Crosshatch Post-Processing Effect give away

[Vaquero]

He there!
As I was digging more into GLSL shader programming and its usage inside Vizard, I implemented the code for a crosshatch post-processing effect as a practice. But I thought, maybe it's useful for anybody, so I share it here.
It also demonstrates how to partially overlay the original image.

Vizard Script:

"""
Crosshatch Post Processing Effect
with adjustable split screen.
"""

import viz
viz.go()

import vizcam
vizcam.PivotNavigate(center=[0,1,0],distance=10)

viz.add('piazza.osgb')

import vizinfo
# Setup info panel
info = vizinfo.InfoPanel()

import vizfx.postprocess

class CrosshatchEffect(vizfx.postprocess.BaseShaderEffec t):

def _getFragmentCode(self):
return """
uniform sampler2D vizpp_InputTex;
uniform float scale;
uniform float vx_offset;
uniform float hatch_y_offset; // 5.0
uniform float lum_threshold_1; // 1.0
uniform float lum_threshold_2; // 0.7
uniform float lum_threshold_3; // 0.5
uniform float lum_threshold_4; // 0.3
void main()
{
vec2 uv = gl_TexCoord[0].xy;

vec3 tc = vec3(1.0, 0.0, 0.0);
if (uv.x < (vx_offset-0.005))
{
float lum_r = texture2D(vizpp_InputTex, uv).r * 0.2126;
float lum_g = texture2D(vizpp_InputTex, uv).g*0.7152;
float lum_b = texture2D(vizpp_InputTex, uv).b*0.0722;
float lum = scale * length(lum_r + lum_g + lum_b);
tc = vec3(1.0, 1.0, 1.0);

if (lum < lum_threshold_1)
{
if (mod(gl_FragCoord.x + gl_FragCoord.y, 10.0) == 0.0)
tc = vec3(0.0, 0.0, 0.0);
}

if (lum < lum_threshold_2)
{
if (mod(gl_FragCoord.x - gl_FragCoord.y, 10.0) == 0.0)
tc = vec3(0.0, 0.0, 0.0);
}

if (lum < lum_threshold_3)
{
if (mod(gl_FragCoord.x + gl_FragCoord.y - hatch_y_offset, 10.0) == 0.0)
tc = vec3(0.0, 0.0, 0.0);
}

if (lum < lum_threshold_4)
{
if (mod(gl_FragCoord.x - gl_FragCoord.y - hatch_y_offset, 10.0) == 0.0)
tc = vec3(0.0, 0.0, 0.0);
}
}
else if (uv.x>=(vx_offset+0.005))
{
tc = texture2D(vizpp_InputTex, uv).rgb;
}

gl_FragColor = vec4(tc, 1.0);
}
"""

def _createUniforms(self):
self.uniforms.addFloat('scale',1.0)
self.uniforms.addFloat('vx_offset',0.5)
self.uniforms.addFloat('hatch_y_offset',5.0)
self.uniforms.addFloat('lum_threshold_1',1.0)
self.uniforms.addFloat('lum_threshold_2',0.7)
self.uniforms.addFloat('lum_threshold_3',0.5)
self.uniforms.addFloat('lum_threshold_4',0.3)

def setScale(self,scale):
self.uniforms.setValue('scale',scale)

def getScale(self):
return self.uniforms.getValue('scale')

def setvx_offset(self,vx_offset):
self.uniforms.setValue('vx_offset',vx_offset)

def getvx_offset(self):
return self.uniforms.getValue('vx_offset')

effect = CrosshatchEffect()
vizfx.postprocess.addEffect(effect)

import vizconfig
# Setup config options for post processing effect
ppConfig = vizconfig.BasicConfigurable('Crosshatch')
ppConfig.addBoolItem('Enable', fget=effect.getEnabled, fset=effect.setEnabled)
ppConfig.addFloatRangeItem('Brightness', [0.5,5.0], fget=lambda: effect.getScale(), fset=lambda v: effect.setScale(v))
ppConfig.addFloatRangeItem('Split Screen', [0.0,1.0], fget=lambda: effect.getvx_offset(), fset=lambda v: effect.setvx_offset(v))
vizconfig.register(ppConfig)

vizconfig.getConfigWindow().setWindowVisible(True)


Source: http://www.geeks3d.com/20110219/shader-library-crosshatching-glsl-filter/