Implement some common class.

.gitignore

@@ -205,5 +205,7 @@ cython_debug/
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-#.idea/
+.idea/
 
+# Visual Studio Code
+.vscode

src/CMakeLists.txt

@@ -1,10 +1,7 @@
 cmake_minimum_required(VERSION 3.9) 
 PROJECT(renderer)
 
-
 aux_source_directory(${CMAKE_CURRENT_SOURCE_DIR} CPP_FILES)
-foreach(FILE_PATH ${CPP_FILES})
-  get_filename_component(FILE_NAME ${FILE_PATH} NAME_WLE)
-  add_executable(${FILE_NAME} ${FILE_PATH})
-  target_link_libraries(${FILE_NAME} LINK_PUBLIC spdlog eigen ${OpenCV_LIBS})
-endforeach()
+
+add_executable(${CMAKE_PROJECT_NAME} ${CPP_FILES})
+target_link_libraries(${CMAKE_PROJECT_NAME} LINK_PUBLIC spdlog eigen ${OpenCV_LIBS})

src/minus_renderer.cc

@@ -1,3 +1,6 @@
+// Copyright 2024 Bytedance Inc. All Rights Reserved.
+// Author: tianlei.richard@qq.com (tianlei.richard)
+
 #include <Eigen/Dense>
 
 #include <opencv2/core/core.hpp>
@@ -6,18 +9,22 @@
 #include "spdlog/spdlog.h"
 #include "spdlog/fmt/ostr.h" // github.com/gabime/spdlog/issues/1638
 
+#include "rasterizer.h"
+#include "triangle.h"
+
 using namespace Eigen;
 using namespace cv;
 
 int main(int argc, char *argv[]) {
-  spdlog::info("Hello, world.");
 
-  MatrixXd m(2,2);
-  m(0,0) = 3;
-  m(1,0) = 2.5;
-  m(0,1) = -1;
-  m(1,1) = m(1,0) + m(0,1);
-  spdlog::info("\n{}", m);
+  const int width = 1280;
+  const int height = 720;
+
+  Triangle t{Triangle::PointType{1, 1, 0}, Triangle::PointType{3, 1, 0},
+             Triangle::PointType{2, 4, 0}};
+
+  Rasterizer rasterizer{width, height};
+  rasterizer.rasterize(t);
 
   return 0;
 }

src/rasterizer.cc

@@ -0,0 +1,24 @@
+// Copyright 2024 Bytedance Inc. All Rights Reserved.
+// Author: tianlei.richard@qq.com (tianlei.richard)
+
+#include "rasterizer.h"
+#include <limits>
+
+Rasterizer::Rasterizer(const int width, const int height)
+    : width_(width), height_(height),
+      pixels_(std::vector<std::vector<int>>(
+          height,
+          std::vector<int>(width, std::numeric_limits<int>::infinity()))) {}
+
+void Rasterizer::rasterize(const Triangle &t) {
+  const auto &aabb = t.axis_align_bbox();
+  const int x_min = aabb.x;
+  const int x_max = aabb.x + aabb.width;
+  const int y_min = aabb.y;
+  const int y_max = aabb.y + aabb.height;
+
+  for (int i = x_min; i < x_max; ++i) {
+    for (int j = y_min; j < y_max; ++j) {
+    }
+  }
+}

src/rasterizer.h

@@ -0,0 +1,24 @@
+// Copyright 2024 Bytedance Inc. All Rights Reserved.
+// Author: tianlei.richard@qq.com (tianlei.richard)
+
+#pragma once
+
+#include "triangle.h"
+#include <opencv2/core/core.hpp>
+#include <vector>
+
+class Rasterizer {
+public:
+  using RasterizeRange = cv::Rect2i;
+
+public:
+  Rasterizer(const int width, const int height);
+
+public:
+  void rasterize(const Triangle &t);
+
+private:
+  int width_;
+  int height_;
+  std::vector<std::vector<int>> pixels_;
+};

src/triangle.cc

@@ -0,0 +1,40 @@
+// Copyright 2024 Bytedance Inc. All Rights Reserved.
+// Author: tianlei.richard@qq.com (tianlei.richard)
+
+#include "triangle.h"
+#include <algorithm>
+
+Triangle::Triangle(const PointType &a, const PointType &b, const PointType &c)
+    : points_({HomoPointType{a[0], a[1], a[2], 1},
+               HomoPointType{b[0], b[1], b[2], 1},
+               HomoPointType{c[0], c[1], c[2], 1}}),
+      aabb_(calculate_aabb(points_[0], points_[1], points_[2])) {}
+
+Triangle::Triangle(const HomoPointType &a, const HomoPointType &b,
+                   const HomoPointType &c)
+    : points_({a, b, c}),
+      aabb_(calculate_aabb(points_[0], points_[1], points_[2])) {}
+
+Triangle::BBoxType Triangle::calculate_aabb(const HomoPointType &a,
+                                            const HomoPointType &b,
+                                            const HomoPointType &c) {
+  const int x_min = std::min({a.x(), b.x(), c.x()});
+  const int y_min = std::min({a.y(), b.y(), c.y()});
+  const int x_max = std::max({a.x(), b.x(), c.x()});
+  const int y_max = std::max({a.y(), b.y(), c.y()});
+  return BBoxType{x_min, y_min, (x_max - x_min), (y_max - y_min)};
+}
+
+Triangle::BBoxType Triangle::axis_align_bbox() const { return aabb_; }
+
+void Triangle::affine_transform(const AffineTransformType &m) {
+  for (auto &p : points_) {
+    p = m * p;
+  }
+}
+
+void Triangle::projective_transform(const ProjectiveTransformType &m) {
+  for (auto &p : points_) {
+    p = m * p;
+  }
+}

src/triangle.h

@@ -0,0 +1,40 @@
+// Copyright 2024 Bytedance Inc. All Rights Reserved.
+// Author: tianlei.richard@qq.com (tianlei.richard)
+
+#pragma once
+
+#include <Eigen/Dense>
+#include <Eigen/Geometry>
+#include <array>
+#include <opencv2/core/core.hpp>
+
+class Triangle {
+public:
+  using AffineTransformType = Eigen::Transform<double, 3, Eigen::Affine>;
+  using ProjectiveTransformType =
+      Eigen::Transform<double, 3, Eigen::Projective>;
+  using PointType = Eigen::Vector3d;
+  using BBoxType = cv::Rect2i;
+
+private:
+  using HomoPointType = Eigen::Vector4d;
+
+public:
+  Triangle(const PointType &a, const PointType &b, const PointType &c);
+  Triangle(const HomoPointType &a, const HomoPointType &b,
+           const HomoPointType &c);
+
+public:
+  BBoxType axis_align_bbox() const;
+
+  void affine_transform(const AffineTransformType &m);
+  void projective_transform(const ProjectiveTransformType &m);
+
+private:
+  static BBoxType calculate_aabb(const HomoPointType &a, const HomoPointType &b,
+                                 const HomoPointType &c);
+
+private:
+  std::array<HomoPointType, 3> points_;
+  BBoxType aabb_;
+};