Glass implemented

main.go

@@ -150,6 +150,13 @@ func Reflect(v Vec3, n Vec3) Vec3 {
 	return v.Sub(n.Mult(2*Dot(v,n)))
 }
 
+func Refract(uv Vec3, n Vec3, etai_over_etat float32) Vec3 {
+	cos_theta := float32(math.Min(float64(Dot(uv.Neg(), n)), 1.0))
+	var r_out_perp Vec3 = (uv.Add(n.Mult(cos_theta))).Mult(etai_over_etat)
+	var r_out_parallel Vec3 = n.Mult(float32(-math.Sqrt(math.Abs(float64(1.0 - r_out_perp.Length_squared())))))
+	return r_out_perp.Add(r_out_parallel)
+}
+
 const pi float32 = 3.1415926535897932385
 
 func Degrees_to_radians(degrees float32) float32 {
@@ -363,33 +370,33 @@ func (hl Hittable) Hit(r *Ray, ray_t Interval, rec *Hit_record) bool {
 
 // =============== MATERIAL =================
 type Material struct {
-	lambertian bool
+	material int
-	metal bool
 	albedo Vec3
 	fuzz float32
+	ir float32
 }
 
-func NewMaterial(l bool, m bool, a Vec3, f float32) Material {
+func NewMaterial(m int, a Vec3, f float32, i float32) Material {
 	if f >= 1.0 {
 		return Material{
-			lambertian: l,
+			material: m,
-			metal: m,
 			albedo : a,
 			fuzz: 1.0,
+			ir: i,
 		}
 	} else {
 		return Material{
-			lambertian: l,
+			material: m,
-			metal: m,
 			albedo : a,
 			fuzz: f,
+			ir: i,
 		}
 	}
 
 }
 
 func (mat Material) Scatter(r_in *Ray, rec *Hit_record, attenuation *Vec3, scattered *Ray) bool {
-	if (mat.lambertian) {	
+	if (mat.material == 0) {	//Lambertian
 		scatter_direction := rec.normal.Add(RandomUnitVector())
 		// Catch degenerate scatter direction
 		if scatter_direction.Near_zero() {
@@ -398,13 +405,24 @@ func (mat Material) Scatter(r_in *Ray, rec *Hit_record, attenuation *Vec3, scatt
 
 		*scattered = *NewRay(rec.p, scatter_direction)
 		*attenuation = mat.albedo
-	} else if (mat.metal) {
+	} else if (mat.material == 1) {   //Metall
 		var reflected Vec3 = Reflect(Unit_vector(r_in.Direction()), rec.normal)
 		*scattered = *NewRay(rec.p, reflected.Add(RandomUnitVector().Mult(mat.fuzz)))
 		*attenuation = mat.albedo
 		if !(Dot(scattered.Direction(), rec.normal) > 0) {
 			return false
 		}
+	} else if (mat.material == 2) { //Dielectric
+		*attenuation = NewColor(1.0, 1.0, 1.0)
+		var refraction_ration float32
+		if rec.front_face {
+			refraction_ration = 1/mat.ir
+		} else {
+			refraction_ration = mat.ir
+		}
+		unit_direction := Unit_vector(r_in.Direction())
+		refracted := Refract(unit_direction, rec.normal, refraction_ration)
+		*scattered = *NewRay(rec.p, refracted)
 	}
 	return true
 }
@@ -512,10 +530,10 @@ func (cam *Camera) Pixel_sample_square() Vec3 {
 // =============== MAIN =====================
 func main() {
 	// Materials
-	material_ground := NewMaterial(true, false, NewColor(0.8, 0.8, 0.0), 0.0)
+	material_ground := NewMaterial(0, NewColor(0.8, 0.8, 0.0), 0.0, 0.0)
-	material_center := NewMaterial(true, false, NewColor(0.7, 0.3, 0.3), 0.0)
+	material_center := NewMaterial(2, NewColor(0.7, 0.3, 0.3), 0.0, 1.5)
-	material_left := NewMaterial(false, true, NewColor(0.8, 0.8, 0.8), 0.3)
+	material_left := NewMaterial(2, NewColor(0.8, 0.8, 0.8), 0.3, 1.5)
-	material_right := NewMaterial(false, true, NewColor(0.8, 0.6, 0.2), 1.0)
+	material_right := NewMaterial(1, NewColor(0.8, 0.6, 0.2), 1.0, 0.0)
 
 	// World