Halo.h

//
// Created by Marek Bereza on 18/01/2024.
//

#pragma once

#include "Layer.h"

class Halo : public Layer {
public:

    Halo(Graphics &g) : Layer(g) {}

    VboRef vbo;

    void draw() override {
        ScopedAlphaBlend blend(g, true);
        // pulse overall alpha
        g.setColor(1.f, 1.f, 1.f, sin(g.currFrameTime * 4.f) * 0.5 + 0.5);

        vbo->draw(g, Vbo::PrimitiveType::TriangleFan);
    }

    void doLayout() override {


        // circle centre
        vec2 c = centre();

        // circle radius
        float r = std::min(width, height) / 2.f;

        vec3 col = {1.f, 1.f, 0.7f};

        ////////////////////////////////////

        vbo = Vbo::create();

        std::vector<vec2> verts;
        std::vector<vec4> colors;


        // centre of circle
        verts.push_back(c);
        // some kind of orange
        colors.emplace_back(col, 1.f);

        int numSteps = 64;
        for (int i = 0; i <= numSteps; i++) {
            double angle = (i / (double) numSteps) * M_PI * 2.0;
            verts.emplace_back(c.x + std::cos(angle) * r, c.y + std::sin(angle) * r);
            colors.emplace_back(col, 0.f);
        }

        vbo->setVertices(verts);
        vbo->setColors(colors);
    }
};