amplify README

Author: monkstone

video_filtering/README.md

@@ -1,8 +1,17 @@
 ### Experiment with different edge-detection algorithms
-In the provide example the sketch uses a sobel filter
+In the provided example the the `EDGE_FUNC` is
+`define EDGE_FUNC edge`
+
+Alternatives are `colorEdge, trueColorEdge`
+
+
+In the provided example the sketch uses a sobel filter algorithm
 
 `#define SOBEL`
 
 Alernatives are `KAYYALI_NESW, KAYYALI_SENW, PREWITT, ROBERTSCROSS, SCHARR`
 
 Modify `edge_detect.glsl` directly to use these alternative algorithms included in the shader.
+
+Other tunable option to experiment is `SCHARR`, that defaults to `1.0` for STEP but if `#define SCHARR` sets step at `0.15`
+