Shader sources are compiled with a host-provided ShaderToy-compatible GLSL
prelude. User source is inserted after a #line 1 directive, so compile errors
normally report line numbers relative to the shader file rather than the
generated wrapper.
Entry points
------------
Image and buffer fragment passes:
void mainImage(out vec4 fragColor, in vec2 fragCoord)
Cubemap fragment passes:
void mainCubemap(
out vec4 fragColor,
in vec2 fragCoord,
in vec3 rayOrigin,
in vec3 rayDirection)
Compute passes:
void mainCompute(ivec2 coord)
The compute wrapper bounds-checks coord against iResolution before calling
mainCompute.
Common uniforms
---------------
Fragment and compute passes receive:
vec3 iResolution
float iTime
float iTimeDelta
float iFrameRate
int iFrame
vec4 iMouse
vec4 iDate
vec3 iChannelResolution[4]
float iChannelTime[4]
Compute passes additionally receive:
int iIteration
Configured inputs are declared as iChannel0 through iChannel3. Their GLSL
sampler type is derived from the input kind:
sampler2D pass/buffer/compute output, texture, keyboard, music, video, webcam
samplerCube cubemap
sampler3D volume
Only configured channels are declared.
Compute outputs
---------------
Compute output 0 is:
image2D iOutput
For extra_outputs, the host declares image2D iOutput1 through iOutput7 as
needed, each with the matching image format qualifier and binding.
Fragment multiple-render-target outputs are not predeclared. Output 0 is the
mainImage result; declare additional locations yourself, for example:
layout(location = 1) out vec4 normalVelocity;
Audio helpers and semantic uniforms
-----------------------------------
The prelude provides:
float sampleAudioSpectrum(sampler2D channel, float x)
float sampleAudioWaveform(sampler2D channel, float x)
x is clamped to 0..1. The waveform helper maps the stored 0..1 texture sample
back to -1..1.
The shader-facing audio aliases are:
iAudioLoudness
iAudioBass
iAudioMid
iAudioTreble
iAudioOnset
iAudioKick
iAudioSnare
iAudioHihat
iAudioBpm
iAudioBeatPhase
iAudioBeatConfidence
iAudioBeatStrength
iAudioStereoWidth
iAudioStereoBalance
iAudioStereoCorrelation
iAudioEnergyTrend
iAudioDrop
iAudioSectionChange
iAudioSpectralCentroid
iAudioSpectralFlux
iAudioAvailable
iAudioSilence
iAudioSampleRate
For the keyboard/music texture layouts, see:
shadertoy docs channels
For target formats, iterations, MRTs, and SSBOs, see:
shadertoy docs passes