Added a density legend to the display. Disabled the depth test so

that the alpha blending and point overlays work as expected for an
orthographic projection.

11 files changed, 124 insertions, 27 deletions

diff --git a/r/connect.R b/r/connect.R
index b42b8bb..75e84df 100644
--- a/r/connect.R
+++ b/r/connect.R
@@ -9,6 +9,8 @@ dbGetQuery (conn, "SELECT COUNT(*) FROM vis_collect");
 
 d <- dbReadTable (conn, "vis_collect");
 
+summary (d);
+
 hist (d$"N_CITES");
 
 dbDisconnect (conn);
diff --git a/src/Makefile.am b/src/Makefile.am
index abedab7..9fd441c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -12,6 +12,7 @@ exp004viz_SOURCES = \
         controller/set_ortho.c \
         db/dbconnect.c \
         exp004viz.c \
+        model/density_legend_geometry.c \
         model/exp004base.c \
         model/protein_geometry.c \
         model/selection_info_init.c \
@@ -36,7 +37,7 @@ noinst_HEADERS = \
         controller/selsave.h \
         controller/set_ortho.h \
         db/dbconnect.h \
-        model/display_list_index.h \
+        model/density_legend_geometry.h \
         model/exp004base.h \
         model/exp004state.h \
         model/protein_geometry.h \
diff --git a/src/controller/exp004reshape.c b/src/controller/exp004reshape.c
index 82f134d..891de08 100644
--- a/src/controller/exp004reshape.c
+++ b/src/controller/exp004reshape.c
@@ -1,6 +1,7 @@
 #include "exp004reshape.h"
 #include "set_ortho.h"
 #include "../view/exp004state0.h"
+#include "../model/density_legend_geometry.h"
 #include <GL/glut.h>
 
 #define S exp004state0
@@ -22,13 +23,13 @@ exp004reshape (int w, int h)
     {
       S.ortho.min_x = S.ortho_min;
       S.ortho.max_x = S.ortho_max;
-      S.ortho.min_y = S.ortho_min * (GLfloat) h / (GLfloat) w;
-      S.ortho.max_y = S.ortho_max * (GLfloat) h / (GLfloat) w;
+      S.ortho.min_y = S.ortho_min * (double) h / (double) w;
+      S.ortho.max_y = S.ortho_max * (double) h / (double) w;
     }
   else
     {
-      S.ortho.min_x = S.ortho_min * (GLfloat) w / (GLfloat) h;
-      S.ortho.max_x = S.ortho_max * (GLfloat) w / (GLfloat) h;
+      S.ortho.min_x = S.ortho_min * (double) w / (double) h;
+      S.ortho.max_x = S.ortho_max * (double) w / (double) h;
       S.ortho.min_y = S.ortho_min;
       S.ortho.max_y = S.ortho_max;
     }
@@ -43,5 +44,7 @@ exp004reshape (int w, int h)
   S.viewport.w = w;
   S.viewport.h = h;
 
+  density_legend_geometry ();
+
   return;
 }
diff --git a/src/model/density_legend_geometry.c b/src/model/density_legend_geometry.c
new file mode 100644
index 0000000..ab3e46c
--- a/dev/null
+++ b/src/model/density_legend_geometry.c
@@ -0,0 +1,81 @@
+#include "density_legend_geometry.h"
+#include "../view/exp004state0.h"
+#include "../controller/exp004reshape.h"
+#include <GL/glut.h>
+#include <stdio.h>
+
+#define S exp004state0
+
+void
+density_legend_geometry (void)
+{
+  glNewList (S.list_offset + DENSITY_LEGEND_GEOMETRY, GL_COMPILE);
+  glPolygonMode (GL_FRONT, GL_FILL);
+  glColor4f (DEFAULT_COLOR_R, DEFAULT_COLOR_G, DEFAULT_COLOR_B,
+             DEFAULT_COLOR_A);
+
+  /*
+   * This value should be a percentage of the world height so that it
+   * remains a fixed number of pixels tall when the window is resized
+   * or zoomed.
+   */
+  double legend_height = 0.5;
+
+  /*
+   * Calculate the bounding box for the legend.
+   */
+
+  double a[2];
+  double b[2];
+  double c[2];
+  double d[2];
+
+  const double *left;
+  const double *right;
+  const double *top;
+
+  if (S.zoom.active)
+    {
+      left = &S.zoom.coords[0];
+      right = &S.zoom.coords[1];
+      top = &S.zoom.coords[3];
+    }
+  else
+    {
+      left = &S.ortho.min_x;
+      top = &S.ortho.max_y;
+      right = &S.ortho.max_x;
+    }
+
+  a[0] = *left;
+  a[1] = *top;
+  b[0] = *right;
+  b[1] = *top;
+  c[0] = *right;
+  c[1] = *top - legend_height;
+  d[0] = *left;
+  d[1] = *top - legend_height;
+
+  /*
+   * Overlay a legend from default saturation / alpha to full saturation.
+   */
+  for (int i = 1; i <= 1 / DEFAULT_COLOR_A; i++)
+    {
+      glBegin (GL_QUADS);
+      glVertex2dv (a);
+      glVertex2dv (b);
+      glVertex2dv (c);
+      glVertex2dv (d);
+      glEnd ();
+
+      /*
+       * Step left to right along the x-coordinate.
+       */
+      a[0] = *left + (*right - *left) * (DEFAULT_COLOR_A * i);
+      d[0] = a[0];
+    }
+
+  glEndList ();
+
+  return;
+}
diff --git a/src/model/density_legend_geometry.h b/src/model/density_legend_geometry.h
new file mode 100644
index 0000000..4745ac0
--- a/dev/null
+++ b/src/model/density_legend_geometry.h
@@ -0,0 +1,9 @@
+#ifndef DENSITY_LEGEND_GEOMETRY_H
+#define DENSITY_LEGEND_GEOMETRY_H
+
+/*
+ * Define the geometry to redner the density legend.
+ */
+void density_legend_geometry (void);
+
+#endif // DENSITY_LEGEND_GEOMETRY_H
diff --git a/src/model/display_list_index.h b/src/model/display_list_index.h
deleted file mode 100644
index a68f8a7..0000000
--- a/src/model/display_list_index.h
+++ b/dev/null
@@ -1,6 +0,0 @@
-#ifndef DISPLAY_LIST_INDEX
-#define DISPLAY_LIST_INDEX
-
-#define PROTEIN_GEOMETRY 0
-
-#endif // DISPLAY_LIST_INDEX
diff --git a/src/model/exp004state.h b/src/model/exp004state.h
index 1af8a5b..5a9761a 100644
--- a/src/model/exp004state.h
+++ b/src/model/exp004state.h
@@ -16,14 +16,16 @@
 #define DEFAULT_COLOR_R 0.00
 #define DEFAULT_COLOR_G 0.00
 #define DEFAULT_COLOR_B 0.01
-#define DEFAULT_COLOR_A 0.25
+#define DEFAULT_COLOR_A (1.0 / 7.0)
 
 #define SELECT_COLOR_R 0.00
 #define SELECT_COLOR_G 0.00
 #define SELECT_COLOR_B 0.00
 #define SELECT_COLOR_A 0.75
 
-typedef enum { PROTEIN_GEOMETRY } LISTS;
+typedef enum
+{ PROTEIN_GEOMETRY, DENSITY_LEGEND_GEOMETRY } LISTS;
+#define NUM_LISTS 2
 
 /*
  * Maintain state of the model.
@@ -61,10 +63,10 @@ typedef struct
    */
   struct
   {
-    float min_x;
-    float max_x;
-    float min_y;
-    float max_y;
+    double min_x;
+    double max_x;
+    double min_y;
+    double max_y;
   } ortho;
 
   /*
diff --git a/src/util/check_error.c b/src/util/check_error.c
index cd00439..c47ca43 100644
--- a/src/util/check_error.c
+++ b/src/util/check_error.c
@@ -1,6 +1,7 @@
 #include <GL/glut.h>
 #include <error.h>
 #include <errno.h>
+#include <stdlib.h>
 #include "sqlinfoprint.h"
 extern struct sqlca sqlca;
 
@@ -15,14 +16,15 @@ check_error (const char *filename, const unsigned int linenum)
   if (errCode != GL_NO_ERROR)
     {
       const GLubyte *errString = gluErrorString (errCode);
-      error_at_line (-1, errno, filename, linenum,
+      error_at_line (EXIT_FAILURE, errno, filename, linenum,
                      "OpenGL Error %s", errString);
     }
 
   /*
    * Check for an error from the Database API.
    */
-  sqlinfoprint ("DB Error", &sqlca, filename, linenum);
+  if (sqlinfoprint ("DB Error", &sqlca, filename, linenum) == 1)
+    exit (EXIT_FAILURE);
 
   return;
 }
diff --git a/src/view/exp004geometry.c b/src/view/exp004geometry.c
index e7193fd..6f3bc17 100644
--- a/src/view/exp004geometry.c
+++ b/src/view/exp004geometry.c
@@ -21,13 +21,14 @@ exp004geometry (GLenum mode)
     {
       glLoadName (i);
       glPushMatrix ();
-      glTranslatef (S.base_vertices_data[i][0], 
-                    S.base_vertices_data[i][1],
-                    0.0);
+      glTranslatef (S.base_vertices_data[i][0],
+                    S.base_vertices_data[i][1], 0.0);
       glColor4fv (S.base_colors_data[i]);
       glCallList (S.list_offset + PROTEIN_GEOMETRY);
       glPopMatrix ();
     }
 
+  glCallList (S.list_offset + DENSITY_LEGEND_GEOMETRY);
+
   return;
 }
diff --git a/src/view/exp004init.c b/src/view/exp004init.c
index e7da51d..ab12d2a 100644
--- a/src/view/exp004init.c
+++ b/src/view/exp004init.c
@@ -1,5 +1,7 @@
 #include "exp004init.h"
 #include "exp004state0.h"
+#include "../model/density_legend_geometry.h"
+#include "../model/protein_geometry.h"
 #include "../model/selection_info_init.h"
 #include "../model/zoom_info_init.h"
 #include <GL/glut.h>
@@ -12,7 +14,9 @@ exp004init (void)
   selection_info_init (&S.selection);
   zoom_info_init (&S.zoom);
 
-  S.list_offset = glGenLists (1);
-  
+  S.list_offset = glGenLists (NUM_LISTS);
+  protein_geometry ();
+  density_legend_geometry ();
+
   return;
 }
diff --git a/src/view/exp004view.c b/src/view/exp004view.c
index 68a4e79..33198ad 100644
--- a/src/view/exp004view.c
+++ b/src/view/exp004view.c
@@ -4,7 +4,6 @@
 #include "../controller/keyboard.h"
 #include "../db/dbconnect.h"
 #include "../model/exp004base.h"
-#include "../model/protein_geometry.h"
 #include "exp004init.h"
 #include "exp004state0.h"
 #include "exp004view.h"
@@ -25,7 +24,7 @@ exp004view (void)
   glClearColor (CLEAR_COLOR);
   glColor3f (DRAW_COLOR);
   glEnable (GL_AUTO_NORMAL);
-  glEnable (GL_DEPTH_TEST);
+  glDisable (GL_DEPTH_TEST);
   glEnable (GL_MAP1_VERTEX_3);
   glShadeModel (GL_SMOOTH);
 
@@ -43,7 +42,6 @@ exp004view (void)
   // Initialize the model.
   exp004base ();
   exp004init ();
-  protein_geometry ();
 
   // Callbacks (Controllers)
   glutDisplayFunc (exp004display);