/usr/share/imagevis3d/shaders/GLRaycaster-Color-FS.glsl is in imagevis3d 3.1.0-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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uniform sampler2D texRayExitPos; ///< the backface (or ray exit point) texture in eyecoords
uniform vec3 vVoxelStepsize; ///< Stepsize (in texcoord) to get to the next voxel
uniform float fRayStepsize; ///< stepsize along the ray
uniform float fIsoval; ///< the isovalue
uniform vec2 vScreensize; ///< the size of the screen in pixels
uniform vec2 vProjParam; ///< X = far / (far - near) / Y = (far * near / (near - far))
uniform vec3 vDomainScale;
varying vec3 vEyePos;
vec3 ComputeNormal(vec3 vHitPosTex, vec3 StepSize,
vec3 DomainScale);
vec3 RefineIsosurface(in vec3 vRayDir,
inout vec3 vCurrentPos,
in float fIsoval);
void main(void)
{
// compute the coordinates to look up the previous pass
vec2 vFragCoords = vec2(gl_FragCoord.x / vScreensize.x , gl_FragCoord.y / vScreensize.y);
// compute the ray parameters
vec3 vRayEntry = texture2D(texRayExitPos, vFragCoords).xyz;
vec3 vRayExit = vEyePos;
vec3 vRayEntryTex = (gl_TextureMatrix[0] * vec4(vRayEntry,1.0)).xyz;
vec3 vRayExitTex = (gl_TextureMatrix[0] * vec4(vRayExit,1.0)).xyz;
float fRayLength = length(vRayExit - vRayEntry);
float fRayLengthTex = length(vRayExitTex - vRayEntryTex);
// compute the maximum number of steps before the domain is left
int iStepCount = int(fRayLength/fRayStepsize)+1;
vec3 vRayIncTex = (vRayExitTex-vRayEntryTex)/(fRayLength/fRayStepsize);
// do the actual raycasting
vec4 vHitPosTex = vec4(0.0,0.0,0.0,0.0);
vec3 vCurrentPosTex = vRayEntryTex;
for (int i = 0;i<iStepCount;i++) {
float fVolumVal = sampleVolume(vCurrentPosTex).a;
if (fVolumVal >= fIsoval) {
vHitPosTex = vec4(vCurrentPosTex.x, vCurrentPosTex.y, vCurrentPosTex.z, 1);
break;
}
vCurrentPosTex += vRayIncTex;
}
// store surface hit if one is found
if (vHitPosTex.a != 0.0)
vHitPosTex.xyz = RefineIsosurface(vRayIncTex, vHitPosTex.xyz, fIsoval);
else
discard;
vec3 fVolumeColor = sampleVolume(vCurrentPosTex).rgb;
// interpolate eye space position
float fInterpolParam = length(vHitPosTex.xyz-vRayEntryTex)/fRayLengthTex;
vec3 vHitPos = vRayEntry * (1.0-fInterpolParam) + vRayExit * fInterpolParam;
// store surface position and red channel
gl_FragData[0] = vec4(vHitPos.xyz,fVolumeColor.r+1.0); // red chanel plus one (to make sure this value is not accideantially zero)
// store non-linear depth
gl_FragDepth = vProjParam.x + (vProjParam.y / -vHitPos.z);
// store normal and green and blue channel
vec3 vNormal = ComputeNormal(vHitPosTex.xyz, vVoxelStepsize,
vDomainScale);
// do a floor just to be sure
gl_FragData[1] = vec4(vNormal,floor(fVolumeColor.g*512.0)+fVolumeColor.b);
}
/*
For more information, please see: http://software.sci.utah.edu
The MIT License
Copyright (c) 2008 Scientific Computing and Imaging Institute,
University of Utah.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/
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