LibNDS drawcircle (inefficient)

#include <iostream>
#include <string>
#include <stdio.h>
#include <nds.h>
#include <math.h>

#include "Vector2D.cpp"

#define PI 3.14159265

#ifndef GRAPHICS_CPP
#define GRAPHICS_CPP

class Graphics {
    private:
        u16* videoRam;

    public:
        Graphics() {
            videoSetMode(MODE_5_2D | DISPLAY_BG3_ACTIVE);
            vramSetBankA(VRAM_A_MAIN_BG_0x06000000);
            REG_BG3CNT = BG_BMP16_256x256 | BG_BMP_BASE(0);
            REG_BG3PA  = 1 << 8;
            REG_BG3PB  = 0;
            REG_BG3PC  = 0;
            REG_BG3PD  = 1 << 8;
            videoRam   = BG_BMP_RAM(0);
        }

        void drawPixel(int x, int y) {
            videoRam[y * SCREEN_WIDTH + x] = RGB15(0,31,0) | (1<<15);
        }

        // Extremely basic and inefficient implementation to draw a circle:
        void drawCircle(int x, int y, int radius) {
            for(int i = 0; i < 360; ++i) {
                int tmpX = x + round(cos(i * PI / 180) * radius);
                int tmpY = y + round(sin(i * PI / 180) * radius);

                drawPixel(tmpX, tmpY);

            }
        }

};


#endif