120 lines
2.5 KiB
Go
120 lines
2.5 KiB
Go
// Open an OpenGl window and display a rectangle using a OpenGl GraphicContext
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package main
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import (
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"image/color"
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"log"
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"runtime"
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"github.com/go-gl/gl/v2.1/gl"
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"github.com/go-gl/glfw/v3.1/glfw"
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"github.com/llgcode/draw2d"
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"github.com/llgcode/draw2d/draw2dgl"
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"github.com/llgcode/draw2d/draw2dkit"
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)
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var (
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// global rotation
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rotate int
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width, height int
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redraw = true
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font draw2d.FontData
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)
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func reshape(window *glfw.Window, w, h int) {
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gl.ClearColor(1, 1, 1, 1)
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/* Establish viewing area to cover entire window. */
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gl.Viewport(0, 0, int32(w), int32(h))
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/* PROJECTION Matrix mode. */
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gl.MatrixMode(gl.PROJECTION)
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/* Reset project matrix. */
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gl.LoadIdentity()
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/* Map abstract coords directly to window coords. */
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gl.Ortho(0, float64(w), 0, float64(h), -1, 1)
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/* Invert Y axis so increasing Y goes down. */
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gl.Scalef(1, -1, 1)
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/* Shift origin up to upper-left corner. */
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gl.Translatef(0, float32(-h), 0)
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gl.Enable(gl.BLEND)
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gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
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gl.Disable(gl.DEPTH_TEST)
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width, height = w, h
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redraw = true
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}
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// Ask to refresh
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func invalidate() {
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redraw = true
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}
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func display() {
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gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
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gl.LineWidth(1)
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gc := draw2dgl.NewGraphicContext(width, height)
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gc.SetFontData(draw2d.FontData{
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Name: "luxi",
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Family: draw2d.FontFamilyMono,
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Style: draw2d.FontStyleBold | draw2d.FontStyleItalic})
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gc.BeginPath()
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draw2dkit.RoundedRectangle(gc, 200, 200, 600, 600, 100, 100)
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gc.SetFillColor(color.RGBA{0, 0, 0, 0xff})
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gc.Fill()
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gl.Flush() /* Single buffered, so needs a flush. */
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}
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func init() {
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runtime.LockOSThread()
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}
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func main() {
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err := glfw.Init()
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if err != nil {
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panic(err)
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}
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defer glfw.Terminate()
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width, height = 800, 800
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window, err := glfw.CreateWindow(width, height, "Show RoundedRect", nil, nil)
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if err != nil {
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panic(err)
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}
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window.MakeContextCurrent()
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window.SetSizeCallback(reshape)
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window.SetKeyCallback(onKey)
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window.SetCharCallback(onChar)
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glfw.SwapInterval(1)
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err = gl.Init()
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if err != nil {
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panic(err)
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}
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reshape(window, width, height)
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for !window.ShouldClose() {
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if redraw {
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display()
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window.SwapBuffers()
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redraw = false
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}
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glfw.PollEvents()
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// time.Sleep(2 * time.Second)
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}
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}
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func onChar(w *glfw.Window, char rune) {
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log.Println(char)
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}
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func onKey(w *glfw.Window, key glfw.Key, scancode int, action glfw.Action, mods glfw.ModifierKey) {
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switch {
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case key == glfw.KeyEscape && action == glfw.Press,
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key == glfw.KeyQ && action == glfw.Press:
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w.SetShouldClose(true)
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}
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}
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