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/*=========================================================================
Program: Visualization Toolkit
Module: vtkGPUVolumeRayCastMapper_CompositeMaskFS.glsl
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
// Fragment program part with ray cast and composite method with masks.
#version 110
uniform sampler3D dataSetTexture;
uniform sampler3D maskTexture;
uniform sampler1D mask1ColorTexture;
uniform sampler1D mask2ColorTexture;
uniform sampler1D opacityTexture;
uniform vec3 lowBounds;
uniform vec3 highBounds;
uniform float maskBlendFactor;
// Entry position (global scope)
vec3 pos;
// Incremental vector in texture space (global scope)
vec3 rayDir;
float tMax;
// from cropping vs no cropping
vec4 initialColor();
// from 1 vs 4 component shader.
float scalarFromValue(vec4 value);
vec4 colorFromValue(vec4 value);
// from noshade vs shade.
void initShade();
vec4 shade(vec4 value);
void trace(void)
{
vec4 destColor=initialColor();
float remainOpacity=1.0-destColor.a;
bool inside=true;
vec4 maskValue;
vec4 color;
vec4 opacity;
initShade();
float t=0.0;
// We NEED two nested while loops. It is trick to work around hardware
// limitation about the maximum number of loops.
while(inside)
{
while(inside)
{
vec4 value=texture3D(dataSetTexture,pos);
float scalar=scalarFromValue(value);
opacity=texture1D(opacityTexture,scalar);
if(maskBlendFactor==0.0)
{
color=shade(value);
}
else
{
// get the mask value at this same location
maskValue=texture3D(maskTexture,pos);
if(maskValue.a==0.0)
{
color=shade(value);
}
else
{
if(maskValue.a==1.0/255.0)
{
color=texture1D(mask1ColorTexture,scalar);
}
else
{
// maskValue.a == 2.0/255.0
color=texture1D(mask2ColorTexture,scalar);
}
color.a=1.0;
if(maskBlendFactor<1.0)
{
color=(1.0-maskBlendFactor)*shade(value)+maskBlendFactor*color;
}
// color.r = 1;
// color.g = 0;
// color.b = 0;
// color.a = 1;
}
}
color=color*opacity.a;
destColor=destColor+color*remainOpacity;
remainOpacity=remainOpacity*(1.0-opacity.a);
pos=pos+rayDir;
t+=1.0;
inside=t<tMax && all(greaterThanEqual(pos,lowBounds))
&& all(lessThanEqual(pos,highBounds))
&& (remainOpacity>=0.0039); // 1/255=0.0039
}
}
gl_FragColor = destColor;
gl_FragColor.a = 1.0-remainOpacity;
}
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