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→Explanation of DistrhoPluginMain.cpp
Two sections
Two sections
# protected:
# '''protected:'''
# private:
# '''private:'''
Protected:
Protected:
Members declared as protected are accessible within the same class and in derived classes
Members declared as protected are accessible within the same class and in derived classes
Some functions are declared
Firstly those that return character strings of text (char*)
getLabel() const overide { return "SimpleGain"; }
getDescription()
getMaker()
getLicense()
then a function that returns an unsigned 32 bit integer 0 -> 4 Gig
uint32_t getVersion() const override { return d_version(1, 0, 0); }
and an even more massive number 64 bit integer ( don't ask)
int64_t getUniqueId() const override { return d_cconst('S', 'G', 'a', 'n'); }
Next we have a function that initializes some Parameters and define a range of values for that handy gain number we'd like to alter.
void initParameter(uint32_t index, Parameter& parameter) override {
if (index != 0) return;
parameter.hints = kParameterIsAutomable;
parameter.name = "Gain";
parameter.symbol = "gain";
parameter.unit = "x";
parameter.ranges.def = 1.0f;
parameter.ranges.min = 0.0f;
parameter.ranges.max = 2.0f;
This applies extra values to the external implementation of this parameter so the two environments can pass data effectively.
index is required to have a value 0 to set these values to what are presumably defaults.
Next we have a Getter & a Setter
float getParameterValue(uint32_t index) const override {
if (index != 0) return 0.0f;
return gain;
}
void setParameterValue(uint32_t index, float value) override {
if (index != 0) return;
gain = value;
}
Again requiring a 0 index to operate.
Lastly in the protected section
void run(const float** inputs, float** outputs, uint32_t frames) override {
const float* inL = inputs[0];
const float* inR = inputs[1];
float* outL = outputs[0];
float* outR = outputs[1];
for (uint32_t i = 0; i < frames; ++i) {
outL[i] = inL[i] * gain;
outR[i] = inR[i] * gain;
}
}
The run function of this class, which will be called by the underlying system to process audio samples appearing at the input and generating appropriate output at the correct time.
i.e. doing the clever stuff between these two...
void run(const float** inputs, float** outputs, uint32_t frames) override
It's defined as a void so it does not return a value, interacting via the arrays passed to it.
The inputs to the tun function are a
an array of inputs
an array of outputs
A frame count. The number of frames in the array.
Don't know what override does.
The arrays are allocated to variables ( notice the assumption here that we only handle the first two arrays handed to us. How it deals with other arrays is a point of discussion.)
const float* inL = inputs[0];
const float* inR = inputs[1];
float* outL = outputs[0];
float* outR = outputs[1];
So for each frame we loop a counter i with that numbered frame of audio
for (uint32_t i = 0; i < frames; ++i) {
and then do stuff
outL[i] = inL[i] * gain;
outR[i] = inR[i] * gain;
}
At the end of the process the out arrays have been filled with the adjusted values from the input arrays. . . .
Private:
Private: