vcl::CanvasBGFX< DerivedRenderApp > Class Template Reference

The Canvas class describes a canvas on which bgfx can draw. More...

#include <vclib/bgfx/canvas.h>

Public Types
using	CallbackReadBuffer = ReadBufferTypes::CallbackReadBuffer

Public Member Functions
	CanvasBGFX (void *winId, uint width, uint height, void *displayId=nullptr)
Point2< uint >	size () const
bgfx::ViewId	viewId () const
bgfx::FrameBufferHandle	frameBuffer () const
void	setDefaultClearColor (const Color &color)
void	onInit ()
	Automatically called by the DerivedRenderApp when the window initializes. Initialization is requires in some backends+window manager combinations, and therefore it must be implemented (also if empty) in every Canvas class.
void	onResize (uint width, uint height)
	Automatically called by the DerivedRenderApp when the window is resized.
void	onPaint ()
	Automatically called by the DerivedRenderApp when the window asks to repaint.
bool	onReadDepth (const Point2i &point, CallbackReadBuffer callback=nullptr)
	Automatically called by the DerivedRenderApp when a drawer asks to read the depth buffer at a specific point.
bool	onScreenshot (const std::string &filename, uint width=0, uint height=0)
	Automatically called by the DerivedRenderApp when a drawer asks for a screenshot.

Protected Types
using	FloatData = ReadBufferTypes::FloatData
using	ByteData = ReadBufferTypes::ByteData
using	ReadData = ReadBufferTypes::ReadData

Private Types
using	ReadFramebufferRequest = detail::ReadFramebufferRequest

Private Member Functions
void	offscreenFrame ()
auto *	derived ()
const auto *	derived () const

Private Attributes
void *	mWinId = nullptr
bgfx::ViewId	mViewId = BGFX_INVALID_VIEW
bgfx::FrameBufferHandle	mFbh = BGFX_INVALID_HANDLE
Point2< uint >	mSize = {0, 0}
vcl::Color	mDefaultClearColor = vcl::Color::Black
uint32_t	mCurrFrame = 0
std::optional< ReadFramebufferRequest >	mReadRequest = std::nullopt

Detailed Description

template<typename DerivedRenderApp>
class vcl::CanvasBGFX< DerivedRenderApp >

The Canvas class describes a canvas on which bgfx can draw.

Its usage requires to have a window object that can be used to initialize the canvas. The window object is not managed by the Canvas class, and can be managed by any of the windowing systems or libraries that allow to retrieve the native window handle (e.g. Qt, GLFW...).

You can create your custom bgfx canvas class by inheriting from this class and passing to the constructor the native window handle and the window size. Alternatively to the constructor, you can also use the init() method to initialize the canvas (if the required parameters are not available at construction time).

This class does not provide a render loop, that must be implemented in one of the derived classes. The render loop must call the frame() member function at the end of each frame, after all the bgfx rendering commands have been issued.

The bgfx rendering code should be implemented in the virtual member function draw(uint viewId), that must be reimplemented in the derived classes. This method is called by the frame() method (that must be called in the render loop), and its argument is the bgfx view ID.

The class provides two important member functions:

• frame(): this function must be called by the derived classes at the end of each frame, after all the bgfx rendering commands have been issued;
• onResize(width, height): this function must be called by the derived classes whenever the window is resized.

Member Function Documentation

onReadDepth()

template<typename DerivedRenderApp >

bool vcl::CanvasBGFX< DerivedRenderApp >::onReadDepth ( const Point2i &  point, CallbackReadBuffer  callback = nullptr  )

inline

Automatically called by the DerivedRenderApp when a drawer asks to read the depth buffer at a specific point.

Parameters

point
callback

Returns

onResize()

template<typename DerivedRenderApp >

void vcl::CanvasBGFX< DerivedRenderApp >::onResize ( uint  width, uint  height  )

inline

Automatically called by the DerivedRenderApp when the window is resized.

Parameters

width
height

onScreenshot()

template<typename DerivedRenderApp >

bool vcl::CanvasBGFX< DerivedRenderApp >::onScreenshot ( const std::string &  filename, uint  width = 0, uint  height = 0  )

inline

Automatically called by the DerivedRenderApp when a drawer asks for a screenshot.

Parameters

filename
width
height

Returns

---

The documentation for this class was generated from the following file:

• vclib/render/include/vclib/bgfx/canvas.h