From 72f026e254a716cbc7e7f9c44ec2e6dfd3c773aa Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Fri, 13 Jan 2023 15:05:57 +0900
Subject: [PATCH] internal/graphicsdriver/opengl/gl: bug fix: searching GL
 libraries failed on some machines

On a Debian machine, LD_LIBRARY_PATH might not be set and libGL.so might
not exist (libGL.so.1 exists instead). In this case, searching for a GL
library fails

This change fixes the issue by not using LD_LIBRARY_PATH and also including
`libGL.so.*` files as candidates for dlopen.

Closes #2539
---
 .../opengl/gl/procaddr_others.go              | 70 +------------------
 1 file changed, 3 insertions(+), 67 deletions(-)

diff --git a/internal/graphicsdriver/opengl/gl/procaddr_others.go b/internal/graphicsdriver/opengl/gl/procaddr_others.go
index 88df71393..adb3ed353 100644
--- a/internal/graphicsdriver/opengl/gl/procaddr_others.go
+++ b/internal/graphicsdriver/opengl/gl/procaddr_others.go
@@ -40,9 +40,7 @@ import "C"
 import (
 	"fmt"
 	"os"
-	"path/filepath"
 	"runtime"
-	"sort"
 	"strings"
 	"unsafe"
 )
@@ -52,59 +50,6 @@ var (
 	libGLES unsafe.Pointer
 )
 
-// listLibs returns an appropriate library file paths based on the given library paths and the library name as a prefix.
-// Note that the found libraries might not be available e.g. due to architecture mismatches.
-func listLibs(libraryPaths []string, libName string) ([]string, error) {
-	// LD_LIBRARY_PATH might be empty. Use the original name as a candidate.
-	libNames := []string{libName}
-
-	// Look for a library file. In some environments like Steam, a library with the exactly same name might not exist (#2523).
-	// For example, libGL.so.1 might exist instead of libGL.so.
-	for _, dir := range libraryPaths {
-		libs, err := listLibsInDirectory(dir, libName)
-		if err != nil {
-			return nil, err
-		}
-		if len(libs) == 0 {
-			continue
-		}
-
-		// The file names are sorted in the alphabetical order.
-		// TODO: What is the best version to use?
-		sort.Strings(libs)
-
-		libNames = append(libNames, libs...)
-	}
-
-	return libNames, nil
-}
-
-// listLibsInDirectory returns library file paths with the given prefix in the directory.
-// Note that the found libraries might not be available e.g. due to architecture mismatches.
-func listLibsInDirectory(dir string, prefix string) ([]string, error) {
-	ents, err := os.ReadDir(dir)
-	if err != nil {
-		return nil, err
-	}
-
-	var files []string
-	for _, ent := range ents {
-		if ent.IsDir() {
-			continue
-		}
-		if ent.Name() == prefix {
-			files = append(files, filepath.Join(dir, ent.Name()))
-			continue
-		}
-		if strings.HasPrefix(ent.Name(), prefix+".") {
-			files = append(files, filepath.Join(dir, ent.Name()))
-			continue
-		}
-	}
-
-	return files, nil
-}
-
 func (c *defaultContext) init() error {
 	var preferES bool
 	if runtime.GOOS == "android" {
@@ -120,15 +65,10 @@ func (c *defaultContext) init() error {
 		}
 	}
 
-	libraryPaths := filepath.SplitList(os.Getenv("LD_LIBRARY_PATH"))
-
 	// Try OpenGL first. OpenGL is preferrable as this doesn't cause context losts.
 	if !preferES {
-		names, err := listLibs(libraryPaths, "libGL.so")
-		if err != nil {
-			return err
-		}
-		for _, name := range names {
+		// Usually libGL.so or libGL.so.1 is used. libGL.so.2 might exist only on NetBSD.
+		for _, name := range []string{"libGL.so", "libGL.so.2", "libGL.so.1", "libGL.so.0"} {
 			cname := C.CString(name)
 			lib := C.dlopen(cname, C.RTLD_LAZY|C.RTLD_GLOBAL)
 			C.free(unsafe.Pointer(cname))
@@ -140,11 +80,7 @@ func (c *defaultContext) init() error {
 	}
 
 	// Try OpenGL ES.
-	names, err := listLibs(libraryPaths, "libGLESv2.so")
-	if err != nil {
-		return err
-	}
-	for _, name := range names {
+	for _, name := range []string{"libGLESv2.so", "libGLESv2.so.2", "libGLESv2.so.1", "libGLESv2.so.0"} {
 		cname := C.CString(name)
 		lib := C.dlopen(cname, C.RTLD_LAZY|C.RTLD_GLOBAL)
 		C.free(unsafe.Pointer(cname))