115 lines
1.8 KiB
Go
115 lines
1.8 KiB
Go
package main
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import (
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"math"
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"math/rand"
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"time"
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"git.kirsle.net/go/render"
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"git.kirsle.net/go/render/sdl"
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)
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// Config variables.
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var (
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Filename = "photo.jpg"
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Width = 640
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Height = 480
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Quality = 4
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// computed.
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Size = Width * Height
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)
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// Runtime variables.
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var (
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app *App
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mw render.Engine
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TargetFPS = 1000 / 60 // run at 60fps
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)
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func main() {
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setup()
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mainloop()
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}
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// setup the applet
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func setup() {
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// Seed the random number generator.
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rand.Seed(time.Now().UnixNano())
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// Create SDL2 window.
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mw = sdl.New("Ripple effect", Width, Height)
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if err := mw.Setup(); err != nil {
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panic(err)
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}
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// Load the jpeg image.
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var err error
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photo, err := render.OpenImage(Filename)
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if err != nil {
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panic(err)
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}
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app = New(mw, photo)
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}
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// loop runs the applet logic for each loop.
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func loop() bool {
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app.Ripple()
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mw.Clear(render.White)
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// Poll events.
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ev, err := mw.Poll()
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if err != nil {
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panic(err)
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}
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// Escape key closes the program.
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if ev.Escape {
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mw.Teardown()
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return false
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}
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// Is mouse over the drawing?
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if ev.CursorX >= 0 && ev.CursorX < Width && ev.CursorY >= 0 && ev.CursorY < Width {
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app.Disturb(ev.CursorX, ev.CursorY, 15000)
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}
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// rain
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app.Disturb(
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int(math.Floor(rand.Float64()*float64(Width))),
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int(math.Floor(rand.Float64()*float64(Height))),
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int(rand.Float64()*10000),
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)
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app.Present()
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return true
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}
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// mainloop runs a loop of loop() while maintaing the frame rate.
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func mainloop() {
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var (
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start time.Time
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elapsed time.Duration
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ok bool
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)
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for {
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// Record how long the frame takes.
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start = time.Now()
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ok = loop()
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// Delay to maintain target frames per second.
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var delay uint32
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elapsed = time.Now().Sub(start) / time.Millisecond
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if TargetFPS-int(elapsed) > 0 {
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delay = uint32(TargetFPS - int(elapsed))
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}
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mw.Delay(delay)
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if !ok {
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break
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}
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}
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}
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