c/main + a/util: Make all pacers start at non-zero frame IDs

Part-of: <https://gitlab.freedesktop.org/monado/monado/-/merge_requests/2512>

src/xrt/auxiliary/util/u_pacing_compositor.c

@@ -221,7 +221,7 @@ get_frame(struct pacing_compositor *pc, int64_t frame_id)
 static struct frame *
 create_frame(struct pacing_compositor *pc, enum frame_state state)
 {
-	int64_t frame_id = pc->next_frame_id++;
+	int64_t frame_id = ++pc->next_frame_id;
 	struct frame *f = get_frame(pc, frame_id);
 
 	f->frame_id = frame_id;

src/xrt/auxiliary/util/u_pacing_compositor_fake.c

@@ -153,7 +153,7 @@ get_frame_or_null(struct fake_timing *ft, int64_t frame_id)
 static struct frame *
 get_new_frame(struct fake_timing *ft)
 {
-	int64_t frame_id = ft->frame_id_generator++;
+	int64_t frame_id = ++ft->frame_id_generator;
 
 	uint64_t index = (uint64_t)frame_id % FRAME_COUNT;
 	struct frame *f = &ft->frames[index];
@@ -460,9 +460,6 @@ u_pc_fake_create(int64_t estimated_frame_period_ns, int64_t now_ns, struct u_pac
 	snprintf(ft->gpu_delay.name, ARRAY_SIZE(ft->gpu_delay.name), "gpu_delay");
 	snprintf(ft->total_frame.name, ARRAY_SIZE(ft->total_frame.name), "total_frame");
 
-	// To make sure the code can start from a non-zero frame id.
-	ft->frame_id_generator = 5;
-
 	// An arbitrary guess, that happens to be based on Index.
 	float present_to_display_offset_ms = debug_get_float_option_present_to_display_offset_ms();
 

src/xrt/compositor/main/comp_target_swapchain.c

@@ -877,7 +877,7 @@ comp_target_swapchain_present(struct comp_target *ct,
 	struct comp_target_swapchain *cts = (struct comp_target_swapchain *)ct;
 	struct vk_bundle *vk = get_vk(cts);
 
-	assert(cts->current_frame_id >= 0);
+	assert(cts->current_frame_id > 0);
 	assert(cts->current_frame_id <= UINT32_MAX);
 
 	VkPresentInfoKHR present_info = {
@@ -908,8 +908,7 @@ comp_target_swapchain_present(struct comp_target *ct,
 #endif
 
 #ifdef VK_KHR_present_id
-	// @note first present should be 1, not 0, as the swapchain starts at ID 0 and increments from that
-	uint64_t present_id = (uint64_t)cts->current_frame_id + 1;
+	uint64_t present_id = (uint64_t)cts->current_frame_id;
 
 	VkPresentIdKHR vk_present_id = {
 	    .sType = VK_STRUCTURE_TYPE_PRESENT_ID_KHR,
@@ -955,8 +954,7 @@ comp_target_swapchain_wait_for_present(struct comp_target *ct, time_duration_ns
 	}
 
 	// @note current frame ID is incremented by 1 to match the ID given to Vulkan, see comp_target_swapchain_present
-	return vk->vkWaitForPresentKHR(vk->device, cts->swapchain.handle, (uint64_t)cts->current_frame_id + 1,
-	                               timeout_ns);
+	return vk->vkWaitForPresentKHR(vk->device, cts->swapchain.handle, (uint64_t)cts->current_frame_id, timeout_ns);
 #else
 	return VK_ERROR_EXTENSION_NOT_PRESENT;
 #endif