BeginDraw

BeginDraw is a term used across various graphics APIs to denote the start of a drawing sequence on a rendering target, such as a window, canvas, or texture. It represents the point at which a program begins recording or issuing drawing commands for a frame or pass.

In practice, BeginDraw serves to prepare the drawing context. When invoked, it may acquire or lock the rendering surface, establish the current render state (transforms, clip regions, bound resources), and configure any target-specific settings required for subsequent drawing operations. The calls made after BeginDraw typically include rendering primitives, images, or UI elements, and are intended to be collected into a single pass or batch.

BeginDraw is usually paired with EndDraw, which finalizes the drawing sequence. EndDraw often flushes or submits the recorded commands to the GPU or compositor and may present the rendered frame to the display. The pairing ensures a clear boundary between state changes and actual rendering, aiding performance and resource management. Depending on the API, EndDraw may also reset state in preparation for the next pass.

Usage patterns vary by platform. Some frameworks use a single BeginDraw/EndDraw pair per frame, while others support nested or multiple passes for offscreen rendering or layered composition. Optional parameters during BeginDraw can include the target surface, viewport region, or initial clear flags, though specifics differ by implementation.

Origins and design goals of BeginDraw-center around formalizing the start of a rendering pass, enabling efficient batching, predictable state management, and synchronization with the display or render queue. See also EndDraw, Draw, and render passes in related graphics pipelines.