vo_gpu: vulkan: initial implementation

This time based on ra/vo_gpu. 2017 is the year of the vulkan desktop!

Current problems / limitations / improvement opportunities:

1. The swapchain/flipping code violates the vulkan spec, by assuming
   that the presentation queue will be bounded (in cases where rendering
   is significantly faster than vsync). But apparently, there's simply
   no better way to do this right now, to the point where even the
   stupid cube.c examples from LunarG etc. do it wrong.
   (cf. https://github.com/KhronosGroup/Vulkan-Docs/issues/370)

2. The memory allocator could be improved. (This is a universal
   constant)

3. Could explore using push descriptors instead of descriptor sets,
   especially since we expect to switch descriptors semi-often for some
   passes (like interpolation). Probably won't make a difference, but
   the synchronization overhead might be a factor. Who knows.

4. Parallelism across frames / async transfer is not well-defined, we
   either need to use a better semaphore / command buffer strategy or a
   resource pooling layer to safely handle cross-frame parallelism.
   (That said, I gave resource pooling a try and was not happy with the
   result at all - so I'm still exploring the semaphore strategy)

5. We aggressively use pipeline barriers where events would offer a much
   more fine-grained synchronization mechanism. As a result of this, we
   might be suffering from GPU bubbles due to too-short dependencies on
   objects. (That said, I'm also exploring the use of semaphores as a an
   ordering tactic which would allow cross-frame time slicing in theory)

Some minor changes to the vo_gpu and infrastructure, but nothing
consequential.

NOTE: For safety, all use of asynchronous commands / multiple command
pools is currently disabled completely. There are some left-over relics
of this in the code (e.g. the distinction between dev_poll and
pool_poll), but that is kept in place mostly because this will be
re-extended in the future (vulkan rev 2).

The queue count is also currently capped to 1, because of the lack of
cross-frame semaphores means we need the implicit synchronization from
the same-queue semantics to guarantee a correct result.

2 files changed, 6 insertions, 0 deletions

diff --git a/options/options.c b/options/options.c
index 1168cc196b..6467468691 100644
--- a/options/options.c
+++ b/options/options.c
@@ -89,6 +89,7 @@ extern const struct m_obj_list vo_obj_list;
 extern const struct m_obj_list ao_obj_list;
 
 extern const struct m_sub_options opengl_conf;
+extern const struct m_sub_options vulkan_conf;
 extern const struct m_sub_options angle_conf;
 extern const struct m_sub_options cocoa_conf;
 
@@ -690,6 +691,10 @@ const m_option_t mp_opts[] = {
     OPT_SUBSTRUCT("", opengl_opts, opengl_conf, 0),
 #endif
 
+#if HAVE_VULKAN
+    OPT_SUBSTRUCT("", vulkan_opts, vulkan_conf, 0),
+#endif
+
 #if HAVE_EGL_ANGLE_WIN32
     OPT_SUBSTRUCT("", angle_opts, angle_conf, 0),
 #endif
diff --git a/options/options.h b/options/options.h
index c02b7a34ca..63dee03612 100644
--- a/options/options.h
+++ b/options/options.h
@@ -329,6 +329,7 @@ typedef struct MPOpts {
     struct gl_video_opts *gl_video_opts;
     struct angle_opts *angle_opts;
     struct opengl_opts *opengl_opts;
+    struct vulkan_opts *vulkan_opts;
     struct cocoa_opts *cocoa_opts;
     struct dvd_opts *dvd_opts;