Implement ray3, timer and a simple viewport scanner.

Fix bitmap wrong pixel sequence.
Remove default constructor of bitmap.
Add pixel mixture method.

1 files changed, 60 insertions, 0 deletions

diff --git a/main_simple_scanner.cpp b/main_simple_scanner.cpp
new file mode 100644
index 0000000..a1d75f7
--- /dev/null
+++ b/main_simple_scanner.cpp
@@ -0,0 +1,60 @@
+//
+// Created by Keuin on 2022/4/11.
+//
+
+#include <cstdint>
+#include <iostream>
+
+#include "vec.h"
+#include "ray.h"
+#include "bitmap.h"
+#include "timer.h"
+
+
+class viewport {
+    uint16_t width, height;
+    vec3d center;
+    bitmap8b bitmap_{width, height};
+
+    static pixel8b color(const ray3d &r) {
+        const auto u = (r.direction().y + 1.0) * 0.5;
+        return mix(
+                pixel8b::from_normalized(1.0, 1.0, 1.0),
+                pixel8b::from_normalized(0.5, 0.7, 1.0),
+                1.0 - u,
+                u
+        );
+    }
+
+public:
+    viewport() = delete;
+
+    viewport(uint16_t width, uint16_t height, vec3d viewport_center) :
+            width(width), height(height), center(viewport_center) {}
+
+    void render(vec3d viewpoint) {
+        const auto r = center - viewpoint;
+        const int half_width = width / 2, half_height = height / 2;
+        for (int j = -half_height; j < half_height; ++j) {
+            for (int i = -half_width; i < half_width; ++i) {
+                const auto dir = r + vec3d{static_cast<double>(i), static_cast<double>(j), 0};
+                const ray3d ray{viewpoint, dir}; // from camera to pixel (on the viewport)
+                const auto pixel = color(ray);
+                bitmap_.set(i + half_width, j + half_height, pixel);
+            }
+        }
+    }
+
+    const bitmap8b &bitmap() const {
+        return bitmap_;
+    }
+};
+
+int main() {
+    viewport vp{1920, 1080, vec3d{0, 0, -100}};
+    timer tm;
+    tm.start_measure();
+    vp.render(vec3d{0, 0, 0}); // camera position as the coordinate origin
+    tm.stop_measure();
+    vp.bitmap().write_plain_ppm(std::cout);
+}
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