/
main.go
133 lines (114 loc) · 2.66 KB
/
main.go
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package main
import (
"log"
"runtime"
"sync"
"time"
"github.com/go-gl/gl/v2.1/gl"
"github.com/go-gl/glfw/v3.2/glfw"
"github.com/golang-ui/cairo"
"github.com/golang-ui/cairo/cairogl"
"github.com/xlab/closer"
)
func init() {
runtime.LockOSThread()
}
func main() {
if err := glfw.Init(); err != nil {
closer.Fatalln(err)
}
glfw.WindowHint(glfw.ContextVersionMajor, 2)
glfw.WindowHint(glfw.ContextVersionMinor, 1)
win, err := glfw.CreateWindow(500, 500, "Cairo Demo", nil, nil)
if err != nil {
closer.Fatalln(err)
}
win.MakeContextCurrent()
ww, wh := win.GetSize()
width, height := win.GetFramebufferSize()
log.Printf("glfw: created window %dx%d (framebuffer: %dx%d)", ww, wh, width, height)
if err := gl.Init(); err != nil {
closer.Fatalln("opengl: init failed:", err)
}
gl.Viewport(0, 0, int32(width), int32(height))
surface := cairogl.NewSurface(width, height)
win.SetFramebufferSizeCallback(func(w *glfw.Window, width int, height int) {
surface.Update(width, height)
})
exitC := make(chan struct{}, 1)
doneC := make(chan struct{}, 1)
closer.Bind(func() {
close(exitC)
<-doneC
})
fpsTicker := time.NewTicker(time.Second / 30)
for {
select {
case <-exitC:
surface.Destroy()
glfw.Terminate()
fpsTicker.Stop()
close(doneC)
return
case <-fpsTicker.C:
if win.ShouldClose() {
close(exitC)
continue
}
glfw.PollEvents()
gfxMain(surface)
win.SwapBuffers()
}
}
}
const PI = 3.1415926
var angle = 45.0
var angleMux sync.RWMutex
func init() {
go func() {
for {
angleMux.Lock()
angle -= 1
if angle <= 0 {
angle = 360.0
}
angleMux.Unlock()
time.Sleep(10 * time.Millisecond)
}
}()
}
func gfxMain(surface *cairogl.Surface) {
cr := surface.Context()
cairo.SetSourceRgba(cr, 0, 0, 0, 1)
cairo.Paint(cr)
offset := 300.0
cairo.SetSourceRgba(cr, 1, 1, 1, 1)
cairo.SetLineWidth(cr, 5)
cairo.MakeRectangle(cr, 10+offset, 10+offset, 300, 300)
cairo.Stroke(cr)
xc := 160.0 + offset
yc := 150.0 + offset
radius := 100.0
angleMux.RLock()
angle1 := angle * (PI / 180.0)
angleMux.RUnlock()
angle2 := 180.0 * (PI / 180.0)
cairo.SetLineWidth(cr, 3.0)
cairo.SetSourceRgba(cr, 1, 1, 1, 1)
cairo.Arc(cr, xc, yc, radius, angle1, angle2)
cairo.Stroke(cr)
cairo.SetSourceRgba(cr, 1, 0.2, 0.2, 0.6)
cairo.SetLineWidth(cr, 6.0)
cairo.Arc(cr, xc, yc, 10.0, 0, 2*PI)
cairo.Fill(cr)
cairo.Arc(cr, xc, yc, radius, angle1, angle2)
cairo.LineTo(cr, xc, yc)
cairo.Arc(cr, xc, yc, radius, angle1, angle2)
cairo.LineTo(cr, xc, yc)
cairo.Stroke(cr)
width, height := surface.Size()
gl.Viewport(0, 0, int32(width), int32(height))
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.ClearColor(1, 1, 1, 1)
surface.Draw()
}