Hey Guys.
I find it super convenient that some of the node actually explains how they
operate, so that you can re-create them in your expressions and blink
scripts.
However the equation descriped in the Gradenode does not match the actuall
output of the node
A = multiply*(gain-lift)/(whitepoint-blackpoint)
B = offset + lift - A*blackpoint
output = pow(A*input+B,1/gamma)
Here is a little comparison:
set cut_paste_input [stack 0]
version 8.0 v4
push $cut_paste_input
Ramp {
p0 {0 408}
p1 {1924 426}
color 10000
name Ramp2
selected true
xpos -2
ypos 379
}
set Ne890edf0 [stack 0]
BlinkScript {
ProgramGroup 1
KernelDescription "1 \"Grade\" iterate componentWise
3aed9d965918ead671ab9383439b4816a7772727775caa4b995181fa06c4c03e 2 \"src\"
Read Point \"dst\" Write Point 0"
kernelSource "kernel Grade : ImageComputationKernel<eComponentWise>\n\{\n
Image<eRead, eAccessPoint, eEdgeClamped> src;\n Image<eWrite> dst;\n
void process() \{\n float4 Colors = src();\n float input =
Colors.x;\n float blackpoint = 0.0f;\n float whitepoint = 1.0f;\n
float lift = 0.0f;\n float gain = 0.01f;\n float multiply = 1.0f;\n
float offset = 0.0f;\n float gamma = 2.0f;\n float A =
multiply*(gain-lift)/(whitepoint-blackpoint);\n float B = offset + lift
- A*blackpoint;\n float output = pow(A*input+B,1/gamma);\n dst() =
output;\n \}\n\};"
rebuild ""
name BlinkScript1
selected true
xpos -86
ypos 423
}
push $Ne890edf0
Grade {
white 0.01
gamma 2
black_clamp false
enable_mix_luminance false
name Grade6
selected true
xpos 78
ypos 431
}
Difference {
inputs 2
output rgba.red
name Difference1
selected true
xpos -12
ypos 494
}
Am i missing something, and or do you guys know what is missing?
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