Swapchain

A swap chain is a collection of buffers used for displaying frames to the user. Each time an application presents a new frame for display, the first buffer in the swap chain takes the place of the displayed buffer. This process is called swapping or flipping.

A graphics adapter holds a pointer to a surface that represents the image being displayed on the monitor, called a front buffer. As the monitor is refreshed, the graphics card sends the contents of the front buffer to the monitor to be displayed. However, this leads to a problem when rendering real-time graphics. The heart of the problem is that monitor refresh rates are very slow in comparison to the rest of the computer. Common refresh rates range from 60 Hz (60 times per second) to 100 Hz. If your application is updating the front buffer while the monitor is in the middle of a refresh, the image that is displayed will be cut in half, with the upper half of the display containing the old image and the lower half containing the new image. This problem is referred to as tearing.

Creation

To create a swap chain, first you need to create the SwapChainDescription struct:

// Create a window...
var windowSystem = new Evergine.WindowsForms.FormsWindowsSystem();
var window = windowSystem.CreateWindow(windowsTitle, width, height);

// Create a swap chain descriptor and assign the surface info...
var swapChainDescriptor = new SwapChainDescription()
{
    Width = window.Width,
    Height = window.Height,
    SurfaceInfo = info,
    ColorTargetFormat = PixelFormat.R8G8B8A8_UNorm,
    ColorTargetFlags = TextureFlags.RenderTarget | TextureFlags.ShaderResource,
    DepthStencilTargetFormat = PixelFormat.D24_UNorm_S8_UInt,
    DepthStencilTargetFlags = TextureFlags.DepthStencil,
    SampleCount = this.SampleCount,
    IsWindowed = true,
    RefreshRate = 60,
    SurfaceInfo = window.SurfaceInfo
};

// Finally, create the swap chain...
var swapChain = this.graphicsContext.CreateSwapChain(swapChainDescriptor);
swapChain.VerticalSync = false;

SwapChainDescription

Property	Type	Description
SurfaceInfo	SurfaceInfo	Surface information.
Width	uint	The swap chain buffers width.
Height	uint	The swap chain buffers height.
RefreshRate	uint	The screen refresh rate.
ColorTargetFormat	PixelFormat	The pixel format of the color target.
ColorTargetFlags	TextureFlags	The color texture flags for binding to pipeline stages. The flags can be combined by a logical OR.
DepthStencilTargetFormat	PixelFormat	The pixel format of the depth stencil target.
DepthStencilTargetFlags	TextureFlags	The depth texture flags for binding to pipeline stages. The flags can be combined by a logical OR.
SampleCount	TextureSampleCount	The sample count of this swap chain.
IsWindowed	bool	Whether the output is in windowed mode.

TextureFlags

Identifies how to bind a texture.

TextureFlags	Description
None	Not specified, default value.
ShaderResource	A texture usable as a Shader Resource View.
RenderTarget	A texture usable as a render target.
UnorderedAccess	A texture usable as an unordered access buffer.
DepthStencil	A texture usable as a depth stencil buffer.
GenerateMipmaps	Enables MIP map generation by GPU.

TextureSampleCount

Describes the number of samples to use in a texture.

TextureSampleCount	Description
None	Not multisample. Default value.
Count2	Multisample count of 2 pixels.
Count4	Multisample count of 4 pixels.
Count8	Multisample count of 8 pixels.
Count16	Multisample count of 16 pixels.
Count32	Multisample count of 32 pixels.