Way to display images(imgui.image) that are already on GPU

[REDxEYE]

Hello, I haven't found a way to display image/texture that i have created in pygfx in wgpu-py/imgui-bundle.

Currently i'm manually adding my texture to ImguiWgpuBackend._texture_views like so

    def _get_imgui_image_id(self, texture: gfx.Texture) -> int:
        """Get the ImGui image ID for the given texture."""
        if self._current_texture_id is None or self._current_texture_id != id(texture):
            self._current_texture_id = id(texture)
            texture_view = GfxTextureView(texture)
            self._current_texture_view = ensure_wgpu_object(texture_view)
            id_32 = ctypes.c_int32(id(self._current_texture_view)).value
            self.window.imgui_renderer.backend._texture_views[id_32] = self._current_texture_view
            return id_32
        return ctypes.c_int32(id(self._current_texture_view)).value

Please help me find correct way to display images

[Vipitis]

hey, can you share an example where you use this?

If by display you mean drawing it to the screen, then you should be able to use copy_texture_to_texture where the target is whatever context.get_current_texture() gives you for that renderpass. Note that this will require you to have the usage COPY_DST which you can request in context.configure.

If instead I read it incorrectly and you want to use the imgui.Image widget, there is .register_texture which is similar to what you are doing in the code above:

wgpu-py/wgpu/utils/imgui/imgui_backend.py

Lines 104 to 113 in 8037a00

	def register_texture(self, texture_view: wgpu.GPUTextureView) -> imgui.ImTextureRef:
	"""Register a custom wgpu.GPUTextureView (which you want to render using Imgui)
	with backend and return a texture reference in Imgui format.
	"""
	# get the id so that imgui can display it
	id_texture = ctypes.c_int32(id(texture_view)).value
	# add texture view to the backend so that it can be retrieved for rendering
	self._texture_views[id_texture] = texture_view
	return imgui.ImTextureRef(id_texture)

[REDxEYE]

Yes, i meant use it in imgui.image. Looks like in version i'm using this method is not yet present

[Vipitis]

ah, there has been exactly one commit since last release and that makes several updates to imgui including this method

[panxinmiao]

Yes, in PR #725 , when updating imgui to version 1.92.0, I also added a register_texture method to make it easier to use custom textures in imgui components. However, this change has not been released yet.

You can refer to the imgui_cmap_picker.py example to see how to use it.

wgpu-py/examples/imgui_cmap_picker.py

Lines 57 to 60 in 8037a00

	texture_view = texture.create_view()
	# register the texture with backend
	return imgui_renderer.backend.register_texture(texture_view)

[REDxEYE]

Also, will it be possible to use imgui window as 3d viewport/canvas?

[Vipitis]

hey, I just had a little try for my imgui implementation and looks like you can easily put the past texture into the image widget, see pygfx/shadertoy@a965642

is this what you were looking for or something else? I think you could technically make a rendercanvas class to display inside this image widget - but not sure if that has any use.