From 0b099a362a814866a7c2b449f37fd8607745dcde Mon Sep 17 00:00:00 2001
From: NickyMateev <bgdunkers@gmail.com>
Date: Wed, 21 Nov 2018 13:30:05 +0200
Subject: [PATCH] Tweaks

---
 Homework3/solution.go      |  6 +++---
 Homework3/solution_test.go | 22 +++++++++++++++++-----
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/Homework3/solution.go b/Homework3/solution.go
index 8236bae..d326956 100644
--- a/Homework3/solution.go
+++ b/Homework3/solution.go
@@ -5,7 +5,7 @@ import (
 	"sync"
 )
 
-const Episilon = 1e-7
+const epsilon = 1e-7
 
 type Triangle struct {
 	a, b, c geom.Vector
@@ -53,7 +53,7 @@ func (triangle Triangle) Intersect(ray geom.Ray) bool {
 	h := geom.Cross(ray.Direction, edge2)
 
 	det := geom.Dot(edge1, h)
-	if det > -Episilon && det < Episilon {
+	if det > -epsilon && det < epsilon {
 		return false // The ray is parallel to triangle plane, impossible that they intersect
 	}
 
@@ -78,7 +78,7 @@ func (triangle Triangle) Intersect(ray geom.Ray) bool {
 
 	// Calculating t - final check to see if ray intersects triangle
 	t := f * geom.Dot(edge2, q)
-	if t > Episilon {
+	if t > epsilon {
 		return true
 	}
 
diff --git a/Homework3/solution_test.go b/Homework3/solution_test.go
index bffefc4..9ff28d1 100644
--- a/Homework3/solution_test.go
+++ b/Homework3/solution_test.go
@@ -18,7 +18,19 @@ func TestSampleSimpleTriangle(t *testing.T) {
 	}
 }
 
-func TestSampleSimpleSphere(t *testing.T) {
+func TestSampleSimpleTriangleBoundaryIntersectionShouldIntersect(t *testing.T) {
+	var prim geom.Intersectable
+
+	a, b, c := geom.NewVector(0, -2, 0), geom.NewVector(3, 0, 0), geom.NewVector(0, 1, 0)
+	prim = NewTriangle(a, b, c)
+	ray := geom.NewRay(geom.NewVector(0, 0, 3), geom.NewVector(0, 0, -2))
+
+	if !prim.Intersect(ray) {
+		t.Errorf("Expected ray %#v to intersect triangle %#v but it did not.", ray, prim)
+	}
+}
+
+func TestSampleSimpleSphereShouldIntersect(t *testing.T) {
 	var prim geom.Intersectable
 
 	origin, r := geom.NewVector(0, 0, 0), 2.0
@@ -30,10 +42,10 @@ func TestSampleSimpleSphere(t *testing.T) {
 	}
 }
 
-func TestSampleSimpleQuadConvex(t *testing.T) {
+func TestSampleSimpleQuadConvexShouldIntersect(t *testing.T) {
 	var prim geom.Intersectable
 
-	a, b, c, d := geom.NewVector(0, -2, 0), geom.NewVector(3, 0, 0), geom.NewVector(0, 1, 0), geom.Vector{-1, 0, 0}
+	a, b, c, d := geom.NewVector(0, -2, 0), geom.NewVector(3, 0, 0), geom.NewVector(0, 1, 0), geom.NewVector(-1, 0, 0)
 	prim = NewQuad(a, b, c, d)
 	ray := geom.NewRay(geom.NewVector(0, 0, 2), geom.NewVector(0, 0, -1))
 
@@ -45,12 +57,12 @@ func TestSampleSimpleQuadConvex(t *testing.T) {
 func TestSampleSimpleQuadConcaveShouldNotIntersect(t *testing.T) {
 	var prim geom.Intersectable
 
-	a, b, c, d := geom.NewVector(0, -2, 0), geom.NewVector(3, 0, 0), geom.NewVector(0, 1, 0), geom.Vector{1, 0, 0}
+	a, b, c, d := geom.NewVector(0, -2, 0), geom.NewVector(3, 0, 0), geom.NewVector(0, 1, 0), geom.NewVector(1, 0, 0)
 	prim = NewQuad(a, b, c, d)
 	ray := geom.NewRay(geom.NewVector(0, 0, 2), geom.NewVector(0, 0, -1))
 
 	if prim.Intersect(ray) {
-		t.Errorf("Expected ray %#v to intersect quad %#v but it did not.", ray, prim)
+		t.Errorf("Expected ray %#v to not intersect quad %#v but it did.", ray, prim)
 	}
 }