Rendering a SubViewport Stereo Texture with OpenXR

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Godot Version

Godot 4.5

Question

Does SubViewport with use_xr = true produce a stereo texture (texture‑array) usable in OpenXR on Magic Leap 2 with Godot 4.5?
If not, what is the recommended way to produce per‑eye textures or masks for OpenXR on Magic Leap 2?

Setup
Scene with a script that sets “use_xr” of the main viewport to true:

SubViewport (use_xr=true)
    + Camera3D
XROrigin
    + XRCamera
        + MeshInstance3D_Box
        + MeshInstance3D_DebugQuad

Shader used on MeshInstance3D_DebugQuad:

shader_type spatial;
render_mode unshaded, cull_disabled;
uniform sampler2DArray xr_viewport_tex : source_color;
uniform int eye_index = 0; // 0 = first image
void fragment() {
    vec4 c = texture(xr_viewport_tex, vec3(UV, float(eye_index)));
    ALBEDO = vec3(0.1) + c.rgb;
}

Script on MeshInstance3D_DebugQuad linking the SubViewport texture to the shader.

extends MeshInstance3D
@export var subviewport: SubViewport
func _ready() → void:    
    var material := self.material_override as ShaderMaterial
    material.set_shader_parameter(“xr_viewport_tex”, subviewport.get_texture())   
    material.set_shader_parameter(“eye_index”, 0)

Observation

  • Windows (Forward+ renderer), “use_xr=false”: debug quad shows projected box :slight_smile:
  • Windows, “use_xr=true”: quad is empty :frowning:
  • Magic Leap: debug quad is empty :frowning: