pitrix/src/effect_twirl.cpp

#include "effect_twirl.h"
#include "functions.h"

void TwirlEffect::loop() {
    for (int x=0; x<window->width; x++) for (int y=0; y<window->height; y++) {
        uint8_t angle = (x==center_x && y==center_y) ? 0 : atan2(y - center_y, x - center_x) / M_PI * 128 + 128 + angleOffset;
        uint8_t brightness = sqrt16((center_x - x) * (center_x - x) + (center_y - y) * (center_y - y)) & 0xFF;
        CRGB color(CHSV(angle, (brightness<<5) & 0xFF, 255));
        window->setPixel(x, y, &color);
    }
    angleOffset += 1;
}