uniform float fGlobalTime; // in seconds
uniform vec2 v2Resolution; // viewport resolution (in pixels)
uniform float fFrameTime; // duration of the last frame, in seconds
uniform sampler1D texFFT; // towards 0.0 is bass / lower freq, towards 1.0 is higher / treble freq
uniform sampler1D texFFTSmoothed; // this one has longer falloff and less harsh transients
uniform sampler1D texFFTIntegrated; // this is continually increasing
uniform sampler2D texPreviousFrame; // screenshot of the previous frame
uniform sampler2D texChecker;
uniform sampler2D texNoise;
uniform sampler2D texTex1;
uniform sampler2D texTex2;
uniform sampler2D texTex3;
uniform sampler2D texTex4;
uniform float fMidiK1;
uniform float fMidiK2;
uniform float fMidiK3;
uniform float fMidiK4;
uniform float fMidiK5;
uniform float fMidiK6;
uniform float fMidiK7;
uniform float fMidiK8;
uniform float fMidiS1;
uniform float fMidiS2;
uniform float fMidiS3;
uniform float fMidiS4;
uniform float fMidiS5;
uniform float fMidiS6;
uniform float fMidiS7;
uniform float fMidiS8;
layout(location = 0) out vec4 out_color; // out_color must be written in order to see anything