You want a wavetable oscillator where:

Hand-Drawn Wavetables: Users can draw a waveform (e.g., via a UI element) to define a single-cycle waveform.
Random Generation: A function generates a random single-cycle waveform.
HISE Integration: The oscillator works within HISE, leveraging its synthesis and modulation capabilities.
HISE already has a built-in WavetableSynth module, but it relies on pre-converted .hwt files and doesn’t natively support real-time drawing or random generation in its UI. You’ll need to create a custom oscillator and possibly extend the UI to meet your needs.

HISE supports multiple DSP development paths:

SNEX: A C++-like scripting language native to HISE for real-time DSP, integrated with its scriptnode system.
RNBO: A Max/MSP-based code export tool from Cycling ’74, which generates C++ code deployable in HISE.
FAUST: A functional programming language for signal processing, which compiles to C++ and can be integrated into HISE.

Step-by-Step Solution

1. Draw a Vertical Slider
   Start with a basic vertical slider (unrotated). For example, a rectangle that moves up and down based on mouse position.

2. Apply Rotation
   Use g.rotate to rotate the slider around a pivot point (e.g., its center). This visually rotates it, but the mouse interaction will still be in the original coordinate system.

3. Adjust Mouse Input
   To fix the "opposite direction" issue, transform the mouse coordinates to align with the rotated slider. For a 90-degree rotation (e.g., turning a horizontal slider vertical), swap and invert the mouse X and Y values.