Fix build for wayland

[r0l1]

This is a work in progress pull request to get the wayland issue fixed as soon as possible.
This is based on #199 work.

Right now the build progress fails with:

# github.com/go-gl/glfw/v3.2/glfw
In file included from ./c_glfw_linbsd.go:16:0:
./glfw/src/wayland-relative-pointer-unstable-v1-client-protocol.c:34:35: error: redefinition of ‘types’
 static const struct wl_interface *types[] = {
                                   ^~~~~
In file included from ./c_glfw_linbsd.go:15:0:
./glfw/src/wayland-pointer-constraints-unstable-v1-client-protocol.c:37:35: note: previous definition of ‘types’ was here
 static const struct wl_interface *types[] = {
                                   ^~~~~

Any hints how to fix this?

Thanks!

[r0l1]

Fixed it. I also removed the generate steps and added a generate script. This is only required for developers. I would update the wiki, if this pull request gets merged.

[r0l1]

The wayland developer wiki should be updated to following content if this pull request gets merged.

Generating wayland source/header files

A helper script located at scripts/generate-wayland-protocols.sh should be used to update the wayland source/header files. The wayland-scanner utility is required.

scripts/generate-wayland-protocols.sh ./v3.2/glfw/glfw/src

[r0l1]

Testing

Install the xorg-xeyes utility and run it with:

xeyes

X11

go build

Move the mouse over the window and the xeyes should move, because glfw uses X11.

Wayland

go build -tags wayland

Move the mouse over the window and the xeyes should not move, because glfw uses wayland.

Code

package main

import (
	"log"
	"runtime"
	"time"

	"github.com/go-gl/gl/v3.2-core/gl"
	"github.com/r0l1/glfw/v3.2/glfw"
)

const (
	winWidth  = 400
	winHeight = 500
	fps       = time.Second / 30
)

func init() {
	runtime.LockOSThread()
}

func main() {
	if err := glfw.Init(); err != nil {
		log.Fatalln(err)
	}
	glfw.WindowHint(glfw.ContextVersionMajor, 3)
	glfw.WindowHint(glfw.ContextVersionMinor, 2)
	glfw.WindowHint(glfw.OpenGLProfile, glfw.OpenGLCoreProfile)
	glfw.WindowHint(glfw.OpenGLForwardCompatible, glfw.True)

	win, err := glfw.CreateWindow(winWidth, winHeight, "Nuklear Demo", nil, nil)
	if err != nil {
		log.Fatalln(err)
	}
	win.MakeContextCurrent()

	width, height := win.GetSize()
	log.Printf("glfw: created window %dx%d", width, height)

	if err := gl.Init(); err != nil {
		log.Fatalln("opengl: init failed:", err)
	}
	gl.Viewport(0, 0, int32(width), int32(height))

	for !win.ShouldClose() {
		win.SwapBuffers()
		glfw.PollEvents()
		time.Sleep(fps)
	}
}

[tapir]

Works as intended for me. Though I get this error: PlatformError: Wayland: Focusing a window requires user interaction

[r0l1]

I have the same problem and after some research I found two possible causes:

1. glew with EGL required
2. No window decorations or close callback on Wayland

It seams, that glfw's wayland support has improved a lot in the new upcoming 3.3 release and that we'll have to wait for it's first public release. Nevertheless I suggest to add initial wayland support to this package as initial base for 3.3.

[tapir]

I'm OK with merging this one so at least we have 'some' wayland support for 3.2
Any comments @shurcooL @pwaller ?

[dmitshur]

I don't use Linux on desktop day to day, so I can't review this very thoroughly.

However, from a general look, I don't see any major issues (just minor things that aren't worth blocking the PR for). The changes are isolated to Wayland, and it currently doesn't work, so I don't have objections to moving forward with this.

LGTM.

[dmitshur]

Thanks @r0l1 and @thomasruiz for working on this, and @tapir for reviewing!

[r0l1]

Thanks for merging! Hope we'll have full wayland support in 3.3...

[pwaller]

@r0l1 I'm late to this party - is there are reason to diverge from upstream and remove _GNU_SOURCE here?

Context is: #271.

[pwaller]

FYI I'm reinstating _GNU_SOURCE here, which documents what you should do if you want to remove it again: bac7f0e