chore: 🍱 Add a new demo

Add a second Utah teapot demo

CMakeLists.txt

@@ -43,6 +43,9 @@ target_link_libraries(cornell_box PUBLIC t)
 add_executable(teapot src/teapot.cpp)
 target_link_libraries(teapot PUBLIC t)
 
+add_executable(teapot2 src/teapot2.cpp)
+target_link_libraries(teapot2 PUBLIC t)
+
 add_executable(triangle src/triangle.cpp)
 target_link_libraries(triangle PUBLIC t)
 

README.md

@@ -105,6 +105,8 @@ ctest
   original Utah teapot (3488 tris) with normal material, with an FPS counter at
   the top-left (might not be visible due to the output being constantly
   overwritten); useful for testing performance.
+- [`teapot2.cpp`](src/teapot2.cpp): a blue Utah teapot with ambient lighting and
+  a point light traveling in a circle. Showcases specular highlights;
 - [`triangle.cpp`](src/triangle.cpp): a simple triangle printed to the terminal
   screen. Demonstrates how to set up a custom 3D geometry.
 

src/teapot.cpp

@@ -12,10 +12,8 @@ int main() {
 
   mesh.translate(0, -1.3, 0);
 
-  // const auto width = 80;
-  // const auto height = 24;
-  const auto width = 213;
-  const auto height = 56;
+  const auto width = 80;
+  const auto height = 24;
   const auto fwidth = static_cast<double>(width);
   const auto fheight = static_cast<double>(height);
 
@@ -63,8 +61,6 @@ int main() {
         auto g = renderTarget.texture.image[index + 1];
         auto b = renderTarget.texture.image[index + 2];
 
-        const auto luminance = t::Color(r, g, b).luminance();
-
         r = std::clamp(r, 0.0, 1.0);
         g = std::clamp(g, 0.0, 1.0);
         b = std::clamp(b, 0.0, 1.0);

src/teapot2.cpp

@@ -0,0 +1,103 @@
+#include "t.hpp"
+#include <chrono>
+#include <iomanip>
+#include <iostream>
+
+using namespace t;
+
+int main() {
+  auto teapot = UtahTeapot();
+  // auto material = NormalColor();
+  auto material = BlinnPhong(Color(0, 0, 244), Color(255, 255, 255), 128);
+  auto mesh = Mesh(teapot, material);
+
+  auto ambient = AmbientLight(Color(64, 64, 64), 1);
+  auto light = PointLight(Color(255, 255, 255), 1);
+  light.translate(0, 1, 0);
+
+  mesh.translate(0, -1.3, 0);
+
+  const auto width = 80;
+  const auto height = 24;
+  const auto fwidth = static_cast<double>(width);
+  const auto fheight = static_cast<double>(height);
+
+  auto scene = Scene();
+  auto camera = PerspectiveCamera(M_PI / 4, fwidth / fheight, 0.0001, 100);
+  camera.translate(0, 0, 2.5);
+
+  scene.add(ambient);
+  scene.add(light);
+  scene.add(mesh);
+  scene.add(camera);
+
+  auto renderer = Rasterizer();
+  auto renderTarget =
+      RenderTarget<double>(width, height, TextureFormat::RgbDouble);
+
+  const auto characters = std::array<char, 12>{'.', ',', '-', '~', ':', ';',
+                                               '=', '!', '*', '#', '$', '@'};
+
+  auto startTime = std::chrono::high_resolution_clock::now();
+  long lastRenderTimestamp = 0;
+
+  while (true) {
+    auto currentTime = std::chrono::high_resolution_clock::now();
+    auto elapsedMs = std::chrono::duration_cast<std::chrono::milliseconds>(
+                         currentTime - startTime)
+                         .count();
+    std::cout << "\x1b[H";
+
+    if (elapsedMs > 0) {
+      std::cout << "FPS: " << std::setfill(' ') << std::setw(3)
+                << 1000 / (elapsedMs - lastRenderTimestamp);
+    }
+
+    // mesh.localRotation.y = 0.001 * elapsedMs;
+    light.localPosition.x = cos(0.001 * elapsedMs) * 2;
+    light.localPosition.z = sin(0.001 * elapsedMs) * 2;
+
+    lastRenderTimestamp = elapsedMs;
+
+    renderer.render(scene, camera, renderTarget);
+
+    for (int j = 0; j < renderTarget.height; j++) {
+      for (int i = renderTarget.width - 1; i > -1; i--) {
+        if (j == 0 && i > renderTarget.width - 8) {
+          continue;
+        }
+
+        int index = (i + j * renderTarget.width) * 3;
+
+        auto r = renderTarget.texture.image[index];
+        auto g = renderTarget.texture.image[index + 1];
+        auto b = renderTarget.texture.image[index + 2];
+
+        const auto luminance = t::Color(r, g, b).luminance();
+
+        r = std::clamp(r, 0.0, 1.0);
+        g = std::clamp(g, 0.0, 1.0);
+        b = std::clamp(b, 0.0, 1.0);
+
+        char c = ' ';
+
+        for (int cs = 11; cs > -1; cs--) {
+          if ((1.0 / 12) * cs < luminance) {
+            c = characters[cs];
+            break;
+          }
+        }
+
+        std::cout << "\033[38;2;" << static_cast<int>(r * 255) << ";"
+                  << static_cast<int>(g * 255) << ";"
+                  << static_cast<int>(b * 255) << "m" << c << "\033[0m";
+      }
+
+      if (j < renderTarget.height - 1) {
+        std::cout << "\n";
+      }
+    }
+  }
+
+  return 0;
+}