Data commit

Task/OpenGL/Go/opengl.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+    gl "github.com/chsc/gogl/gl21"
+    "github.com/go-gl/glfw/v3.2/glfw"
+    "log"
+    "runtime"
+)
+
+// Window dimensions.
+const (
+    Width  = 640
+    Height = 480
+)
+
+func check(err error) {
+    if err != nil {
+        log.Fatal(err)
+    }
+}
+
+func main() {
+    // OpenGL requires a dedicated OS thread.
+    runtime.LockOSThread()
+    defer runtime.UnlockOSThread()
+
+    err := glfw.Init()
+    check(err)
+    defer glfw.Terminate()
+
+    // Open window with the specified dimensions.
+    window, err := glfw.CreateWindow(Width, Height, "Triangle", nil, nil)
+    check(err)
+
+    window.MakeContextCurrent()
+
+    err = gl.Init()
+    check(err) /* may need to comment out this line for this program to work on Windows 10 */
+
+    // Initiate viewport.
+    resize(Width, Height)
+
+    // Register that we are interested in receiving close and resize events.
+    window.SetCloseCallback(func(w *glfw.Window) {
+        return
+    })
+    window.SetSizeCallback(func(w *glfw.Window, width, height int) {
+        resize(width, height)
+    })
+
+    for !window.ShouldClose() {
+        draw()
+        window.SwapBuffers()
+        glfw.PollEvents()
+    }
+}
+
+// resize resizes the window to the specified dimensions.
+func resize(width, height int) {
+    gl.Viewport(0, 0, gl.Sizei(width), gl.Sizei(height))
+    gl.MatrixMode(gl.PROJECTION)
+    gl.LoadIdentity()
+    gl.Ortho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0)
+    gl.MatrixMode(gl.MODELVIEW)
+}
+
+// draw draws the triangle.
+func draw() {
+    gl.ClearColor(0.3, 0.3, 0.3, 0.0)
+    gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
+
+    gl.ShadeModel(gl.SMOOTH)
+
+    gl.LoadIdentity()
+    gl.Translatef(-15.0, -15.0, 0.0)
+
+    gl.Begin(gl.TRIANGLES)
+
+    gl.Color3f(1.0, 0.0, 0.0)
+    gl.Vertex2f(0.0, 0.0)
+
+    gl.Color3f(0.0, 1.0, 0.0)
+    gl.Vertex2f(30.0, 0.0)
+
+    gl.Color3f(0.0, 0.0, 1.0)
+    gl.Vertex2f(0.0, 30.0)
+
+    gl.End()
+
+    gl.Flush()
+}