Fix first 5 tutorials

tutorials/GLWindow.jl

@@ -0,0 +1,44 @@
+"""
+GLWindow was/is a package by Simon Danisch et al that wrapped some functionality of
+GLFW. I think it's obsoleted now? This little module reimplements only those parts
+required to get the tutorials working again.
+
+https://github.com/JuliaGL/GLWindow.jl
+
+"""
+module GLWindow
+
+import GLFW
+
+using ModernGL: GL_TRUE
+
+export create_glcontext
+
+# A more comprehensive setting of GLFW window hints. Setting all
+# window hints reduces platform variance.
+const window_hints = [
+    (GLFW.SAMPLES,      4),
+    (GLFW.DEPTH_BITS,   0),
+
+    (GLFW.ALPHA_BITS,   8),
+    (GLFW.RED_BITS,     8),
+    (GLFW.GREEN_BITS,   8),
+    (GLFW.BLUE_BITS,    8),
+    (GLFW.STENCIL_BITS, 0),
+    (GLFW.AUX_BUFFERS,  0),
+    (GLFW.CONTEXT_VERSION_MAJOR, 3),# minimum OpenGL v. 3
+    (GLFW.CONTEXT_VERSION_MINOR, 0),# minimum OpenGL v. 3.0
+    (GLFW.OPENGL_PROFILE, GLFW.OPENGL_ANY_PROFILE),
+    (GLFW.OPENGL_FORWARD_COMPAT, GL_TRUE),
+]
+
+function create_glcontext(title; resolution)
+    for (key, value) in window_hints
+        GLFW.WindowHint(key, value)
+    end
+    window = GLFW.CreateWindow(resolution..., title)
+    GLFW.MakeContextCurrent(window)
+    return window
+end
+
+end