray(self.draw_image_index_attribute as GLuint);
gl::BindBuffer(gl::ELEMENT_ARRAY_BUFFER, glyph_buffers.indices);
gl::BindBufferBase(gl::UNIFORM_BUFFER, 1, glyph_buffers.descriptors);
gl::BindBufferBase(gl::UNIFORM_BUFFER, 2, batch.images);
gl::UniformBlockBinding(self.draw_program, self.draw_glyph_descriptors_uniform, 1);
gl::UniformBlockBinding(self.draw_program, self.draw_image_info_uniform, 2);
gl::Uniform2ui(self.draw_atlas_size_uniform,
atlas_rect.size.width,
atlas_rect.size.height);
gl::PatchParameteri(gl::PATCH_VERTICES, 3);
// Use blending on our floating point framebuffer to accumulate coverage.
gl::Enable(gl::BLEND);
gl::BlendEquation(gl::FUNC_ADD);
gl::BlendFunc(gl::ONE, gl::ONE);
// Enable backface culling. See comments in `draw.tcs.glsl` for more information
// regarding why this is necessary.
gl::CullFace(gl::BACK);
gl::FrontFace(gl::CCW);
gl::Enable(gl::CULL_FACE);
// Now draw the glyph ranges.
debug_assert!(batch.counts.len() == batch.start_indices.len());
gl::MultiDrawElements(gl::PATCHES,
batch.counts.as_ptr(),
gl::UNSIGNED_INT,
batch.start_indices.as_ptr() as *const *const GLvoid,
batch.counts.len() as GLsizei);
}
let atlas_rect_uniform = [
atlas_rect.origin.x,