022508a5a3
LGTM=nigeltao R=nigeltao, bryanturley, crawshaw CC=adg, davidday, golang-codereviews https://golang.org/cl/136550043
79 lines
1.8 KiB
Go
79 lines
1.8 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package debug provides GL-based debugging tools for apps.
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package debug
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import (
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"fmt"
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"image"
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"image/draw"
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"io/ioutil"
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"log"
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"runtime"
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"sync"
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"time"
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"code.google.com/p/freetype-go/freetype"
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"code.google.com/p/go.mobile/geom"
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)
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var lastDraw = time.Now()
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var monofont = freetype.NewContext()
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var fps struct {
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sync.Once
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*rgba
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}
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// TODO(crawshaw): It looks like we need a gl.RegisterInit feature.
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// TODO(crawshaw): The gldebug mode needs to complain loudly when GL functions
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// are called before init, because often they fail silently.
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func fpsInit() {
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font := "/system/fonts/DroidSansMono.ttf"
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if runtime.GOOS == "darwin" {
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font = "/Library/Fonts/Andale Mono.ttf"
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}
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b, err := ioutil.ReadFile(font)
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if err != nil {
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panic(err)
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}
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f, err := freetype.ParseFont(b)
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if err != nil {
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panic(err)
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}
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monofont.SetFont(f)
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monofont.SetSrc(image.Black)
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monofont.SetHinting(freetype.FullHinting)
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fps.rgba = newRGBA(geom.Point{50, 12})
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monofont.SetDst(fps.Image)
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monofont.SetClip(fps.Image.Bounds())
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monofont.SetDPI(72 * float64(geom.Scale))
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monofont.SetFontSize(12)
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log.Printf("fps.Image bounds: %s", fps.Image.Bounds())
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}
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// DrawFPS draws the per second framerate in the bottom-left of the screen.
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func DrawFPS() {
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fps.Do(fpsInit)
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now := time.Now()
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diff := now.Sub(lastDraw)
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str := fmt.Sprintf("%.0f FPS", float32(time.Second)/float32(diff))
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draw.Draw(fps.Image, fps.Image.Rect, image.White, image.Point{}, draw.Src)
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ftpt12 := freetype.Pt(0, int(12*geom.Scale))
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if _, err := monofont.DrawString(str, ftpt12); err != nil {
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log.Printf("DrawFPS: %v", err)
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return
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}
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fps.Upload()
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fps.Draw(geom.Point{0, geom.Height - 12})
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lastDraw = now
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}
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