func tween(a, b mgl32.Vec2) (x, y float32) {
v := b.Sub(a)
v = v.Mul(0.5)
v = a.Add(v)
return v.Elem()
}
/** Calculate line boundary points.
*
* Sketch:
*
* uh1___uh2
* .' '.
* .' q '.
* .' ' ' '.
*.' ' .'. ' '.
* ' .' ul'. '
* p .' '. r
*
*
* ul can be found as above, uh1 and uh2 are much simpler:
*
* uh1 = q + ns * w/2, uh2 = q + nt * w/2
*/
func (polyline *polyLine) renderBevelEdge(sleeve, current, next mgl32.Vec2) {
t := next.Sub(current)
len_t := t.Len()
det := determinant(sleeve, t)
if mgl32.Abs(det)/(sleeve.Len()*len_t) < LINES_PARALLEL_EPS && sleeve.Dot(t) > 0 {
// lines parallel, compute as u1 = q + ns * w/2, u2 = q - ns * w/2
n := getNormal(t, polyline.halfwidth/len_t)
polyline.normals = append(polyline.normals, n)
polyline.normals = append(polyline.normals, n.Mul(-1))
polyline.generateEdges(current, 2)
return // early out
}
// cramers rule
sleeve_normal := getNormal(sleeve, polyline.halfwidth/sleeve.Len())
nt := getNormal(t, polyline.halfwidth/len_t)
lambda := determinant(nt.Sub(sleeve_normal), t) / det
d := sleeve_normal.Add(sleeve.Mul(lambda))
if det > 0 { // 'left' turn -> intersection on the top
polyline.normals = append(polyline.normals, d)
polyline.normals = append(polyline.normals, sleeve_normal.Mul(-1))
polyline.normals = append(polyline.normals, d)
polyline.normals = append(polyline.normals, nt.Mul(-1))
} else {
polyline.normals = append(polyline.normals, sleeve_normal)
polyline.normals = append(polyline.normals, d.Mul(-1))
polyline.normals = append(polyline.normals, nt)
polyline.normals = append(polyline.normals, d.Mul(-1))
}
polyline.generateEdges(current, 4)
}
func (c *Container) mouseClick(button int, release bool, position mgl32.Vec2) {
offsetPos := position.Sub(c.offset)
c.Hitbox.MouseClick(button, release, offsetPos.Sub(c.backgroundOffset))
for _, child := range c.children {
child.mouseClick(button, release, offsetPos.Sub(c.elementsOffset))
}
}
func (c *Container) mouseMove(position mgl32.Vec2) {
offsetPos := position.Sub(c.offset)
c.Hitbox.MouseMove(offsetPos.Sub(c.backgroundOffset))
for _, child := range c.children {
child.mouseMove(offsetPos.Sub(c.elementsOffset))
}
}
func SegmentCircleIntersect(radius float32, center, start, finish mgl32.Vec2) (mgl32.Vec2, error) {
d := finish.Sub(start)
f := start.Sub(center)
a := d.Dot(d)
b := f.Mul(2).Dot(d)
c := f.Dot(f) - radius*radius
discriminant := b*b - 4*a*c
if discriminant < 0 {
return mgl32.Vec2{}, fmt.Errorf("No intersection")
} else {
discriminant = float32(math.Sqrt(float64(discriminant)))
t1 := (-b - discriminant) / (2 * a)
t2 := (-b + discriminant) / (2 * a)
if t1 >= 0 && t1 <= 1 {
return mgl32.Vec2{start.X() + t1*d.X(), start.Y() + t1*d.Y()}, nil
}
if t2 >= 0 && t2 <= 1 {
return mgl32.Vec2{start.X() + t2*d.X(), start.Y() + t2*d.Y()}, nil
}
}
return mgl32.Vec2{}, fmt.Errorf("No intersections")
}
func (polyline *polyLine) render(coords []float32) {
var sleeve, current, next mgl32.Vec2
polyline.vertices = []mgl32.Vec2{}
polyline.normals = []mgl32.Vec2{}
coords_count := len(coords)
is_looping := (coords[0] == coords[coords_count-2]) && (coords[1] == coords[coords_count-1])
if !is_looping { // virtual starting point at second point mirrored on first point
sleeve = mgl32.Vec2{coords[2] - coords[0], coords[3] - coords[1]}
} else { // virtual starting point at last vertex
sleeve = mgl32.Vec2{coords[0] - coords[coords_count-4], coords[1] - coords[coords_count-3]}
}
for i := 0; i+3 < coords_count; i += 2 {
current = mgl32.Vec2{coords[i], coords[i+1]}
next = mgl32.Vec2{coords[i+2], coords[i+3]}
polyline.renderEdge(sleeve, current, next)
sleeve = next.Sub(current)
}
if is_looping {
polyline.renderEdge(sleeve, next, mgl32.Vec2{coords[2], coords[3]})
} else {
polyline.renderEdge(sleeve, next, next.Add(sleeve))
}
if polyline.join == LINE_JOIN_NONE {
polyline.vertices = polyline.vertices[2 : len(polyline.vertices)-2]
}
polyline.draw(is_looping)
}
func (polyline *polyLine) renderNoEdge(sleeve, current, next mgl32.Vec2) {
sleeve_normal := getNormal(sleeve, polyline.halfwidth/sleeve.Len())
polyline.normals = append(polyline.normals, sleeve_normal)
polyline.normals = append(polyline.normals, sleeve_normal.Mul(-1))
sleeve = next.Sub(current)
sleeve_normal = getNormal(sleeve, polyline.halfwidth/sleeve.Len())
polyline.normals = append(polyline.normals, sleeve_normal.Mul(-1))
polyline.normals = append(polyline.normals, sleeve_normal)
polyline.generateEdges(current, 4)
}
// TwoSegmentIntersect - find the intersection point of two line segments <p11-p12> and <p21-p22>
func TwoSegmentIntersect(p11, p12, p21, p22 mgl32.Vec2) (mgl32.Vec2, error) {
p := p11
q := p21
r := p12.Sub(p11)
s := p22.Sub(p21)
if math.Abs(float64(Vec2Cross(r, s))) < 0.0000001 {
return mgl32.Vec2{}, fmt.Errorf("No intersections: lines parallel")
}
t := Vec2Cross(q.Sub(p), s) / Vec2Cross(r, s)
u := Vec2Cross(p.Sub(q), r) / Vec2Cross(s, r)
if t >= 0 && t <= 1 && u >= 0 && u <= 1 {
return p.Add(r.Mul(t)), nil
}
return mgl32.Vec2{}, fmt.Errorf("No intersections")
}
func ClickAndDragWindow(window *Window, hitbox Hitbox, c controller.Controller) {
grabbed := false
grabOffset := mgl32.Vec2{}
hitbox.AddOnClick(func(button int, release bool, position mgl32.Vec2) {
grabOffset = position
grabbed = !release
})
c.BindMouseAction(func() {
grabbed = false
}, controller.MouseButton1, controller.Release)
c.BindAxisAction(func(xpos, ypos float32) {
if grabbed {
position := mgl32.Vec2{xpos, ypos}
window.SetTranslation(position.Sub(grabOffset).Vec3(0))
}
})
}
func (c *Container) Render(size, offset mgl32.Vec2) mgl32.Vec2 {
c.size, c.offset = size, offset
padding := convertMargin(c.padding, c.paddingPercent, size.X())
margin := convertMargin(c.margin, c.marginPercent, size.X())
sizeMinusMargins := size.Sub(mgl32.Vec2{
margin.Left + margin.Right + padding.Left + padding.Right,
margin.Top + margin.Bottom + padding.Top + padding.Bottom,
})
containerSize := sizeMinusMargins
if c.width > 0 {
containerSize[0] = c.getWidth(size.X()) - padding.Left - padding.Right
}
if c.height > 0 {
containerSize[1] = c.getHeight(size.X()) - padding.Top - padding.Bottom
}
var width, height, highest float32 = 0, 0, 0
for _, child := range c.children {
childSize := child.Render(containerSize, mgl32.Vec2{width, height})
width += childSize.X()
if width > containerSize.X() {
height += highest
highest = 0
childSize = child.Render(containerSize, mgl32.Vec2{0, height})
width = childSize.X()
}
if childSize.Y() > highest {
highest = childSize.Y()
}
}
height += highest
if mgl32.FloatEqual(c.height, 0) {
containerSize[1] = height
}
//offsets and sizes
c.backgroundOffset = mgl32.Vec2{margin.Left, margin.Top}
c.elementsOffset = mgl32.Vec2{margin.Left + padding.Left, margin.Top + padding.Top}
backgroundSize := containerSize.Add(mgl32.Vec2{padding.Left + padding.Right, padding.Top + padding.Bottom})
totalSize := backgroundSize.Add(mgl32.Vec2{margin.Left + margin.Right, margin.Top + margin.Bottom})
c.background.SetScale(backgroundSize.Vec3(0))
c.background.SetTranslation(c.backgroundOffset.Vec3(0))
c.elementsNode.SetTranslation(c.elementsOffset.Vec3(0))
c.node.SetTranslation(c.offset.Vec3(0))
c.Hitbox.SetSize(backgroundSize)
return totalSize
}
/** Calculate line boundary points.
*
* Sketch:
*
* u1
* -------------+---...___
* | ```'''-- ---
* p- - - - - - q- - . _ _ | w/2
* | ` ' ' r +
* -------------+---...___ | w/2
* u2 ```'''-- ---
*
* u1 and u2 depend on four things:
* - the half line width w/2
* - the previous line vertex p
* - the current line vertex q
* - the next line vertex r
*
* u1/u2 are the intersection points of the parallel lines to p-q and q-r,
* i.e. the point where
*
* (q + w/2 * ns) + lambda * (q - p) = (q + w/2 * nt) + mu * (r - q) (u1)
* (q - w/2 * ns) + lambda * (q - p) = (q - w/2 * nt) + mu * (r - q) (u2)
*
* with nt,nt being the normals on the segments s = p-q and t = q-r,
*
* ns = perp(s) / |s|
* nt = perp(t) / |t|.
*
* Using the linear equation system (similar for u2)
*
* q + w/2 * ns + lambda * s - (q + w/2 * nt + mu * t) = 0 (u1)
* <=> q-q + lambda * s - mu * t = (nt - ns) * w/2
* <=> lambda * s - mu * t = (nt - ns) * w/2
*
* the intersection points can be efficiently calculated using Cramer's rule.
*/
func (polyline *polyLine) renderMiterEdge(sleeve, current, next mgl32.Vec2) {
sleeve_normal := getNormal(sleeve, polyline.halfwidth/sleeve.Len())
t := next.Sub(current)
len_t := t.Len()
det := determinant(sleeve, t)
// lines parallel, compute as u1 = q + ns * w/2, u2 = q - ns * w/2
if mgl32.Abs(det)/(sleeve.Len()*len_t) < LINES_PARALLEL_EPS && sleeve.Dot(t) > 0 {
polyline.normals = append(polyline.normals, sleeve_normal)
polyline.normals = append(polyline.normals, sleeve_normal.Mul(-1))
} else {
// cramers rule
nt := getNormal(t, polyline.halfwidth/len_t)
lambda := determinant(nt.Sub(sleeve_normal), t) / det
d := sleeve_normal.Add(sleeve.Mul(lambda))
polyline.normals = append(polyline.normals, d)
polyline.normals = append(polyline.normals, d.Mul(-1))
}
polyline.generateEdges(current, 2)
}
func (m *Mob) moveTowardExit(elapsed time.Duration, level *Level) {
var (
dest mgl32.Vec2
ok bool
pct = float32(elapsed) / float32(time.Second)
gridDist mgl32.Vec2
goalDist int32
stepDist = pct * m.Speed
)
if dest, goalDist, ok = level.Grid.GetNextStepToSink(m.Pos); !ok {
return
}
gridDist = dest.Sub(m.Pos)
if goalDist == 1 && gridDist.Len() < stepDist+0.5 {
m.PendingDisable = true
}
if gridDist.X() > 0 {
m.swapState(Left, Right)
} else {
m.swapState(Right, Left)
}
m.Pos = m.Pos.Add(gridDist.Normalize().Mul(stepDist))
}
func moveC(v mgl32.Vec2) {
d := v.Sub(lstPnt) // calculate delta vec
lstPnt = v
switch slctdC {
case 0:
c0dy += d[1]
case 1:
c1dy += d[1]
case 2:
c2dy += d[1]
case 4:
c4dx += d[0]
case 5:
c5dx += d[0]
c5dy += d[1]
}
}
func (w *Window) mouseMove(position mgl32.Vec2) {
w.mousePos = position.Sub(w.position)
if w.element != nil {
w.element.mouseMove(w.mousePos)
}
}
func (ie *ImageElement) mouseClick(button int, release bool, position mgl32.Vec2) {
offsetPos := position.Sub(ie.offset)
ie.Hitbox.MouseClick(button, release, offsetPos)
}
func (ie *ImageElement) mouseMove(position mgl32.Vec2) {
offsetPos := position.Sub(ie.offset)
ie.Hitbox.MouseMove(offsetPos)
}
func direction(a, b mgl32.Vec2) mgl32.Vec2 {
return a.Sub(b).Normalize()
}
func dist2(a, b mgl32.Vec2) float32 {
diff := b.Sub(a)
return square(diff.X()) + square(diff.Y())
}