public void grab(IRenderDevice device, IDeviceContext context, ITexture texture, ConsumeTextureDelegate consume)
{
TextureDesc desc = texture.GetDesc();
// Create staging texture if needed
if (null == stagingTexture || stagingDesc.Size != desc.Size || stagingDesc.Format != desc.Format)
{
ComUtils.clear(ref stagingTexture);
desc.Type = ResourceDimension.Tex2d;
desc.BindFlags = BindFlags.None;
desc.CPUAccessFlags = CpuAccessFlags.Read;
desc.Usage = Usage.Staging;
stagingTexture = device.CreateTexture(ref desc, "ScreenGrabber staging");
stagingDesc = desc;
}
// In D3D12, Diligent engine fails instead of waiting for GPU. Need to wait manually, need a fence for that.
if (RuntimeEnvironment.runningWindows && null == fence)
{
var fd = new FenceDesc(false);
fence = device.CreateFence(ref fd);
}
// Finish the rendering, if any
waitForGpu(context);
// Unset the targets
context.SetRenderTargets(0, null, null);
waitForGpu(context);
// Copy source texture to staging
context.copyTexture(stagingTexture, texture);
waitForGpu(context);
// Map the texture
Box box = new Box(false)
{
MaxX = desc.Size.cx,
MaxY = desc.Size.cy
};
MappedTextureSubresource mapped = context.MapTextureSubresource(stagingTexture, 0, 0, MapType.Read, MapFlags.DoNotWait, ref box);
try
{
consume(desc.Format, desc.Size, mapped);
}
finally
{
context.UnmapTextureSubresource(stagingTexture, 0, 0);
}
}
static void encodeScreenshot(TextureFormat format, CSize size, MappedTextureSubresource mapped, string dest)
{
// Pick the right set of PNG options
ePngOptions options;
switch (format)
{
case TextureFormat.Rgba8Sint:
case TextureFormat.Rgba8Snorm:
case TextureFormat.Rgba8Typeless:
case TextureFormat.Rgba8Unorm:
options = ePngOptions.None;
break;
case TextureFormat.Rgba8UnormSrgb:
options = ePngOptions.SrgbMetadata;
break;
case TextureFormat.Bgra8Typeless:
case TextureFormat.Bgrx8Typeless:
case TextureFormat.Bgra8Unorm:
case TextureFormat.Bgrx8Unorm:
options = ePngOptions.FlipChannels;
break;
case TextureFormat.Bgra8UnormSrgb:
case TextureFormat.Bgrx8UnormSrgb:
options = ePngOptions.FlipChannels | ePngOptions.SrgbMetadata;
break;
default:
throw new ArgumentException($"{ format } textures can’t be PNG encoded. Do something else, e.g. DDS.");
}
// No idea why, but identical C# and C++ code produces good images on Windows and vertically flipped ones on Linux.
// Need to pass a bit to encoder to distinguish.
// Fortunately, LibPNG takes an array of row pointers and thus doesn't care about rows RAM layout, the implementation doesn't need to make copies.
if (RuntimeEnvironment.runningLinux)
{
options |= ePngOptions.FlipRows;
}
// Finally, write the PNG
using (var fs = File.Create(dest))
GraphicsUtils.encodeRgbaPng(size, mapped, options, fs);
}
