Drawing SharpDX effects on bitmap is too slow, what am I doing wrong? - directx

Question

SO basically, I need performance. Currently in my job we use GDI+ graphics to draw bitmap. Gdi+ graphics contains a method called DrawImage(Bitmap,Points[]). That array contains 3 points and the rendered image result with a skew effect.
Here is an image of what is a skew effect :
Skew effect
At work, we need to render between 5000 and 6000 different images each single frame which takes ~ 80ms.
Now I thought of using SharpDX since it provides GPU accelerations. I use direct2D since all I need is in 2 dimensions. However, the only way I saw to reproduce a skew effect is the use the SharpDX.effects.Skew and calculate matrix to draw the initial bitmap with a skew effect ( I will provide the code below). The rendered image is exactly the same as GDI+ and it is what I want. The only problem is it takes 600-700ms to render the 5000-6000images.
Here is the code of my SharpDX :
To initiate device :
private void InitializeSharpDX()
{
swapchaindesc = new SwapChainDescription()
{
BufferCount = 2,
ModeDescription = new ModeDescription(this.Width, this.Height, new Rational(60, 1), Format.B8G8R8A8_UNorm),
IsWindowed = true,
OutputHandle = this.Handle,
SampleDescription = new SampleDescription(1, 0),
SwapEffect = SwapEffect.Discard,
Usage = Usage.RenderTargetOutput,
Flags = SwapChainFlags.None
};
SharpDX.Direct3D11.Device.CreateWithSwapChain(DriverType.Hardware, DeviceCreationFlags.BgraSupport | DeviceCreationFlags.Debug, swapchaindesc, out device, out swapchain);
SharpDX.DXGI.Device dxgiDevice = device.QueryInterface<SharpDX.DXGI.Device>();
surface = swapchain.GetBackBuffer<Surface>(0);
factory = new SharpDX.Direct2D1.Factory1(FactoryType.SingleThreaded, DebugLevel.Information);
d2device = new SharpDX.Direct2D1.Device(factory, dxgiDevice);
d2deviceContext = new SharpDX.Direct2D1.DeviceContext(d2device, SharpDX.Direct2D1.DeviceContextOptions.EnableMultithreadedOptimizations);
bmpproperties = new BitmapProperties(new SharpDX.Direct2D1.PixelFormat(SharpDX.DXGI.Format.B8G8R8A8_UNorm, SharpDX.Direct2D1.AlphaMode.Premultiplied),
96, 96);
d2deviceContext.AntialiasMode = AntialiasMode.Aliased;
bmp = new SharpDX.Direct2D1.Bitmap(d2deviceContext, surface, bmpproperties);
d2deviceContext.Target = bmp;
}
And here is my code I use to recalculate every image positions each frame (each time I do a mouse zoom in or out, I asked for a redraw). You can see in the code two loop of 5945 images where I asked to draw the image. No effects takes 60ms and with effects, it takes up to 700ms as I mentionned before :
private void DrawSkew()
{
d2deviceContext.BeginDraw();
d2deviceContext.Clear(SharpDX.Color.Blue);
//draw skew effect to 5945 images using SharpDX (370ms)
for (int i = 0; i < 5945; i++)
{
AffineTransform2D effect = new AffineTransform2D(d2deviceContext);
PointF[] points = new PointF[3];
points[0] = new PointF(50, 50);
points[1] = new PointF(400, 40);
points[2] = new PointF(40, 400);
effect.SetInput(0, actualBmp, true);
float xAngle = (float)Math.Atan(((points[1].Y - points[0].Y) / (points[1].X - points[0].X)));
float yAngle = (float)Math.Atan(((points[2].X - points[0].X) / (points[2].Y - points[0].Y)));
Matrix3x2 Matrix = Matrix3x2.Identity;
Matrix3x2.Skew(xAngle, yAngle, out Matrix);
Matrix.M11 = Matrix.M11 * (((points[1].X - points[0].X) + (points[2].X - points[0].X)) / actualBmp.Size.Width);
Matrix.M22 = Matrix.M22 * (((points[1].Y - points[0].Y) + (points[2].Y - points[0].Y)) / actualBmp.Size.Height);
effect.TransformMatrix = Matrix;
d2deviceContext.DrawImage(effect, new SharpDX.Vector2(points[0].X, points[0].Y));
effect.Dispose();
}
//draw no effects, only actual bitmap 5945 times using SharpDX (60ms)
for (int i = 0; i < 5945; i++)
{
d2deviceContext.DrawBitmap(actualBmp, 1.0f, BitmapInterpolationMode.NearestNeighbor);
}
d2deviceContext.EndDraw();
swapchain.Present(1, PresentFlags.None);
}
After benching a lot, I realized the line that make it really slow is :
d2deviceContext.DrawImage(effect, new SharpDX.Vector2(points[0].X, points[0].Y));
My guess is my code or my setup does not use GPU acceleration of SharpDX like it should and this is why the code is really slow. I would expect at least better performance from SharpDX than GDI+ for this kind of stuff.