ShapeGroups are now a seperate class: SingleGroup, which can only contain a single Shape

RayTracer/shape/SingleGroup.cpp

+#include "SingleGroup.h"
+
+#include "../material/Material.h"
+#include "../tools/Vec3.h"
+
+namespace shapes {
+SingleGroup::SingleGroup(const util::Transformation& transform,
+                         std::shared_ptr<Shape> shape)
+    : shape(shape), transform(transform) {
+	boundingVolume = shape->bounds() * transform.toWorld;
+}
+SingleGroup::SingleGroup(const util::Mat4& matrix, std::shared_ptr<Shape> shape)
+    : shape(shape), transform(util::Transformation(matrix)) {
+	boundingVolume = shape->bounds() * transform.toWorld;
+}
+
+std::optional<cam::Hit> SingleGroup::intersect(const cam::Ray& r) const {
+	cam::Ray imagR(transform.fromWorld.transformPoint(r.x0),
+	               transform.fromWorld.transformDir(r.d), r.tmin, r.tmax,
+	               r.normalize);
+
+	std::optional<cam::Hit> result = std::nullopt;
+
+	if (shape->bounds().intersects(imagR)) {
+		result = shape->intersect(imagR);
+	}
+
+	if (result) {
+		result = std::optional<cam::Hit>(
+		    {transform.toWorld.transformPoint(result->point()),
+		     transform.toWorldN.transformDir(result->normal()),
+		     result->scalar(), result->material});
+	}
+	return result;
+}
+util::AxisAlignedBoundingBox SingleGroup::bounds() const {
+	return boundingVolume;
+}
+
+}  // namespace shapes
\ No newline at end of file

RayTracer/shape/SingleGroup.h

+#pragma once
+
+#include "../tools/Mat4.h"
+#include "../tools/Transformation.h"
+#include "Shape.h"
+
+namespace shapes {
+class SingleGroup : public Shape {
+   public:
+	SingleGroup(const util::Transformation& trans,
+	            std::shared_ptr<Shape> shape);
+	SingleGroup(const util::Mat4& matrix, std::shared_ptr<Shape> shape);
+
+	std::optional<cam::Hit> intersect(const cam::Ray& r) const override;
+	util::AxisAlignedBoundingBox bounds() const override;
+
+   private:
+	util::AxisAlignedBoundingBox boundingVolume;
+	std::shared_ptr<Shape> shape;
+	util::Transformation transform;
+};
+}  // namespace shapes