private void PartialAdvectCenter(int x0, int y0, int width, int height, float delta, Vector2 pos)
{
for (int x = x0; x < x0 + width; x++)
{
for (int y = y0; y < y0 + height; y++)
{
if (OldDensity[x, y].LengthSquared() > 1)
{
var velocity = fluidSystem.VelocityAt(
pos + (new Vector2(x, y) * Resolution)) * VISCOSITY;
// This is ran in parallel, this may not touch the other compound clouds
float dx = x + (delta * velocity.x);
float dy = y + (delta * velocity.y);
// So this is clamped to not go to the other clouds
dx = dx.Clamp(x0 - 0.5f, x0 + width + 0.5f);
dy = dy.Clamp(y0 - 0.5f, y0 + height + 0.5f);
CalculateMovementFactors(dx, dy, out var q0, out var q1, out var r0, out var r1,
out var s1, out var s0, out var t1, out var t0);
Density[q0, r0] += OldDensity[x, y] * s0 * t0;
Density[q0, r1] += OldDensity[x, y] * s0 * t1;
Density[q1, r0] += OldDensity[x, y] * s1 * t0;
Density[q1, r1] += OldDensity[x, y] * s1 * t1;
}
}
}
}
private void PartialAdvectCenter(int x0, int y0, int width, int height, float delta, Vector2 pos)
{
for (int x = x0; x < x0 + width; x++)
{
for (int y = y0; y < y0 + height; y++)
{
if (OldDensity[x, y].LengthSquared() > 1)
{
// TODO: give each cloud a viscosity value in the
// JSON file and use it instead.
const float viscosity = 0.0525f;
var velocity = fluidSystem.VelocityAt(
pos + (new Vector2(x, y) * Resolution)) * viscosity;
// This is ran in parallel, this may not touch the other compound clouds
float dx = x + (delta * velocity.x);
float dy = y + (delta * velocity.y);
// So this is clamped to not go to the other clouds
dx = dx.Clamp(x0 - 0.5f, x0 + width + 0.5f);
dy = dy.Clamp(y0 - 0.5f, y0 + height + 0.5f);
int q0 = (int)Math.Floor(dx);
int q1 = q0 + 1;
int r0 = (int)Math.Floor(dy);
int r1 = r0 + 1;
float s1 = Math.Abs(dx - q0);
float s0 = 1.0f - s1;
float t1 = Math.Abs(dy - r0);
float t0 = 1.0f - t1;
Density[q0, r0] += OldDensity[x, y] * s0 * t0;
Density[q0, r1] += OldDensity[x, y] * s0 * t1;
Density[q1, r0] += OldDensity[x, y] * s1 * t0;
Density[q1, r1] += OldDensity[x, y] * s1 * t1;
}
}
}
}
private void PartialAdvectCenter(int x0, int y0, int width, int height, float delta, Vector2 pos)
{
for (int x = x0; x < x0 + width; x++)
{
for (int y = y0; y < y0 + height; y++)
{
if (OldDensity[x, y].LengthSquared() > 1)
{
var velocity = fluidSystem.VelocityAt(
pos + (new Vector2(x, y) * Resolution)) * VISCOSITY;
// This is ran in parallel, this may not touch the other compound clouds
float dx = x + (delta * velocity.x);
float dy = y + (delta * velocity.y);
// So this is clamped to not go to the other clouds
dx = dx.Clamp(x0 - 0.5f, x0 + width + 0.5f);
dy = dy.Clamp(y0 - 0.5f, y0 + height + 0.5f);
CalculateMovementFactors(dx, dy, out var q0, out var q1, out var r0, out var r1,
out var s1, out var s0, out var t1, out var t0);
// NOTE: we add modulo to avoid overflow due to large time steps
// This makes this function a duplicate of PartialAdvectEdges
// TODO: check for refactorization (and in general of the whole file) --Maxonovien
q0 = q0.PositiveModulo(Size);
q1 = q1.PositiveModulo(Size);
r0 = r0.PositiveModulo(Size);
r1 = r1.PositiveModulo(Size);
Density[q0, r0] += OldDensity[x, y] * s0 * t0;
Density[q0, r1] += OldDensity[x, y] * s0 * t1;
Density[q1, r0] += OldDensity[x, y] * s1 * t0;
Density[q1, r1] += OldDensity[x, y] * s1 * t1;
}
}
}
}
private void Advect(float[,] oldDens, float[,] density, float dt, Vector2 pos)
{
for (int x = 0; x < size; x++)
{
for (int y = 0; y < size; y++)
{
density[x, y] = 0;
}
}
for (int x = 1; x < size - 1; x++)
{
for (int y = 1; y < size - 1; y++)
{
if (oldDens[x, y] > 1)
{
// TODO: give each cloud a viscosity value in the
// JSON file and use it instead.
const float viscosity =
0.0525f;
var velocity = fluidSystem.VelocityAt(
pos + (new Vector2(x, y) * resolution)) * viscosity;
float dx = x + (dt * velocity.x);
float dy = y + (dt * velocity.y);
dx = dx.Clamp(0.5f, size - 1.5f);
dy = dy.Clamp(0.5f, size - 1.5f);
int x0 = (int)dx;
int x1 = x0 + 1;
int y0 = (int)dy;
int y1 = y0 + 1;
float s1 = dx - x0;
float s0 = 1.0f - s1;
float t1 = dy - y0;
float t0 = 1.0f - t1;
density[x0, y0] += oldDens[x, y] * s0 * t0;
density[x0, y1] += oldDens[x, y] * s0 * t1;
density[x1, y0] += oldDens[x, y] * s1 * t0;
density[x1, y1] += oldDens[x, y] * s1 * t1;
}
}
}
}
public void AdvectEdges(float delta, Vector2 pos)
{
int[] edgeValues = { 0, size - 1 };
for (int x = 0; x < size; x++)
{
// The top edge and bottom edge
foreach (int y in edgeValues)
{
// This code is inlined here to improve performance
if (OldDensity[x, y] > 1)
{
// TODO: give each cloud a viscosity value in the
// JSON file and use it instead.
const float viscosity =
0.0525f;
var velocity = fluidSystem.VelocityAt(
pos + (new Vector2(x, y) * resolution)) * viscosity;
float dx = x + delta * velocity.x;
float dy = y + delta * velocity.y;
int x0 = (int)Math.Floor(dx);
int x1 = x0 + 1;
int y0 = (int)Math.Floor(dy);
int y1 = y0 + 1;
float s1 = Math.Abs(dx - x0);
float s0 = 1.0f - s1;
float t1 = Math.Abs(dy - y0);
float t0 = 1.0f - t1;
parentPlane.AddCloudDensity(index, x0, y0,
OldDensity[x, y] * s0 * t0);
parentPlane.AddCloudDensity(index, x0, y1,
OldDensity[x, y] * s0 * t1);
parentPlane.AddCloudDensity(index, x1, y0,
OldDensity[x, y] * s1 * t0);
parentPlane.AddCloudDensity(index, x1, y1,
OldDensity[x, y] * s1 * t1);
}
}
}
// The left edge and right edge
foreach (int x in edgeValues)
{
for (int y = 1; y < size - 1; y++)
{
// This code is inlined here to improve performance
if (OldDensity[x, y] > 1)
{
// TODO: give each cloud a viscosity value in the
// JSON file and use it instead.
const float viscosity = 0.0525f;
var velocity = fluidSystem.VelocityAt(
pos + (new Vector2(x, y) * resolution)) * viscosity;
float dx = x + delta * velocity.x;
float dy = y + delta * velocity.y;
int x0 = (int)Math.Floor(dx);
int x1 = x0 + 1;
int y0 = (int)Math.Floor(dy);
int y1 = y0 + 1;
float s1 = Math.Abs(dx - x0);
float s0 = 1.0f - s1;
float t1 = Math.Abs(dy - y0);
float t0 = 1.0f - t1;
parentPlane.AddCloudDensity(index, x0, y0,
OldDensity[x, y] * s0 * t0);
parentPlane.AddCloudDensity(index, x0, y1,
OldDensity[x, y] * s0 * t1);
parentPlane.AddCloudDensity(index, x1, y0,
OldDensity[x, y] * s1 * t0);
parentPlane.AddCloudDensity(index, x1, y1,
OldDensity[x, y] * s1 * t1);
}
}
}
}