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example/raycasting: Refactoring

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This commit is contained in:
Hajime Hoshi 2019-01-12 23:54:15 +09:00
parent 1a0c20c478
commit 1f277f7a2c
1 changed files with 18 additions and 19 deletions
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37
examples/raycasting/main.go
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@ -68,6 +68,10 @@ type Line struct {
X1, Y1, X2, Y2 float64
}
func (l *Line) angle() float64 {
return math.Atan2(l.Y2-l.Y1, l.X2-l.X1)
}
func newRay(x, y, length, angle float64) Line {
return Line{
X1: x,
@ -78,8 +82,8 @@ func newRay(x, y, length, angle float64) Line {
}
// intersection calculates the intersection of given two lines.
// https://en.wikipedia.org/wiki/Line%E2%80%93line_intersection#Given_two_points_on_each_line
func intersection(l1, l2 Line) (float64, float64, error) {
// https://en.wikipedia.org/wiki/Line%E2%80%93line_intersection#Given_two_points_on_each_line
denom := (l1.X1-l1.X2)*(l2.Y1-l2.Y2) - (l1.Y1-l1.Y2)*(l2.X1-l2.X2)
tNum := (l1.X1-l2.X1)*(l2.Y1-l2.Y2) - (l1.Y1-l2.Y1)*(l2.X1-l2.X2)
uNum := -((l1.X1-l1.X2)*(l1.Y1-l2.Y1) - (l1.Y1-l1.Y2)*(l1.X1-l2.X1))
@ -103,10 +107,6 @@ func intersection(l1, l2 Line) (float64, float64, error) {
return x, y, nil
}
func calcAngle(l Line) float64 {
return math.Atan2(l.Y2-l.Y1, l.X2-l.X1)
}
// rayCasting returns a slice of Line originating from point cx, cy and intersecting with objects
func rayCasting(cx, cy float64, objects [][]Line) []Line {
var rays []Line
@ -124,7 +124,8 @@ func rayCasting(cx, cy float64, objects [][]Line) []Line {
// Cast two rays per point
for _, p := range objPoints {
angle := calcAngle(Line{cx, cy, p[0], p[1]})
l := Line{cx, cy, p[0], p[1]}
angle := l.angle()
for _, offset := range []float64{-0.005, 0.005} {
points := [][2]float64{}
@ -156,26 +157,26 @@ func rayCasting(cx, cy float64, objects [][]Line) []Line {
// Sort rays based on angle, otherwise light triangles will not come out right
sort.Slice(rays, func(i int, j int) bool {
return calcAngle(rays[i]) < calcAngle(rays[j])
return rays[i].angle() < rays[j].angle()
})
return rays
}
func vertices(x1, y1, x2, y2, x3, y3 float64) []ebiten.Vertex {
return []ebiten.Vertex{
ebiten.Vertex{float32(x1), float32(y1), 0, 0, 1, 1, 1, 1},
ebiten.Vertex{float32(x2), float32(y2), 0, 0, 1, 1, 1, 1},
ebiten.Vertex{float32(x3), float32(y3), 0, 0, 1, 1, 1, 1},
{float32(x1), float32(y1), 0, 0, 1, 1, 1, 1},
{float32(x2), float32(y2), 0, 0, 1, 1, 1, 1},
{float32(x3), float32(y3), 0, 0, 1, 1, 1, 1},
}
}
func rect(x, y, w, h float64) []Line {
var lines []Line
lines = append(lines, Line{x, y, x, y + h})
lines = append(lines, Line{x, y + h, x + w, y + h})
lines = append(lines, Line{x + w, y + h, x + w, y})
lines = append(lines, Line{x + w, y, x, y})
return lines
return []Line{
{x, y, x, y + h},
{x, y + h, x + w, y + h},
{x + w, y + h, x + w, y},
{x + w, y, x, y},
}
}
func handleMovement() {
@ -284,7 +285,6 @@ func update(screen *ebiten.Image) error {
var (
showRays bool
numRays float64
px, py float64
objects [][]Line
)
@ -294,13 +294,12 @@ const padding = 20
func main() {
px = screenWidth / 2
py = screenHeight / 2
numRays = 128
// Add outer walls
objects = append(objects, rect(padding, padding, screenWidth-2*padding, screenHeight-2*padding))
// Angled wall
objects = append(objects, []Line{Line{50, 110, 100, 150}})
objects = append(objects, []Line{{50, 110, 100, 150}})
// Rectangles
objects = append(objects, rect(45, 50, 70, 20))