UwUGL/primatives/triangle.cpp

#pragma once

#include <stdint.h>

#include "../datatypes.cpp"
#include "../helpers.cpp"
#include "../buffer.cpp"

namespace UwU {
  class Triangle {
    private:
      

    public:
      Triangle(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2) {
        this->x0 = x0;
        this->y0 = y0;
        this->x1 = x1;
        this->y1 = y1;
        this->x2 = x2;
        this->y2 = y2;
      }
      Triangle() {}
      uint16_t x0;
      uint16_t y0;
      uint16_t x1;
      uint16_t y1;
      uint16_t x2;
      uint16_t y2;
      
      // Draw a triangle
      void draw (Buffer buffer, Color color) {
        Coord2 top = Coord2();
        Coord2 mid = Coord2();
        Coord2 btm = Coord2();
        // cases: left-handed, right-handed
        if (y0 <= y1 && y0 <= y2) {
          top.x = x0;
          top.y = y0;
          if (y1 < y2) {
            mid.x = x1;
            mid.y = y1;
            btm.x = x2;
            btm.y = y2;
          } else {
            mid.x = x2;
            mid.y = y2;
            btm.x = x1;
            btm.y = y1;
          }
        } else if (y1 <= y0 && y1 <= y2) {
          top.x = x1;
          top.y = y1;
          if (y0 < y2) {
            mid.x = x0;
            mid.y = y0;
            btm.x = x2;
            btm.y = y2;
          } else {
            mid.x = x2;
            mid.y = y2;
            btm.x = x0;
            btm.y = y0;
          }
        } else {
          top.x = x2;
          top.y = y2;
          if (y0 < y1) {
            mid.y = y0;
            mid.x = x0;
            btm.x = x1;
            btm.y = y1;
          } else {
            mid.x = x1;
            mid.y = y1;
            btm.x = x0;
            btm.y = y0;
          }
        }
        // printf("top: (%u, %u)\n", top.x, top.y);
        // printf("mid: (%u, %u)\n", mid.x, mid.y);
        // printf("btm: (%u, %u)\n", btm.x, btm.y);
        
        uint16_t height = 1 + btm.y - top.y;
        int16_t longBound[height];
        int16_t splitBound[height];
        // int16_t rightBound[height];
        Helpers::bresenham(0, top.x, height - 1, btm.x, longBound);
        // printf("longBound\n");
        if ((int16_t)mid.x < longBound[mid.y - top.y]) {
          // left-handed triangle
          // printf("left-handed\n");
          // rightBound = longBound;
          Helpers::bresenham(0, top.x, mid.y - top.y, mid.x, splitBound);
          // printf("splitTop\n");
          Helpers::bresenham(mid.y - top.y, mid.x, height - 1, btm.x, splitBound);
          // printf("splitBtm\n");
          // for (uint16_t i = 0; i < height; i++) {
          //   printf("(%u, %u)\n", i, splitBound[i]);
          // }
          for (uint16_t i = 0; i < height; i++) {
            for (uint16_t x = (uint16_t)splitBound[i]; x <= (uint16_t)longBound[i]; x++) {
              // Helpers::putPixel(buffer, x, i + (uint32_t)top.y, color.r, color.g, color.b, color.a);
              buffer.drawPixel(Coord2(x, i + (uint16_t)top.y), color);
            }
          }
        } else {
          // right-handed triangle
          // printf("right-handed\n");
          // leftBound = longBound;
          Helpers::bresenham(0, top.x, mid.y - top.y, mid.x, splitBound);
          // printf("splitTop\n");
          Helpers::bresenham(mid.y - top.y, mid.x, height - 1, btm.x, splitBound);
          // printf("splitBtm\n");
          for (uint16_t i = 0; i < height; i++) {
            for (uint16_t x = (uint16_t)longBound[i]; x <= (uint16_t)splitBound[i]; x++) {
              // Helpers::putPixel(buffer, x, i + (uint32_t)top.y, color.r, color.g, color.b, color.a);
              buffer.drawPixel(Coord2(x, i + (uint16_t)top.y), color);
            }
          }
        }
        return;
      }
    };
}