Implement Object::Place

Places the object by manipulating its translation matrix.

src/basics/matrix.cc

@@ -44,6 +44,16 @@ Matrix4::Identity()
 }
 
 
+/*
+ * charles::basics::Translation --
+ */
+/* static */ Matrix4
+Matrix4::Translation(const Vector4& p)
+{
+    return Translation(p.X(), p.Y(), p.Z());
+}
+
+
 /*
  * charles::basics::TranslationMatrix --
  */

src/basics/matrix.hh

@@ -30,6 +30,7 @@ struct Matrix4
 
     /** Create a 4x4 translation matrix. */
     static Matrix4 Translation(Double x, Double y, Double z);
+    static Matrix4 Translation(const Vector4 &p);
 
     Matrix4();
     Matrix4(const Double *data);

src/object.cc

@@ -47,6 +47,16 @@ Object::GetMaterial()
 }
 
 
+/*
+ * charles::Object::Place --
+ */
+void
+Object::Place(const Vector4 &p)
+{
+    mTranslation = Matrix4::Translation(p);
+}
+
+
 /*
  * charles::Object::SetMaterial --
  */

src/object.hh

@@ -27,6 +27,8 @@ struct Object
     Material& GetMaterial();
     void SetMaterial(const Material& material);
 
+    void Place(const basics::Vector4 &p);
+
     /**
      * Determine if the given ray intersects with this object. Converts the
      * ray's origin and direction to object space before calling the protected
@@ -67,6 +69,7 @@ private:
     /** Convert `v` to global space from object space. */
     basics::Vector4 FromObjectSpace(const basics::Vector4& v) const;
 
+
     /** A translation matrix from global coordinates to this object's space. */
     basics::Matrix4 mTranslation;