[FEAT] cylinder is now ok

apps/chapter_13.cpp

@@ -69,6 +69,7 @@ int main(void)
     the_cylinder = new Cylinder();
     the_cylinder->set_minimum(0);
     the_cylinder->set_maximum(0.75);
+    the_cylinder->set_closed(true);
     the_cylinder->set_transform(Matrix::translation(-1, 0, 1) *
                                 Matrix::scaling(0.5, 1, 0.5));
     Material &the_cylinder_material = the_cylinder->material();
@@ -125,6 +126,7 @@ int main(void)
     the_concentric_cylinder4 = new Cylinder();
     the_concentric_cylinder4->set_minimum(0);
     the_concentric_cylinder4->set_maximum(0.5);
+    the_concentric_cylinder4->set_closed(true);
     the_concentric_cylinder4->set_transform(Matrix::translation(1, 0, 0) *
                                             Matrix::scaling(0.2, 1, 0.2));
     Material &the_concentric_cylinder4_material = the_concentric_cylinder4->material();
@@ -139,6 +141,7 @@ int main(void)
     the_decorative_cylinder1 = new Cylinder();
     the_decorative_cylinder1->set_minimum(0);
     the_decorative_cylinder1->set_maximum(0.3);
+    the_decorative_cylinder1->set_closed(true);
     the_decorative_cylinder1->set_transform(Matrix::translation(0, 0, -0.75) *
                                             Matrix::scaling(0.05, 1, 0.05));
     Material &the_decorative_cylinder1_material = the_decorative_cylinder1->material();
@@ -153,6 +156,7 @@ int main(void)
     the_decorative_cylinder2 = new Cylinder();
     the_decorative_cylinder2->set_minimum(0);
     the_decorative_cylinder2->set_maximum(0.3);
+    the_decorative_cylinder2->set_closed(true);
     the_decorative_cylinder2->set_transform(Matrix::translation(0, 0, -2.25) * Matrix::rotation_y(-0.15) *
                                             Matrix::translation(0, 0, 1.5) * Matrix::scaling(0.05, 1, 0.05));
     Material &the_decorative_cylinder2_material = the_decorative_cylinder2->material();
@@ -167,6 +171,7 @@ int main(void)
     the_decorative_cylinder3 = new Cylinder();
     the_decorative_cylinder3->set_minimum(0);
     the_decorative_cylinder3->set_maximum(0.3);
+    the_decorative_cylinder3->set_closed(true);
     the_decorative_cylinder3->set_transform(Matrix::translation(0, 0, -2.25) * Matrix::rotation_y(-0.3) *
                                             Matrix::translation(0, 0, 1.5) * Matrix::scaling(0.05, 1, 0.05));
     Material &the_decorative_cylinder3_material = the_decorative_cylinder3->material();
@@ -181,6 +186,7 @@ int main(void)
     the_decorative_cylinder4 = new Cylinder();
     the_decorative_cylinder4->set_minimum(0);
     the_decorative_cylinder4->set_maximum(0.3);
+    the_decorative_cylinder4->set_closed(true);
     the_decorative_cylinder4->set_transform(Matrix::translation(0, 0, -2.25) * Matrix::rotation_y(-0.45) *
                                             Matrix::translation(0, 0, 1.5) * Matrix::scaling(0.05, 1, 0.05));
     Material &the_decorative_cylinder4_material = the_decorative_cylinder4->material();
@@ -195,6 +201,7 @@ int main(void)
     the_glass_cylinder = new Cylinder();
     the_glass_cylinder->set_minimum(0.0001);
     the_glass_cylinder->set_maximum(0.5);
+    the_glass_cylinder->set_closed(true);
     the_glass_cylinder->set_transform(Matrix::translation(0, 0, -1.5) *
                                       Matrix::scaling(0.33, 1, 0.33));
     Material &the_glass_cylinder_material = the_glass_cylinder->material();

raytracing/src/shapes/cylinder.cpp

@@ -95,6 +95,18 @@ Intersections Cylinder::local_intersect(const Ray &a_ray)
 
 Tuple Cylinder::local_normal_at(const Tuple &a_local_point) const
 {
+    double the_distance;
+    // Compute the sqare of the distance from the y axis
+    the_distance = std::pow(a_local_point.x(), 2) + std::pow(a_local_point.z(), 2);
+    if ((the_distance < 1) && (a_local_point.y() >= m_maximum - kEpsilon))
+    {
+        return Tuple::Vector(0, 1, 0);
+    }
+    else if ((the_distance < 1) && (a_local_point.y() <= m_maximum + kEpsilon))
+    {
+        return Tuple::Vector(0, -1, 0);
+    }
+
     return Tuple::Vector(a_local_point.x(), 0, a_local_point.z());
 }
 

tests/13_cylinders.cpp

@@ -313,3 +313,52 @@ SCENARIO("Intersecting the caps of a closed cylinder", "[features/cylinders.feat
         }
     }
 }
+
+/* ------------------------------------------------------------------------- */
+
+SCENARIO("The normal vector on the cylinder's end caps", "[features/cylinders.feature]")
+{
+    // | point            | normal           |
+    // | point(0, 1, 0)   | vector(0, -1, 0) |
+    // | point(0.5, 1, 0) | vector(0, -1, 0) |
+    // | point(0, 1, 0.5) | vector(0, -1, 0) |
+    // | point(0, 2, 0)   | vector(0, 1, 0)  |
+    // | point(0.5, 2, 0) | vector(0, 1, 0)  |
+    // | point(0, 2, 0.5) | vector(0, 1, 0)  |
+    CylinderTestNormal the_test[] = {
+        {  Tuple::Point(0, 1,   0), Tuple::Vector(0, -1, 0)},
+        {Tuple::Point(0.5, 1,   0), Tuple::Vector(0, -1, 0)},
+        {  Tuple::Point(0, 1, 0.5), Tuple::Vector(0, -1, 0)},
+        {  Tuple::Point(0, 2,   0), Tuple::Vector(0,  1, 0)},
+        {Tuple::Point(0.5, 2,   0), Tuple::Vector(0,  1, 0)},
+        {  Tuple::Point(0, 2, 0.5), Tuple::Vector(0,  1, 0)}
+    };
+    GIVEN("cyl <- cylinder()")
+    {
+        Cylinder cyl;
+        AND_GIVEN("cyl.minimum <- 1")
+        {
+            cyl.set_minimum(1);
+            AND_GIVEN("cyl.maximum <- 2")
+            {
+                cyl.set_maximum(2);
+                AND_GIVEN("cyl.closed <- true")
+                {
+                    cyl.set_closed(true);
+                    WHEN("n <- local_normal_at(cyl,<point>)")
+                    {
+                        for (int i = 0; i < 6; i++)
+                        {
+                            Tuple p = the_test[i].point;
+                            Tuple normal = cyl.local_normal_at(p);
+                            THEN("n = <normal>")
+                            {
+                                REQUIRE(normal == the_test[i].normal);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}