Update the README for Pathfinder 3

README.md

@@ -1,69 +1,61 @@
-# Pathfinder 2
+# Pathfinder 3
 
-Pathfinder 2 is a fast, practical, work in progress GPU-based rasterizer for fonts and vector
-graphics using OpenGL and OpenGL ES 2.0+.
+Pathfinder 3 is a fast, practical, GPU-based rasterizer for fonts and vector graphics using OpenGL
+and OpenGL ES 3.0+.
 
 Please note that Pathfinder is under heavy development and is incomplete in various areas.
 
 The project features:
 
-* Low setup time. Typical glyph outlines can be prepared for GPU rendering in about 5 microseconds
-  each (typically O(n log n) in the number of vertices), making Pathfinder suitable for dynamic
-  environments. The setup process is lossless and fully resolution independent; paths need only be
-  prepared once and can thereafter be rendered at any zoom level without any loss in quality.
-  Pathfinder can also render outlines without any mesh at all, reducing the setup time to nearly
-  zero, at the cost of some runtime performance. For static paths such as game assets, the
-  resulting meshes can be saved to disk to avoid having to generate them at runtime.
-
 * High quality antialiasing. Pathfinder can compute exact fractional trapezoidal area coverage on a
-  per-pixel basis for the highest-quality antialiasing, provided that either OpenGL 3.0+ or a few
-  common extensions are available. Supersampling is available as an alternative for 3D scenes
-  and/or lower-end hardware.
+  per-pixel basis for the highest-quality antialiasing possible (effectively 256xAA).
 
-* Fast rendering, even at small pixel sizes. Even on lower-end GPUs, Pathfinder typically matches
-  or exceeds the performance of the best CPU rasterizers. The difference is particularly pronouced
-  at large sizes, where Pathfinder regularly achieves multi-factor speedups. All shaders have no
-  loops and minimal branching.
+* Fast CPU setup, making full use of parallelism. Pathfinder 3 uses the Rayon library to quickly
+  perform a CPU tiling prepass to prepare vector scenes for the GPU. This prepass can be pipelined
+  with the GPU to hide its latency.
+
+* Fast GPU rendering, even at small pixel sizes. Even on lower-end GPUs, Pathfinder typically
+  matches or exceeds the performance of the best CPU rasterizers. The difference is particularly
+  pronouced at large sizes, where Pathfinder regularly achieves multi-factor speedups. All shaders
+  have no loops and minimal branching.
 
 * Advanced font rendering. Pathfinder can render fonts with slight hinting and can perform subpixel
   antialiasing on LCD screens. It can do stem darkening/font dilation like macOS and FreeType in
   order to make text easier to read at small sizes. The library also has support for gamma
   correction.
 
-* Support for full vector scenes. Pathfinder 2 is designed to efficiently handle workloads that
-  consist of many overlapping vector paths, such as those commonly found in SVG and PDF files. It
-  makes heavy use of the hardware Z buffer to perform occlusion culling, which often results in
-  dramatic performance wins over typical software renderers that use the painter's algorithm.
+* Support for SVG. Pathfinder 3 is designed to efficiently handle workloads that consist of many
+  overlapping vector paths, such as those commonly found in SVG and PDF files. It can perform
+  occlusion culling, which often results in dramatic performance wins over typical software
+  renderers that use the painter's algorithm. A simple loader that leverages the `resvg` library
+  to render a subset of SVG is included, so it's easy to get started.
 
-* 3D capability. Pathfinder 2 can render fonts and vector paths in 3D environments. Vector meshes
-  are rendered just like any other mesh, with a simple shader applied.
+* 3D capability. Pathfinder can render fonts and vector paths in 3D environments without any loss
+  in quality. This is intended to be useful for vector-graphics-based user interfaces in VR, for
+  example.
+
+* Lightweight. Unlike large vector graphics packages that mix and match many different algorithms,
+  Pathfinder 3 uses a single, simple technique. It consists of a set of modular crates, so
+  applications can pick and choose only the components that are necessary to minimize dependencies.
 
 * Portability to most GPUs manufactured in the last decade, including integrated and mobile GPUs.
   Geometry, tessellation, and compute shader functionality is not required.
 
 ## Building
 
-Pathfinder 2 is a set of modular packages, allowing you to choose which parts of the library you
-need. A WebGL demo is included, so you can try Pathfinder right in your browser. (Please note that,
-like the rest of Pathfinder, it's under heavy development and has known bugs.)
+Pathfinder 3 is a set of modular packages, allowing you to choose which parts of the library you
+need. An SVG rendering demo, written in Rust, is included, so you can try Pathfinder out right
+away. It also provides an example of how to use the library. (Note that, like the rest of
+Pathfinder, the demo is under heavy development and has known bugs.)
 
-To run the demo, make sure [Node.js](https://nodejs.org/en/), [nightly Rust](https://doc.rust-lang.org/1.5.0/book/nightly-rust.html) and [CMake](https://cmake.org/install/) are installed, then run the following commands:
+Running the demo is as simple as:
 
-    $ cd demo/client
-    $ npm install
-    $ npm run build
-    $ cd ../server
-    $ cargo run --release
+    $ cd demo/native
+    $ RUSTFLAGS="-C target-cpu=native" cargo run --release
 
-Then navigate to http://localhost:8000/.
-
-## Testing
-
-Pathfinder contains reference tests that compare its output to that of other rendering libraries,
-such as Cairo. To run them, install Cairo and FreeType if necessary, then perform the above steps,
-substituting the last line with:
-
-    $ cargo run --release --features reftests
+On macOS, it is recommended that you force the use of the integrated GPU, as issues with Apple's
+OpenGL drivers may limit performance on discrete GPUs. You can use
+[gfxCardStatus.app](https://gfx.io/) for this.
 
 ## Authors
 
@@ -72,7 +64,7 @@ community.
 
 The logo was designed by Jay Vining.
 
-Pathfinder abides by the same Code of Conduct as Rust itself.
+Contributors to Pathfinder are expected to abide by the same Code of Conduct as Rust itself.
 
 ## License