ASGE
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asge::video

Classes & Structs

Camera

Struct

IRenderer

Class

ITexture

Class

IWindow

Class

SDLRenderer

Class

SDLTexture

Class

SDLUploadBuffer

Struct

SDLWindow

Class

VideoSystem

Class

Enumerations

#enum class GraphicsBackend : std::uint8_t
SDL

Typedefs

#using Viewport = math::Rect

Functions

#math::Float2 WorldToScreen(Camera const &inCamera, math::Float2 inWorldPos) noexcept

Converts a world-space point to screen space via inCamera's position and zoom.

#math::Float2 WorldToScreen(Camera const &inCamera, Viewport const &inViewport, math::Float2 inWorldPos) noexcept

Converts a world-space point to screen space, offsetting by inViewport's origin.

Viewport clipping is already handled by the renderer backend this only adds inViewport's (x, y) so the camera is anchored within it.

#math::Float2 ScreenToWorld(Camera const &inCamera, Viewport const &inViewport, math::Float2 inScreenPos) noexcept
#math::Rect TransformRect(Camera const &inCamera, math::Rect const &inWorldRect) noexcept
#math::Rect VisibleWorldRect(Camera const &inCamera, Viewport const &inViewport) noexcept

The world-space rect currently visible through inViewport at inCamera's position/zoom.

Inverse of TransformRect's size math: inViewport's size divided by zoom gives how much world-space area is on screen, anchored at the camera's own (m_X, m_Y). Used by systems::RenderSystem to cull sprites whose destination rect doesn't overlap it at all, rather than drawing (and having the backend clip) every entity in the world every frame.

#BoolResult InitializeBackend(GraphicsBackend inBackend)

Initializes the given graphics backend's subsystem.

Must be called once before CreateWindow/CreateRenderer for that backend, and paired with a matching ShutdownBackend call.

Parameters
inBackend

The graphics backend to initialize

#void ShutdownBackend(GraphicsBackend inBackend)

Shuts down the given graphics backend's subsystem.

Parameters
inBackend

The graphics backend to shut down

#std::unique_ptr< IWindow > CreateWindow(GraphicsBackend inBackend, std::string const &inTitle, int inWidth, int inHeight, bool inResizable)

Creates a window for the given graphics backend.

Parameters
inBackend

The graphics backend to create the window for

inTitle

The title of the window

inWidth

The width of the window

inHeight

The height of the window

inResizable

Whether the window can be resized by the user

#std::unique_ptr< IRenderer > CreateRenderer(GraphicsBackend inBackend, IWindow const &inWindow)

Creates a renderer for the given graphics backend, bound to the input window.

Parameters
inBackend

The graphics backend to create the renderer for

inWindow

The window the renderer will draw to

#void DrawTextureAnchored(IRenderer const &inRenderer, ITexture const &inTexture, math::Rect const &inSrcRect, math::Rect const &inDestRect, math::Float2 const &inSrcAnchor=math::Float2{ 0.0f, 0.0f }) noexcept

Draws inSrcRect anchored at a normalized point within it, so that point (not inDestRect's top-left corner) lands at inDestRect's (x, y) — {0,0} reproduces plain DrawTexture(srcRect, destRect).

Lets one fixed anchor stay put on screen while inSrcRect's size varies call to call (e.g. differently-cropped animation frames).

#SDL_PixelFormat MapPixelFormat(graphics::PixelFormat inFormat) noexcept

Maps an asge::graphics::PixelFormat to the SDL_PixelFormat SDLTexture uploads as.

#SDLUploadBuffer ExpandPixelsForUpload(media::Image const &inImage)

Converts an Image's pixel bytes into the layout MapPixelFormat's return value expects.

RGBA8 images pass through unchanged. A8 images are expanded one byte into four: RGB set to white, alpha set to the source byte the standard trick for uploading single-channel glyph/mask data as a normal alpha-blended RGBA texture, tinted via SDL_SetTextureColorMod by the caller.