graphicsdriver/opengl: Remove init order dependency

internal/graphicsdriver/opengl/context_desktop.go

@@ -69,8 +69,6 @@ func init() {
 	dstAlpha = gl.DST_ALPHA
 	oneMinusSrcAlpha = gl.ONE_MINUS_SRC_ALPHA
 	oneMinusDstAlpha = gl.ONE_MINUS_DST_ALPHA
-
-	initializeArrayBuferLayout()
 }
 
 type contextImpl struct {

internal/graphicsdriver/opengl/context_js.go

@@ -109,8 +109,6 @@ func init() {
 	unpackAlignment = c.Get("UNPACK_ALIGNMENT")
 	unsignedByte = c.Get("UNSIGNED_BYTE")
 	unsignedShort = c.Get("UNSIGNED_SHORT")
-
-	initializeArrayBuferLayout()
 }
 
 type contextImpl struct {

internal/graphicsdriver/opengl/context_mobile.go

@@ -66,8 +66,6 @@ func init() {
 	dstAlpha = mgl.DST_ALPHA
 	oneMinusSrcAlpha = mgl.ONE_MINUS_SRC_ALPHA
 	oneMinusDstAlpha = mgl.ONE_MINUS_DST_ALPHA
-
-	initializeArrayBuferLayout()
 }
 
 type contextImpl struct {

internal/graphicsdriver/opengl/program.go

@@ -78,30 +78,26 @@ func (a *arrayBufferLayout) disable(context *context, program program) {
 }
 
 // theArrayBufferLayout is the array buffer layout for Ebiten.
-var theArrayBufferLayout arrayBufferLayout
+var theArrayBufferLayout = arrayBufferLayout{
-
+	// Note that GL_MAX_VERTEX_ATTRIBS is at least 16.
-func initializeArrayBuferLayout() {
+	parts: []arrayBufferLayoutPart{
-	theArrayBufferLayout = arrayBufferLayout{
+		{
-		// Note that GL_MAX_VERTEX_ATTRIBS is at least 16.
+			name: "vertex",
-		parts: []arrayBufferLayoutPart{
+			num:  2,
-			{
-				name: "vertex",
-				num:  2,
-			},
-			{
-				name: "tex",
-				num:  2,
-			},
-			{
-				name: "tex_region",
-				num:  4,
-			},
-			{
-				name: "color_scale",
-				num:  4,
-			},
 		},
-	}
+		{
+			name: "tex",
+			num:  2,
+		},
+		{
+			name: "tex_region",
+			num:  4,
+		},
+		{
+			name: "color_scale",
+			num:  4,
+		},
+	},
 }
 
 func init() {