Add small client for testing shm surfaces
diff --git a/clients/smoke.c b/clients/smoke.c
new file mode 100644
index 0000000..edd036c
--- /dev/null
+++ b/clients/smoke.c
@@ -0,0 +1,315 @@
+/*
+ * Copyright © 2010 Kristian Høgsberg
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <math.h>
+#include <time.h>
+#include <cairo.h>
+#include <glib.h>
+
+#include "wayland-client.h"
+#include "wayland-glib.h"
+#include "window.h"
+
+struct smoke {
+	struct display *display;
+	struct window *window;
+	cairo_surface_t *surface;
+	int x, y, width, height;
+	int offset, current;
+	struct { float *d, *u, *v; } b[2];
+};
+
+static void set_boundary(struct smoke *smoke, float x, float y, float *p)
+{
+	int i, l;
+
+	l = (smoke->height - 2) * smoke->width;
+	for (i = 1; i < smoke->width - 1; i++) {
+		p[i] = y * p[i + smoke->width];
+		p[l + i + smoke->width] = y * p[l + i];
+	}
+
+	for (i = 1; i < smoke->height - 1; i++) {
+		p[i * smoke->width] = x * p[i * smoke->width + 1];
+		p[i * smoke->width + smoke->width - 1] =
+			x * p[i * smoke->width + smoke->width - 2];
+	}
+}
+
+static void diffuse(struct smoke *smoke, uint32_t time,
+		    float *source, float *dest)
+{
+	cairo_t *cr;
+	float *s, *d;
+	int x, y, k, stride;
+	float t, a = 0.0002;
+
+	stride = smoke->width;
+
+	for (k = 0; k < 5; k++) {
+		for (y = 1; y < smoke->height - 1; y++) {
+			s = source + y * stride;
+			d = dest + y * stride;
+			for (x = 1; x < smoke->width - 1; x++) {
+				t = d[x - 1] + d[x + 1] +
+					d[x - stride] + d[x + stride];
+				d[x] = (s[x] + a * t) / (1 + 4 * a) * 0.995;
+			}
+		}
+	}
+}
+
+static void advect(struct smoke *smoke, uint32_t time,
+		   float *uu, float *vv, float *source, float *dest)
+{
+	cairo_t *cr;
+	float *s, *d;
+	float *u, *v;
+	int x, y, k, stride;
+	int i, j;
+	float px, py, fx, fy;
+
+	stride = smoke->width;
+
+	for (y = 1; y < smoke->height - 1; y++) {
+		d = dest + y * stride;
+		u = uu + y * stride;
+		v = vv + y * stride;
+
+		for (x = 1; x < smoke->width - 1; x++) {
+			px = x - u[x];
+			py = y - v[x];
+			if (px < 0.5)
+				px = 0.5;
+			if (py < 0.5)
+				py = 0.5;
+			if (px > smoke->width - 0.5)
+				px = smoke->width - 0.5;
+			if (py > smoke->height - 0.5)
+				py = smoke->height - 0.5;
+			i = (int) px;
+			j = (int) py;
+			fx = px - i;
+			fy = py - j;
+			s = source + j * stride + i;
+			d[x] = (s[0] * (1 - fx) + s[1] * fx) * (1 - fy) +
+				(s[stride] * (1 - fx) + s[stride + 1] * fx) * fy;
+		}
+	}
+}
+
+static void project(struct smoke *smoke, uint32_t time,
+		    float *u, float *v, float *p, float *div)
+{
+	int x, y, k, l, s;
+	float h, *d, *q;
+
+	h = 1.0 / smoke->width;
+	s = smoke->width;
+	memset(p, 0, smoke->height * smoke->width);
+	for (y = 1; y < smoke->height - 1; y++) {
+		l = y * s;
+		for (x = 1; x < smoke->width - 1; x++) {
+			div[l + x] = -0.5 * h * (u[l + x + 1] - u[l + x - 1] +
+						 v[l + x + s] - v[l + x - s]);
+			p[l + x] = 0;
+		}
+	}
+
+	for (k = 0; k < 5; k++) {
+		for (y = 1; y < smoke->height - 1; y++) {
+			l = y * s;
+			for (x = 1; x < smoke->width - 1; x++) {
+				p[l + x] = (div[l + x] +
+					    p[l + x - 1] +
+					    p[l + x + 1] +
+					    p[l + x - s] +
+					    p[l + x + s]) / 4;
+			}
+		}
+	}
+
+	for (y = 1; y < smoke->height - 1; y++) {
+		l = y * s;
+		for (x = 1; x < smoke->width - 1; x++) {
+			u[l + x] -= 0.5 * (p[l + x + 1] - p[l + x - 1]) / h;
+			v[l + x] -= 0.5 * (p[l + x + s] - p[l + x - s]) / h;
+		}
+	}
+}
+
+static void render(struct smoke *smoke)
+{
+	cairo_t *cr;
+	unsigned char *source, *dest;
+	int x, y, width, height, stride;
+	int k, t;
+	float *s;
+	uint32_t *d, c, a;
+
+	dest = cairo_image_surface_get_data (smoke->surface);
+	width = cairo_image_surface_get_width (smoke->surface);
+	height = cairo_image_surface_get_height (smoke->surface);
+	stride = cairo_image_surface_get_stride (smoke->surface);
+
+	for (y = 1; y < height - 1; y++) {
+		s = smoke->b[smoke->current].d + y * smoke->height;
+		d = (uint32_t *) (dest + y * stride);
+		for (x = 1; x < width - 1; x++) {
+			c = (int) (s[x] * 800);
+			if (c > 255)
+				c = 255;
+			a = c;
+			if (a < 0x33)
+				a = 0x33;
+			d[x] = (a << 24) | (c << 16) | (c << 8) | c;
+		}
+	}
+}
+
+static void
+frame_callback(void *data, uint32_t time)
+{
+	cairo_surface_t *t;
+	struct smoke *smoke = data;
+	static int i;
+
+	diffuse(smoke, time / 30, smoke->b[0].u, smoke->b[1].u);
+	diffuse(smoke, time / 30, smoke->b[0].v, smoke->b[1].v);
+	project(smoke, time / 30,
+		smoke->b[1].u, smoke->b[1].v,
+		smoke->b[0].u, smoke->b[0].v);
+	advect(smoke, time / 30,
+	       smoke->b[1].u, smoke->b[1].v,
+	       smoke->b[1].u, smoke->b[0].u);
+	advect(smoke, time / 30,
+	       smoke->b[1].u, smoke->b[1].v,
+	       smoke->b[1].v, smoke->b[0].v);
+	project(smoke, time / 30,
+		smoke->b[0].u, smoke->b[0].v,
+		smoke->b[1].u, smoke->b[1].v);
+
+	diffuse(smoke, time / 30, smoke->b[0].d, smoke->b[1].d);
+	advect(smoke, time / 30,
+	       smoke->b[0].u, smoke->b[0].v,
+	       smoke->b[1].d, smoke->b[0].d);
+
+	render(smoke);
+
+	window_damage(smoke->window, 0, 0, smoke->width, smoke->height);
+	wl_display_frame_callback(display_get_display(smoke->display),
+				  frame_callback, smoke);
+}
+
+static int
+smoke_motion_handler(struct window *window,
+		     struct input *input, uint32_t time,
+		     int32_t x, int32_t y,
+		     int32_t surface_x, int32_t surface_y, void *data)
+{
+	struct smoke *smoke = data;
+	int i, i0, i1, j, j0, j1, k, d = 5;
+
+	if (surface_x - d < 1)
+		i0 = 1;
+	else
+		i0 = surface_x - d;
+	if (i0 + 2 * d > smoke->width - 1)
+		i1 = smoke->width - 1;
+	else
+		i1 = i0 + 2 * d;
+
+	if (surface_y - d < 1)
+		j0 = 1;
+	else
+		j0 = surface_y - d;
+	if (j0 + 2 * d > smoke->height - 1)
+		j1 = smoke->height - 1;
+	else
+		j1 = j0 + 2 * d;
+
+	for (i = i0; i < i1; i++)
+		for (j = j0; j < j1; j++) {
+			k = j * smoke->width + i;
+			smoke->b[0].u[k] += 256 - (random() & 512);
+			smoke->b[0].v[k] += 256 - (random() & 512);
+			smoke->b[0].d[k] += 1;
+		}
+
+	return POINTER_HAND1;
+}
+
+int main(int argc, char *argv[])
+{
+	struct timespec ts;
+	struct smoke smoke;
+	struct display *d;
+	int size, x, y;
+
+	d = display_create(&argc, &argv, NULL);
+
+	smoke.x = 200;
+	smoke.y = 200;
+	smoke.width = 200;
+	smoke.height = 200;
+	smoke.display = d;
+	smoke.window = window_create(d, "smoke", smoke.x, smoke.y,
+				      smoke.width, smoke.height);
+
+	window_set_buffer_type(smoke.window, WINDOW_BUFFER_TYPE_SHM);
+	clock_gettime(CLOCK_MONOTONIC, &ts);
+	srandom(ts.tv_nsec);
+	smoke.offset = random();
+
+	smoke.current = 0;
+	size = smoke.height * smoke.width;
+	smoke.b[0].d = calloc(size, sizeof(float));
+	smoke.b[0].u = calloc(size, sizeof(float));
+	smoke.b[0].v = calloc(size, sizeof(float));
+	smoke.b[1].d = calloc(size, sizeof(float));
+	smoke.b[1].u = calloc(size, sizeof(float));
+	smoke.b[1].v = calloc(size, sizeof(float));
+
+	window_set_decoration(smoke.window, 0);
+	window_create_surface(smoke.window);
+	smoke.surface = window_get_surface(smoke.window);
+
+	window_flush(smoke.window);
+
+	window_set_motion_handler(smoke.window,
+				  smoke_motion_handler);
+
+	window_set_user_data(smoke.window, &smoke);
+	wl_display_frame_callback(display_get_display(d),
+				  frame_callback, &smoke);
+
+	display_run(d);
+
+	return 0;
+}