Shaders

simpleFace - A procedural shader for a face

This Renderman shader paints a simple face on an object, consisting of two eyes and a mouth. It should map onto most surfaces okay, but may require some experimentation to get the desired results. In this image, the simpleFace shader is applied to a sphere.

VIDI Presenter can animate several parameters, e. g. the size and shape of the mouth, the direction the eyes are looking, etc. A sample model is included.

The basic mapping strategy is to apply the shader to the desired object. Render the scene with the default parameters to establish a starting point.

If the face appears sideways on the head, change the "mapCode" parameter to swap s and t coordinates. This will rotate the face 90 degrees on the head.

If the face is upside down, try using the "mapCode" parameter to invert s or t.

If the face is not properly centered on the head, adjust the "faceCenter" parameter.

If the aspect ratio of the eyes and mouth need adjustment, use the "scaleS" parameter.

The "eyeLevel" and "mouthLevel" move the eyes and mouth up or down on the head.

After the basic positioning of the face is done, use these parameters to animate the face:

Use "mouthOffset" to move the edges of the mouth up and down with respect to the center of the mouth. A negative "mouthOffset" value gives a frown, a positive "mouthOffset" value gives a smile.

Use the "mouthOpen" to set the size of the mouth opening. This can be used for talking motion.

Pupil movement is controlled by specifying the distance from the center of the eye to the center of the pupil, and the angle of the pupil with respect to the eye center. This works well for making the eyes roll.

Parameter	Data Type	Usage	Example
mouthLevel	float 0.0 to 1.0	Vertical placement of center of the mouth.	mouthLevel = 0.35
mouthWidth	float 0.0 to 1.0	The width of the mouth	mouthWidth = 0.5
mouthOffset	float 0.0 to 1.0	The vertical offset of the edges of the mouth from the center. Positive values give a smile, negative values give a frown.	mouthOffset = 0.05
mouthOpen	float 0.0 to 1.0	The vertical opening size of the mouth.	mouthOpen = 0.02
eyeLevel	float 0.0 to 1.0	Vertical placement of the center of the eyes	eyeLevel = 0.55
eyeOffset	float 0.0 to 1.0	The horizontal distance from faceCenter to center of each eye	eyeOffset = 0.09
eyeRadius	float 0.0 to 1.0	The radius of the ring around each eye	eyeRadius = 0.05
pupilAngle	float 0.0 to pi * 2	The pupil rotation in radians	pupilAngle = 3.14159
pupilOffset	float 0.0 to eyeRadius	The distance between center of pupil and center of eye	pupilOffset = 0.02
mouthColor	RGB color	The color of the mouth	mouthColor = color(0, 0, 0)
pupilColor	RGB color	The color of the pupil	pupilColor = color(0, 0, 0)
eyeColor	RGB color	The color of the eye around the pupil	pupilColor = color(1, 1, 1)
ringColor	RGB color	The color of the ring around the ey	ringColor = color(0, 1, 0)
faceCenter	float 0.0 to 1.0	The horizontal center of the face	faceCenter = 0.5
mapCode	integer 0 to 7	Controls s,t mapping: 0 = default 1 = invert s 2 = invert t 3 = invert s and t 4 = swap s and t 5 = swap s and t, invert s 6 = swap s and t, invert t 7 = swap s and t, invert s and t	mapCode = 0
scaleS	float	scaling factor for aspect ratio, may be greater than 1.0	scaleS = 2.0
fuzz	float 0.0 to 1.0	The fuzz factor for anti-aliasing	fuzz = 0.0025
Ka	float 0.0 to 1.0	The usual meaning for matte shading	Ka = 1.0
Ks	float 0.0 to 1.0	The usual meaning for matte shading	Ks = 1.0

View the simpleFace5.sl shader source

Download the simpleFace5 package for Presenter 3D