minor changes

README.md

@@ -0,0 +1,87 @@
+# Scratch
+An OSL shader that generates texture to make swirly micro scratch look by controlling the anisotropy and roughness.
+
+It works well with both metal:
+
+<img src="./images/a.png" width="600" height="600">
+
+and dielectric:
+
+<img src="./images/b.png" width="600" height="600">
+
+The original idea is based on Hang Li(悬挂鲤)'s article. Here I implemented it using OSL and exposured some arts friendly parameters.
+
+
+# Parameters
+
+### density
+Controls the heaviness of the scratches.
+
+More scratches takes longer to generate.
+
+<img src="./images/0000.png" width="400" height="400">
+<img src="./images/0008.png" width="400" height="400">
+<img src="./images/0020.png" width="400" height="400">
+
+### roughness default/min/max
+*default* values set the roughness of areas that isn't scrached.
+
+*min/max* controls the range of roughness randomness.
+
+Bigger roughtness makes the swirl longer along it's direction.
+
+<img src="./images/0114.png" width="400" height="400">
+<img src="./images/0123.png" width="400" height="400">
+<img src="./images/0131.png" width="400" height="400">
+
+### anisotropy default/min/max
+Similiar to roughness default/min/max, but namely controls the anisotropy.
+
+Bigger anisotropy enlarge the swirl radius.
+
+<img src="./images/0083.png" width="400" height="400">
+<img src="./images/0092.png" width="400" height="400">
+<img src="./images/0099.png" width="400" height="400">
+
+### offset
+Rotation offset.
+
+> ##### 💡 Tips
+> Tweak this parameter to achieve some intersting effect, like radiant or spiral scraches!
+
+<img src="./images/0030.png" width="400" height="400">
+<img src="./images/0033.png" width="400" height="400">
+<img src="./images/0044.png" width="400" height="400">
+
+### width
+Width of the scratches, in UV space.
+
+> ##### 💡 Tips
+> 0.001 is a good value to start with.
+
+<img src="./images/0132.png" width="400" height="400">
+<img src="./images/0136.png" width="400" height="400">
+<img src="./images/0141.png" width="400" height="400">
+
+# Output
+ - R: Should be connected to *roughness*.
+ - G: Should be connected to *rotation* of anisotropy. With arnold you should add a aiNegate and set the offset to 0.25.
+ - B: Should be connected to *anisotropy*.
+
+
+# Usage
+
+Take a look at the examples under "example_scenes/". For now there are only mtoa and Clarisse scenes shipped. But anyone is welcome to contribute any DCC oriented examples.
+
+For clarisse:
+
+![](./images/clarisse.png)
+
+For maya:
+
+![](./images/maya.png)
+
+(Of course, again, the compatibility is not limited to the DCCs listed above.)
+
+Note that the definition of "Anisotropic Rotation" is slightly different between Clarisse and Arnold. That's the reason that in maya we need some conversion when handling the rotation attribute.
+

scratch.osl

@@ -1,6 +1,12 @@
 // Micro Scratched Texture
-// Author: John Su
-// Based on the idea of 
+//
+// Author: John Su <[email protected]>
+//
+// An OSL shader that generates texture to make swirly micro scratch look by
+// controlling the anistropy and roughness.
+// The original idea is based on Hang Li(悬挂鲤)'s article. I just implemented it
+// using OSL and added some arts friendly parameters.
+
 #define DIVISION 40
 #define DEBUG(_) Cf=_; return;