/// <summary>
/// </summary>
protected override void OnSetRenderInfo(PropertyBasedEffectConfigToken token, RenderArgs dstArgs, RenderArgs srcArgs)
{
//
// This is an expensive operation, so pull the effect configuration once here rather than each time its needed during
// effect rendering
//
_effectConfiguration = ShadowEffectConfiguration.FromToken(token);
base.OnSetRenderInfo(token, dstArgs, srcArgs);
}
/// <summary>
/// Creates the shadow of the source image
/// </summary>
/// <param name="dst">Describes the destination surface.</param>
/// <param name="src">Describes the source surface.</param>
/// <param name="rect">The rectangle that describes the region of interest.</param>
/// <param name="configuration"></param>
///
private unsafe void RenderRectangle(Surface dst, Surface src, Rectangle rect, ShadowEffectConfiguration configuration)
{
double shadowFactor = configuration.Opacity / ShadowEffectProperties.MaxOpacity;
//
// The blurring algorithm was stolen directly from the BlurEffect code. I couldn't
// use it directly because the source image must be transformed prior to applying
// the blur effect. Also, I gradually increase the blur radius from one end
// of the shadow to the other, which the blur effect code doesn't support either.
//
if (rect.Height >= 1 && rect.Width >= 1)
{
// For each row in the rectangle
for (int y = rect.Top; y < rect.Bottom; ++y)
{
//
// Shadow Diffusion - The blur radius increases the further the row is from the bottom
// Diffusion Factor - [0-100] How much the shadow is diffused. 0 = None, 100 = Max
//
double blurRadius = 0;
if (configuration.DiffusionFactor > 0)
{
// diffusion factor of 50 = 5 rows/blur_radius
double rowsPerBlurRadius = 250.0 / (double)configuration.DiffusionFactor;
blurRadius = invertedYcoordinate(y, src.Height) / rowsPerBlurRadius;
}
int[] w = CreateGaussianBlurRow(blurRadius);
int wlen = w.Length;
int r = (wlen - 1) / 2;
long[] waSums = new long[wlen];
long[] aSums = new long[wlen];
long waSum = 0;
long aSum = 0;
ColorBgra *dstPtr = dst.GetPointAddressUnchecked(rect.Left, y);
// For each item in the gaussian blur row
for (int wx = 0; wx < wlen; ++wx)
{
int srcX = rect.Left + wx - r;
waSums[wx] = 0;
aSums[wx] = 0;
if (srcX >= 0 && srcX < src.Width)
{
for (int wy = 0; wy < wlen; ++wy)
{
int srcY = y + wy - r;
if (srcY >= 0 && srcY < src.Height)
{
ColorBgra c = getShadowPixel(srcX, srcY, src, shadowFactor, configuration.Angle, configuration.DepthAngle);
int wp = w[wy];
waSums[wx] += wp;
aSums[wx] += wp * c.A;
}
}
int wwx = w[wx];
waSum += wwx * waSums[wx];
aSum += wwx * aSums[wx];
}
}
if (waSum == 0)
{
dstPtr->Bgra = 0;
}
else
{
dstPtr->Bgra = ColorBgra.BgraToUInt32(0, 0, 0, (int)(aSum / waSum));
}
++dstPtr;
for (int x = rect.Left + 1; x < rect.Right; ++x)
{
ColorBgra OrginalImage = src[x, y];
for (int i = 0; i < wlen - 1; ++i)
{
waSums[i] = waSums[i + 1];
aSums[i] = aSums[i + 1];
}
waSum = 0;
aSum = 0;
int wx;
for (wx = 0; wx < wlen - 1; ++wx)
{
long wwx = (long)w[wx];
waSum += wwx * waSums[wx];
aSum += wwx * aSums[wx];
}
wx = wlen - 1;
waSums[wx] = 0;
aSums[wx] = 0;
int srcX = x + wx - r;
if (srcX >= 0 && srcX < src.Width)
{
for (int wy = 0; wy < wlen; ++wy)
{
int srcY = y + wy - r;
if (srcY >= 0 && srcY < src.Height)
{
ColorBgra c = getShadowPixel(srcX, srcY, src, shadowFactor, configuration.Angle, configuration.DepthAngle);
int wp = w[wy];
waSums[wx] += wp;
aSums[wx] += wp * (long)c.A;
}
}
int wr = w[wx];
waSum += (long)wr * waSums[wx];
aSum += (long)wr * aSums[wx];
}
ColorBgra Shadow = new ColorBgra();
if (waSum == 0)
{
Shadow = ColorBgra.FromBgra(0, 0, 0, 0);
}
else
{
Shadow = ColorBgra.FromBgra(0, 0, 0, (byte)(aSum / waSum));
}
if (configuration.KeepOriginalImage)
{
dstPtr->Bgra = (uint)_normalOp.Apply(Shadow, OrginalImage);
}
else
{
dstPtr->Bgra = (uint)Shadow;
}
++dstPtr;
}
}
}
}
