clients/smoke.c

   1 /*
   2  * Copyright © 2010 Kristian Høgsberg
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <stdint.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <time.h>
  28 #include <fcntl.h>
  29 #include <unistd.h>
  30 #include <math.h>
  31 #include <time.h>
  32 #include <cairo.h>
  33 #include <glib.h>
  34
  35 #include "wayland-client.h"
  36 #include "wayland-glib.h"
  37 #include "window.h"
  38
  39 struct smoke {
  40         struct display *display;
  41         struct window *window;
  42         cairo_surface_t *surface;
  43         int x, y, width, height;
  44         int offset, current;
  45         struct { float *d, *u, *v; } b[2];
  46 };
  47
  48 static void diffuse(struct smoke *smoke, uint32_t time,
  49                     float *source, float *dest)
  50 {
  51         float *s, *d;
  52         int x, y, k, stride;
  53         float t, a = 0.0002;
  54
  55         stride = smoke->width;
  56
  57         for (k = 0; k < 5; k++) {
  58                 for (y = 1; y < smoke->height - 1; y++) {
  59                         s = source + y * stride;
  60                         d = dest + y * stride;
  61                         for (x = 1; x < smoke->width - 1; x++) {
  62                                 t = d[x - 1] + d[x + 1] +
  63                                         d[x - stride] + d[x + stride];
  64                                 d[x] = (s[x] + a * t) / (1 + 4 * a) * 0.995;
  65                         }
  66                 }
  67         }
  68 }
  69
  70 static void advect(struct smoke *smoke, uint32_t time,
  71                    float *uu, float *vv, float *source, float *dest)
  72 {
  73         float *s, *d;
  74         float *u, *v;
  75         int x, y, stride;
  76         int i, j;
  77         float px, py, fx, fy;
  78
  79         stride = smoke->width;
  80
  81         for (y = 1; y < smoke->height - 1; y++) {
  82                 d = dest + y * stride;
  83                 u = uu + y * stride;
  84                 v = vv + y * stride;
  85
  86                 for (x = 1; x < smoke->width - 1; x++) {
  87                         px = x - u[x];
  88                         py = y - v[x];
  89                         if (px < 0.5)
  90                                 px = 0.5;
  91                         if (py < 0.5)
  92                                 py = 0.5;
  93                         if (px > smoke->width - 0.5)
  94                                 px = smoke->width - 0.5;
  95                         if (py > smoke->height - 0.5)
  96                                 py = smoke->height - 0.5;
  97                         i = (int) px;
  98                         j = (int) py;
  99                         fx = px - i;
 100                         fy = py - j;
 101                         s = source + j * stride + i;
 102                         d[x] = (s[0] * (1 - fx) + s[1] * fx) * (1 - fy) +
 103                                 (s[stride] * (1 - fx) + s[stride + 1] * fx) * fy;
 104                 }
 105         }
 106 }
 107
 108 static void project(struct smoke *smoke, uint32_t time,
 109                     float *u, float *v, float *p, float *div)
 110 {
 111         int x, y, k, l, s;
 112         float h;
 113
 114         h = 1.0 / smoke->width;
 115         s = smoke->width;
 116         memset(p, 0, smoke->height * smoke->width);
 117         for (y = 1; y < smoke->height - 1; y++) {
 118                 l = y * s;
 119                 for (x = 1; x < smoke->width - 1; x++) {
 120                         div[l + x] = -0.5 * h * (u[l + x + 1] - u[l + x - 1] +
 121                                                  v[l + x + s] - v[l + x - s]);
 122                         p[l + x] = 0;
 123                 }
 124         }
 125
 126         for (k = 0; k < 5; k++) {
 127                 for (y = 1; y < smoke->height - 1; y++) {
 128                         l = y * s;
 129                         for (x = 1; x < smoke->width - 1; x++) {
 130                                 p[l + x] = (div[l + x] +
 131                                             p[l + x - 1] +
 132                                             p[l + x + 1] +
 133                                             p[l + x - s] +
 134                                             p[l + x + s]) / 4;
 135                         }
 136                 }
 137         }
 138
 139         for (y = 1; y < smoke->height - 1; y++) {
 140                 l = y * s;
 141                 for (x = 1; x < smoke->width - 1; x++) {
 142                         u[l + x] -= 0.5 * (p[l + x + 1] - p[l + x - 1]) / h;
 143                         v[l + x] -= 0.5 * (p[l + x + s] - p[l + x - s]) / h;
 144                 }
 145         }
 146 }
 147
 148 static void render(struct smoke *smoke)
 149 {
 150         unsigned char *dest;
 151         int x, y, width, height, stride;
 152         float *s;
 153         uint32_t *d, c, a;
 154
 155         dest = cairo_image_surface_get_data (smoke->surface);
 156         width = cairo_image_surface_get_width (smoke->surface);
 157         height = cairo_image_surface_get_height (smoke->surface);
 158         stride = cairo_image_surface_get_stride (smoke->surface);
 159
 160         for (y = 1; y < height - 1; y++) {
 161                 s = smoke->b[smoke->current].d + y * smoke->height;
 162                 d = (uint32_t *) (dest + y * stride);
 163                 for (x = 1; x < width - 1; x++) {
 164                         c = (int) (s[x] * 800);
 165                         if (c > 255)
 166                                 c = 255;
 167                         a = c;
 168                         if (a < 0x33)
 169                                 a = 0x33;
 170                         d[x] = (a << 24) | (c << 16) | (c << 8) | c;
 171                 }
 172         }
 173 }
 174
 175 static void
 176 frame_callback(struct wl_surface *surface, void *data, uint32_t time)
 177 {
 178         struct smoke *smoke = data;
 179
 180         diffuse(smoke, time / 30, smoke->b[0].u, smoke->b[1].u);
 181         diffuse(smoke, time / 30, smoke->b[0].v, smoke->b[1].v);
 182         project(smoke, time / 30,
 183                 smoke->b[1].u, smoke->b[1].v,
 184                 smoke->b[0].u, smoke->b[0].v);
 185         advect(smoke, time / 30,
 186                smoke->b[1].u, smoke->b[1].v,
 187                smoke->b[1].u, smoke->b[0].u);
 188         advect(smoke, time / 30,
 189                smoke->b[1].u, smoke->b[1].v,
 190                smoke->b[1].v, smoke->b[0].v);
 191         project(smoke, time / 30,
 192                 smoke->b[0].u, smoke->b[0].v,
 193                 smoke->b[1].u, smoke->b[1].v);
 194
 195         diffuse(smoke, time / 30, smoke->b[0].d, smoke->b[1].d);
 196         advect(smoke, time / 30,
 197                smoke->b[0].u, smoke->b[0].v,
 198                smoke->b[1].d, smoke->b[0].d);
 199
 200         render(smoke);
 201
 202         window_damage(smoke->window, 0, 0, smoke->width, smoke->height);
 203         wl_display_frame_callback(display_get_display(smoke->display),
 204                                   window_get_wl_surface(smoke->window),
 205                                   frame_callback, smoke);
 206 }
 207
 208 static int
 209 smoke_motion_handler(struct window *window,
 210                      struct input *input, uint32_t time,
 211                      int32_t x, int32_t y,
 212                      int32_t surface_x, int32_t surface_y, void *data)
 213 {
 214         struct smoke *smoke = data;
 215         int i, i0, i1, j, j0, j1, k, d = 5;
 216
 217         if (surface_x - d < 1)
 218                 i0 = 1;
 219         else
 220                 i0 = surface_x - d;
 221         if (i0 + 2 * d > smoke->width - 1)
 222                 i1 = smoke->width - 1;
 223         else
 224                 i1 = i0 + 2 * d;
 225
 226         if (surface_y - d < 1)
 227                 j0 = 1;
 228         else
 229                 j0 = surface_y - d;
 230         if (j0 + 2 * d > smoke->height - 1)
 231                 j1 = smoke->height - 1;
 232         else
 233                 j1 = j0 + 2 * d;
 234
 235         for (i = i0; i < i1; i++)
 236                 for (j = j0; j < j1; j++) {
 237                         k = j * smoke->width + i;
 238                         smoke->b[0].u[k] += 256 - (random() & 512);
 239                         smoke->b[0].v[k] += 256 - (random() & 512);
 240                         smoke->b[0].d[k] += 1;
 241                 }
 242
 243         return POINTER_HAND1;
 244 }
 245
 246 int main(int argc, char *argv[])
 247 {
 248         struct timespec ts;
 249         struct smoke smoke;
 250         struct display *d;
 251         int size;
 252
 253         d = display_create(&argc, &argv, NULL);
 254         if (d == NULL) {
 255                 fprintf(stderr, "failed to create display: %m\n");
 256                 return -1;
 257         }
 258
 259         smoke.x = 200;
 260         smoke.y = 200;
 261         smoke.width = 200;
 262         smoke.height = 200;
 263         smoke.display = d;
 264         smoke.window = window_create(d, smoke.width, smoke.height);
 265         window_set_title(smoke.window, "smoke");
 266
 267         window_set_buffer_type(smoke.window, WINDOW_BUFFER_TYPE_SHM);
 268         clock_gettime(CLOCK_MONOTONIC, &ts);
 269         srandom(ts.tv_nsec);
 270         smoke.offset = random();
 271
 272         smoke.current = 0;
 273         size = smoke.height * smoke.width;
 274         smoke.b[0].d = calloc(size, sizeof(float));
 275         smoke.b[0].u = calloc(size, sizeof(float));
 276         smoke.b[0].v = calloc(size, sizeof(float));
 277         smoke.b[1].d = calloc(size, sizeof(float));
 278         smoke.b[1].u = calloc(size, sizeof(float));
 279         smoke.b[1].v = calloc(size, sizeof(float));
 280
 281         window_set_decoration(smoke.window, 0);
 282         window_create_surface(smoke.window);
 283         smoke.surface = window_get_surface(smoke.window);
 284
 285         window_flush(smoke.window);
 286
 287         window_set_motion_handler(smoke.window,
 288                                   smoke_motion_handler);
 289
 290         window_set_user_data(smoke.window, &smoke);
 291         wl_display_frame_callback(display_get_display(d),
 292                                   window_get_wl_surface(smoke.window),
 293                                   frame_callback, &smoke);
 294
 295         display_run(d);
 296
 297         return 0;
 298 }