public unsafe void UpdateBitmap()
{
if (m_Owner == null)
{
Invalidate();
return;
}
// Build histogram
const int BUCKETS_COUNT = 100;
int[] histo = new int[BUCKETS_COUNT];
for (int i = 0; i < Form1.PIXELS_COUNT; i++)
{
Form1.Pixel P = m_Owner.m_Pixels[i];
float2 N = P.Normal;
if (N.x < 0.0f)
{
N = -N;
}
float angle = (float)Math.Atan2(N.y, N.x);
float normAngle = 0.5f + angle / (float)Math.PI;
int bucketIndex = Math.Max(0, Math.Min(BUCKETS_COUNT - 1, (int)(BUCKETS_COUNT * normAngle)));
histo[bucketIndex]++;
}
int maxBucket = 0;
for (int i = 0; i < BUCKETS_COUNT; i++)
{
maxBucket = Math.Max(maxBucket, histo[i]);
}
// Render
int W = m_Bitmap.Width;
int H = m_Bitmap.Height;
using (Graphics G = Graphics.FromImage(m_Bitmap)) {
G.FillRectangle(Brushes.White, 0, 0, W, H);
for (int X = 0; X < W; X++)
{
int bucketIndex = X * BUCKETS_COUNT / W;
float count = (float)histo[bucketIndex] / maxBucket;
G.DrawLine(Pens.Black, X, H, X, H * (1.0f - 0.9f * count));
}
}
Invalidate();
}
float2 SamplePosition(float _angle)
{
float pixelAngle = _angle * Form1.PIXELS_COUNT / (float)(2.0 * Math.PI);
int i0 = Math.Max(0, Math.Min(Form1.PIXELS_COUNT - 1, (int)Math.Floor(pixelAngle)));
int i1 = Math.Min(Form1.PIXELS_COUNT - 1, i0 + 1);
float t = pixelAngle - i0;
Form1.Pixel P0 = m_Owner.m_Pixels[i0];
Form1.Pixel P1 = m_Owner.m_Pixels[i1];
float dist = P0.Distance * (1.0f - t) + P1.Distance * t;
dist = Math.Min(1000.0f, dist);
float2 result = dist * new float2((float)Math.Cos(_angle), (float)Math.Sin(_angle));
return(result);
}