pitrix/src/effect_twirl.cpp

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

void TwirlEffect::loop() {
	double center_x = _real_center_x; // - (cos8(_center_offset_angle)>>6);
    double center_y = _real_center_y; // + (sin8(_center_offset_angle)>>6);
    for (int x=0; x<window->width; x++) for (int y=0; y<window->height; y++) {
        uint8_t angle = atan2(y - center_y, x - center_x) / M_PI * 128 + 128 + angleOffset;
        uint16_t distance = sqrt16((center_x - x) * (center_x - x) + (center_y - y) * (center_y - y));
        if (distance > 255) distance = 255;
        angle -= distance << 2;
        CRGB color(CHSV(angle, 255, 255 - distance*16));
        window->setPixel(x, y, &color);
    }
    angleOffset += 1;
    if (angleOffset % 17 == 0) _center_offset_angle++;
}