HYPER MIKAN BOX

文書の過去の版を表示しています。

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<codeprism lang=cpp el=true css=full> #include <raylib.h>

#include <cassert> #include <cmath> #include <iterator> #include <vector>

#include “vmath.h”

int const Cw = 600; int const Ch = 600;

using vec2 = vmath::vec2<float>;

void PutPixel(int x, int y, Color const &color) {

  DrawPixel(x + Cw / 2, -y + Ch / 2, color);

}

template <typename Iter>

  requires std::output_iterator<Iter, float>

void Interpolate(int i0, float d0, int i1, float d1, Iter out) {

  if (i0 == i1) {
      *out = d0;
      return;
  }

  auto a = (d1 - d0) / (i1 - i0);
  auto d = d0;

  for (int i = i0; i <= i1; ++i) {
      *out++ = d;
      d += a;
  }

}

void DrawLine(vec2 const &p0, vec2 const &p1, Color const &color) {

  auto x0 = p0.x;
  auto y0 = p0.y;
  auto x1 = p1.x;
  auto y1 = p1.y;

  if (std::abs(x1 - x0) > std::abs(y1 - y0)) {
      if (x0 > x1) {
          std::swap(x0, x1);
          std::swap(y0, y1);
      }
      auto i0 = static_cast<int>(std::floor(x0));
      auto i1 = static_cast<int>(std::floor(x1));
      auto ys = std::vector<float>(i1 - i0 + 1);

      Interpolate(i0, y0, i1, y1, ys.begin());

      for (int i = i0; i <= i1; ++i) {
          PutPixel(i, ys[i - i0], color);
      }
  } else {
      if (y0 > y1) {
          std::swap(y0, y1);
          std::swap(x0, x1);
      }
      auto i0 = static_cast<int>(std::floor(y0));
      auto i1 = static_cast<int>(std::floor(y1));
      auto xs = std::vector<float>(i1 - i0 + 1);

      Interpolate(i0, x0, i1, x1, xs.begin());

      for (int i = i0; i <= i1; ++i) {
          PutPixel(xs[i - i0], i, color);
      }
  }

}

void DrawWireframeTriangle(vec2 const &p0,

                         vec2 const &p1,
                         vec2 const &p2,
                         Color const &color) {
  DrawLine(p0, p1, color);
  DrawLine(p1, p2, color);
  DrawLine(p2, p0, color);

}

void DrawFilledTriangle(vec2 const &p0,

                      vec2 const &p1,
                      vec2 const &p2,
                      Color const &color) {
  vec2 P0{p0}, P1{p1}, P2{p2};
  if (P1.y < P0.y) {
      std::swap(P1, P0);
  }
  if (P2.y < P0.y) {
      std::swap(P2, P0);
  }
  if (P2.y < P1.y) {
      std::swap(P2, P1);
  }

  auto i0 = static_cast<int>(std::floor(P0.y));
  auto i1 = static_cast<int>(std::floor(P1.y));
  auto i2 = static_cast<int>(std::floor(P2.y));
  auto x01 = std::vector<float>(i1 - i0 + 1);
  auto x12 = std::vector<float>(i2 - i1 + 1);
  auto x02 = std::vector<float>(i2 - i0 + 1);

  Interpolate(i0, P0.x, i1, P1.x, x01.begin());
  Interpolate(i1, P1.x, i2, P2.x, x12.begin());
  Interpolate(i0, P0.x, i2, P2.x, x02.begin());

  x01.pop_back();

  auto x012 = std::vector<float>(x01.size() + x12.size());
  assert(x012.size() == x02.size());

  auto corner = std::copy(x01.begin(), x01.end(), x012.begin());
  std::copy(x12.begin(), x12.end(), corner);

  auto &x_left = x012;
  auto &x_right = x02;
  auto m = x012.size() / 2;
  if (x02[m] < x012[m]) {
      std::swap(x_left, x_right);
  }

  for (int y = i0; y < i2; ++y) {
      auto x_l = static_cast<int>(std::floor(x_left[y - i0]));
      auto x_r = static_cast<int>(std::floor(x_right[y - i0]));
      for (int x = x_l; x <= x_r; ++x) {
          PutPixel(x, y, color);
      }
  }

}

int main() {

  InitWindow(Cw, Ch, "Filled Triangles");

  vec2 p0{-100, 200};
  vec2 p1{100, 100};
  vec2 p2{-200, -200};

  while (!WindowShouldClose()) {
      BeginDrawing();

      ClearBackground(RAYWHITE);

      PutPixel(p0.x, p0.y, RED);
      PutPixel(p1.x, p1.y, RED);
      PutPixel(p2.x, p2.y, RED);

      DrawFilledTriangle(p0, p1, p2, BLUE);
      DrawWireframeTriangle(p0, p1, p2, PURPLE);

      EndDrawing();
  }

} </codeprism>