graphics: count occlusion queries on the host GPU behind --occlusion-queries

src/graphics/host_gpu/renderer/occlusionQueries.h

@@ -0,0 +1,85 @@
+#ifndef EMULATOR_SRC_GRAPHICS_HOST_GPU_RENDERER_OCCLUSIONQUERIES_H_
+#define EMULATOR_SRC_GRAPHICS_HOST_GPU_RENDERER_OCCLUSIONQUERIES_H_
+
+#include "common/common.h"
+#include "graphics/host_gpu/vulkanCommon.h"
+
+#include <cstdint>
+#include <vector>
+
+namespace Libs::Graphics {
+
+class CommandScheduler;
+struct GraphicContext;
+
+// The guest's query results (16-byte aligned): a begin/end pair of running z-pass counters per DB,
+// 16 bytes apart; bit 63 marks a written counter. A query's samples are the sum of end - begin.
+constexpr uint32_t OCCLUSION_QUERY_DBS   = 16;
+constexpr uint64_t OCCLUSION_QUERY_READY = 1ull << 63u;
+
+// A dump of the running count, all of it in DB 0. A begin also clears its end counters.
+inline void WriteZPassCounters(volatile uint64_t* results, uint64_t samples, bool begin) {
+	for (uint32_t db = 0; db < OCCLUSION_QUERY_DBS; db++) {
+		results[db * 2] = OCCLUSION_QUERY_READY | (db == 0 ? samples : 0);
+		if (begin) {
+			results[db * 2 + 1] = 0;
+		}
+	}
+}
+
+// The guest's z-pass counters from host occlusion queries: a draw counts its samples while a guest
+// query is open, and the dumps' counters are written before the guest can see the GPU ran them.
+class OcclusionQueries {
+public:
+	OcclusionQueries(GraphicContext& graphics, CommandScheduler& scheduler);
+	~OcclusionQueries();
+	KYTY_CLASS_NO_COPY(OcclusionQueries);
+
+	[[nodiscard]] bool Enabled() const { return m_pool != nullptr; }
+
+	// In the draw's rendering: the query that counts its samples, or -1.
+	[[nodiscard]] int32_t Begin(vk::CommandBuffer command) {
+		return m_open == 0 ? -1 : BeginQuery(command);
+	}
+	void End(vk::CommandBuffer command, int32_t query) const {
+		if (query >= 0) {
+			command.endQuery(m_pool, static_cast<uint32_t>(query));
+		}
+	}
+
+	// A PIXEL_PIPE_STAT_DUMP to address, after the draws recorded so far.
+	void Dump(uint64_t address);
+	// Waits for the GPU to run the dumps and writes their counters.
+	void Publish() {
+		if (!m_dumps.empty()) {
+			PublishDumps();
+		}
+	}
+
+private:
+	struct PendingDump {
+		uint64_t address;
+		uint64_t tick;
+		uint64_t queries;
+		uint64_t uncounted;
+	};
+
+	int32_t BeginQuery(vk::CommandBuffer command);
+	void    PublishDumps();
+
+	CommandScheduler&        m_scheduler;
+	vk::Device               m_device;
+	vk::QueryPool            m_pool;
+	vk::QueryControlFlags    m_control;
+	std::vector<PendingDump> m_dumps;
+	std::vector<uint64_t>    m_results;
+	uint32_t                 m_open      = 0;
+	uint64_t                 m_begun     = 0;
+	uint64_t                 m_read      = 0;
+	uint64_t                 m_samples   = 0;
+	uint64_t                 m_uncounted = 0;
+};
+
+} // namespace Libs::Graphics
+
+#endif // EMULATOR_SRC_GRAPHICS_HOST_GPU_RENDERER_OCCLUSIONQUERIES_H_