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#include <stdlib.h>
#ifdef __APPLE__
#include <OpenGL/gl.h>
#else
#include <GL/gl.h>
#endif
#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();
}
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