Big push to implement 10mp fluid simulations.

fluid/field.go

@@ -0,0 +1,74 @@
+package fluid
+
+import "math"
+
+type CellType int
+
+const (
+	CellTypeFluid = iota
+	CellTypeAir
+	CellTypeSolid
+	CellTypeMax
+)
+
+type VelocityField struct {
+	Dimensions   FieldVector //in meters
+	Numcells     int
+	Nx, Ny       int     //number of cells in x, y
+	H            float32 //field spacing, in meters
+	InvH         float32
+	U, V         []float32 //field components < u(x,y), v(x,y) >
+	PrevU, PrevV []float32 //previous field components < u(x,y), v(x,y) >
+	DU, DV       []float32 //weighted sums for components < u(x,y), v(x,y) >
+	S            []float32 //fluid cell scales
+	CellType     []float32 //type of cell
+}
+
+func NewVelocityField(dimensions FieldVector, spacing float32) *VelocityField {
+	vf := &VelocityField{
+		Dimensions: dimensions,
+		H:          spacing,
+		InvH:       1 / spacing,
+	}
+
+	vf.Initialize()
+	return vf
+}
+
+func (vf *VelocityField) Initialize() {
+
+	vf.Nx = int(math.Floor(float64(vf.Dimensions.X/vf.H))) + 1
+	vf.Ny = int(math.Floor(float64(vf.Dimensions.Y/vf.H))) + 1
+
+	cellcount := vf.Nx * vf.Ny
+
+	vf.Numcells = cellcount
+
+	vf.U = make([]float32, cellcount)
+	vf.V = make([]float32, cellcount)
+	vf.PrevU = make([]float32, cellcount)
+	vf.PrevV = make([]float32, cellcount)
+	vf.DU = make([]float32, cellcount)
+	vf.DV = make([]float32, cellcount)
+	vf.S = make([]float32, cellcount)
+	vf.CellType = make([]float32, cellcount)
+
+	for i := 0; i < vf.Nx; i++ {
+		for j := 0; j < vf.Ny; j++ {
+			var stype float32 = CellTypeAir //port, code corrected
+			//var stype float32 = 1 //10mp value, claims fluid but isn't
+			//var stype float32 = CellTypeSolid //port, with 10mp intent
+			if i == 0 || i == vf.Nx-1 || j == 0 {
+				stype = CellTypeFluid //port, code corrected
+				//stype = 0 //10mp value, claims solid but isn't
+				//stype = CellTypeFluid //port, with 10mp intent
+			}
+			vf.S[i*vf.Ny+j] = stype
+		}
+	}
+
+}
+
+func (vf *VelocityField) GetIndex(i, j int) int {
+	return i*vf.Ny + j
+}