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 const float LogicSignal::Margin = 10.0f;
  37
  38 const float LogicSignal::EdgeColour[3] =        {0.50f, 0.50f, 0.50f};
  39 const float LogicSignal::HighColour[3] =        {0.00f, 0.75f, 0.00f};
  40 const float LogicSignal::LowColour[3] = {0.75f, 0.00f, 0.00f};
  41
  42 LogicSignal::LogicSignal(QString name, shared_ptr<LogicData> data,
  43         int probe_index) :
  44         Signal(name),
  45         _data(data),
  46         _probe_index(probe_index)
  47 {
  48         assert(_probe_index >= 0);
  49 }
  50
  51 void LogicSignal::paint(QGLWidget &widget, const QRect &rect,
  52         double scale, double offset)
  53 {
  54         Point2F *vertex;
  55
  56         vector< pair<int64_t, bool> > edges;
  57
  58         assert(scale > 0);
  59         assert(_data);
  60
  61         const float high_offset = rect.top() + Margin;
  62         const float low_offset = rect.bottom() - Margin;
  63
  64         const queue< shared_ptr<LogicDataSnapshot> > &snapshots =
  65                 _data->get_snapshots();
  66         if(snapshots.empty())
  67                 return;
  68
  69         const shared_ptr<LogicDataSnapshot> &snapshot = snapshots.front();
  70
  71         const double pixels_offset = offset / scale;
  72         const double samplerate = _data->get_samplerate();
  73         const double start_time = _data->get_start_time();
  74         const int64_t last_sample = (int64_t)snapshot->get_sample_count() - 1;
  75         const double samples_per_pixel = samplerate * scale;
  76         const int64_t start = min(max((int64_t)(samplerate * (offset - start_time)),
  77                 (int64_t)0), last_sample);
  78         const int64_t end = min((int64_t)(start + samples_per_pixel * rect.width()),
  79                 last_sample);
  80         const int64_t quantization_length = 1LL << (int64_t)floorf(
  81                 max(logf(samples_per_pixel / Log2), 0.0f));
  82
  83         snapshot->get_subsampled_edges(edges, start, end,
  84                 quantization_length, _probe_index);
  85
  86         // Paint the edges
  87         const unsigned int edge_point_count = (edges.size() - 2) * 2;
  88         Point2F *const edge_points = new Point2F[edge_point_count];
  89         vertex = edge_points;
  90
  91         for(vector<LogicDataSnapshot::EdgePair>::const_iterator i = edges.begin() + 1;
  92             i != edges.end() - 1; i++)
  93         {
  94                 const int x = (int)((*i).first / samples_per_pixel - pixels_offset) +
  95                         rect.left();
  96
  97                 vertex->x = x, vertex->y = high_offset;
  98                 vertex++;
  99                 vertex->x = x, vertex->y = low_offset;
 100                 vertex++;
 101         }
 102
 103         glColor3fv(EdgeColour);
 104         paint_lines(edge_points, edge_point_count);
 105         delete[] edge_points;
 106
 107         // Paint the caps
 108         const unsigned int max_cap_point_count = (edges.size() - 1) * 2;
 109         Point2F *const cap_points = new Point2F[max_cap_point_count];
 110
 111         glColor3fv(HighColour);
 112         paint_caps(cap_points, edges, true, samples_per_pixel,
 113                 pixels_offset, rect.left(), high_offset);
 114         glColor3fv(LowColour);
 115         paint_caps(cap_points, edges, false, samples_per_pixel,
 116                 pixels_offset, rect.left(), low_offset);
 117
 118         delete[] cap_points;
 119 }
 120
 121 int LogicSignal::paint_caps(Point2F *const cap_points,
 122         vector< pair<int64_t, bool> > &edges, bool level,
 123         double samples_per_pixel, double pixels_offset, int x_offset,
 124         int y_offset)
 125 {
 126         Point2F *vertex = cap_points;
 127
 128         for(vector<LogicDataSnapshot::EdgePair>::const_iterator i = edges.begin();
 129             i != (edges.end() - 1); i++)
 130                 if((*i).second == level)
 131                 {
 132                         vertex->x = (int)((*i).first / samples_per_pixel -
 133                                 pixels_offset) + x_offset - 1;
 134                         vertex->y = y_offset;
 135                         vertex++;
 136
 137                         vertex->x = (int)((*(i+1)).first / samples_per_pixel -
 138                                 pixels_offset) + x_offset;
 139                         vertex->y = y_offset;
 140                         vertex++;
 141                 }
 142
 143         paint_lines(cap_points, vertex - cap_points);
 144 }
 145
 146 void LogicSignal::paint_lines(Point2F *points, int count)
 147 {
 148         GLuint vbo_id;
 149
 150         assert(points);
 151
 152         glGenBuffers(1, &vbo_id);
 153         glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 154
 155         const unsigned int vbo_length = count * sizeof(Point2F);
 156         glBufferData(GL_ARRAY_BUFFER, vbo_length, NULL, GL_STATIC_DRAW);
 157         glBufferSubData(GL_ARRAY_BUFFER, 0, vbo_length, points);
 158
 159         glBindBuffer(GL_ARRAY_BUFFER, vbo_id);
 160
 161         glVertexPointer(2, GL_FLOAT, sizeof(Point2F), 0);
 162
 163         glEnableClientState(GL_VERTEX_ARRAY);
 164         glDrawArrays(GL_LINES,  0,  count);
 165         glDisableClientState(GL_VERTEX_ARRAY);
 166
 167         glDeleteBuffers(1, &vbo_id);
 168 }