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/*
* a starfield simulation library from: https://github.com/ph1l/stars
* Copyright 2014 Philip J. Freeman <elektron@halo.nu>
*/
#include <stdlib.h>
#ifdef DEBUG
#include <stdio.h>
#endif
#include "starslib.h"
struct points
{
int x, y, z;
struct points *next;
};
void new_universe( struct universe** u, int width, int height, int depth )
{
*u = malloc(sizeof(struct universe));
(*u)->width = width;
(*u)->height = height;
(*u)->depth = depth;
(*u)->iterator = NULL;
(*u)->points = NULL;
#ifdef DEBUG
printf("NEW UNIVERSE: %lx: (%i,%i,%i)\n", (long unsigned int )(*u), (*u)->width, (*u)->height, (*u)->depth);
#endif
return;
}
void new_point( struct universe* u )
{
struct points* p_ptr = malloc(sizeof(struct points));
p_ptr->x = (rand()%u->width - (u->width/2)) * u->depth;
p_ptr->y = (rand()%u->height - (u->height/2)) * u->depth;
p_ptr->z = u->depth;
p_ptr->next = u->points;
u->points = p_ptr;
#ifdef DEBUG
printf("NEW POINT: %lx: (%i,%i,%i) next=%lx\n", (long unsigned int )p_ptr, p_ptr->x, p_ptr->y, p_ptr->z, (long unsigned int) p_ptr->next);
#endif
return;
}
void kill_point( struct universe* universe, struct points* to_kill )
{
struct points *p_ptr, *last_ptr = NULL;
for ( p_ptr = universe->points; p_ptr != NULL; p_ptr = p_ptr->next)
{
if (p_ptr == to_kill)
{
#ifdef DEBUG
printf("KILL POINT: %lx: (%i,%i,%i).\n", (long unsigned int )p_ptr, p_ptr->x, p_ptr->y, p_ptr->z);
#endif
if (last_ptr == NULL)
{
universe->points = p_ptr->next;
} else {
last_ptr->next = p_ptr->next;
}
free(p_ptr);
} else {
last_ptr = p_ptr;
}
}
#ifdef DEBUG
printf("KILL POINT: %lx\n", (long unsigned int )p_ptr);
#endif
return;
}
int process_point( struct universe *u, struct return_point *rp )
{
if ( u->iterator == NULL ) {
if (u->points == NULL){
return 0;
} else {
u->iterator = u->points;
}
}
if ( u->iterator->z == 0 ){
// Delete point that has reached us.
struct points *tmp = u->iterator;
u->iterator = u->iterator->next;
kill_point( u, tmp );
return(-1);
} else {
// Plot the point
int x, y;
x = u->iterator->x / u->iterator->z;
y = u->iterator->y / u->iterator->z;
if ( abs(x) >= u->width/2 || abs(y) >= u->height/2 ){
// Delete point that is off screen
struct points *tmp = u->iterator;
u->iterator = u->iterator->next;
kill_point( u, tmp );
if ( u->iterator == NULL ) {
return(0);
} else {
return(-1);
}
} else {
int m = OPACITY_MAX*((u->depth-u->iterator->z)*4)/u->depth;
if ( m>=OPACITY_MAX ){ m=OPACITY_MAX-1; }
u->iterator->z = u->iterator->z - 1;
#ifdef DEBUG
printf("RETURN POINT: %lx\n", (long unsigned int )u->iterator);
#endif
u->iterator = u->iterator->next;
rp->x = x;
rp->y = y;
rp->opacity = m;
if ( u->iterator == NULL ) {
return(0);
} else {
return(1);
}
}
}
}
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