1 files changed, 117 insertions, 0 deletions
diff --git a/src/graph.c b/src/graph.c
new file mode 100644
index 0000000..9a69ba5
--- /dev/null
+++ b/src/graph.c
@@ -0,0 +1,117 @@
+#include <stdlib.h>
+#include <GL/gl.h>
+
+#include "graph.h"
+
+/****************************
+ * Graph memory
+ ***************************/
+
+// Free the memory for a graph and substructures
+void grFree(grGraph *g)
+{
+  if (g)
+  {
+    if (g->nodes)
+      free(g->nodes);
+    if (g->edges)
+      free(g->edges);
+    free(g);
+  }
+}
+
+
+// Allocate memory for a new graph, return NULL on any error
+grGraph* grAlloc(int numnodes, int numedges)
+{
+  grGraph *g;
+
+  g = malloc(sizeof(grGraph));
+  if (!g)
+    return NULL;
+
+  g->nodes = malloc(sizeof(grNode[numnodes]));
+  g->edges = malloc(sizeof(grEdge[numedges]));
+  if (!g->nodes || !g->edges)
+    goto ERR;
+
+  g->numnodes = numnodes;
+  g->numedges = numedges;
+
+  return g;
+
+  ERR:
+  grFree(g);
+  return NULL;
+}
+
+
+
+/****************************
+ * Graph generation
+ ***************************/
+
+// Randomize a graph
+void grGenRandom(grGraph *g)
+{
+  int i;
+  int ns = g->numnodes;
+  int es = g->numedges;
+
+  for (i = 0; i < ns; i++)
+  {
+    grNode *n = &g->nodes[i];
+
+    n->x = (float)rand() / (RAND_MAX/4);
+    n->y = (float)rand() / (RAND_MAX/4);
+    n->z = (float)rand() / (RAND_MAX/4);
+    n->colour = 0.0;
+  }
+
+  for (i = 0; i < es; i++)
+  {
+    grEdge *e = &g->edges[i];
+
+    e->n1 = rand() / (RAND_MAX/ns);
+    e->n2 = rand() / (RAND_MAX/ns);
+  }
+}
+
+
+
+/****************************
+ * Graph drawing functions
+ ***************************/
+
+// Draw the graph on the current OpenGL context
+void graphDrawGL(grGraph *g)
+{
+  int i;
+  int ns = g->numnodes;
+  int es = g->numedges;
+
+  // Draw edges
+  glColor4f(0.0, 0.0, 1.0, 0.5);
+  for (i = 0; i < es; i++)
+  {
+    grNode *n1 = &g->nodes[g->edges[i].n1];
+    grNode *n2 = &g->nodes[g->edges[i].n2];
+
+    glBegin(GL_LINE_STRIP);
+      glVertex3f(n1->x, n1->y, n1->z);
+      glVertex3f(n2->x, n2->y, n2->z);
+    glEnd();
+  }
+
+  // Draw nodes
+  glPointSize(5.0);
+  glBegin(GL_POINTS);
+    for (i = 0; i < ns; i++)
+    {
+      grNode *n = &g->nodes[i];
+      //glLoadName(i);    // Load point number into depth buffer for selection
+      glColor4f(n->colour, 1.0, 0.3, 0.7);
+      glVertex3f(n->x, n->y, n->z);
+    }
+  glEnd();
+}