blob: 8d91cdc7b36fc4a9b97fae984ebc4df26ee3019d [file] [log] [blame]
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build example
//
// This build tag means that "go install golang.org/x/exp/shiny/..." doesn't
// install this example program. Use "go run main.go" to run it or "go install
// -tags=example" to install it.
// Tile demonstrates tiling a screen with textures.
package main
import (
"fmt"
"image"
"image/color"
"image/draw"
"log"
"sync"
"golang.org/x/exp/shiny/driver"
"golang.org/x/exp/shiny/screen"
"golang.org/x/image/font"
"golang.org/x/image/font/inconsolata"
"golang.org/x/image/math/fixed"
"golang.org/x/mobile/event/key"
"golang.org/x/mobile/event/lifecycle"
"golang.org/x/mobile/event/mouse"
"golang.org/x/mobile/event/paint"
"golang.org/x/mobile/event/size"
)
func main() {
driver.Main(func(s screen.Screen) {
w, err := s.NewWindow(nil)
if err != nil {
log.Fatal(err)
}
defer w.Release()
var (
pool = &tilePool{
screen: s,
drawRGBA: drawRGBA,
m: map[image.Point]*tilePoolEntry{},
}
dragging bool
paintPending bool
drag image.Point
origin image.Point
sz size.Event
)
for {
switch e := w.NextEvent().(type) {
case lifecycle.Event:
if e.To == lifecycle.StageDead {
return
}
case key.Event:
if e.Code == key.CodeEscape {
return
}
case mouse.Event:
p := image.Point{X: int(e.X), Y: int(e.Y)}
if e.Button == mouse.ButtonLeft && e.Direction != mouse.DirNone {
dragging = e.Direction == mouse.DirPress
drag = p
}
if !dragging {
break
}
origin = origin.Sub(p.Sub(drag))
drag = p
if origin.X < 0 {
origin.X = 0
}
if origin.Y < 0 {
origin.Y = 0
}
if !paintPending {
paintPending = true
w.Send(paint.Event{})
}
case paint.Event:
generation++
var wg sync.WaitGroup
for y := -(origin.Y & 0xff); y < sz.HeightPx; y += 256 {
for x := -(origin.X & 0xff); x < sz.WidthPx; x += 256 {
wg.Add(1)
go drawTile(&wg, w, pool, origin, x, y)
}
}
wg.Wait()
w.Publish()
paintPending = false
pool.releaseUnused()
case size.Event:
sz = e
case error:
log.Print(e)
}
}
})
}
func drawTile(wg *sync.WaitGroup, w screen.Window, pool *tilePool, origin image.Point, x, y int) {
defer wg.Done()
tp := image.Point{
(x + origin.X) >> 8,
(y + origin.Y) >> 8,
}
tex, err := pool.get(tp)
if err != nil {
log.Println(err)
return
}
w.Copy(image.Point{x, y}, tex, tileBounds, screen.Src, nil)
}
func drawRGBA(m *image.RGBA, tp image.Point) {
draw.Draw(m, m.Bounds(), image.White, image.Point{}, draw.Src)
for _, p := range crossPoints {
m.SetRGBA(p.X, p.Y, crossColor)
}
d := font.Drawer{
Dst: m,
Src: image.Black,
Face: inconsolata.Regular8x16,
Dot: fixed.Point26_6{
Y: inconsolata.Regular8x16.Metrics().Ascent,
},
}
d.DrawString(fmt.Sprint(tp))
}
var (
crossColor = color.RGBA{0x7f, 0x00, 0x00, 0xff}
crossPoints = []image.Point{
{0x00, 0xfe},
{0x00, 0xff},
{0xfe, 0x00},
{0xff, 0x00},
{0x00, 0x00},
{0x01, 0x00},
{0x02, 0x00},
{0x00, 0x01},
{0x00, 0x02},
{0x80, 0x7f},
{0x7f, 0x80},
{0x80, 0x80},
{0x81, 0x80},
{0x80, 0x81},
{0x80, 0x00},
{0x00, 0x80},
}
generation int
tileSize = image.Point{256, 256}
tileBounds = image.Rectangle{Max: tileSize}
)
type tilePoolEntry struct {
tex screen.Texture
gen int
}
type tilePool struct {
screen screen.Screen
drawRGBA func(*image.RGBA, image.Point)
mu sync.Mutex
m map[image.Point]*tilePoolEntry
}
func (p *tilePool) get(tp image.Point) (screen.Texture, error) {
p.mu.Lock()
v, ok := p.m[tp]
if v != nil {
v.gen = generation
}
p.mu.Unlock()
if ok {
return v.tex, nil
}
tex, err := p.screen.NewTexture(tileSize)
if err != nil {
return nil, err
}
buf, err := p.screen.NewBuffer(tileSize)
if err != nil {
tex.Release()
return nil, err
}
p.drawRGBA(buf.RGBA(), tp)
tex.Upload(image.Point{}, buf, tileBounds)
buf.Release()
p.mu.Lock()
p.m[tp] = &tilePoolEntry{
tex: tex,
gen: generation,
}
n := len(p.m)
p.mu.Unlock()
fmt.Printf("%4d textures; created %v\n", n, tp)
return tex, nil
}
func (p *tilePool) releaseUnused() {
p.mu.Lock()
defer p.mu.Unlock()
for tp, v := range p.m {
if v.gen == generation {
continue
}
v.tex.Release()
delete(p.m, tp)
fmt.Printf("%4d textures; released %v\n", len(p.m), tp)
}
}