ui/main_window.go
Noah Petherbridge 0efc577fa7 Initial WebAssembly Build Target
* Initial WebAssembly build target for Doodle in the wasm/ folder.
* Add a new render.Engine implementation, lib/render/canvas that uses
  the HTML 5 Canvas API instead of SDL2 for the WebAssembly target.
  * Ported the basic DrawLine(), DrawBox() etc. functions from SDL2 to
    Canvas context2d API.
  * Fonts are handled with CSS embedded fonts named after the font
    filename and defined in wasm/index.html
* `make wasm` builds the WASM program, and `make wasm-serve` runs a dev
  Go server that hosts the WASM file for development. The server also
  watches the dev tree for *.go files and rebuilds the WASM binary
  automatically on change.
* This build "basically" runs the game. UI and fonts all work and mouse
  movements and clicks are detected. No wallpaper support yet or texture
  caching (which will crash the game as soon as you click and draw a
  pixel in your map!)
2019-06-26 18:40:40 -07:00

129 lines
2.4 KiB
Go

// +build !js
package ui
import (
"fmt"
"time"
"git.kirsle.net/apps/doodle/lib/render"
"git.kirsle.net/apps/doodle/lib/render/sdl"
)
// Target frames per second for the MainWindow to render at.
var (
FPS = 60
)
// MainWindow is the parent window of a UI application.
type MainWindow struct {
engine render.Engine
supervisor *Supervisor
frame *Frame
w int
h int
}
// NewMainWindow initializes the MainWindow. You should probably only have one
// of these per application.
func NewMainWindow(title string) (*MainWindow, error) {
mw := &MainWindow{
w: 800,
h: 600,
supervisor: NewSupervisor(),
}
mw.engine = sdl.New(
title,
mw.w,
mw.h,
)
if err := mw.engine.Setup(); err != nil {
return nil, err
}
// Add a default frame to the window.
mw.frame = NewFrame("MainWindow Body")
mw.frame.SetBackground(render.RGBA(0, 153, 255, 100))
mw.Add(mw.frame)
// Compute initial window size.
mw.resized()
return mw, nil
}
// Add a child widget to the window.
func (mw *MainWindow) Add(w Widget) {
mw.supervisor.Add(w)
}
// Pack a child widget into the window's default frame.
func (mw *MainWindow) Pack(w Widget, pack Pack) {
mw.Add(w)
mw.frame.Pack(w, pack)
}
// resized handles the window being resized.
func (mw *MainWindow) resized() {
mw.frame.Resize(render.Rect{
W: int32(mw.w),
H: int32(mw.h),
})
}
// Present the window.
func (mw *MainWindow) Present() {
mw.supervisor.Present(mw.engine)
}
// MainLoop starts the main event loop and blocks until there's an error.
func (mw *MainWindow) MainLoop() error {
for true {
if err := mw.Loop(); err != nil {
return err
}
}
return nil
}
// Loop does one loop of the UI.
func (mw *MainWindow) Loop() error {
mw.engine.Clear(render.White)
// Record how long this loop took.
start := time.Now()
// Poll for events.
ev, err := mw.engine.Poll()
if err != nil {
return fmt.Errorf("event poll error: %s", err)
}
if ev.Resized.Now {
w, h := mw.engine.WindowSize()
if w != mw.w || h != mw.h {
mw.w = w
mw.h = h
mw.resized()
}
}
mw.frame.Compute(mw.engine)
// Render the child widgets.
mw.supervisor.Present(mw.engine)
mw.engine.Present()
// Delay to maintain target frames per second.
var delay uint32
var targetFPS = 1000 / FPS
elapsed := time.Now().Sub(start) / time.Millisecond
if targetFPS-int(elapsed) > 0 {
delay = uint32(targetFPS - int(elapsed))
}
mw.engine.Delay(delay)
return nil
}