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"

#ifdef ANDROID_ENABLED
#include <jni.h>

// Copied here from openxr_platform.h, in order to avoid including that whole header,
// which can cause compilation issues on some platforms.
typedef XrResult(XRAPI_PTR *PFN_xrCreateSwapchainAndroidSurfaceKHR)(XrSession session, const XrSwapchainCreateInfo *info, XrSwapchain *swapchain, jobject *surface);
#endif

class JavaObject;
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_instance_created(const XrInstance p_instance) 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);
	bool is_android_surface_swapchain_available() { return android_surface_ext_available; }

#ifdef ANDROID_ENABLED
	bool create_android_surface_swapchain(XrSwapchainCreateInfo *p_info, XrSwapchain *r_swapchain, jobject *r_surface);
	void free_android_surface_swapchain(XrSwapchain p_swapchain);
#endif

private:
	static OpenXRCompositionLayerExtension *singleton;

	Vector<OpenXRViewportCompositionLayerProvider *> composition_layers;

	bool cylinder_ext_available = false;
	bool equirect_ext_available = false;
	bool android_surface_ext_available = false;

#ifdef ANDROID_ENABLED
	Vector<XrSwapchain> android_surface_swapchain_free_queue;
	void free_queued_android_surface_swapchains();

	EXT_PROTO_XRRESULT_FUNC1(xrDestroySwapchain, (XrSwapchain), swapchain)
	EXT_PROTO_XRRESULT_FUNC4(xrCreateSwapchainAndroidSurfaceKHR, (XrSession), session, (const XrSwapchainCreateInfo *), info, (XrSwapchain *), swapchain, (jobject *), surface)
#endif
};

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

	struct {
		RID viewport;
		Size2i viewport_size;
		OpenXRAPI::OpenXRSwapChainInfo swapchain_info;
		bool static_image = false;
	} subviewport;

#ifdef ANDROID_ENABLED
	struct {
		XrSwapchain swapchain = XR_NULL_HANDLE;
		Ref<JavaObject> surface;
	} android_surface;
#endif

	bool use_android_surface = false;
	Size2i swapchain_size;

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

	// Only for SubViewports.
	bool update_and_acquire_swapchain(bool p_static_image);
	RID get_current_swapchain_texture();

	void update_swapchain_sub_image(XrSwapchainSubImage &r_swapchain_sub_image);
	void free_swapchain();

#ifdef ANDROID_ENABLED
	void create_android_surface();
#endif

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 subviewport.viewport; }

	void set_use_android_surface(bool p_enable, Size2i p_size);
	bool get_use_android_surface() const { return use_android_surface; }

	Ref<JavaObject> get_android_surface();

	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