vo_gpu: vulkan: add a vk_signal abstraction

This combines VkSemaphores and VkEvents into a common umbrella
abstraction which can resolve to either.

We aggressively try to prefer VkEvents over VkSemaphores whenever the
conditions are met (1. we can unsignal the semaphore, i.e. it comes from
the same frame; and 2. it comes from the same queue).

1 files changed, 29 insertions, 0 deletions

diff --git a/video/out/vulkan/utils.h b/video/out/vulkan/utils.h
index bdbbe0aa70..538897afae 100644
--- a/video/out/vulkan/utils.h
+++ b/video/out/vulkan/utils.h
@@ -121,6 +121,35 @@ void vk_cmd_dep(struct vk_cmd *cmd, VkSemaphore dep, VkPipelineStageFlags stage)
 // after the command completes.
 void vk_cmd_sig(struct vk_cmd *cmd, VkSemaphore sig);
 
+// Signal abstraction: represents an abstract synchronization mechanism.
+// Internally, this may either resolve as a semaphore or an event depending
+// on whether the appropriate conditions are met.
+struct vk_signal {
+    VkSemaphore semaphore;
+    VkEvent event;
+    VkQueue event_source;
+};
+
+// Generates a signal after the execution of all previous commands matching the
+// given the pipeline stage. The signal is owned by the caller, and must be
+// consumed eith vk_cmd_wait or released with vk_signal_cancel in order to
+// free the resources.
+struct vk_signal *vk_cmd_signal(struct mpvk_ctx *vk, struct vk_cmd *cmd,
+                                VkPipelineStageFlags stage);
+
+// Consumes a previously generated signal. This signal must fire by the
+// indicated stage before the command can run. If *event is not NULL, then it
+// MAY be set to a VkEvent which the caller MUST manually wait on in the most
+// appropriate way. This function takes over ownership of the signal (and the
+// signal will be released/reused automatically)
+void vk_cmd_wait(struct mpvk_ctx *vk, struct vk_cmd *cmd,
+                 struct vk_signal **sigptr, VkPipelineStageFlags stage,
+                 VkEvent *out_event);
+
+// Destroys a currently pending signal, for example if the resource is no
+// longer relevant.
+void vk_signal_destroy(struct mpvk_ctx *vk, struct vk_signal **sig);
+
 // Command pool / queue family hybrid abstraction
 struct vk_cmdpool {
     VkQueueFamilyProperties props;