Add explosion

README.md

@@ -45,6 +45,16 @@ Two frames of a fluid simlulation from [Yining Karl
 Li](http://www.yiningkarlli.com)'s nifty [Ariel fluid
 simulator](http://www.yiningkarlli.com/projects/arielflip.html).
 
+## Explosion
+
+<img alt="Explosion" src="images/explosion/explosion.png" height="400"/>
+
+[explosion/](https://github.com/mmp/pbrt-v4-scenes/tree/master/explosion/)
+
+A volumetric fiery explosion, stored in a NanoVDB volume that was converted
+from an OpenVDB volume from the [OpenVDB
+repository](https://www.openvdb.org/download/).
+
 ## Ganesha
 
 <img alt="Ganesha" src="images/ganesha/ganesha.png" height="400"/>

explosion/explosion.pbrt

@@ -0,0 +1,49 @@
+
+LookAt 00 120 20       -.5 0 30   0 0 1
+#LookAt 00 400 0       -20 0 150   0 0 1
+
+Camera "perspective"
+    "float fov" 37
+
+Film "rgb"
+  "integer xresolution" 1300
+  "integer yresolution" 1800
+  "string sensor" "nikon_d850"
+  "float whitebalance" 6000
+  "float iso" 100
+  "string filename" "explosion.exr"
+
+Integrator "volpath" "integer maxdepth" 5
+
+WorldBegin
+
+AttributeBegin
+Rotate 10 1 0 0
+LightSource "infinite"
+  "string filename" "textures/sky.exr" "float scale" 2
+AttributeEnd
+
+TransformBegin
+Scale 1 1 1.6
+Rotate 90 1 0 0
+MakeNamedMedium "kaboom" "string type" "nanovdb"
+   "string filename" "fire.nvdb"
+   "spectrum sigma_s" [200 10 900 10] "spectrum sigma_a" [200 10 900 10]
+   "float LeScale" .005  "float temperaturecutoff" 1 "float temperaturescale" 100
+TransformEnd
+
+AttributeBegin
+MediumInterface "kaboom" ""
+Material ""
+Translate 0 40 0
+Shape "sphere" "float radius" 80
+AttributeEnd
+
+AttributeBegin
+Translate 0 -50 0
+
+Material "coateddiffuse" "rgb reflectance" [ .4 .4 .4 ] "float roughness" .001
+
+Translate 0 0 -4
+Shape "disk" "float radius" 1000
+AttributeEnd