Merge pull request #91750 from BastiaanOlij/openxr_visibility_mask

OpenXR: Add support for visibility mask

modules/openxr/config.py

@@ -22,6 +22,7 @@ def get_doc_classes():
         "OpenXRInteractionProfileMetadata",
         "OpenXRIPBinding",
         "OpenXRHand",
+        "OpenXRVisibilityMask",
         "OpenXRCompositionLayer",
         "OpenXRCompositionLayerQuad",
         "OpenXRCompositionLayerCylinder",

modules/openxr/doc_classes/OpenXRVisibilityMask.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="OpenXRVisibilityMask" inherits="VisualInstance3D" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../doc/class.xsd">
+	<brief_description>
+		Draws a stereo correct visibility mask.
+	</brief_description>
+	<description>
+		The visibility mask allows us to black out the part of the render result that is invisible due to lens distortion.
+		As this is rendered first, it prevents fragments with expensive lighting calculations to be processed as they are discarded through z-checking.
+	</description>
+	<tutorials>
+	</tutorials>
+</class>

modules/openxr/extensions/openxr_visibility_mask_extension.cpp

@@ -0,0 +1,279 @@
+/**************************************************************************/
+/*  openxr_visibility_mask_extension.cpp                                  */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#include "openxr_visibility_mask_extension.h"
+
+#include "../openxr_api.h"
+#include "core/string/print_string.h"
+#include "core/variant/array.h"
+#include "core/variant/variant.h"
+#include "servers/rendering_server.h"
+
+static const char *VISIBILITY_MASK_SHADER_CODE =
+		"shader_type spatial;\n"
+		"render_mode unshaded, shadows_disabled, cull_disabled;\n"
+		"void vertex() {\n"
+		"\tif (int(VERTEX.z) == VIEW_INDEX) {\n"
+		"\t\tVERTEX.z = -1.0;\n"
+		"\t\tVERTEX += EYE_OFFSET;\n"
+		"\t\tPOSITION = PROJECTION_MATRIX * vec4(VERTEX, 1.0);\n"
+		"\t\tPOSITION.xy /= POSITION.w;\n"
+		"\t\tPOSITION.z = 1.0;\n"
+		"\t\tPOSITION.w = 1.0;\n"
+		"\t} else {\n"
+		"\t\tPOSITION = vec4(2.0, 2.0, 2.0, 1.0);\n"
+		"\t}\n"
+		"}\n"
+		"void fragment() {\n"
+		"\tALBEDO = vec3(0.0, 0.0, 0.0);\n"
+		"}\n";
+
+OpenXRVisibilityMaskExtension *OpenXRVisibilityMaskExtension::singleton = nullptr;
+
+OpenXRVisibilityMaskExtension *OpenXRVisibilityMaskExtension::get_singleton() {
+	return singleton;
+}
+
+OpenXRVisibilityMaskExtension::OpenXRVisibilityMaskExtension() {
+	singleton = this;
+}
+
+OpenXRVisibilityMaskExtension::~OpenXRVisibilityMaskExtension() {
+	singleton = nullptr;
+}
+
+HashMap<String, bool *> OpenXRVisibilityMaskExtension::get_requested_extensions() {
+	HashMap<String, bool *> request_extensions;
+
+	request_extensions[XR_KHR_VISIBILITY_MASK_EXTENSION_NAME] = &available;
+
+	return request_extensions;
+}
+
+void OpenXRVisibilityMaskExtension::on_instance_created(const XrInstance p_instance) {
+	if (available) {
+		EXT_INIT_XR_FUNC(xrGetVisibilityMaskKHR);
+	}
+}
+
+void OpenXRVisibilityMaskExtension::on_session_created(const XrSession p_instance) {
+	if (available) {
+		RS *rendering_server = RS::get_singleton();
+		ERR_FAIL_NULL(rendering_server);
+
+		OpenXRAPI *openxr_api = (OpenXRAPI *)OpenXRAPI::get_singleton();
+		ERR_FAIL_NULL(openxr_api);
+
+		// Create our shader.
+		shader = rendering_server->shader_create();
+		rendering_server->shader_set_code(shader, VISIBILITY_MASK_SHADER_CODE);
+
+		// Create our material.
+		material = rendering_server->material_create();
+		rendering_server->material_set_shader(material, shader);
+		rendering_server->material_set_render_priority(material, 99);
+
+		// Create our mesh.
+		mesh = rendering_server->mesh_create();
+
+		// Get our initial mesh data.
+		mesh_count = openxr_api->get_view_count(); // We need a mesh for each view.
+		for (uint32_t i = 0; i < mesh_count; i++) {
+			_update_mesh_data(i);
+		}
+
+		// And update our mesh
+		_update_mesh();
+	}
+}
+
+void OpenXRVisibilityMaskExtension::on_session_destroyed() {
+	RS *rendering_server = RS::get_singleton();
+	ERR_FAIL_NULL(rendering_server);
+
+	// Free our mesh.
+	if (mesh.is_valid()) {
+		rendering_server->free(mesh);
+		mesh = RID();
+	}
+
+	// Free our material.
+	if (material.is_valid()) {
+		rendering_server->free(material);
+		material = RID();
+	}
+
+	// Free our shader.
+	if (shader.is_valid()) {
+		rendering_server->free(shader);
+		shader = RID();
+	}
+
+	mesh_count = 0;
+}
+
+void OpenXRVisibilityMaskExtension::on_pre_render() {
+	// Update mesh data if its dirty.
+	// Here we call this from the rendering thread however as we're going through the rendering server this is safe.
+	_update_mesh();
+}
+
+bool OpenXRVisibilityMaskExtension::on_event_polled(const XrEventDataBuffer &event) {
+	if (event.type == XR_TYPE_EVENT_DATA_VISIBILITY_MASK_CHANGED_KHR) {
+		XrEventDataVisibilityMaskChangedKHR *vismask_event = (XrEventDataVisibilityMaskChangedKHR *)&event;
+
+		print_verbose("OpenXR EVENT: Visibility mask changed for view " + String::num_uint64(vismask_event->viewIndex));
+
+		if (available) { // This event won't be called if this extension is not available but better safe than sorry.
+			_update_mesh_data(vismask_event->viewIndex);
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
+bool OpenXRVisibilityMaskExtension::is_available() {
+	return available;
+}
+
+RID OpenXRVisibilityMaskExtension::get_mesh() {
+	return mesh;
+}
+
+void OpenXRVisibilityMaskExtension::_update_mesh_data(uint32_t p_view) {
+	if (available) {
+		ERR_FAIL_UNSIGNED_INDEX(p_view, 4);
+
+		OpenXRAPI *openxr_api = OpenXRAPI::get_singleton();
+		ERR_FAIL_NULL(openxr_api);
+
+		XrSession session = openxr_api->get_session();
+		XrViewConfigurationType view_configuration_type = openxr_api->get_view_configuration();
+
+		// Figure out how much data we're getting.
+		XrVisibilityMaskKHR visibility_mask_data = {
+			XR_TYPE_VISIBILITY_MASK_KHR,
+			nullptr,
+			0,
+			0,
+			nullptr,
+			0,
+			0,
+			nullptr,
+		};
+
+		XrResult result = xrGetVisibilityMaskKHR(session, view_configuration_type, p_view, XR_VISIBILITY_MASK_TYPE_HIDDEN_TRIANGLE_MESH_KHR, &visibility_mask_data);
+		if (XR_FAILED(result)) {
+			print_line("OpenXR: Unable to obtain visibility mask metrics [", openxr_api->get_error_string(result), "]");
+			return;
+		}
+
+		// Resize buffers
+		mesh_data[p_view].vertices.resize(visibility_mask_data.vertexCountOutput);
+		mesh_data[p_view].indices.resize(visibility_mask_data.indexCountOutput);
+
+		visibility_mask_data.vertexCapacityInput = visibility_mask_data.vertexCountOutput;
+		visibility_mask_data.vertices = mesh_data[p_view].vertices.ptrw();
+		visibility_mask_data.indexCapacityInput = visibility_mask_data.indexCountOutput;
+		visibility_mask_data.indices = mesh_data[p_view].indices.ptrw();
+
+		result = xrGetVisibilityMaskKHR(session, view_configuration_type, p_view, XR_VISIBILITY_MASK_TYPE_HIDDEN_TRIANGLE_MESH_KHR, &visibility_mask_data);
+		if (XR_FAILED(result)) {
+			print_line("OpenXR: Unable to obtain visibility mask data [", openxr_api->get_error_string(result), "]");
+			return;
+		}
+
+		// Mark as dirty, we have updated mesh data.
+		is_dirty = true;
+	}
+}
+
+void OpenXRVisibilityMaskExtension::_update_mesh() {
+	if (available && is_dirty && mesh_count > 0) {
+		RS *rendering_server = RS::get_singleton();
+		ERR_FAIL_NULL(rendering_server);
+
+		OpenXRAPI *openxr_api = (OpenXRAPI *)OpenXRAPI::get_singleton();
+		ERR_FAIL_NULL(openxr_api);
+
+		// Combine all vertex and index buffers into one.
+		PackedVector3Array vertices;
+		PackedInt32Array indices;
+
+		uint64_t vertice_count = 0;
+		uint64_t index_count = 0;
+
+		for (uint32_t i = 0; i < mesh_count; i++) {
+			vertice_count += mesh_data[i].vertices.size();
+			index_count += mesh_data[i].indices.size();
+		}
+
+		vertices.resize(vertice_count);
+		indices.resize(index_count);
+		uint64_t offset = 0;
+
+		Vector3 *v_out = vertices.ptrw();
+		int32_t *i_out = indices.ptrw();
+
+		for (uint32_t i = 0; i < mesh_count; i++) {
+			const XrVector2f *v_in = mesh_data[i].vertices.ptr();
+			for (uint32_t j = 0; j < mesh_data[i].vertices.size(); j++) {
+				v_out->x = v_in->x;
+				v_out->y = v_in->y;
+				v_out->z = float(i); // We store our view in our Z component, our shader will filter the right faces out.
+				v_out++;
+				v_in++;
+			}
+			const uint32_t *i_in = mesh_data[i].indices.ptr();
+			for (uint32_t j = 0; j < mesh_data[i].indices.size(); j++) {
+				*i_out = offset + *i_in;
+				i_out++;
+				i_in++;
+			}
+
+			offset += mesh_data[i].vertices.size();
+		}
+
+		// Update our mesh.
+		Array arr;
+		arr.resize(RS::ARRAY_MAX);
+		arr[RS::ARRAY_VERTEX] = vertices;
+		arr[RS::ARRAY_INDEX] = indices;
+
+		rendering_server->mesh_clear(mesh);
+		rendering_server->mesh_add_surface_from_arrays(mesh, RS::PRIMITIVE_TRIANGLES, arr);
+		rendering_server->mesh_surface_set_material(mesh, 0, material);
+
+		// Set no longer dirty.
+		is_dirty = false;
+	}
+}

modules/openxr/extensions/openxr_visibility_mask_extension.h

@@ -0,0 +1,95 @@
+/**************************************************************************/
+/*  openxr_visibility_mask_extension.h                                    */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef OPENXR_VISIBILITY_MASK_EXTENSION_H
+#define OPENXR_VISIBILITY_MASK_EXTENSION_H
+
+#include "../util.h"
+
+#include "core/templates/vector.h"
+#include "openxr_extension_wrapper.h"
+#include "scene/resources/mesh.h"
+
+// The OpenXR visibility mask extension provides a mesh for each eye that
+// can be used as a mask to determine which part of our rendered result
+// is actually visible to the user. Due to lens distortion the edges of
+// the rendered image are never used in the final result output on the HMD.
+//
+// Blacking out this are of the render result can remove a fair amount of
+// overhead in rendering part of the screen that is unused.
+//
+// https://registry.khronos.org/OpenXR/specs/1.0/html/xrspec.html#XR_KHR_visibility_mask
+
+class OpenXRVisibilityMaskExtension : public OpenXRExtensionWrapper {
+public:
+	static OpenXRVisibilityMaskExtension *get_singleton();
+
+	OpenXRVisibilityMaskExtension();
+	virtual ~OpenXRVisibilityMaskExtension() 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_instance) override;
+	virtual void on_session_destroyed() override;
+
+	virtual void on_pre_render() override;
+	virtual bool on_event_polled(const XrEventDataBuffer &event) override;
+
+	bool is_available();
+	RID get_mesh();
+
+private:
+	static OpenXRVisibilityMaskExtension *singleton;
+
+	bool available = false;
+	bool is_dirty = false;
+
+	RID shader;
+	RID material;
+	RID mesh;
+
+	struct MeshData {
+		Vector<XrVector2f> vertices;
+		Vector<uint32_t> indices;
+	};
+
+	uint32_t mesh_count = 0;
+	MeshData mesh_data[4];
+
+	void _update_mesh_data(uint32_t p_view);
+	void _update_mesh();
+
+	// OpenXR API call wrappers
+	EXT_PROTO_XRRESULT_FUNC5(xrGetVisibilityMaskKHR, (XrSession), session, (XrViewConfigurationType), viewConfigurationType, (uint32_t), viewIndex, (XrVisibilityMaskTypeKHR), visibilityMaskType, (XrVisibilityMaskKHR *), visibilityMask);
+};
+
+#endif // OPENXR_VISIBILITY_MASK_EXTENSION_H