#include <algorithm>
#include <chrono>
#include <cstdint>
#include <optional>
#include <string>
#include <vector>

Enumerations
enum class	RHI_PRESENT_MODE : uint8_t { FIFO , MAILBOX , IMMEDIATE }
	How a swapchain hands finished images to the display. More...

Functions
RHI_PRESENT_MODE	RhiChoosePresentMode (const std::vector< RHI_PRESENT_MODE > &aOffered, bool aComposited, bool aImmediateUnderCompositor=false)
	Choose the present mode for a swapchain from the modes the surface offers.

template<typename TIME_POINT>
TIME_POINT	RhiNextFrameAt (TIME_POINT aFrameStart, double aRefreshHz, std::optional< TIME_POINT > aVblank)
	The earliest time the frame after one started at `aFrameStart` may start, for a window whose presents do not wait for the display.

Variables
constexpr int	RHI_PRESENTS_IN_FLIGHT = 2
	Presents allowed to wait for the display at once while frames are paced.

Enumeration Type Documentation

◆ RHI_PRESENT_MODE

enum class RHI_PRESENT_MODE : uint8_t

strong

How a swapchain hands finished images to the display.

Enumerator
FIFO	Waits for a vertical blank, never tears, adds up to a refresh of latency.
MAILBOX	Replaces the queued image at each blank, never tears, no wait.
IMMEDIATE	Shows the image at once, tears unless a compositor owns the final present.

Definition at line 40 of file rhi_present_mode.h.

Function Documentation

◆ RhiChoosePresentMode()

RHI_PRESENT_MODE RhiChoosePresentMode	(	const std::vector< RHI_PRESENT_MODE > &	aOffered,
		bool	aComposited,
		bool	aImmediateUnderCompositor = false )

inline

Choose the present mode for a swapchain from the modes the surface offers.

MAILBOX is preferred. Without it a composited window uses IMMEDIATE, since the compositor's vsynced frame keeps it from tearing, and anything else uses FIFO, which every surface offers. With aImmediateUnderCompositor a composited window prefers IMMEDIATE over MAILBOX because Mesa's MAILBOX adds latency under a compositor.

Parameters

aComposited	true when a compositor owns the final present.
aImmediateUnderCompositor	true on Linux.

Definition at line 59 of file rhi_present_mode.h.

References FIFO, IMMEDIATE, and MAILBOX.

Referenced by RHI_VULKAN_DEVICE::ChoosePresentMode().

◆ RhiNextFrameAt()

template<typename TIME_POINT>

TIME_POINT RhiNextFrameAt	(	TIME_POINT	aFrameStart,
		double	aRefreshHz,
		std::optional< TIME_POINT >	aVblank )

The earliest time the frame after one started at aFrameStart may start, for a window whose presents do not wait for the display.

With a known vertical blank this is the next blank after aFrameStart, so at most one frame starts per refresh and frames do not drift against the display. Without one it is a refresh later.

Parameters

aRefreshHz	the display's refresh rate, above zero.
aVblank	a time the display refreshed, before or after `aFrameStart`.

Division truncates towards zero, and a blank reported after the frame start needs the floor.

Definition at line 91 of file rhi_present_mode.h.

Referenced by KIGFX::RENDER_THREAD::ProcessActiveWindows().

Variable Documentation

◆ RHI_PRESENTS_IN_FLIGHT

int RHI_PRESENTS_IN_FLIGHT = 2

constexpr

Presents allowed to wait for the display at once while frames are paced.

Definition at line 34 of file rhi_present_mode.h.