virtualx-engine/modules/openxr/extensions/openxr_composition_layer_extension.h

/**************************************************************************/
/*  openxr_composition_layer_extension.h                                  */
/**************************************************************************/
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#ifndef OPENXR_COMPOSITION_LAYER_EXTENSION_H
#define OPENXR_COMPOSITION_LAYER_EXTENSION_H

#include "openxr_composition_layer_provider.h"
#include "openxr_extension_wrapper.h"

#include "../openxr_api.h"

class OpenXRViewportCompositionLayerProvider;

// This extension provides access to composition layers for displaying 2D content through the XR compositor.

// OpenXRCompositionLayerExtension enables the extensions related to this functionality
class OpenXRCompositionLayerExtension : public OpenXRExtensionWrapper, public OpenXRCompositionLayerProvider {
public:
	static OpenXRCompositionLayerExtension *get_singleton();

	OpenXRCompositionLayerExtension();
	virtual ~OpenXRCompositionLayerExtension() override;

	virtual HashMap<String, bool *> get_requested_extensions() override;
	virtual void on_session_created(const XrSession p_session) override;
	virtual void on_session_destroyed() override;
	virtual void on_pre_render() override;

	virtual int get_composition_layer_count() override;
	virtual XrCompositionLayerBaseHeader *get_composition_layer(int p_index) override;
	virtual int get_composition_layer_order(int p_index) override;

	void register_viewport_composition_layer_provider(OpenXRViewportCompositionLayerProvider *p_composition_layer);
	void unregister_viewport_composition_layer_provider(OpenXRViewportCompositionLayerProvider *p_composition_layer);

	bool is_available(XrStructureType p_which);

private:
	static OpenXRCompositionLayerExtension *singleton;

	Vector<OpenXRViewportCompositionLayerProvider *> composition_layers;

	bool cylinder_ext_available = false;
	bool equirect_ext_available = false;
};

class OpenXRViewportCompositionLayerProvider {
	XrCompositionLayerBaseHeader *composition_layer = nullptr;
	int sort_order = 1;
	bool alpha_blend = false;
	Dictionary extension_property_values;
	bool extension_property_values_changed = true;

	RID viewport;
	Size2i viewport_size;

	OpenXRAPI::OpenXRSwapChainInfo swapchain_info;
	Size2i swapchain_size;
	bool static_image = false;

	OpenXRAPI *openxr_api = nullptr;
	OpenXRCompositionLayerExtension *composition_layer_extension = nullptr;

	bool update_and_acquire_swapchain(bool p_static_image);
	void free_swapchain();
	RID get_current_swapchain_texture();

public:
	XrStructureType get_openxr_type() { return composition_layer->type; }

	void set_sort_order(int p_sort_order) { sort_order = p_sort_order; }
	int get_sort_order() const { return sort_order; }

	void set_alpha_blend(bool p_alpha_blend);
	bool get_alpha_blend() const { return alpha_blend; }

	void set_viewport(RID p_viewport, Size2i p_size);
	RID get_viewport() const { return viewport; }

	void set_extension_property_values(const Dictionary &p_property_values);

	void on_pre_render();
	XrCompositionLayerBaseHeader *get_composition_layer();

	OpenXRViewportCompositionLayerProvider(XrCompositionLayerBaseHeader *p_composition_layer);
	~OpenXRViewportCompositionLayerProvider();
};

#endif // OPENXR_COMPOSITION_LAYER_EXTENSION_H