func ExampleBoundingBox_AddPoint() {
box := NewBoundingBox()
box.AddPoint(maths.NewVec3(-1, -1, -1))
box.AddPoint(maths.NewVec3(0, 5, -0.5))
box.AddPoint(maths.NewVec3(1, 0, 2))
fmt.Printf("%s\n", box)
// Output:
// bbox[min: (-1, -1, -1), max: (1, 5, 2)]
}
func ExampleBoundingBox_Inside() {
box := &BoundingBox{
MinVolume: [3]float64{-1, -1, -1},
MaxVolume: [3]float64{1, 1, 1},
}
fmt.Printf("0, 0, 0: %v\n", box.Inside(maths.NewVec3(0, 0, 0)))
fmt.Printf("0, 0, 2: %v\n", box.Inside(maths.NewVec3(0, 0, 2)))
// Output:
// 0, 0, 0: true
// 0, 0, 2: false
}
func TestGetBoundingBox(t *testing.T) {
meshData := []byte(`{
"vertices": [
{
"normal": [0, 0, 1],
"coordinates": [-1, -2, 0]
},
{
"normal": [0, 0, 1],
"coordinates": [1, 5, -8]
},
{
"normal": [0, 0, 1],
"coordinates": [1, 2, 0]
},
{
"normal": [0, 0, 1],
"coordinates": [1, 1, 0]
}
],
"faces": [
{
"vertices": [0, 1, 2],
"material": 42
},
{
"vertices": [1, 2, 3],
"material": 42
}
]
}`)
mesh := &Mesh{}
err := json.Unmarshal(meshData, &mesh)
if err != nil {
t.Fatalf("Error reading json: %s\n", err)
return
}
mesh.Init()
bbox := mesh.GetBoundingBox()
assertEqualVectors(t, maths.NewVec3(1, 5, 0), maths.NewVec3Array(bbox.MaxVolume))
assertEqualVectors(t, maths.NewVec3(-1, -2, -8), maths.NewVec3Array(bbox.MinVolume))
}
func ExamplePinholeCamera_ShootRay_weirdfocus() {
var c Camera = &PinholeCamera{
Focus: *maths.NewVec3(-2, 15, 3),
TopLeft: *maths.NewVec3(-3, 16, 4),
TopRight: *maths.NewVec3(-1, 16, 4),
BottomLeft: *maths.NewVec3(-3, 16, 2),
}
ray := c.ShootRay(0, 0)
fmt.Printf("0, 0: %s\n", ray)
ray = c.ShootRay(0.5, 0.5)
fmt.Printf("0.5, 0.5: %s\n", ray)
// Output:
// 0, 0: (-2, 15, 3) -> (-0.577, 0.577, 0.577)
// 0.5, 0.5: (-2, 15, 3) -> (0, 1, 0)
}
// Vec3Sphere returns a random unit vector
func (r *Random) Vec3Sphere() *maths.Vec3 {
u := r.FloatAB(-1, 1)
theta := r.Float02Pi()
return maths.NewVec3(
math.Sqrt(1-u*u)*math.Cos(theta),
math.Sqrt(1-u*u)*math.Sin(theta),
u,
)
}
func TestPinholeCameraJson(t *testing.T) {
data := []byte(`{
"focus": [1, 2, 3],
"top_left": [4, 5, 6],
"top_right": [7, 8, 9],
"bottom_left": [10, 11, 12]
}`)
c := &PinholeCamera{}
err := json.Unmarshal(data, &c)
if err != nil {
t.Error(err)
}
assertEqualVectors(t, maths.NewVec3(1, 2, 3), &c.Focus)
assertEqualVectors(t, maths.NewVec3(4, 5, 6), &c.TopLeft)
assertEqualVectors(t, maths.NewVec3(7, 8, 9), &c.TopRight)
assertEqualVectors(t, maths.NewVec3(10, 11, 12), &c.BottomLeft)
}
func ExamplePinholeCamera_ShootRay() {
var c Camera = &PinholeCamera{
Focus: *maths.NewVec3(0, 0, 0),
TopLeft: *maths.NewVec3(-1, 1, 1),
TopRight: *maths.NewVec3(1, 1, 1),
BottomLeft: *maths.NewVec3(-1, 1, -1),
}
ray := c.ShootRay(0, 0)
fmt.Printf("0, 0: %s\n", ray)
ray = c.ShootRay(0.5, 0.5)
fmt.Printf("0.5, 0.5: %s\n", ray)
// Output:
// 0, 0: (0, 0, 0) -> (-0.577, 0.577, 0.577)
// 0.5, 0.5: (0, 0, 0) -> (0, 1, 0)
}
// Init of Mesh sets the Triangle indices in the Faces array, calculates the bounding box
// and KD tree, sets the surfaceOx and Oy and Cross Products of the sides of each triangle
func (m *Mesh) Init() {
allIndices := make([]int, len(m.Faces))
for i := range allIndices {
allIndices[i] = i
}
m.BoundingBox = m.GetBoundingBox()
m.tree = m.newKDtree(m.BoundingBox, allIndices, 0)
for i := range m.Faces {
triangle := &m.Faces[i]
A := &m.Vertices[triangle.Vertices[0]].Coordinates
B := &m.Vertices[triangle.Vertices[1]].Coordinates
C := &m.Vertices[triangle.Vertices[2]].Coordinates
AB := maths.MinusVectors(B, A)
AC := maths.MinusVectors(C, A)
triangle.AB = AB
triangle.AC = AC
triangle.ABxAC = maths.CrossProduct(AB, AC)
surfaceA := &m.Vertices[triangle.Vertices[0]].UV
surfaceB := &m.Vertices[triangle.Vertices[1]].UV
surfaceC := &m.Vertices[triangle.Vertices[2]].UV
surfaceAB := maths.MinusVectors(surfaceB, surfaceA)
surfaceAC := maths.MinusVectors(surfaceC, surfaceA)
// Solve using Cramer:
// |surfaceAB.X * px + surfaceAX.X *qx + 1 = 0
// |surfaceAB.Y * px + surfaceAX.Y *qx = 0
// and
// surfaceAB.X * py + surfaceAX.X *qy = 0
// surfaceAB.X * py + surfaceAX.X *qy + 1 = 0
px, qx := maths.SolveEquation(surfaceAB, surfaceAC, maths.NewVec3(1, 0, 0))
py, qy := maths.SolveEquation(surfaceAB, surfaceAC, maths.NewVec3(0, 1, 0))
triangle.surfaceOx = maths.AddVectors(AB.Scaled(px), AC.Scaled(qx))
triangle.surfaceOy = maths.AddVectors(AB.Scaled(py), AC.Scaled(qy))
}
}
func TestAnyCameraJson(t *testing.T) {
data := []byte(`{
"type": "pinhole",
"focus": [0, 0, 0],
"top_left": [-1, 1, 1],
"top_right": [1, 1, 1],
"bottom_left": [-1, 1, -1]
}`)
c := &AnyCamera{}
err := json.Unmarshal(data, &c)
if err != nil {
t.Error(err)
}
ray := c.ShootRay(0.5, 0.5)
assertEqualVectors(t, maths.NewVec3(0, 1, 0), &ray.Direction)
assertEqualVectors(t, maths.NewVec3(0, 0, 0), &ray.Start)
}
func TestBoundingBoxSplit(t *testing.T) {
box := &BoundingBox{
MinVolume: [3]float64{-3.18, -3.96, -1.77},
MaxVolume: [3]float64{4.58, 1.74, 4.56},
}
ray := &ray.Ray{
Start: *maths.NewVec3(4.49, -7.3, 5.53),
Direction: *maths.NewVec3(-0.60, 0.5, -0.62),
}
ray.Init()
if !box.Intersect(ray) {
t.Error("ray should intersect big box")
}
left, right := box.Split(2, 1.39)
assertEqualVectors(t, maths.NewVec3(-3.18, -3.96, -1.77), maths.NewVec3Array(left.MinVolume))
assertEqualVectors(t, maths.NewVec3(-3.18, -3.96, 1.39), maths.NewVec3Array(right.MinVolume))
assertEqualVectors(t, maths.NewVec3(4.58, 1.74, 1.39), maths.NewVec3Array(left.MaxVolume))
assertEqualVectors(t, maths.NewVec3(4.58, 1.74, 4.56), maths.NewVec3Array(right.MaxVolume))
if box.IntersectWall(2, 1.39, ray) {
t.Error("ray shouldn't intersect the wall")
}
if right.Intersect(ray) {
t.Error("ray shouldn't intersect right")
}
if !left.Intersect(ray) {
t.Error("ray should intersect left")
}
}
// UnmarshalJSON implements the json.Unmarshaler interface
func (n *NumberSampler) UnmarshalJSON(data []byte) error {
err := json.Unmarshal(data, &n.Fac)
if err != nil {
return err
}
n.Colour = hdrcolour.New(
float32(n.Fac),
float32(n.Fac),
float32(n.Fac),
)
n.Vector = maths.NewVec3(n.Fac, n.Fac, n.Fac)
return nil
}
func ExampleBoundingBox_Intersect() {
box := &BoundingBox{
MinVolume: [3]float64{-1, -1, -1},
MaxVolume: [3]float64{1, 1, 1},
}
ray1 := &ray.Ray{
Start: *maths.NewVec3(0, 0, 0),
Direction: *maths.NewVec3(1, 0, 0),
}
ray2 := &ray.Ray{
Start: *maths.NewVec3(-5, 0, 0.5),
Direction: *maths.NewVec3(1, 0, 0),
}
ray3 := &ray.Ray{
Start: *maths.NewVec3(-5, 0, 0.5),
Direction: *maths.NewVec3(-1, 0, 0),
}
ray4 := &ray.Ray{
Start: *maths.NewVec3(-5, 0, 0),
Direction: *maths.NewVec3(1, 0, 5),
}
ray1.Init()
ray2.Init()
ray3.Init()
ray4.Init()
fmt.Printf("ray 1: %v\n", box.Intersect(ray1))
fmt.Printf("ray 2: %v\n", box.Intersect(ray2))
fmt.Printf("ray 3: %v\n", box.Intersect(ray3))
fmt.Printf("ray 4: %v\n", box.Intersect(ray4))
// Output:
// ray 1: true
// ray 2: true
// ray 3: false
// ray 4: false
}
// Vec3HemiCos returns a random unit vector chosen on a
// cosine-weighed hemisphere defined by normal
func (r *Random) Vec3HemiCos(normal *maths.Vec3) *maths.Vec3 {
ox := maths.CrossProduct(maths.NewVec3(42, 56, -15), normal)
for math.Abs(ox.Length()) < maths.Epsilon {
ox = maths.CrossProduct(r.Vec3Sphere(), normal)
}
oy := maths.CrossProduct(ox, normal)
ox.Normalise()
oy.Normalise()
u := r.Float01()
radius := math.Sqrt(u)
theta := r.Float02Pi()
vec := normal.Scaled(math.Sqrt(math.Max(0, 1-u)))
vec.Add(ox.Scaled(radius * math.Cos(theta)))
vec.Add(oy.Scaled(radius * math.Sin(theta)))
return vec
}
func TestIntersectBoundingBoxZeroVolume(t *testing.T) {
box := NewBoundingBox()
box.AddPoint(maths.NewVec3(0, 0, 0))
box.AddPoint(maths.NewVec3(1, 0, 0))
box.AddPoint(maths.NewVec3(0, 1, 0))
box.AddPoint(maths.NewVec3(1, 1, 0))
ray := &ray.Ray{
Start: *maths.NewVec3(0.5, 0.5, 1),
Direction: *maths.NewVec3(0, 0, -1),
}
if !box.Intersect(ray) {
t.Error("ray.Ray must intersect box")
}
}
// GetVec3 returns the colour at (u, v)'s components as a vector
func (i *ImageTexture) GetVec3(intersection *ray.Intersection) *maths.Vec3 {
colour := i.GetColour(intersection)
return maths.NewVec3(float64(colour.R), float64(colour.G), float64(colour.B))
}
func TestIntersectTwoTriangles(t *testing.T) {
meshData := []byte(`{
"vertices": [
{
"normal": [0, 0, 1],
"coordinates": [0, 0, 0],
"uv": [0, 0]
},
{
"normal": [0, 0, 1],
"coordinates": [1, 0, 0],
"uv": [1, 0]
},
{
"normal": [0, 0, 1],
"coordinates": [0, 1, 0],
"uv": [0, 1]
},
{
"normal": [0, 0, -1],
"coordinates": [0, 0, 4],
"uv": [0, 0]
},
{
"normal": [0, 0, -1],
"coordinates": [1, 0, 4],
"uv": [1, 0]
},
{
"normal": [0, 0, -1],
"coordinates": [0, 1, 4],
"uv": [0, 1]
}
],
"faces": [
{
"vertices": [3, 4, 5],
"material": 5
},
{
"vertices": [0, 1, 2],
"material": 42
}
]
}`)
mesh := &Mesh{}
err := json.Unmarshal(meshData, &mesh)
if err != nil {
t.Fatalf("Error reading json: %s\n", err)
}
mesh.Init()
testRay := &ray.Ray{
Start: *maths.NewVec3(0.15, 0.11, 1),
Direction: *maths.NewVec3(0, 0, -1),
}
var intersection *ray.Intersection
intersection = mesh.Intersect(testRay)
if intersection == nil {
t.Fatal("Intersection shouldn't be nil")
}
if intersection.Material != 42 {
t.Error("Intersected wrong triangle")
}
testRay.Direction.Z = 1
intersection = mesh.Intersect(testRay)
if intersection == nil {
t.Fatal("Intersection shouldn't be nil")
}
if intersection.Material != 5 {
t.Error("Intersected wrong triangle")
}
}
func ExampleMesh_Intersect() {
meshData := []byte(`{
"vertices": [
{
"normal": [0, 0, 1],
"coordinates": [0, 0, 0],
"uv": [0, 0]
},
{
"normal": [0, 0, 1],
"coordinates": [1, 0, 0],
"uv": [1, 0]
},
{
"normal": [0, 0, 1],
"coordinates": [0, 1, 0],
"uv": [0, 1]
}
],
"faces": [
{
"vertices": [0, 1, 2],
"material": 42
}
]
}`)
mesh := &Mesh{}
err := json.Unmarshal(meshData, &mesh)
if err != nil {
fmt.Printf("Error reading json: %s\n", err)
return
}
mesh.Init()
testRay := &ray.Ray{
Start: *maths.NewVec3(0.15, 0.11, 1),
Direction: *maths.NewVec3(0, 0, -1),
}
var (
intersection *ray.Intersection
)
intersection = mesh.Intersect(testRay)
if intersection == nil {
fmt.Printf("no intersection\n")
} else {
fmt.Printf("intersection point: %s\n", intersection.Point)
fmt.Printf("caused by ray: %s\n", intersection.Incoming)
fmt.Printf("at a distance: %.3g\n", intersection.Distance)
fmt.Printf("with surface coordinates: (%.3g, %.3g)\n",
intersection.U, intersection.V)
fmt.Printf("surface normal: %s\n", intersection.Normal)
fmt.Printf("surface coordinate system: Ox: %s, Oy: %s\n",
intersection.SurfaceOx, intersection.SurfaceOy)
fmt.Printf("surface material: %d\n", intersection.Material)
}
// Output:
// intersection point: (0.15, 0.11, 0)
// caused by ray: (0.15, 0.11, 1) -> (0, 0, -1)
// at a distance: 1
// with surface coordinates: (0.15, 0.11)
// surface normal: (0, 0, 1)
// surface coordinate system: Ox: (1, 0, 0), Oy: (0, 1, 0)
// surface material: 42
}