Render images, README.

README.md

@@ -7,6 +7,8 @@ Terry Sun; Arch Linux, Intel i5-4670, GTX 750
 
 A CUDA-accelerated path tracer: a global-illumination renderer.
 
+![](img/main-10000.png)
+
 ## Features
 
 ### Materials
@@ -17,8 +19,14 @@ The pathtracer supports the following material surfaces:
 * specular/reflective (perfect and imperfect): light reflects perfectly off the
   surface; or, light takes an imperfect reflected directly using the [Phong
   BRDF][gpu-specular].
-* refractive (using [Schlick's Approximation][wiki-schlick] to blend reflective
-  and refractive light bounces): glass, water
+* refractive (using [Schlick's Approximation][wiki-schlick] of the Fresnel
+  effect to blend reflective and refractive light bounces).
+
+![](img/specular-5000.png)
+![](img/refract-5000.png)
+
+*(Left: specular exponent 200; specular exponent 25)*
+*(Right: indices of refraction 1.31 (water ice), 1.7 (impure glass))*
 
   [gpu-specular]: http://http.developer.nvidia.com/GPUGems3/gpugems3_ch20.html
   [wiki-schlick]: https://en.wikipedia.org/wiki/Schlick%27s_approximation
@@ -30,30 +38,74 @@ of rays shot from the camera. DOF is defined with a focal distance from the
 camera, at which objects are perfectly in focus, and an aperture radius,
 defining the amount of variance added to each ray.
 
-![](img/nodof.png)
-![](img/dof05.png)
-![](img/dof03.png)
+![](img/dof-none-5000.png)
+![](img/dof04-5000.png)
+
+*(no DOF; DOF with distance 5.5, aperture 0.4; 5000 iterations each)*
 
 ### Antialiasing
 
 Camera rays are shot from the camera's position in the direction of a pixel.
-Antialiasing jitters the target of the ray within a pixel.
+Antialiasing jitters the target of the ray within a pixel. This is a brief
+computation that happens once per pixel per iteration; it has little impact on
+performance.
+
+![](img/aa-none-5000.png)
+![](img/aa-5000.png)
+
+*(note antialiasing along cube, light, and wall corners)*
+
+### Texture mapping
+
+Textures can be read in to define diffuse colors for a material.
 
-[TODO: picture]
+For spheres, polar coordinates *phi* and *theta* are used as the UV coordinates,
+wrapping a texture across a sphere. For cubes, polar coordinates are calculated
+relative to the cube face; each face of the cube has an identical copy of the
+texture.
+
+For both texture and normal mapping: add a small amount of complexity to the
+intersection tesitng code in order to output UV coordinates. Most of the cost,
+if any, would come from additional memory requirements (access into global
+memory when reading the texture).
+
+![](img/uv1-5000.png)
+![](img/uv2-5000.png)
+
+### Normal mapping
+
+Textures can be read in to define ray-bounce surface normals (superceding normal
+vectors generated by the geometry intersection).
+
+Combining the two above effects:
+
+![](img/globe-texture-5000.png)
+![](img/globe-normal-5000.png)
+![](img/globe-both-5000.png)
+
+*(normal map only; texture map only; texture and normal map)*
 
 ### Stream compaction.
 
-Shared-memory work-efficient stream compaction.
+This pathtracer uses `thrust::remove_if` to perform stream compaction on dead
+rays.
 
-[TODO: analysis]
+I also implemented a [GPU-shared-memory, work-efficient stream compaction
+algorithm][p2-shared-mem]. Unfortunately I couldn't integrate that into this
+project -- I suspect there are memory errors when I translated the stream
+compaction to handle pathtracing structs rather than integer values.
 
-### Texture mapping
+  [p2-shared-mem]: https://github.com/terrynsun/CIS565-P2-Stream-Compaction
+
+![](data/live_rays.png)
 
-[TODO: picture(s)]
+The type of scene has a large effect on the number of rays alive in a scene.
 
-### Bump mapping
+![](data/ray_scatter.png)
 
-[TODO: picture(s)]
+Comparisons done with the demo scene at the top of this README (found in
+`scenes/main.txt`) at 700x700. Open scenes have the front wall removed. Large
+lights are 10x10 (entire ceiling); normal lights are 6x6.
 
 ## Run
 
@@ -104,7 +156,6 @@ MATERIAL  (material ID)                 //material header
 RGB       (float r) (float g) (float b) //diffuse color
 SPECX     (float specx)                 //specular exponent
 SPECRGB   (float r) (float g) (float b) //specular color
-REFR      (bool refr)       //refractivity flag, 0 for no, 1 for yes
 REFRIOR   (float ior)       //index of refraction for Fresnel effects
 EMITTANCE (float emittance) //the emittance of the material; >0 is a light source
 TEXTURE   (int textureid)   //texture corresponding to diffuse coloring

data/closed_large_light.csv

@@ -0,0 +1,21 @@
+depth, intersect time, compact time, live rays
+0, 345.800403, 189.747829, 19897834.300000
+1, 529.565765, 152.956438, 16707276.450000
+2, 609.487291, 129.201187, 14613067.300000
+3, 549.965330, 114.281574, 12999635.500000
+4, 490.922901, 102.845467, 11703350.400000
+5, 442.483781, 95.139066, 10599731.200000
+6, 400.311603, 86.168085, 9632819.550000
+7, 363.525166, 79.759112, 8802539.850000
+8, 331.648603, 73.327230, 8089032.300000
+9, 304.331611, 68.235384, 7476352.100000
+10, 280.627125, 64.967070, 6950144.350000
+11, 259.992184, 60.099235, 6497065.800000
+12, 242.463538, 56.711714, 6106920.000000
+13, 226.842378, 54.055035, 5771159.800000
+14, 213.753557, 51.672931, 5481962.900000
+15, 201.839717, 49.385086, 5232776.700000
+16, 191.812510, 48.190931, 5018265.850000
+17, 182.690216, 46.272653, 4833342.300000
+18, 174.978714, 44.708288, 4674002.200000
+19, 167.555973, 43.778882, 4536869.200000