Complete the documentation

examples/generate-atlas.rs

@@ -75,7 +75,6 @@ fn main() {
         None => 0,
     };
 
-    // FIXME(pcwalton)
     let (outlines, atlas);
     unsafe {
         let font = Font::from_collection_index(file.as_slice(), font_index).unwrap();

src/lib.rs

@@ -36,13 +36,40 @@
 //!
 //! See `examples/generate-atlas.rs` for a simple example.
 //!
-//! Typically, the steps to use Pathfidner are:
+//! Typically, the steps to use Pathfinder are:
 //!
 //! 1. Create a `Rasterizer` object. This holds the OpenGL state.
 //!
 //! 2. Open the font from disk (or elsewhere), and call `Font::new()` (or
 //!    `Font::from_collection_index` in the case of a `.ttc` or `.dfont` collection) to load it.
-//!     
+//!
+//! 3. If the text to be rendered is not already shaped, call
+//!    `Font::glyph_mapping_for_codepoint_ranges()` to determine the glyphs needed to render the
+//!    text, and call `shaper::shape_text()` to convert the text to glyph IDs.
+//!
+//! 4. Create an `OutlineBuilder` and call `OutlineBuilder::add_glyph()` on each glyph to parse
+//!    each outline from the font. Then upload the outlines to the GPU with
+//!    `OutlineBuilder::create_buffers()`.
+//!
+//! 5. Create an `AtlasBuilder` with a suitable width (1024 or 2048 is usually fine) and call
+//!    `AtlasBuilder::pack_glyph()` on each glyph you need to render. Then call
+//!    `AtlasBuilder::create_atlas()` to upload the atlas buffer to the GPU.
+//!
+//! 6. Make a `CoverageBuffer` of an appropriate size (1024 or 2048 pixels on each side is
+//!    typically reasonable).
+//!
+//! 7. Create an image to render the atlas to with `Rasterizer::device().create_image()`. The
+//!    format should be `R8` and the buffer should be created read-write.
+//!
+//! 8. Draw the glyphs with `Rasterizer::draw_atlas()`.
+//!
+//! Don't forget to flush the queue (`Rasterizer::queue().flush()`) and/or perform appropriate
+//! synchronization (`glMemoryBarrier()`) as necessary.
+//!
+//! ## Hardware requirements
+//!
+//! Pathfinder requires at least OpenGL 3.3 and either OpenGL 4.3 compute shader or OpenCL 1.2.
+//! Intel GPUs in Sandy Bridge processors or later should be OK.
 
 #![cfg_attr(test, feature(test))]