Rewrite the README.

Closes #26.

README.md

@@ -1,52 +1,63 @@
-# Pathfinder
+# Pathfinder 2
 
-Pathfinder is a fast, practical GPU-based rasterizer for OpenType fonts using OpenGL 4.3. It
-features:
+Pathfinder 2 is a fast, practical, work in progress GPU-based rasterizer for fonts and vector
+graphics using OpenGL and OpenGL ES 2.0+.
 
-* Very low setup time. Glyph outlines can go from the `.otf` file to the GPU in a form ready for
-  rasterization in less than a microsecond. There is no expensive tessellation or preprocessing
-  step.
+Please note that Pathfinder is under heavy development and is incomplete in various areas.
 
-* High quality antialiasing. Unlike techniques that rely on multisample antialiasing, Pathfinder
-  computes exact fractional trapezoidal area coverage on a per-pixel basis.
+The project features:
 
-* Fast rendering, even at small pixel sizes. On typical systems, Pathfinder should easily exceed
-  the performance of the best CPU rasterizers.
+* 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. For
+  static paths such as game assets, the resulting meshes can be saved to disk to avoid having to
+  generate them at runtime.
 
-* Low memory consumption. The only memory overhead over the glyph and outline storage itself is
-  that of a coverage buffer which typically consumes somewhere between 4MB-16MB and can be
-  discarded under memory pressure. Outlines are stored on-GPU in a compressed format and usually
-  take up only a few dozen kilobytes.
+* High quality antialiasing. Pathfinder can compute exact fractional trapezoidal area coverage on a
+  per-pixel basis for crisp 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.
 
-* Portability to most GPUs manufactured in the last few years, including integrated GPUs.
+* 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.
+
+* 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.
+
+* 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.
+
+* Portability to most GPUs manufactured in the last decade, including integrated and mobile GPUs.
+  Geometry, tessellation, and compute shader functionality is not required.
 
 ## Building
 
-Check out the code and run `cargo build --release`.
+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.)
 
-Try the demo with `cargo run --release --example lorem-ipsum -- resources/tests/nimbus-sans/NimbusSanL-Regu.ttf`.
-Use the mouse wheel or touchpad scrolling to move, and do the same while holding Alt or Option to
-zoom.
+To run the demo, make sure NPM and nightly Rust are installed, and run the following commands:
 
-As an alternative, debug builds (without the `--release`) build quickly and are typically fast,
-since most of the code runs on GPU.
+    $ cd demo/client
+    $ npm install
+    $ npm run build
+    $ cd ../server
+    $ cargo run --release
 
-On Windows, running the demos requires GLFW, which requires CMake to be installed and in your PATH.
-Get it from [cmake.org](https://cmake.org/).
-
-On Linux, some development packages are needed to compile. On Ubuntu, the following line has been
-reported to suffice to install them:
-
-    sudo apt-get install cmake libgl-dev libx11-dev xrandr-dev
+Then navigate to http://localhost:8000/.
 
 ## Authors
 
 The primary author is Patrick Walton (@pcwalton), with contributions from the Servo development
 community.
 
-The code is owned by the Mozilla Foundation.
+Pathfinder abides by the same Code of Conduct as Rust itself.
 
 ## License
 
 Licensed under the same terms as Rust itself. See `LICENSE-APACHE` and `LICENSE-MIT`.
-