git.hungrycats.org Git - xscreensaver/blob - hacks/glx/b_draw.c

   1 #if 0
   2 static const char sccsid[] = "@(#)b_draw.c  4.11 98/06/16 xlockmore";
   3 #endif
   4
   5 /*-
   6  * BUBBLE3D (C) 1998 Richard W.M. Jones.
   7  * b_draw.c: This code creates new bubbles, manages them and controls
   8  * them as they are drawn on the screen.
   9  */
  10
  11 #include "bubble3d.h"
  12
  13 typedef struct draw_context {
  14         /* The list of bubbles currently on the screen. */
  15         void      **bubble_list;
  16         int         nr_bubbles;
  17
  18         /* When was the last time we created a new bubble? */
  19         int         bubble_count;
  20 } draw_context;
  21
  22 void       *
  23 glb_draw_init(void)
  24 {
  25         draw_context *c;
  26
  27         GLfloat     mat_specular[] =
  28         {1, 1, 1, 1};
  29         GLfloat     mat_emission[] =
  30         {0, 0, 0, 1};
  31         GLfloat     mat_shininess[] =
  32         {100};
  33         GLfloat     ambient[] =
  34         {0.5, 0.5, 0.5, 1.0};
  35         GLfloat     light_position[][4] =
  36         {
  37                 {0, -1, 0, 0},
  38                 {1, 1, 0, 0},
  39                 {-1, 0, 1, 0}};
  40         GLfloat     light_diffuse[][4] =
  41         {
  42                 {1, 1, 1, 1},
  43                 {1, 1, 1, 1},
  44                 {1, 1, 1, 1}};
  45         GLfloat     light_specular[][4] =
  46         {
  47                 {1, 1, 1, 1},
  48                 {1, 1, 1, 1},
  49                 {1, 1, 1, 1}};
  50
  51         /* Initialize the context. */
  52         c = (struct draw_context *) malloc(sizeof (struct draw_context));
  53
  54         if (c == 0)
  55                 return 0;
  56         c->bubble_list = 0;
  57         c->nr_bubbles = 0;
  58         c->bubble_count = glb_config.create_bubbles_every;
  59
  60         /* Do some GL initialization. */
  61         glClearColor(glb_config.bg_colour[0],
  62                      glb_config.bg_colour[1],
  63                      glb_config.bg_colour[2],
  64                      glb_config.bg_colour[3]);
  65
  66         glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, glb_config.bubble_colour);
  67         glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_specular);
  68         glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, mat_emission);
  69         glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, mat_shininess);
  70
  71         if (glb_config.transparent_p)
  72           glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  73
  74         glEnable(GL_LIGHTING);
  75         glEnable(GL_LIGHT0);
  76         glEnable(GL_LIGHT1);
  77         glEnable(GL_LIGHT2);
  78
  79         if (glb_config.transparent_p)
  80           glEnable(GL_BLEND);
  81         else
  82           glEnable(GL_DEPTH_TEST);
  83
  84         glEnable(GL_AUTO_NORMAL);
  85         glEnable(GL_NORMALIZE);
  86
  87         if (glb_config.transparent_p)
  88           glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
  89
  90         glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambient);
  91         glLightfv(GL_LIGHT0, GL_POSITION, light_position[0]);
  92         glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse[0]);
  93         glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular[0]);
  94         glLightfv(GL_LIGHT1, GL_POSITION, light_position[1]);
  95         glLightfv(GL_LIGHT1, GL_DIFFUSE, light_diffuse[1]);
  96         glLightfv(GL_LIGHT1, GL_SPECULAR, light_specular[1]);
  97         glLightfv(GL_LIGHT2, GL_POSITION, light_position[2]);
  98         glLightfv(GL_LIGHT2, GL_DIFFUSE, light_diffuse[2]);
  99         glLightfv(GL_LIGHT2, GL_SPECULAR, light_specular[2]);
 100
 101         return c;
 102 }
 103
 104 static void
 105 delete_bubble(draw_context * c, int j)
 106 {
 107         int         i;
 108
 109         glb_bubble_delete(c->bubble_list[j]);
 110
 111         for (i = j; i < c->nr_bubbles - 1; ++i)
 112                 c->bubble_list[i] = c->bubble_list[i + 1];
 113
 114         c->nr_bubbles--;
 115 }
 116
 117 void
 118 glb_draw_end(void *cc)
 119 {
 120         draw_context *c = (draw_context *) cc;
 121         int         i;
 122
 123         for (i = 0; i < c->nr_bubbles; ++i) {
 124                 delete_bubble(c, i);
 125                 i--;
 126         }
 127         (void) free((void *) c->bubble_list);
 128         (void) free((void *) c);
 129 }
 130
 131 static int
 132 create_new_bubbles(draw_context * c)
 133 {
 134         int         n, i;
 135         double      r = glb_drand();
 136         GLfloat     size, speed, scale_incr, x, y, z;
 137         void       *b[4];
 138         void      **old_bubble_list;
 139
 140         /* How many bubbles to make? */
 141         if (r < glb_config.p_bubble_group[0])
 142                 n = 1;
 143         else if (r < glb_config.p_bubble_group[1])
 144                 n = 2;
 145         else if (r < glb_config.p_bubble_group[2])
 146                 n = 3;
 147         else
 148                 n = 4;
 149
 150         /* Initial position of top-most bubble in group. */
 151         x = glb_drand() * 4 - 2;
 152         y = glb_config.screen_bottom;
 153         z = glb_drand() * 2 - 2;
 154
 155         /* What size? */
 156         size = glb_config.min_size
 157                 + glb_drand() * (glb_config.max_size - glb_config.min_size);
 158
 159         /* What speed? */
 160         speed = glb_config.min_speed
 161                 + glb_drand() * (glb_config.max_speed - glb_config.min_speed);
 162
 163         /* Work out the scaling increment. Bubbles should increase by scale_factor
 164          * as they go from bottom to top of screen.
 165          */
 166         scale_incr = (size * glb_config.scale_factor - size)
 167                 / ((glb_config.screen_top - glb_config.screen_bottom) / speed);
 168
 169         /* Create the bubble(s). */
 170         for (i = 0; i < n; ++i) {
 171                 if ((b[i] = glb_bubble_new(x, y, z, size, speed, scale_incr)) == 0) {
 172                         /* Out of memory - recover. */
 173                         i--;
 174                         while (i >= 0)
 175                                 glb_bubble_delete(b[i]);
 176                         return 0;
 177                 }
 178                 /* Create the next bubble below the last bubble. */
 179                 y -= size * 3;
 180         }
 181
 182         /* Add the bubbles to the list. */
 183         c->nr_bubbles += n;
 184         old_bubble_list = c->bubble_list;
 185         if (c->bubble_list == 0) {
 186                 c->bubble_list = (void **) malloc(c->nr_bubbles * sizeof (void *));
 187         } else {
 188                 c->bubble_list = (void **) realloc(c->bubble_list,
 189                                             c->nr_bubbles * sizeof (void *));
 190         }
 191
 192         if (c->bubble_list == 0) {
 193                 /* Out of memory - recover. */
 194                 for (i = 0; i < n; ++i)
 195                         glb_bubble_delete(b[i]);
 196                 c->bubble_list = old_bubble_list;
 197                 c->nr_bubbles -= n;
 198                 return 0;
 199         }
 200         for (i = 0; i < n; ++i)
 201                 c->bubble_list[c->nr_bubbles - i - 1] = b[i];
 202
 203         return 1;
 204 }
 205
 206 void
 207 glb_draw_step(void *cc)
 208 {
 209         draw_context *c = (draw_context *) cc;
 210         int         i;
 211
 212         /* Consider creating a new bubble or bubbles. */
 213         if (c->nr_bubbles < glb_config.max_bubbles &&
 214             c->bubble_count++ > glb_config.create_bubbles_every) {
 215                 if (create_new_bubbles(c))
 216                         c->bubble_count = 0;
 217         }
 218         /* Clear the display. */
 219         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 220
 221         /* XXX Draw the background here ... */
 222
 223         /* Draw all the bubbles on the display. */
 224         for (i = 0; i < c->nr_bubbles; ++i) {
 225                 void       *b = c->bubble_list[i];
 226
 227                 glb_bubble_step(b);
 228                 glb_bubble_draw(b);
 229
 230                 /* Has the bubble reached the top of the screen? */
 231                 if (glb_bubble_get_y(b) >= glb_config.screen_top) {
 232                         delete_bubble(c, i);
 233                         i--;
 234                 }
 235         }
 236 }