This file is indexed.

/usr/share/psychtoolbox-3/PsychOpenGL/PsychGLSLShaders/moglFDFSamplingShader.frag.txt is in psychtoolbox-3-common 3.0.11.20131230.dfsg1-1build1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
/* FDF shader for sampling of rendered silhouette at provided random
 * sampling positions in order to update sample distribution.
 *
 * (c) 2008 by Mario Kleiner, licensed under MIT license.
 */

#extension GL_ARB_texture_rectangle : enable


uniform sampler2DRect SilSamplePositions;
uniform sampler2DRect Silhouette;

uniform vec4 TextureOffsetBias;

void main(void)
{
    /* Read sample position from random textures RA channels */
    vec2 pos = texture2DRect(SilSamplePositions, gl_TexCoord[0].st).ra;

    /* Readout sample location from Silhouette - Writeout to sampleBuffer: */
    gl_FragColor = texture2DRect(Silhouette, pos);

    /* Need to remap texture coordinate range to available range in trackingBuffer: */
    gl_FragColor.xy = (gl_FragColor.xy - TextureOffsetBias.xy) * TextureOffsetBias.zw;
}