// Render the fractal on a single thread using raw Vector<float> data types
// For a well commented version, go see VectorFloatRenderer.RenderSingleThreadedWithADT in VectorFloat.cs
public override bool RenderSingleThreaded(double xmind, double xmaxd, double ymind, double ymaxd, double stepd, int maxIterations)
{
float xmin = (float)xmind;
float xmax = (float)xmaxd;
float ymin = (float)ymind;
float ymax = (float)ymaxd;
float step = (float)stepd;
// Initialize a pile of method constant vectors
Vector <float> vmax_iters = new Vector <float>((float)maxIterations);
Vector <float> vlimit = new Vector <float>(limit);
Vector <float> vstep = new Vector <float>(step);
Vector <float> vxmax = new Vector <float>(xmax);
Vector <float> vinc = new Vector <float>((float)Vector <float> .Count * step);
// Use my little helper routine: it's kind of slow, but I find it pleasantly readable.
// The alternative would be this:
// float[] xmins = new float[Vector<float>.Length];
// for (int i = 0; i < xmins.Length; i++)
// xmins[i] = xmin + step * i;
// Vector<float> vxmin = new Vector<float>(xmins);
// Both allocate some memory, this one just does it in a separate routine
Vector <float> vxmin = VectorHelper.Create(i => xmin + step * i);
float y = ymin;
int yp = 0;
for (Vector <float> vy = new Vector <float>(ymin); y <= ymax && !Abort; vy += vstep, y += step, yp++)
{
if (Abort)
{
return(false);
}
int xp = 0;
for (Vector <float> vx = vxmin; Vector.LessThanOrEqualAll(vx, vxmax); vx += vinc, xp += Vector <int> .Count)
{
Vector <float> accumx = vx;
Vector <float> accumy = vy;
Vector <float> viters = Vector <float> .Zero;
Vector <float> increment = Vector <float> .One;
do
{
// This is work that can be vectorized
Vector <float> naccumx = accumx * accumx - accumy * accumy;
Vector <float> naccumy = accumx * accumy + accumx * accumy;
accumx = naccumx + vx;
accumy = naccumy + vy;
// Increment the iteration count Only pixels that haven't already hit the
// limit will be incremented because the increment variable gets masked below
viters += increment;
Vector <float> sqabs = accumx * accumx + accumy * accumy;
// Create a mask that correspons to the element-wise logical operation
// "accum <= limit && iters <= max_iters" Note that the bitwise and is used,
// because the Vector.{comparision} operations return masks, not boolean values
Vector <float> vCond = Vector.LessThanOrEqual <float>(sqabs, vlimit) &
Vector.LessThanOrEqual <float>(viters, vmax_iters);
increment = increment & vCond;
// Keep going until we have no elements that haven't either hit the value
// limit or the iteration count
} while (increment != Vector <float> .Zero);
// This is another little helper I created. It's definitely kind of slow but I
// find it pleasantly succinct. It could also be written like this:
//
// for (int eNum = 0; eNum < Vector<int>.Length; eNum++)
// DrawPixel(xp + eNum, yp, viters[eNum]);
//
// Neither implementation is particularly fast, because pulling individual elements
// is a slow operation for vector types.
viters.ForEach((iter, elemNum) => DrawPixel(xp + elemNum, yp, (int)iter));
}
}
return(true);
}
