vulkan: build stubs unconditionally

To avoid users having to check for libplacebo vulkan support before
linking against libplacebo vulkan functions, and to provide a consistent
ABI regardless of build settings.

Fixes: #224
Fixes: https://github.com/mpv-player/mpv-build/issues/194

src/common.h

@@ -80,10 +80,7 @@
 #include <libplacebo/tone_mapping.h>
 #include <libplacebo/utils/frame_queue.h>
 #include <libplacebo/utils/upload.h>
-
-#ifdef PL_HAVE_VULKAN
 #include <libplacebo/vulkan.h>
-#endif
 #ifdef PL_HAVE_OPENGL
 #include <libplacebo/opengl.h>
 #endif

src/meson.build

@@ -52,6 +52,7 @@ headers = [
   'utils/libav.h',
   'utils/libav_internal.h',
   'utils/upload.h',
+  'vulkan.h',
 ]
 
 sources = [

src/vulkan/meson.build

@@ -16,20 +16,18 @@ elif fs.is_dir(thirdparty/'Vulkan-Headers')
   registry_xml = thirdparty/'Vulkan-Headers/registry/vk.xml'
 endif
 
-if vulkan_build.enabled() and not vulkan_headers.found()
+build_deps += vulkan_headers
+if not vulkan_headers.found()
   error('vulkan.h was not found on the system, nor inside ' +
         '`3rdparty/Vulkan-Headers`. Please run `git submodule update --init` ' +
         'followed by `meson --wipe`.')
 endif
 
-vulkan_build = vulkan_build.require(vulkan_headers.found())
 vulkan_link = vulkan_link.require(vulkan_loader.found())
 components.set('vulkan', vulkan_build.allowed())
 components.set('vk-proc-addr', vulkan_link.allowed())
 
 if vulkan_build.allowed()
-  build_deps += vulkan_headers
-  headers += 'vulkan.h'
   sources += [
     'vulkan/command.c',
     'vulkan/context.c',
@@ -55,4 +53,6 @@ if vulkan_build.allowed()
     build_deps += vulkan_loader
     tests += 'vulkan.c'
   endif
+else
+  sources += 'vulkan/stubs.c'
 endif

src/vulkan/stubs.c

+/*
+ * This file is part of libplacebo.
+ *
+ * libplacebo is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * libplacebo is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with libplacebo. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "../common.h"
+#include "log.h"
+
+const struct pl_vk_inst_params pl_vk_inst_default_params = {0};
+const struct pl_vulkan_params pl_vulkan_default_params = { PL_VULKAN_DEFAULTS };
+
+pl_vk_inst pl_vk_inst_create(pl_log log, const struct pl_vk_inst_params *params)
+{
+    pl_fatal(log, "libplacebo compiled without Vulkan support!");
+    return NULL;
+}
+
+void pl_vk_inst_destroy(pl_vk_inst *pinst)
+{
+    pl_vk_inst inst = *pinst;
+    pl_assert(!inst);
+}
+
+pl_vulkan pl_vulkan_create(pl_log log, const struct pl_vulkan_params *params)
+{
+    pl_fatal(log, "libplacebo compiled without Vulkan support!");
+    return NULL;
+}
+
+void pl_vulkan_destroy(pl_vulkan *pvk)
+{
+    pl_vulkan vk = *pvk;
+    pl_assert(!vk);
+}
+
+pl_vulkan pl_vulkan_get(pl_gpu gpu)
+{
+    return NULL;
+}
+
+VkPhysicalDevice pl_vulkan_choose_device(pl_log log,
+                              const struct pl_vulkan_device_params *params)
+{
+    pl_err(log, "libplacebo compiled without Vulkan support!");
+    return NULL;
+}
+
+pl_swapchain pl_vulkan_create_swapchain(pl_vulkan vk,
+                              const struct pl_vulkan_swapchain_params *params)
+{
+    pl_unreachable();
+}
+
+bool pl_vulkan_swapchain_suboptimal(pl_swapchain sw)
+{
+    pl_unreachable();
+}
+
+pl_vulkan pl_vulkan_import(pl_log log, const struct pl_vulkan_import_params *params)
+{
+    pl_fatal(log, "libplacebo compiled without Vulkan support!");
+    return NULL;
+}
+
+pl_tex pl_vulkan_wrap(pl_gpu gpu, const struct pl_vulkan_wrap_params *params)
+{
+    pl_unreachable();
+}
+
+VkImage pl_vulkan_unwrap(pl_gpu gpu, pl_tex tex,
+                         VkFormat *out_format, VkImageUsageFlags *out_flags)
+{
+    pl_unreachable();
+}
+
+bool pl_vulkan_hold(pl_gpu gpu, pl_tex tex, VkImageLayout layout,
+                    pl_vulkan_sem sem_out)
+{
+    pl_unreachable();
+}
+
+bool pl_vulkan_hold_raw(pl_gpu gpu, pl_tex tex, VkImageLayout *layout,
+                        pl_vulkan_sem sem_out)
+{
+    pl_unreachable();
+}
+
+void pl_vulkan_release(pl_gpu gpu, pl_tex tex, VkImageLayout layout,
+                       pl_vulkan_sem sem_in)
+{
+    pl_unreachable();
+}