Starting working on area lights.

source/shapes/light.cpp

@@ -8,6 +8,7 @@
  */
 #include <stdio.h>
 #include <light.h>
+#include <world.h>
 
 void Light::dumpMe(FILE *fp)
 {
@@ -16,4 +17,35 @@ void Light::dumpMe(FILE *fp)
     fprintf(fp, "\"Position\": {\"x\": %f, \"y\": %f, \"z\":%f},\n",
             this->position.x, this->position.y, this->position.z);
     fprintf(fp, "\"Type\": \"PointLight\",\n");
+}
+
+double Light::intensityAt(World &w, Tuple point)
+{
+    switch(this->type)
+    {
+    case POINT_LIGHT:
+    default:
+        return (w.isShadowed(point, this->position))?0.0:1.0;
+
+    case AREA_LIGHT:
+        double total = 0.0;
+        uint32_t v, u;
+        for(v = 0; v < this->vSteps; v++)
+        {
+            for(u = 0; u < this->uSteps; u++)
+            {
+                if (!w.isShadowed(point, this->pointOnLight(u, v)))
+                {
+                    total = total + 1.0;
+                }
+            }
+        }
+        return total / this->samples;
+        break;
+    }
+}
+
+Tuple Light::pointOnLight(uint32_t u, uint32_t v)
+{
+    return this->corner + this->uVec * (u+0.5) + this->vVec * (v+0.5);
 }