Major progress in introducing arbitrary boundaries! EDT in the house.

fluid/fluid.go

@@ -4,6 +4,7 @@
 package fluid
 
 import (
+	"fluids/edt"
 	"fluids/utils"
 	"math"
 )
@@ -41,6 +42,9 @@ type Fluid struct {
 	flipPicRatio        float32
 	numSubSteps         int  //number of simulation substeps
 	Block               bool //rectangular or circular field container
+
+	//for arbitrary boundaries
+	edt *edt.EDT
 }
 
 func NewFluid(dimensions FieldVector, spacing float32) *Fluid {
@@ -52,6 +56,7 @@ func NewFluid(dimensions FieldVector, spacing float32) *Fluid {
 		flipPicRatio:        FluidDefaultFlipPicRatio,
 		numSubSteps:         FluidDefaultSubSteps,
 		Block:               true,
+		edt:                 nil,
 	}
 
 	f.Initialize()
@@ -268,6 +273,11 @@ func (f *Fluid) HandleParticleCollisions() {
 		minDist2 := minDist * minDist
 	*/
 
+	if f.edt != nil {
+		f.HandleBoundaryCollisions()
+		return
+	}
+
 	if f.Block {
 		minX := f.Field.H + f.particleRadius
 		maxX := float32(f.Field.Nx-1)*f.Field.H - f.particleRadius
@@ -651,3 +661,53 @@ func (f *Fluid) SolveIncompressibility() {
 func (f *Fluid) ToggleShape() {
 	f.Block = !f.Block
 }
+
+func (f *Fluid) SetBoundary(b *Boundary) {
+
+	if b != nil {
+		dim := edt.Bounds{
+			X: b.Dimensions.X,
+			Y: b.Dimensions.Y,
+		}
+
+		f.edt = edt.NewEDT(dim)
+		f.edt.AssignOccupancy(b.Cells)
+		f.edt.ComputeDistanceTransform()
+	} else {
+		f.edt = nil
+	}
+}
+
+// we perform our boundary resolution on particles according to our defined fluid boundary
+func (f *Fluid) HandleBoundaryCollisions() {
+
+	//grid spacing within our distance field
+	dx := f.Field.Dimensions.X / float32(f.edt.Dimensions.X)
+	dy := f.Field.Dimensions.Y / float32(f.edt.Dimensions.Y)
+
+	//find cell of distance field for which particles belong, check if it's in bounds
+	for i := range f.Particles {
+		p := &f.Particles[i]
+
+		xi := utils.Clamp(int(math.Floor(float64(p.Position.X/dx))), 0, f.edt.Dimensions.X-1)
+		yi := utils.Clamp(int(math.Floor(float64(p.Position.Y/dy))), 0, f.edt.Dimensions.Y-1)
+
+		cellidx := xi + yi*f.edt.Dimensions.X
+
+		//if our current cell isn't a boundary, then we skip
+		if f.edt.D[cellidx] == 0 {
+			continue
+		}
+
+		//find where the particle actually belongs
+		pos := f.edt.L[cellidx]
+		newx := (float32(pos.X-xi) + f.particleRadius) * dx
+		newy := (float32(pos.Y-yi) + f.particleRadius) * dy
+		p.Position.X += newx
+		p.Position.Y += newy
+		p.Velocity.X = 0
+		p.Velocity.Y = 0
+
+	}
+
+}