Add rounded Rect sample

cmd/roundedrectgl.go

@@ -0,0 +1,129 @@
+// Ported from GLUT's samples.  Original copyright below applies.
+
+/* Copyright (c) Mark J. Kilgard, 1996. */
+
+/* This program is freely distributable without licensing fees
+   and is provided without guarantee or warrantee expressed or
+   implied. This program is -not- in the public domain. */
+
+/* This program is a response to a question posed by Gil Colgate
+   <gcolgate@sirius.com> about how lengthy a program is required using
+   OpenGL compared to using  Direct3D immediate mode to "draw a
+   triangle at screen coordinates 0,0, to 200,200 to 20,200, and I
+   want it to be blue at the top vertex, red at the left vertex, and
+   green at the right vertex".  I'm not sure how long the Direct3D
+   program is; Gil has used Direct3D and his guess is "about 3000
+   lines of code". */
+
+package main
+
+import (
+	"image/color"
+	"log"
+	"runtime"
+
+	"github.com/go-gl/gl/v2.1/gl"
+	"github.com/go-gl/glfw/v3.1/glfw"
+	"github.com/llgcode/draw2d/draw2d"
+	"github.com/llgcode/draw2d/draw2dgl"
+)
+
+var (
+	// global rotation
+	rotate        int
+	width, height int
+	redraw        = true
+	font          draw2d.FontData
+)
+
+func reshape(window *glfw.Window, w, h int) {
+	gl.ClearColor(1, 1, 1, 1)
+	/* Establish viewing area to cover entire window. */
+	gl.Viewport(0, 0, int32(w), int32(h))
+	/* PROJECTION Matrix mode. */
+	gl.MatrixMode(gl.PROJECTION)
+	/* Reset project matrix. */
+	gl.LoadIdentity()
+	/* Map abstract coords directly to window coords. */
+	gl.Ortho(0, float64(w), 0, float64(h), -1, 1)
+	/* Invert Y axis so increasing Y goes down. */
+	gl.Scalef(1, -1, 1)
+	/* Shift origin up to upper-left corner. */
+	gl.Translatef(0, float32(-h), 0)
+	gl.Enable(gl.BLEND)
+	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
+	gl.Disable(gl.DEPTH_TEST)
+	width, height = w, h
+	redraw = true
+}
+
+// Ask to refresh
+func invalidate() {
+	redraw = true
+}
+
+func display() {
+	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
+
+	gl.LineWidth(1)
+	gc := draw2dgl.NewGraphicContext(width, height)
+	gc.SetFontData(draw2d.FontData{"luxi", draw2d.FontFamilyMono, draw2d.FontStyleBold | draw2d.FontStyleItalic})
+
+	gc.BeginPath()
+	draw2d.RoundRect(gc, 200, 200, 600, 600, 100, 100)
+
+	gc.SetFillColor(color.RGBA{0, 0, 0, 0xff})
+	gc.Fill()
+
+	gl.Flush() /* Single buffered, so needs a flush. */
+}
+
+func init() {
+	runtime.LockOSThread()
+}
+
+func main() {
+	err := glfw.Init()
+	if err != nil {
+		panic(err)
+	}
+	defer glfw.Terminate()
+	width, height = 800, 800
+	window, err := glfw.CreateWindow(width, height, "Show RoundedRect", nil, nil)
+	if err != nil {
+		panic(err)
+	}
+
+	window.MakeContextCurrent()
+	window.SetSizeCallback(reshape)
+	window.SetKeyCallback(onKey)
+	window.SetCharCallback(onChar)
+
+	glfw.SwapInterval(1)
+
+	err = gl.Init()
+	if err != nil {
+		panic(err)
+	}
+
+	reshape(window, width, height)
+	for !window.ShouldClose() {
+		if redraw {
+			display()
+			window.SwapBuffers()
+			redraw = false
+		}
+		glfw.PollEvents()
+		//		time.Sleep(2 * time.Second)
+	}
+}
+func onChar(w *glfw.Window, char rune) {
+	log.Println(char)
+}
+func onKey(w *glfw.Window, key glfw.Key, scancode int, action glfw.Action, mods glfw.ModifierKey) {
+	switch {
+	case key == glfw.KeyEscape && action == glfw.Press,
+		key == glfw.KeyQ && action == glfw.Press:
+		w.SetShouldClose(true)
+	}
+}