comp: add VkDisplayKHR window backend

Must be activated/selected with an env var for now: XRT_COMPOSITOR_FORCE_VK_DISPLAY=2

CMakeLists.txt

@@ -250,7 +250,9 @@ endif()
 if(WIN32)
 	set(VK_USE_PLATFORM_WIN32_KHR TRUE)
 endif()
-
+if (XRT_HAVE_VULKAN AND NOT ANDROID)
+	set(VK_USE_PLATFORM_DISPLAY_KHR TRUE)
+endif()
 
 if(NOT MSVC)
 	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pedantic -Wall -Wextra -Wno-unused-parameter")

meson.build

@@ -131,6 +131,9 @@ endif
 
 build_xcb_xrandr_direct = build_xcb and build_xlib and xcb_randr.found() and x11_xcb.found()
 
+# requires only vulkan
+build_vk_khr_display = true
+
 build_wayland = false
 if get_option('wayland').enabled() or get_option('wayland').auto()
         build_wayland = wayland.found() and wayland_protos.found() and wayland_scanner.found()

src/xrt/compositor/CMakeLists.txt

@@ -119,7 +119,11 @@ if(XRT_FEATURE_COMPOSITOR_MAIN)
 			main/comp_window_mswin.c
 			)
 	endif()
-
+	if (VK_USE_PLATFORM_DISPLAY_KHR)
+		list(APPEND MAIN_SOURCE_FILES
+			main/comp_window_vk_display.c
+			)
+	endif()
 
 	# generate wayland protocols
 	if(XRT_HAVE_WAYLAND)

src/xrt/compositor/main/comp_compositor.c

@@ -694,6 +694,13 @@ static const char *instance_extensions_direct_mode[] = {
 };
 #endif
 
+#ifdef VK_USE_PLATFORM_DISPLAY_KHR
+static const char *instance_extensions_vk_display[] = {
+    COMP_INSTANCE_EXTENSIONS_COMMON,
+    VK_KHR_DISPLAY_EXTENSION_NAME,
+};
+#endif
+
 #ifdef VK_USE_PLATFORM_ANDROID_KHR
 static const char *instance_extensions_android[] = {COMP_INSTANCE_EXTENSIONS_COMMON,
                                                     VK_KHR_ANDROID_SURFACE_EXTENSION_NAME};
@@ -785,6 +792,12 @@ select_instances_extensions(struct comp_compositor *c, const char ***out_exts, u
 		*out_exts = instance_extensions_windows;
 		*out_num = ARRAY_SIZE(instance_extensions_windows);
 		break;
+#endif
+#ifdef VK_USE_PLATFORM_DISPLAY_KHR
+	case WINDOW_VK_DISPLAY:
+		*out_exts = instance_extensions_vk_display;
+		*out_num = ARRAY_SIZE(instance_extensions_vk_display);
+		break;
 #endif
 	default: return VK_ERROR_INITIALIZATION_FAILED;
 	}
@@ -1106,8 +1119,8 @@ compositor_try_window(struct comp_compositor *c, struct comp_target *ct)
 static bool
 compositor_init_window_pre_vulkan(struct comp_compositor *c)
 {
-	// Nothing to do for nvidia.
+	// Nothing to do for nvidia and vk_display.
-	if (c->settings.window_type == WINDOW_DIRECT_NVIDIA) {
+	if (c->settings.window_type == WINDOW_DIRECT_NVIDIA || c->settings.window_type == WINDOW_VK_DISPLAY) {
 		return true;
 	}
 
@@ -1197,16 +1210,25 @@ compositor_init_window_pre_vulkan(struct comp_compositor *c)
 static bool
 compositor_init_window_post_vulkan(struct comp_compositor *c)
 {
-	if (c->settings.window_type != WINDOW_DIRECT_NVIDIA) {
+	if (c->settings.window_type == WINDOW_DIRECT_NVIDIA) {
-		return true;
-	}
-
 #ifdef VK_USE_PLATFORM_XLIB_XRANDR_EXT
 		return compositor_try_window(c, comp_window_direct_nvidia_create(c));
 #else
 		assert(false && "NVIDIA direct mode depends on the xlib/xrandr direct mode.");
 		return false;
 #endif
+	}
+
+	if (c->settings.window_type == WINDOW_VK_DISPLAY) {
+#ifdef VK_USE_PLATFORM_DISPLAY_KHR
+		return compositor_try_window(c, comp_window_vk_display_create(c));
+#else
+		assert(false && "VkDisplayKHR direct mode depends on VK_USE_PLATFORM_DISPLAY_KHR.");
+		return false;
+#endif
+	}
+
+	return true;
 }
 
 static bool

src/xrt/compositor/main/comp_settings.c

@@ -16,6 +16,7 @@ DEBUG_GET_ONCE_BOOL_OPTION(print_modes, "XRT_COMPOSITOR_PRINT_MODES", false)
 DEBUG_GET_ONCE_BOOL_OPTION(force_randr, "XRT_COMPOSITOR_FORCE_RANDR", false)
 DEBUG_GET_ONCE_BOOL_OPTION(force_nvidia, "XRT_COMPOSITOR_FORCE_NVIDIA", false)
 DEBUG_GET_ONCE_OPTION(nvidia_display, "XRT_COMPOSITOR_FORCE_NVIDIA_DISPLAY", NULL)
+DEBUG_GET_ONCE_NUM_OPTION(vk_display, "XRT_COMPOSITOR_FORCE_VK_DISPLAY", -1)
 DEBUG_GET_ONCE_BOOL_OPTION(force_xcb, "XRT_COMPOSITOR_FORCE_XCB", false)
 DEBUG_GET_ONCE_BOOL_OPTION(force_wayland, "XRT_COMPOSITOR_FORCE_WAYLAND", false)
 DEBUG_GET_ONCE_BOOL_OPTION(wireframe, "XRT_COMPOSITOR_WIREFRAME", false)
@@ -60,6 +61,10 @@ comp_settings_init(struct comp_settings *s, struct xrt_device *xdev)
 	}
 
 	s->nvidia_display = debug_get_option_nvidia_display();
+	s->vk_display = debug_get_num_option_vk_display();
+	if (s->vk_display >= 0) {
+		s->window_type = WINDOW_VK_DISPLAY;
+	}
 
 	if (debug_get_bool_option_force_randr()) {
 		s->window_type = WINDOW_DIRECT_RANDR;

src/xrt/compositor/main/comp_settings.h

@@ -48,6 +48,7 @@ enum window_type
 	WINDOW_DIRECT_NVIDIA,
 	WINDOW_ANDROID,
 	WINDOW_MSWIN,
+	WINDOW_VK_DISPLAY,
 };
 
 
@@ -70,6 +71,9 @@ struct comp_settings
 	//! display string forced by user or NULL
 	const char *nvidia_display;
 
+	//! vk display number to use when forcing vk_display
+	int vk_display;
+
 	struct
 	{
 		uint32_t width;

src/xrt/compositor/main/comp_window.h

@@ -68,6 +68,14 @@ struct comp_target *
 comp_window_direct_nvidia_create(struct comp_compositor *c);
 #endif
 
+/*!
+ * Create a direct surface to an HMD on VkDisplay.
+ *
+ * @ingroup comp_main
+ * @public @memberof comp_window_direct_vk_display
+ */
+struct comp_target *
+comp_window_vk_display_create(struct comp_compositor *c);
 
 #ifdef XRT_OS_ANDROID
 

src/xrt/compositor/main/comp_window_vk_display.c

@@ -0,0 +1,248 @@
+// Copyright 2019-2021, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief  Direct mode on PLATFORM_DISPLAY_KHR code.
+ * @author Christoph Haag <christoph.haag@collabora.com>
+ * @author Lubosz Sarnecki <lubosz.sarnecki@collabora.com>
+ * @author Jakob Bornecrantz <jakob@collabora.com>
+ * @ingroup comp_main
+ */
+
+#include "util/u_misc.h"
+
+#include "main/comp_window_direct.h"
+
+/*
+ *
+ * Private structs
+ *
+ */
+
+/*!
+ * Probed display.
+ */
+struct vk_display
+{
+	VkDisplayPropertiesKHR display_properties;
+	VkDisplayKHR display;
+};
+
+/*!
+ * Direct mode "window" into a device, using PLATFORM_DISPLAY_KHR.
+ *
+ * @implements comp_target_swapchain
+ */
+struct comp_window_vk_display
+{
+	struct comp_target_swapchain base;
+
+	struct vk_display *displays;
+	uint16_t num_displays;
+};
+
+/*
+ *
+ * Forward declare functions
+ *
+ */
+
+static void
+comp_window_vk_display_destroy(struct comp_target *ct);
+
+static bool
+comp_window_vk_display_init(struct comp_target *ct);
+
+static struct vk_display *
+comp_window_vk_display_current_display(struct comp_window_vk_display *w);
+
+static bool
+comp_window_vk_display_init_swapchain(struct comp_target *ct, uint32_t width, uint32_t height);
+
+
+/*
+ *
+ * Functions.
+ *
+ */
+
+static void
+_flush(struct comp_target *ct)
+{
+	(void)ct;
+}
+
+static void
+_update_window_title(struct comp_target *ct, const char *title)
+{
+	(void)ct;
+	(void)title;
+}
+
+struct comp_target *
+comp_window_vk_display_create(struct comp_compositor *c)
+{
+	struct comp_window_vk_display *w = U_TYPED_CALLOC(struct comp_window_vk_display);
+
+	comp_target_swapchain_init_set_fnptrs(&w->base);
+
+	w->base.base.name = "VkDisplayKHR";
+	w->base.base.destroy = comp_window_vk_display_destroy;
+	w->base.base.flush = _flush;
+	w->base.base.init_pre_vulkan = comp_window_vk_display_init;
+	w->base.base.init_post_vulkan = comp_window_vk_display_init_swapchain;
+	w->base.base.set_title = _update_window_title;
+	w->base.base.c = c;
+
+	return &w->base.base;
+}
+
+static void
+comp_window_vk_display_destroy(struct comp_target *ct)
+{
+	struct comp_window_vk_display *w_direct = (struct comp_window_vk_display *)ct;
+
+	comp_target_swapchain_cleanup(&w_direct->base);
+
+	for (uint32_t i = 0; i < w_direct->num_displays; i++) {
+		struct vk_display *d = &w_direct->displays[i];
+		d->display = VK_NULL_HANDLE;
+	}
+
+	if (w_direct->displays != NULL)
+		free(w_direct->displays);
+
+	free(ct);
+}
+
+static bool
+append_vk_display_entry(struct comp_window_vk_display *w, struct VkDisplayPropertiesKHR *disp)
+{
+	w->base.base.c->settings.preferred.width = disp->physicalResolution.width;
+	w->base.base.c->settings.preferred.height = disp->physicalResolution.height;
+	struct vk_display d = {.display_properties = *disp, .display = disp->display};
+
+	w->num_displays += 1;
+
+	U_ARRAY_REALLOC_OR_FREE(w->displays, struct vk_display, w->num_displays);
+
+	if (w->displays == NULL)
+		COMP_ERROR(w->base.base.c, "Unable to reallocate vk_display displays");
+
+	w->displays[w->num_displays - 1] = d;
+
+	return true;
+}
+
+static void
+print_found_displays(struct comp_compositor *c, struct VkDisplayPropertiesKHR *display_props, uint32_t display_count)
+{
+	COMP_ERROR(c, "== Found Displays ==");
+	for (uint32_t i = 0; i < display_count; i++) {
+		struct VkDisplayPropertiesKHR *p = &display_props[i];
+
+		COMP_ERROR(c, "[%d] %s with resolution %dx%d, dims %dx%d", i, p->displayName,
+		           p->physicalResolution.width, p->physicalResolution.height, p->physicalDimensions.width,
+		           p->physicalDimensions.height);
+	}
+}
+
+static bool
+comp_window_vk_display_init(struct comp_target *ct)
+{
+	struct comp_window_vk_display *w_direct = (struct comp_window_vk_display *)ct;
+
+	// Sanity check.
+	if (ct->c->vk.instance == VK_NULL_HANDLE) {
+		COMP_ERROR(ct->c, "Vulkan not initialized before vk display init!");
+		return false;
+	}
+
+	struct vk_bundle comp_vk = ct->c->vk;
+
+	uint32_t display_count;
+	if (comp_vk.vkGetPhysicalDeviceDisplayPropertiesKHR(comp_vk.physical_device, &display_count, NULL) !=
+	    VK_SUCCESS) {
+		COMP_ERROR(ct->c, "Failed to get vulkan display count");
+		return false;
+	}
+
+	if (display_count == 0) {
+		COMP_ERROR(ct->c, "No Vulkan displays found.");
+		return false;
+	}
+
+	struct VkDisplayPropertiesKHR *display_props = U_TYPED_ARRAY_CALLOC(VkDisplayPropertiesKHR, display_count);
+
+	if (display_props && comp_vk.vkGetPhysicalDeviceDisplayPropertiesKHR(comp_vk.physical_device, &display_count,
+	                                                                     display_props) != VK_SUCCESS) {
+		COMP_ERROR(ct->c, "Failed to get display properties");
+		free(display_props);
+		return false;
+	}
+
+	if (ct->c->settings.vk_display > (int)display_count) {
+		COMP_ERROR(ct->c, "Requested display %d, but only %d found.", ct->c->settings.vk_display,
+		           display_count);
+		print_found_displays(ct->c, display_props, display_count);
+		free(display_props);
+		return false;
+	}
+
+	append_vk_display_entry(w_direct, &display_props[ct->c->settings.vk_display]);
+
+	struct vk_display *d = comp_window_vk_display_current_display(w_direct);
+	if (!d) {
+		COMP_ERROR(ct->c, "display not found!");
+		print_found_displays(ct->c, display_props, display_count);
+		free(display_props);
+		return false;
+	}
+
+	free(display_props);
+
+	return true;
+}
+
+static struct vk_display *
+comp_window_vk_display_current_display(struct comp_window_vk_display *w)
+{
+	int index = w->base.base.c->settings.display;
+	if (index == -1)
+		index = 0;
+
+	if (w->num_displays <= (uint32_t)index)
+		return NULL;
+
+	return &w->displays[index];
+}
+
+static bool
+init_swapchain(struct comp_target_swapchain *cts, VkDisplayKHR display, uint32_t width, uint32_t height)
+{
+	VkResult ret;
+
+	ret = comp_window_direct_create_surface(cts, display, width, height);
+	if (ret != VK_SUCCESS) {
+		COMP_ERROR(cts->base.c, "Failed to create surface! '%s'", vk_result_string(ret));
+		return false;
+	}
+
+	return true;
+}
+
+static bool
+comp_window_vk_display_init_swapchain(struct comp_target *ct, uint32_t width, uint32_t height)
+{
+	struct comp_window_vk_display *w_direct = (struct comp_window_vk_display *)ct;
+
+	struct vk_display *d = comp_window_vk_display_current_display(w_direct);
+	if (!d) {
+		COMP_ERROR(ct->c, "display not found.");
+		return false;
+	}
+
+	COMP_DEBUG(ct->c, "Will use display: %s", d->display_properties.displayName);
+
+	return init_swapchain(&w_direct->base, d->display, width, height);
+}

src/xrt/compositor/meson.build

@@ -36,6 +36,10 @@ compositor_srcs = [
 
 compile_args = []
 
+if build_vk_khr_display
+	compositor_srcs += ['main/comp_window_vk_display.c']
+endif
+
 if build_xcb
 	compositor_srcs += ['main/comp_window_xcb.c']
 	compositor_deps += [xcb]

src/xrt/include/xrt/meson.build

@@ -151,6 +151,9 @@ endif
 if build_xcb_xrandr_direct
 	vulkan_conf.set('VK_USE_PLATFORM_XLIB_XRANDR_EXT', true)
 endif
+if build_vk_khr_display
+	vulkan_conf.set('VK_USE_PLATFORM_DISPLAY_KHR', true)
+endif
 
 xrt_config_vulkan_h = configure_file(
 	output: 'xrt_config_vulkan.h',

src/xrt/include/xrt/xrt_config_vulkan.h.cmake_in

@@ -14,3 +14,4 @@
 #cmakedefine VK_USE_PLATFORM_XCB_KHR
 #cmakedefine VK_USE_PLATFORM_XLIB_XRANDR_EXT
 #cmakedefine VK_USE_PLATFORM_WIN32_KHR
+#cmakedefine VK_USE_PLATFORM_DISPLAY_KHR