81 lines
2.4 KiB
Go
81 lines
2.4 KiB
Go
//go:build js && wasm
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package main
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import (
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"image/color"
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"syscall/js"
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"time"
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"github.com/llgcode/draw2d/draw2dimg"
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"github.com/llgcode/draw2d/draw2dkit"
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"github.com/markfarnan/go-canvas/canvas"
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)
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type gameState struct{ laserX, laserY, directionX, directionY, laserSize float64 }
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var done chan struct{}
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var cvs *canvas.Canvas2d
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var width float64
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var height float64
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var gs = gameState{laserSize: 35, directionX: 13.7, directionY: -13.7, laserX: 40, laserY: 40}
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// This specifies how long a delay between calls to 'render'. To get Frame Rate, 1s / renderDelay
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var renderDelay time.Duration = 20 * time.Millisecond
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func main() {
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FrameRate := time.Second / renderDelay
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println("Hello Browser FPS:", FrameRate)
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//cvs, _ = canvas.NewCanvas2d(true)
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cvs, _ = canvas.NewCanvas2d(false)
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cvs.Create(int(js.Global().Get("innerWidth").Float()), int(js.Global().Get("innerHeight").Float())) // Make Canvas 90% of window size. For testing rendering canvas smaller than full windows
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height = float64(cvs.Height())
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width = float64(cvs.Width())
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cvs.Start(60, Render)
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//go doEvery(renderDelay, Render) // Kick off the Render function as go routine as it never returns
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<-done
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}
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// Helper function which calls the required func (in this case 'render') every time.Duration, Call as a go-routine to prevent blocking, as this never returns
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func doEvery(d time.Duration, f func(time.Time)) {
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for x := range time.Tick(d) {
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f(x)
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}
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}
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// Called from the 'requestAnnimationFrame' function. It may also be called seperatly from a 'doEvery' function, if the user prefers drawing to be seperate from the annimationFrame callback
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func Render(gc *draw2dimg.GraphicContext) bool {
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if gs.laserX+gs.directionX > width-gs.laserSize || gs.laserX+gs.directionX < gs.laserSize {
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gs.directionX = -gs.directionX
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}
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if gs.laserY+gs.directionY > height-gs.laserSize || gs.laserY+gs.directionY < gs.laserSize {
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gs.directionY = -gs.directionY
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}
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gc.SetFillColor(color.RGBA{0xff, 0xff, 0xff, 0xff})
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gc.Clear()
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// move red laser
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gs.laserX += gs.directionX
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gs.laserY += gs.directionY
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// draws red 🔴 laser
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gc.SetFillColor(color.RGBA{0xff, 0x00, 0xff, 0xff})
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gc.SetStrokeColor(color.RGBA{0xff, 0x00, 0xff, 0xff})
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gc.BeginPath()
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//gc.ArcTo(gs.laserX, gs.laserY, gs.laserSize, gs.laserSize, 0, math.Pi*2)
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draw2dkit.Circle(gc, gs.laserX, gs.laserY, gs.laserSize)
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gc.FillStroke()
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gc.Close()
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return true
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}
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