logicsignal.cpp

   1 /*
   2  * This file is part of the sigrok project.
   3  *
   4  * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #define GL_GLEXT_PROTOTYPES
  22 #include <GL/gl.h>
  23 #include <GL/glext.h>
  24
  25 #include <math.h>
  26
  27 #include "logicdata.h"
  28 #include "logicdatasnapshot.h"
  29 #include "logicsignal.h"
  30
  31 using namespace boost;
  32 using namespace std;
  33
  34 const float Log2 = logf(2.0f);
  35
  36 LogicSignal::LogicSignal(QString name, shared_ptr<LogicData> data,
  37         int probe_index) :
  38         Signal(name),
  39         _data(data),
  40         _probe_index(probe_index)
  41 {
  42         assert(_probe_index >= 0);
  43 }
  44
  45 void LogicSignal::paint(QGLWidget &widget, const QRect &rect,
  46         double scale, double offset)
  47 {
  48         Point2F *vertex;
  49
  50         vector< pair<int64_t, bool> > edges;
  51
  52         assert(scale > 0);
  53         assert(_data);
  54
  55         const queue< shared_ptr<LogicDataSnapshot> > &snapshots =
  56                 _data->get_snapshots();
  57         if(snapshots.empty())
  58                 return;
  59
  60         const shared_ptr<LogicDataSnapshot> &snapshot = snapshots.front();
  61
  62         const double pixels_offset = offset / scale;
  63         const double samplerate = _data->get_samplerate();
  64         const double start_time = _data->get_start_time();
  65         const int64_t last_sample = (int64_t)snapshot->get_sample_count() - 1;
  66         const double samples_per_pixel = samplerate * scale;
  67         const int64_t start = min(max((int64_t)(samplerate * (offset - start_time)),
  68                 (int64_t)0), last_sample);
  69         const int64_t end = min((int64_t)(start + samples_per_pixel * rect.width()),
  70                 last_sample);
  71         const int64_t quantization_length = 1LL << (int64_t)floorf(
  72                 max(logf(samples_per_pixel / Log2), 0.0f));
  73
  74         snapshot->get_subsampled_edges(edges, start, end,
  75                 quantization_length, _probe_index);
  76
  77         // Paint the edges
  78         const unsigned int edge_point_count = (edges.size() - 2) * 2;
  79         Point2F *const edge_points = new Point2F[edge_point_count];
  80         vertex = edge_points;
  81
  82         for(vector<LogicDataSnapshot::EdgePair>::const_iterator i = edges.begin() + 1;
  83             i != edges.end() - 1; i++)
  84         {
  85                 const int x = (int)((*i).first / samples_per_pixel - pixels_offset) +
  86                         rect.left();
  87
  88                 vertex->x = x, vertex->y = 10 + rect.top() - 1;
  89                 vertex++;
  90                 vertex->x = x, vertex->y = 40 + rect.top();
  91                 vertex++;
  92         }
  93
  94         glColor3f(0,0,1);
  95         paint_lines(edge_points, edge_point_count);
  96         delete[] edge_points;
  97
  98         // Paint the caps
  99         const unsigned int cap_point_count = (edges.size() - 1) * 2;
 100         Point2F *const cap_points = new Point2F[cap_point_count];
 101         vertex = cap_points;
 102
 103         for(vector<LogicDataSnapshot::EdgePair>::const_iterator i = edges.begin();
 104             i != (edges.end() - 1); i++)
 105         {
 106                 const int y = ((*i).second ? 10 : 40) + rect.top();
 107
 108                 vertex->x = (int)((*i).first / samples_per_pixel - pixels_offset) +
 109                         rect.left() - 1;
 110                 vertex->y = y;
 111                 vertex++;
 112
 113                 vertex->x = (int)((*(i+1)).first / samples_per_pixel - pixels_offset) +
 114                         rect.left();
 115                 vertex->y = y;
 116                 vertex++;
 117         }
 118
 119         glColor3f(0,0,1);
 120         paint_lines(cap_points, cap_point_count);
 121         delete[] cap_points;
 122 }
 123
 124 void LogicSignal::paint_lines(Point2F *points, int count)
 125 {
 126         GLuint vbo_id;
 127
 128         assert(points);
 129
 130         glGenBuffers(1, &vbo_id);
 131         glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 132
 133         const unsigned int vbo_length = count * sizeof(Point2F);
 134         glBufferData(GL_ARRAY_BUFFER, vbo_length, NULL, GL_STATIC_DRAW);
 135         glBufferSubData(GL_ARRAY_BUFFER, 0, vbo_length, points);
 136
 137         glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 138
 139         glVertexPointer(2, GL_FLOAT, sizeof(Point2F), 0);
 140
 141         glEnableClientState(GL_VERTEX_ARRAY);
 142         glDrawArrays(GL_LINES,  0,  count);
 143         glDisableClientState(GL_VERTEX_ARRAY);
 144
 145         glDeleteBuffers(1, &vbo_id);
 146 }