@@ -16,6 +16,12 @@ To build, run `make`. You need the following dependencies on your system:

 -   [GLEW][]

 -   [GLFW][]

+If you're having trouble building or running this and just want to see the

+result, some output is saved in [`windings.ppm`](windings.ppm) and

+[`resolve.ppm`](resolve.ppm). If you want to compare them with [Figure 7][] you

+can run `make FE6.gif` (sic) to download it to the repository root (with

+`wget`).

+

 The code prioritizes conciseness and takes a number of shortcuts:

 -   We don't actually generate the SDFs and winding numbers from contours, we

@@ -16,6 +16,18 @@ To build, run `make`. You need the following dependencies on your system:

 -   [GLEW][]

 -   [GLFW][]

+The code prioritizes conciseness and takes a number of shortcuts:

+

+-   We don't actually generate the SDFs and winding numbers from contours, we

+    just hard code simple circle SDFs with given winding numbers.

+-   We don't always take care to explicitly bind OpenGL state at the point of

+    use if we happen to know that the currently bound thing is correct or

+    harmless, which we often do for this simple program.

+-   We abuse the blend mode to add winding numbers, to avoid juggling multiple

+    textures. If you're using clever geometry tricks to generate the SDFs this

+    might be a problem. You might be able to use some overdraw reducing

+    technique, like a depth pre-pass, to mitigate that.

+

 [`sdf-winding`]:  https://git.rcrnstn.net/rcrnstn/sdf-winding

 [glyph]:          https://en.wikipedia.org/wiki/Glyph

 [winding number]: https://en.wikipedia.org/wiki/Winding_number

@@ -10,12 +10,20 @@ the inside from the outside of a glyph][TrueType]:

 I have not read a single word of that reference manual, proceed accordingly.

+To build, run `make`. You need the following dependencies on your system:

+

+-   OpenGL

+-   [GLEW][]

+-   [GLFW][]

+

 [`sdf-winding`]:  https://git.rcrnstn.net/rcrnstn/sdf-winding

 [glyph]:          https://en.wikipedia.org/wiki/Glyph

 [winding number]: https://en.wikipedia.org/wiki/Winding_number

 [SDF]:            https://en.wikipedia.org/wiki/Signed_distance_function

 [Figure 7]:       https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/FE6.gif

 [TrueType]:       https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/Chap2.html#distinguishing

+[GLEW]:           https://glew.sourceforge.net

+[GLFW]:           https://www.glfw.org

 ## License

@@ -2,10 +2,20 @@

 [Glyph][] contour [winding number][] and [SDF][] OpenGL experiment.

+This repository has a singular purpose: to roughly reproduce [Figure 7][] from

+the [Apple TrueType Reference Manual - Chapter 2: Font Engine - Distinguishing

+the inside from the outside of a glyph][TrueType]:

+

+![Figure 7][]

+

+I have not read a single word of that reference manual, proceed accordingly.

+

 [`sdf-winding`]:  https://git.rcrnstn.net/rcrnstn/sdf-winding

 [glyph]:          https://en.wikipedia.org/wiki/Glyph

 [winding number]: https://en.wikipedia.org/wiki/Winding_number

 [SDF]:            https://en.wikipedia.org/wiki/Signed_distance_function

+[Figure 7]:       https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/FE6.gif

+[TrueType]:       https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/Chap2.html#distinguishing

 ## License

@@ -6,3 +6,11 @@

 [glyph]:          https://en.wikipedia.org/wiki/Glyph

 [winding number]: https://en.wikipedia.org/wiki/Winding_number

 [SDF]:            https://en.wikipedia.org/wiki/Signed_distance_function

+

+## License

+

+Licensed under the [ISC License][] unless otherwise noted, see the

+[`LICENSE`][] file.

+

+[ISC License]: https://choosealicense.com/licenses/isc

+[`LICENSE`]: LICENSE

new file mode 100644

@@ -0,0 +1,8 @@

+# [`sdf-winding`][]

+

+[Glyph][] contour [winding number][] and [SDF][] OpenGL experiment.

+

+[`sdf-winding`]:  https://git.rcrnstn.net/rcrnstn/sdf-winding

+[glyph]:          https://en.wikipedia.org/wiki/Glyph

+[winding number]: https://en.wikipedia.org/wiki/Winding_number

+[SDF]:            https://en.wikipedia.org/wiki/Signed_distance_function