Add Chapter 5 "putting it together" example.

tests/ch5_test.cpp

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+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Render test for chapter 5 "Put it together".
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#include <ray.h>
+#include <sphere.h>
+#include <colour.h>
+#include <canvas.h>
+#include <transformation.h>
+
+int main()
+{
+    int x, y;
+    Canvas c = Canvas(100, 100);
+
+    Sphere s = Sphere();
+    Colour red = Colour(1, 0, 0);
+
+    Point cameraOrigin = Point(0, 0, -5);
+    double wallDistance = 10;
+    double wallSize = 7;
+    double pixelSize = wallSize / c.width;
+    for(y = 0; y < c.height; y++)
+    {
+        double worldY = (wallSize / 2) - pixelSize * y;
+        for(x = 0; x < c.width; x++)
+        {
+            double worldX = (wallSize / 2) - pixelSize * x;
+            Point position = Point(worldX, worldY, wallDistance);
+            Ray r = Ray(cameraOrigin, (position - cameraOrigin).normalise());
+            Intersect xs = s.intersect(r);
+
+            if (!xs.hit().nothing())
+            {
+                c.put_pixel(x, y, red);
+            }
+        }
+    }
+
+    c.SaveAsPNG("ch5_test.png");
+    return 0;
+}