Merge pull request #28 from slmtnm/refraction

Fix previous refraction pull request changes

examples/19_refraction.py

@@ -0,0 +1,46 @@
+from pyrt.geometry.vertex import Vertex
+from pyrt import material
+from pyrt.math import Vec3
+from pyrt.scene import Scene
+from pyrt.light import PointLight
+from pyrt.geometry import Sphere, Triangle
+from pyrt.material import PhongMaterial
+from pyrt.camera import PerspectiveCamera
+from pyrt.renderer import SimpleRT
+from PIL import Image
+
+width = 400
+height = 300
+
+camera = PerspectiveCamera(width, height, 60)
+camera.setView(Vec3(0,-10,0), Vec3(0,0,0), Vec3(0,0,1))
+
+scene = Scene()
+scene.addLight(PointLight(Vec3(-1,-8,1)))
+
+# Triangle behind lens
+A = Vertex(position=(-1.5, 6, 0))
+B = Vertex(position=(3.5, 6, 0))
+C = Vertex(position=(1, 6, 5.))
+scene.add(Triangle(A, B, C, material=PhongMaterial(color=Vec3(1,1,1))))
+
+# Floor
+A = Vertex(position=(-5.0, -5.0, -2.0))
+B = Vertex(position=( 5.0, -5.0, -2.0))
+C = Vertex(position=( 5.0,  5.0, -2.0))
+D = Vertex(position=(-5.0,  5.0, -2.0))
+
+floormaterial = PhongMaterial(color=Vec3(.2,.2,.2)  )
+scene.add(Triangle(A,B,C, material=floormaterial))
+scene.add(Triangle(A,C,D, material=floormaterial))
+
+# Two lenses
+scene.add(Sphere(Vec3(-1, 5.7, -1), 2.5, PhongMaterial(color=Vec3(.9, .9, .9),
+    transparency=.8, refraction=1.5)))
+scene.add(Sphere(Vec3(2.8, 5, .5), 1.8, PhongMaterial(color=Vec3(.9, .9, .9),
+    transparency=.8, refraction=1.5)))
+
+scene.setCamera(camera)
+engine = SimpleRT(iterations=4, shadow=True)
+image = engine.render(scene)
+image.save("16.png")

pyrt/geometry/sphere.py

@@ -6,7 +6,7 @@
 
 from ..geometry import Shape
 from ..math import Ray, HitRecord, Vec2, Vec3, dot3, G_EPSILON
-from ..material import Material, PhongMaterial
+from ..material import Material, PhongMaterial, TextureMaterial, NormalMappedMaterial
 from .bbox import BBox
 from math import sqrt, pi, asin, atan2
 
@@ -73,7 +73,8 @@ def hit(self, ray: Ray, hitrecord: HitRecord) -> bool:
             hitrecord.normal = hitrecord.normal_g
             hitrecord.color = Vec3(1., 1., 1.)  # spheres don't have interpolated colors, set to white
             hitrecord.material = self.material
-            hitrecord.texcoord = self.calcTexcoord(hitrecord.point)
+            if isinstance(hitrecord.material, TextureMaterial) or isinstance(hitrecord.material, NormalMappedMaterial):
+                hitrecord.texcoord = self.calcTexcoord(hitrecord.point)
             return True
         return False
 

pyrt/geometry/triangle.py

@@ -5,7 +5,7 @@
 """
 
 from ..geometry import Shape, Vertex
-from ..material import PhongMaterial
+from ..material import PhongMaterial, TextureMaterial, NormalMappedMaterial
 from ..math import *
 
 
@@ -202,7 +202,8 @@ def hit(self, ray: Ray, hitrecord: HitRecord) -> bool:
             cV = self.c.color - self.a.color
             hitrecord.color = self.a.color + cU * u + cV * v
             hitrecord.material = self.material
-            hitrecord.texcoord = self.calcTexcoord(hitrecord.point)
+            if isinstance(hitrecord.material, TextureMaterial) or isinstance(hitrecord.material, NormalMappedMaterial):
+                hitrecord.texcoord = self.calcTexcoord(hitrecord.point)
 
             # why would we?
             # hitrecord.point = ray.start + t * ray.direction

pyrt/math/constants.py

@@ -5,3 +5,4 @@
 """
 
 G_EPSILON = 1E-11
+G_REFRACTION_EPSILON = 1E-4

pyrt/math/vecops.py

@@ -103,7 +103,10 @@ def refract3(N, I, eta):
     I: Incident vector
     eta: Refraction koefficient
     """
-    d = dot3(I, N)
+    d = dot3(N, I)
+    if d > 0:
+        return refract3(I, N * -1, 1 / eta)
+    eta = 1 / eta
     k = 1 - eta * eta * (1 - d * d)
     if k < 0:
         return I

pyrt/renderer/simplert.py

@@ -78,7 +78,7 @@ def _recurse_shade(self, scene: Scene, ray: Ray, iteration_num: int) -> tuple:
         if not hit or iteration_num == 0:
             return r, g, b
 
-        if hitrecord.material.reflectivity != 0.0:
+        if abs(hitrecord.material.reflectivity) > G_EPSILON:
             reflect_ray = Ray(hitrecord.point, reflect3(hitrecord.normal_g, ray.direction))
             new_r, new_g, new_b = self._recurse_shade(scene, reflect_ray, iteration_num - 1)
 
@@ -90,8 +90,11 @@ def _recurse_shade(self, scene: Scene, ray: Ray, iteration_num: int) -> tuple:
 
             self.num_secondary_rays += 1
 
-        if hitrecord.material.transparency != 0.0:
-            refract_ray = Ray(hitrecord.point + ray.direction * 0.01, refract3(hitrecord.normal_g, ray.direction, hitrecord.material.refraction))
+        if abs(hitrecord.material.transparency) > G_EPSILON:
+            refract_ray = Ray(
+                hitrecord.point + ray.direction * G_REFRACTION_EPSILON, 
+                refract3(normalize3(hitrecord.normal_g), normalize3(ray.direction), hitrecord.material.refraction)
+            )
             new_r, new_g, new_b = self._recurse_shade(scene, refract_ray, iteration_num - 1)
 
             ref1 = hitrecord.material.transparency