Init.HEADmaster

1 files changed, 87 insertions, 0 deletions

diff --git a/hw6/src/areaLightsource.cpp b/hw6/src/areaLightsource.cpp
new file mode 100644
index 0000000..9005939
--- /dev/null
+++ b/hw6/src/areaLightsource.cpp
@@ -0,0 +1,87 @@
+/******************************************************************/
+/* This file is part of the homework assignments for CSCI-427/527 */
+/* at The College of William & Mary and authored by Pieter Peers. */
+/* No part of this file, whether altered or in original form, can */
+/* be distributed or used outside the context of CSCI-427/527     */
+/* without consent of either the College of William & Mary or     */
+/* Pieter Peers.                                                  */
+/******************************************************************/
+#include <cassert>
+#include "constants.h"
+#include "areaLightsource.h"
+
+//////////////////
+// Constructors //
+//////////////////
+areaLightsource::areaLightsource(const color& power, const std::shared_ptr<const boundedPrimitive>& geometry, const vec3d& attenuation)
+{
+  _power = power;
+  _geometry = geometry;
+  _attenuation = attenuation;
+
+  if(_geometry)
+  {
+    _center = _geometry->sample(0.5f, 0.5).position();
+    _area = _geometry->area();
+  }
+}
+
+
+/////////////
+// Methods //
+/////////////
+lightSample areaLightsource::intensityAt(const vec3d& point) const
+{
+  // use the 'center position' and emulate a point light source
+  vec3d direction = point - _center;
+  float distance = direction.length();
+  float attenuation = ((_attenuation[2]*distance + _attenuation[1])*distance + _attenuation[0]);
+
+  // Done.
+  return lightSample(direction, _power / attenuation, distance - 2.0f * EPSILON);  // reduce distance to avoid self-intersection
+}
+
+
+lightSample areaLightsource::emittanceAt(const vec3d& point, float r1, float r2) const
+{
+  if(!_geometry) return lightSample();
+
+  // sample surface
+  surfaceSample sample = _geometry->sample(r1, r2);
+
+  // direction
+  vec3d direction = point - sample.position();
+  float distance = direction.length();
+
+  // handle backside case
+  if(direction.dot(sample.normal()) < 0.0f) return lightSample();
+
+  // Done.
+  return lightSample(direction,
+		     _power / (2.0f * PI * _area),
+		     distance - 2.0f * EPSILON,     // reduce distance to avoid self-intersection
+		     sample.pdf(),
+		     direction.dot( sample.normal() ) / distance);
+}
+
+
+color areaLightsource::_emittance(const intersectionPoint& ip) const
+{
+  // check if back hit
+  // Note: ip.direction toward the intersection point
+  if(ip.normal().dot(ip.direction()) > 0.0f) return color();
+
+  // evaluate emittance (assume point lies on light source)
+  return _power / (2.0f * PI * _area);
+}
+
+/////////////////////
+// Private Methods //
+/////////////////////
+void areaLightsource::_print(std::ostream& s) const
+{
+  if(_geometry)
+    s << "Area Lightsource: power=" << _power << ", attenuation=" << _attenuation << ", area=" << _area << " centered at: " << _center;
+  else s << "Invalid Area Lightsource";
+}
+