Shaderboy is a GLSL playground with a live fragment shader coding environment. It performs face tracking and supplies the fragment shader with facial landmark coordinates. Click Save & Compile or Ctrl-S in the editor to update the shader running in the canvas.
Two sample effects are commented out on lines 58 and 61-62. An effect that reveals facial landmarks is commented out on line 65. Un-collapse their functions and recompile to see what they do.
The shader's uniforms for landmarks are:
Coordinate: center of left eye
Coordinate: center of right eye
Line with 3 coordinates along bridge of nose
A unitless slope between the chin and the bridge of the nose
Coordinate: center of mouth
How open the mouth is in pixels
All 70 of the tracked landmarks (including the ones listed above)