drand() needs <cstdlib>

diff --git a/QuadAreaLight.cxx b/QuadAreaLight.cxx
index ed64910..24e0b8e 100644 (file)
--- a/QuadAreaLight.cxx
+++ b/QuadAreaLight.cxx
@@ -1,4 +1,5 @@
 #include <cmath>
+#include <cstdlib>
 
 #include "QuadAreaLight.hxx"
 
@@ -16,7 +17,7 @@ QuadAreaLight::QuadAreaLight(Scene* scene,
 {
   m_n = m_e1.cross(m_e2);
   m_area = m_n.norm();
-  m_n.normalize(); 
+  m_n.normalize();
 }
 
 QuadAreaLight::QuadAreaLight()
@@ -36,21 +37,21 @@ QuadAreaLight::~QuadAreaLight()
 bool
 QuadAreaLight::Illuminate(Ray& shadow_ray, Vec3f& intensity)
 {
-  // generate random factors 
+  // generate random factors
   float xi1 = drand48();
   float xi2 = drand48();
-  
+
   // bilinear interpolation of position
   Vec3f pos = m_p0 + m_e1 * xi1 + m_e2* xi2;
   // direction of shadow ray
   Vec3f dir = pos-shadow_ray.origin();
-  
+
   float dist = dir.norm();
   float cosN = (dir.dot(m_n)) / dist;
 
   if(cosN <= 0.0f )
     return false;
-  
+
   // squared falloff and projected area
   intensity = m_intensity * ( m_area * cosN / ( dist*dist));