+#include <SDL_image.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "config.h"
+#include "file.h"
+#include "globals.h"
+#include "rocks.h"
+#include "shape.h"
+
+struct rock_struct {
+ float x,y,dx,dy;
+ int active;
+ int dead; // has been blown out of the way
+ // to make room for a new ship appearing.
+ SDL_Surface *image;
+ struct shape *shape;
+ int type_number;
+};
+
+struct rock_struct rock[MAXROCKS], *rockptr = rock;
+
+float rockrate,rockspeed;
+
+SDL_Surface *surf_rock[NROCKS];
+struct shape rock_shapes[NROCKS];
+
+int countdown = 0;
+
+float rnd(void);
+
+uint32_t area;
+
+int
+init_rocks(void)
+{
+ int i;
+ char a[MAX_PATH_LEN];
+ SDL_Surface *temp;
+
+ area = 0;
+
+ for(i = 0; i<NROCKS; i++) {
+ snprintf(a,MAX_PATH_LEN,add_path("sprites/rock%02d.png"),i);
+ NULLERROR(temp = IMG_Load(a));
+ NULLERROR(surf_rock[i] = SDL_DisplayFormat(temp));
+ get_shape(surf_rock[i], &rock_shapes[i]);
+ }
+ return 0;
+}
+
+void
+new_rocks(void)
+{
+ if(--countdown <= 0 && (rnd()*100.0<(rockrate += 0.025))) {
+ // Possibly create a rock
+ rockptr++;
+ if(rockptr-rock >= MAXROCKS) {
+ rockptr = rock;
+ }
+ if(!rockptr->active) {
+ rockptr->dx = -(rockspeed)*(1 + rnd());
+ rockptr->dy = rnd()-0.5;
+ rockptr->type_number = random() % NROCKS;
+ rockptr->image = surf_rock[rockptr->type_number];
+ rockptr->shape = &rock_shapes[rockptr->type_number];
+ rockptr->x = (float)XSIZE;
+ rockptr->y = rnd()*(YSIZE + rockptr->image->h);
+ rockptr->active = 1;
+ area += rockptr->shape->area;
+ }
+ if(gamerate>0.1) {
+ countdown = (int)(ROCKRATE/gamerate);
+ } else {
+ countdown = 0;
+ }
+ }
+}
+
+void
+move_rocks(void)
+{
+ int i;
+
+ // Move all the rocks
+ for(i = 0; i < MAXROCKS; i++) {
+ if(rock[i].active) {
+ rock[i].x += rock[i].dx*gamerate;
+ rock[i].y += rock[i].dy*gamerate + yscroll;
+ if(rock[i].y > YSIZE || rock[i].y < -rock[i].image->h) {
+ if(rock[i].dead) {
+ area -= rock[i].shape->area;
+ rock[i].dead = 0;
+ rock[i].active = 0;
+ } else {
+ // wrap
+ rock[i].y = (YSIZE - rock[i].image->h) - rock[i].y;
+ rock[i].y += (rock[i].dy*gamerate + yscroll) * 1.01;
+ }
+ }
+ if(rock[i].x < -rock[i].image->w || rock[i].x > XSIZE) {
+ area -= rock[i].shape->area;
+ rock[i].active = 0;
+ rock[i].dead = 0;
+ }
+ }
+ }
+}
+
+void
+reset_rocks(void)
+{
+ int i;
+
+ area = 0;
+ for(i = 0; i<MAXROCKS; i++ ) {
+ rock[i].active = 0;
+ rock[i].dead = 0;
+ }
+
+ rockrate = 54.0;
+ rockspeed = 5.0;
+}
+
+void
+draw_rocks(void)
+{
+ int i;
+ SDL_Rect src, dest;
+
+ src.x = 0; src.y = 0;
+
+ for(i = 0; i<MAXROCKS; i++) {
+ if(rock[i].active) {
+ src.w = rock[i].image->w;
+ src.h = rock[i].image->h;
+
+ dest.w = src.w;
+ dest.h = src.h;
+ dest.x = (int) rock[i].x;
+ dest.y = (int) rock[i].y;
+
+ SDL_BlitSurface(rock[i].image,&src,surf_screen,&dest);
+
+ }
+ }
+}
+
+int
+hit_rocks(float x, float y, struct shape *shape)
+{
+ int i;
+
+ for(i=0; i<MAXROCKS; i++) {
+ if(rock[i].active) {
+ if(collide(x-rock[i].x, y-rock[i].y, rock[i].shape, shape))
+ return 1;
+ }
+ }
+ return 0;
+}
+
+void
+blast_rocks(float x, float y, float radius, int onlyslow)
+{
+ int i;
+ float dx, dy, n;
+
+ for(i = 0; i<MAXROCKS; i++ ) {
+ if(rock[i].x <= 0) continue;
+
+ // This makes it so your explosion from dying magically doesn't leave
+ // any rocks that aren't moving much on the x axis. If onlyslow is set,
+ // only rocks that are barely moving will be pushed.
+ if(onlyslow && (!rock[i].dead || rock[i].dx < -4 || rock[i].dx > 3)) {
+ continue;
+ }
+
+ dx = rock[i].x - x;
+ dy = rock[i].y - y;
+
+ n = sqrt(dx*dx + dy*dy);
+ if(n < radius) {
+ n *= 20;
+ rock[i].dx += rockrate*(dx+30)/n;
+ rock[i].dy += rockrate*dy/n;
+ rock[i].dead = 1;
+ }
+ }
+}
Got questions, comments, patches, etc.? Contact Jason Woofenden