// Render the fractal on a single thread using the ComplexFloatVec data type
// This is the implementation that has the best comments.
public void RenderSingleThreadedWithADT(float xmin, float xmax, float ymin, float ymax, float step)
{
// Initialize a pile of method constant vectors
Vector <int> vmax_iters = new Vector <int>(max_iters);
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>.Count];
// for (int i = 0; i < xmins.Count; 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++)
{
int xp = 0;
for (Vector <float> vx = vxmin;
Vector.LessThanOrEqualAny(vx, vxmax); // Vector.{comparision}Any|All return bools, not masks
vx += vinc, xp += Vector <int> .Count)
{
ComplexVecFloat num = new ComplexVecFloat(vx, vy);
ComplexVecFloat accum = num;
Vector <int> viters = Vector <int> .Zero; // Iteration counts start at all zeros
Vector <int> increment = Vector <int> .One; // Increment starts out as all ones
do
{
// This is work that can be vectorized
accum = accum.square() + num;
// 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;
// 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 <int> vCond = Vector.LessThanOrEqual(accum.sqabs(), vlimit) &
Vector.LessThanOrEqual(viters, vmax_iters);
// increment becomes zero for the elems that have hit the limit because
// vCond is a mask of all zeros or ones, based on the results of the
// Vector.{comparison} operations
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 <int> .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>.Count; 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, iter));
}
}
}