Hardware-Accelerated / GPU Surface Changes

As of SkiaSharp v1.68.0, there has been a fairly major change to the way hardware-accelerated (GPU) surfaces are created.

These changes were made to better support the new GPU backends. Right now, we just support OpenGL, but the changes open the door to Vulkan and Metal support.

The good news is that even though there were many changes, we have been able to preserve the existing functionality so that you aren't forced to update your code immediately after upgrading. However, you should migrate your code as soon as possible as there is no guarantee that the next update will still support all the existing functionality.

Migration

The most visible change is that we are no longer using the GRBackendRenderTargetDesc and GRBackendTextureDesc types, but rather we use the similarly-named GRBackendRenderTarget and GRBackendTexture. The properties are mostly the same, except that PixelConfig and Origin have been moved to the surface construction - and should not affect the manner in which you draw to that surface.

Another change is that the old structures have been split into two parts, one to describe the surface we are creating, and the other to explicitly describe the backend-specific configuration needed to write to that surface.

For example, GRBackendRenderTargetDesc has been split into GRBackendRenderTarget which describes the general surface (such as width, height, and samples) and GRGlFramebufferInfo which describes OpenGL-specific surface (with the FBO ID and color format). If we were to support Vulkan, this may be swapped out with GRVkImageInfo, which will describe the Vulkan- specific surface (with the image handle and format).

Existing Code

csharp

// create the GPU context (UNCHANGED)
var glInterface = GRGlInterface.CreateNativeGlInterface();
var context = GRContext.Create(GRBackend.OpenGL, glInterface);

// create the surface (OLD)
var renderTarget = new GRBackendRenderTargetDesc {
    Width = 1024,
    Height = 1024,
    Config = GRPixelConfig.Rgba8888,
    Origin = GRSurfaceOrigin.BottomLeft,
    SampleCount = 0,
    StencilBits = 0,
    RenderTargetHandle = IntPtr.Zero,
};
var surface = SKSurface.Create(context, renderTarget);

// draw (UNCHANGED)
var canvas = surface.Canvas;
// ...

New Code

csharp

// create the GPU context (UNCHANGED)
var glInterface = GRGlInterface.CreateNativeGlInterface();
var context = GRContext.Create(GRBackend.OpenGL, glInterface);

// create the surface (UPDATED)
var glInfo = new GRGlFramebufferInfo(
    fboId: 0,
    format: SKColorType.Rgba8888.ToGlSizedFormat());
var renderTarget = new GRBackendRenderTarget(
    width: 1024,
    height: 1024,
    sampleCount: 0,
    stencilBits: 0,
    glInfo: glInfo);
var surface = SKSurface.Create(
    context, renderTarget, GRSurfaceOrigin.BottomLeft, SKColorType.Rgba8888);

// draw (UNCHANGED)
var canvas = surface.Canvas;
// ...