From 74b8483457b51727dba38aa05a5be9bc773d8a28 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Thu, 4 Jun 2015 19:51:33 +0200
Subject: octopus, pt, aruco: optimize image copying

Perform less operations in inner loop where pixels are accessed.
---
 ftnoir_tracker_ht/ht_video_widget.cpp | 49 ++++++++++++++++++++++-------------
 ftnoir_tracker_ht/ht_video_widget.h   |  5 ++--
 2 files changed, 34 insertions(+), 20 deletions(-)

(limited to 'ftnoir_tracker_ht')

diff --git a/ftnoir_tracker_ht/ht_video_widget.cpp b/ftnoir_tracker_ht/ht_video_widget.cpp
index c6d59b34..1c5f565c 100644
--- a/ftnoir_tracker_ht/ht_video_widget.cpp
+++ b/ftnoir_tracker_ht/ht_video_widget.cpp
@@ -14,31 +14,44 @@ using namespace std;
 void HTVideoWidget::update_image(unsigned char *frame, int width, int height)
 {
     QMutexLocker foo(&mtx);
-    memcpy(fb, frame, width * height * 3);
-    this->width = width;
-    this->height = height;
+    if (!fresh)
+    {
+        memcpy(fb, frame, width * height * 3);
+        this->width = width;
+        this->height = height;
+        fresh = true;
+    }
 }
 
 void HTVideoWidget::update_and_repaint()
 {
-    QMutexLocker foo(&mtx);
-    if (width*height <= 0)
-        return;
-    QImage qframe = QImage(width, height, QImage::Format_RGB888);
-    uchar* data = qframe.bits();
-    const int pitch = qframe.bytesPerLine();
-    for (int y = 0; y < height; y++)
+    QImage qframe;
     {
-        const int part = y*width;
-        for (int x = 0; x < width; x++)
+        QMutexLocker foo(&mtx);
+        if (width*height <= 0 || !fresh)
+            return;
+        fresh = false;
+        qframe = QImage(width, height, QImage::Format_RGB888);
+        uchar* data = qframe.bits();
+        const int pitch = qframe.bytesPerLine();
+        for (int y = 0; y < height; y++)
         {
-            const int pos = 3 * (part + x);
-            data[y * pitch + x * 3 + 0] = fb[pos + 2];
-            data[y * pitch + x * 3 + 1] = fb[pos + 1];
-            data[y * pitch + x * 3 + 2] = fb[pos + 0];
+            const int part = y*width;
+            for (int x = 0; x < width; x++)
+            {
+                const int pos = 3 * (part + x);
+                const int x_ = x * 3;
+                data[x_ + 0] = fb[pos + 2];
+                data[x_ + 1] = fb[pos + 1];
+                data[x_ + 2] = fb[pos + 0];
+            }
+            data += pitch;
         }
     }
-    auto qframe2 = qframe.scaled(size(), Qt::IgnoreAspectRatio, Qt::FastTransformation);
-    texture = qframe2;
+    qframe = qframe.scaled(size(), Qt::IgnoreAspectRatio, Qt::FastTransformation);
+    {
+        QMutexLocker foo(&mtx);
+        texture = qframe;
+    }
     update();
 }
diff --git a/ftnoir_tracker_ht/ht_video_widget.h b/ftnoir_tracker_ht/ht_video_widget.h
index cbfe6ddc..be4aee44 100644
--- a/ftnoir_tracker_ht/ht_video_widget.h
+++ b/ftnoir_tracker_ht/ht_video_widget.h
@@ -23,7 +23,7 @@ class HTVideoWidget : public QWidget
     Q_OBJECT
 
 public:
-    HTVideoWidget(QWidget *parent) : QWidget(parent), fb(), width(0), height(0) {
+    HTVideoWidget(QWidget *parent) : QWidget(parent), fb(), width(0), height(0), fresh(false) {
         connect(&timer, SIGNAL(timeout()), this, SLOT(update_and_repaint()));
         timer.start(60);
     }
@@ -40,8 +40,9 @@ private:
     QMutex mtx;
     QImage texture;
     QTimer timer;
-    char fb[2048*2048*3];
+    unsigned char fb[2048*2048*3];
     int width,height;
+    bool fresh;
 };
 
 #endif // VIDEOWIDGET_H
-- 
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