MBMCustomLayerHost

 
@protocol MBMCustomLayerHost <NSObject>

Interface for hosting a custom map style layer.

  • Initialize any Metal 3D graphic API state needed by the custom layer. This method is called once when view starts or resumes to foreground but before rendering for the first time.

    colorPixelFormat and depthStencilPixelFormat are values of MTLPixelFormat and are declared here as underlying NSUinteger to avoid import here.

    This method is called if underlying map rendering backend uses Metal graphic API.

    Resources that are acquired in this method must be released in the deinitialize function.

    Declaration

    Objective-C

    - (void)renderingWillStart:(nonnull id<MTLDevice>)metalDevice
           colorPixelFormat:(NSUInteger)colorPixelFormat
    depthStencilPixelFormat:(NSUInteger)depthStencilPixelFormat;

  • Render the layer. This method is called once per frame.

    This method is called if underlying map rendering backend uses Metal graphic API.

    Declaration

    Objective-C

    - (void)render:(nonnull MBMCustomLayerRenderParameters *)parameters
           mtlCommandBuffer:(nonnull id<MTLCommandBuffer>)mtlCommandBuffer
    mtlRenderPassDescriptor:
        (nonnull MTLRenderPassDescriptor *)mtlRenderPassDescriptor;

    Parameters

    The

    MTLRenderPassDescriptor that defines rendering map to view drawable.
    The

    MTLRenderPassDescriptor that defines rendering map to view drawable.
    The

    MTLRenderPassDescriptor that defines rendering map to view drawable.

  • Destroy any state needed by the custom layer, and deallocate context, if necessary. This method is called once, from the main thread, at a point when Metal or OpenGL context is active.

    Note that it may be called even when the renderingWillStart function has not been called.

    Declaration

    Objective-C

    - (void)renderingWillEnd;

    Swift

    func renderingWillEnd()

  • Initialize any OpenGL 3D graphic API state needed by the custom layer. This method is called once when view starts or resumes to foreground but before rendering for the first time.

    As Apple is deprecating legacy OpenGL API, this method is optional and is called only if underlying map rendering backend uses OpenGL graphic API.

    Resources that are acquired in this method must be released in the deinitialize function.

    Declaration

    Objective-C

    - (void)renderingWillStartOpenGL;

    Swift

    optional func renderingWillStartOpenGL()

  • Render the layer. This method is called once per frame. The implementation should not make any assumptions about the GL state (other than that the correct context is active). It may make changes to the state, and is not required to reset values such as the depth mask, stencil mask, and corresponding test flags to their original values. Make sure that you are drawing your fragments with a z value of 1 to take advantage of the opaque fragment culling in case there are opaque layers above your custom layer.

    As Apple is deprecating legacy OpenGL API, this method is optional and is called only if underlying map rendering backend uses OpenGL graphic API.

    Declaration

    Objective-C

    - (void)renderOpenGL:(nonnull MBMCustomLayerRenderParameters *)parameters;

    Swift

    optional func renderOpenGL(_ parameters: MBMCustomLayerRenderParameters)

    Parameters

    The

    parameters that define the current camera position.

  • Called when the system has destroyed the underlying OpenGL context. The renderingWillEnd function will not be called in this case, however setupRendering will be called instead to prepare for a new render.

    As Apple is deprecating legacy OpenGL API, this method is optional and is called only if underlying map rendering backend uses OpenGL graphic API.

    Declaration

    Objective-C

    - (void)openGLContextLost;

    Swift

    optional func openGLContextLost()