opengl: Move ZeroFramebuffer to context.go

internal/graphics/opengl/context.go

@@ -14,6 +14,8 @@
 
 package opengl
 
+var ZeroFramebuffer Framebuffer
+
 type Context struct {
 	Nearest            Filter
 	Linear             Filter

internal/graphics/opengl/context_desktop.go

@@ -31,8 +31,6 @@ type Shader uint32
 type Program uint32
 type Buffer uint32
 
-var ZeroFramebuffer Framebuffer
-
 type uniformLocation int32
 type attribLocation int32
 

internal/graphics/opengl/context_js.go

@@ -31,8 +31,6 @@ type Framebuffer struct {
 	*js.Object
 }
 
-var ZeroFramebuffer Framebuffer
-
 type Shader struct {
 	*js.Object
 }

internal/graphics/opengl/context_mobile.go

@@ -29,8 +29,6 @@ type Shader mgl.Shader
 type Program mgl.Program
 type Buffer mgl.Buffer
 
-var ZeroFramebuffer Framebuffer
-
 type uniformLocation mgl.Uniform
 type attribLocation mgl.Attrib