d/ht; aux/util: Move ringbuffer implementation into aux/util

src/xrt/auxiliary/CMakeLists.txt

@@ -153,6 +153,7 @@ set(UTIL_SOURCE_FILES
 	util/u_sink_queue.c
 	util/u_sink_quirk.c
 	util/u_sink_split.c
+	util/u_template_historybuf.hpp
 	util/u_time.cpp
 	util/u_time.h
 	util/u_timing.h

src/xrt/auxiliary/meson.build

@@ -64,6 +64,7 @@ lib_aux_util = static_library(
 		'util/u_timing_fake.c',
 		'util/u_timing_frame.c',
 		'util/u_timing_render.c',
+		'util/u_template_historybuf.hpp',
 		'util/u_trace_marker.c',
 		'util/u_trace_marker.h',
 		'util/u_var.cpp',

src/xrt/auxiliary/util/u_template_historybuf.hpp

@@ -2,16 +2,14 @@
 // SPDX-License-Identifier: BSL-1.0
 /*!
  * @file
- * @brief  Camera based hand tracking ringbuffer implementation.
+ * @brief Ringbuffer implementation for keeping track of the past state of things
  * @author Moses Turner <moses@collabora.com>
  * @ingroup drv_ht
  */
 
 #pragma once
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
+#include <algorithm>
 #include <assert.h>
 
 
@@ -19,23 +17,28 @@
 // OR
 //|  -4   |   -3   |  -2 | -1 | Top | -7 | -6 | -5 |
 
+namespace xrt::auxiliary::util {
 
-
-template <typename T, int maxSize> struct DiscardLastBuffer
+template <typename T, int maxSize> struct HistoryBuffer
 {
 	T internalBuffer[maxSize];
 	int topIdx = 0;
+	int length = 0;
 
 	/* Put something at the top, overwrite whatever was at the back*/
 	void
 	push(const T inElement);
 
 	T *operator[](int inIndex);
+
+	// Lazy convenience.
+	T *
+	last();
 };
 
 template <typename T, int maxSize>
 void
-DiscardLastBuffer<T, maxSize>::push(const T inElement)
+HistoryBuffer<T, maxSize>::push(const T inElement)
 {
 	topIdx++;
 	if (topIdx == maxSize) {
@@ -43,10 +46,16 @@ DiscardLastBuffer<T, maxSize>::push(const T inElement)
 	}
 
 	memcpy(&internalBuffer[topIdx], &inElement, sizeof(T));
+	length++;
+	length = std::min(length, maxSize);
+	// U_LOG_E("new length is %zu", length);
 }
 
-template <typename T, int maxSize> T *DiscardLastBuffer<T, maxSize>::operator[](int inIndex)
+template <typename T, int maxSize> T *HistoryBuffer<T, maxSize>::operator[](int inIndex)
 {
+	if (length == 0) {
+		return NULL;
+	}
 	assert(inIndex <= maxSize);
 	assert(inIndex >= 0);
 
@@ -62,3 +71,4 @@ template <typename T, int maxSize> T *DiscardLastBuffer<T, maxSize>::operator[](
 
 	return &internalBuffer[index];
 }
+} // namespace xrt::auxiliary::util

src/xrt/drivers/CMakeLists.txt

@@ -261,7 +261,6 @@ if(XRT_BUILD_DRIVER_HANDTRACKING)
 		ht/ht_hand_math.hpp
 		ht/ht_image_math.hpp
 		ht/ht_nms.hpp
-		ht/templates/DiscardLastBuffer.hpp
 		ht/templates/NaivePermutationSort.hpp
 		)
 	add_library(drv_ht STATIC ${HT_SOURCE_FILES})

src/xrt/drivers/ht/ht_driver.hpp

@@ -26,7 +26,7 @@
 #include "util/u_debug.h"
 #include "util/u_device.h"
 
-#include "templates/DiscardLastBuffer.hpp"
+#include "util/u_template_historybuf.hpp"
 
 #include <opencv2/opencv.hpp>
 
@@ -44,8 +44,7 @@ DEBUG_GET_ONCE_LOG_OPTION(ht_log, "HT_LOG", U_LOGGING_WARN)
 #define HT_WARN(htd, ...) U_LOG_XDEV_IFL_W(&htd->base, htd->ll, __VA_ARGS__)
 #define HT_ERROR(htd, ...) U_LOG_XDEV_IFL_E(&htd->base, htd->ll, __VA_ARGS__)
 
-// #define ht_
-
+using namespace xrt::auxiliary::util;
 
 // To make clang-tidy happy
 #define opencv_distortion_param_num 4
@@ -148,7 +147,7 @@ struct HandHistory3D
 	// Index 0 is current frame, index 1 is last frame, index 2 is second to last frame.
 	// No particular reason to keep the last 5 frames. we only really only use the current and last one.
 	float handedness;
-	DiscardLastBuffer<Hand3D, 5> last_hands;
+	HistoryBuffer<Hand3D, 5> last_hands;
 	// Euro filter for 21kps.
 	m_filter_euro_vec3 filters[21];
 };
@@ -158,8 +157,8 @@ struct HandHistory2DBBox
 	m_filter_euro_vec2 m_filter_wrist;
 	m_filter_euro_vec2 m_filter_middle;
 
-	DiscardLastBuffer<xrt_vec2, 50> wrist_unfiltered;
-	DiscardLastBuffer<xrt_vec2, 50> middle_unfiltered;
+	HistoryBuffer<xrt_vec2, 50> wrist_unfiltered;
+	HistoryBuffer<xrt_vec2, 50> middle_unfiltered;
 };
 
 

src/xrt/drivers/meson.build

@@ -94,7 +94,6 @@ lib_drv_ht = static_library(
 		'ht/ht_hand_math.hpp',
 		'ht/ht_image_math.hpp',
 		'ht/ht_nms.hpp',
-		'ht/templates/DiscardLastBuffer.hpp',
 		'ht/templates/NaivePermutationSort.hpp',
 	),
 	include_directories: [xrt_include, cjson_include],