weston/clients/nested-client.c
Kristian Høgsberg 1cc5ac34b5 clients: Nested compositor example
A wayland compositor doesn't provide a mechanism for buffer sharing between
clients.  Under X, one client can render to a Pixmap and another can use it
as a source in a subsequent drawing operations.  Wayland doesn't have a
mechanims to share Pixmaps or textures between clients like that, but it's
possible for one client to act as a nested compositor to another client.

This less work than it sounds, since the nested compositor won't have to
provide input devices or even any kind of shell extension.  The nested
compositor and its client can be very tightly coupled and have very specific
expectations of what the other process should provide.

In this example, nested.c is a toytoolkit application that uses cairo-gl
for rendering and forks and execs nested-client.c.  As it execs the client,
it passes it one end of a socketpair that will be the clients connection
to the nested compositor.  The nested compositor doesn't even create a
listening socket.

The client is a minimal GLES2 application, which just renders a spinning
triangle in its frame callback.
2013-06-04 02:47:12 -04:00

362 lines
8.6 KiB
C

/*
* Copyright © 2013 Intel Corporation
*
* 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wayland-egl.h>
#include <wayland-cursor.h>
#include <GLES2/gl2.h>
#include <EGL/egl.h>
struct window;
struct seat;
struct nested_client {
struct wl_display *display;
struct wl_registry *registry;
struct wl_compositor *compositor;
EGLDisplay egl_display;
EGLContext egl_context;
EGLConfig egl_config;
EGLSurface egl_surface;
struct program *color_program;
GLuint vert, frag, program;
GLuint rotation;
GLuint pos;
GLuint col;
struct wl_surface *surface;
struct wl_egl_window *native;
int width, height;
};
#define POS 0
#define COL 1
static GLuint
create_shader(const char *source, GLenum shader_type)
{
GLuint shader;
GLint status;
shader = glCreateShader(shader_type);
if (shader == 0)
return 0;
glShaderSource(shader, 1, (const char **) &source, NULL);
glCompileShader(shader);
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (!status) {
char log[1000];
GLsizei len;
glGetShaderInfoLog(shader, 1000, &len, log);
fprintf(stderr, "Error: compiling %s: %*s\n",
shader_type == GL_VERTEX_SHADER ? "vertex" : "fragment",
len, log);
return 0;
}
return shader;
}
static void
create_program(struct nested_client *client,
const char *vert, const char *frag)
{
GLint status;
client->vert = create_shader(vert, GL_VERTEX_SHADER);
client->frag = create_shader(frag, GL_FRAGMENT_SHADER);
client->program = glCreateProgram();
glAttachShader(client->program, client->frag);
glAttachShader(client->program, client->vert);
glBindAttribLocation(client->program, POS, "pos");
glBindAttribLocation(client->program, COL, "color");
glLinkProgram(client->program);
glGetProgramiv(client->program, GL_LINK_STATUS, &status);
if (!status) {
char log[1000];
GLsizei len;
glGetProgramInfoLog(client->program, 1000, &len, log);
fprintf(stderr, "Error: linking:\n%*s\n", len, log);
exit(1);
}
client->rotation =
glGetUniformLocation(client->program, "rotation");
}
static const char vertex_shader_text[] =
"uniform mat4 rotation;\n"
"attribute vec4 pos;\n"
"attribute vec4 color;\n"
"varying vec4 v_color;\n"
"void main() {\n"
" gl_Position = rotation * pos;\n"
" v_color = color;\n"
"}\n";
static const char color_fragment_shader_text[] =
"precision mediump float;\n"
"varying vec4 v_color;\n"
"void main() {\n"
" gl_FragColor = v_color;\n"
"}\n";
static void
render_triangle(struct nested_client *client, uint32_t time)
{
static const GLfloat verts[3][2] = {
{ -0.5, -0.5 },
{ 0.5, -0.5 },
{ 0, 0.5 }
};
static const GLfloat colors[3][3] = {
{ 1, 0, 0 },
{ 0, 1, 0 },
{ 0, 0, 1 }
};
GLfloat angle;
GLfloat rotation[4][4] = {
{ 1, 0, 0, 0 },
{ 0, 1, 0, 0 },
{ 0, 0, 1, 0 },
{ 0, 0, 0, 1 }
};
static const int32_t speed_div = 5;
static uint32_t start_time = 0;
if (client->program == 0)
create_program(client, vertex_shader_text,
color_fragment_shader_text);
if (start_time == 0)
start_time = time;
angle = ((time - start_time) / speed_div) % 360 * M_PI / 180.0;
rotation[0][0] = cos(angle);
rotation[0][2] = sin(angle);
rotation[2][0] = -sin(angle);
rotation[2][2] = cos(angle);
glClearColor(0.4, 0.4, 0.4, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(client->program);
glViewport(0, 0, client->width, client->height);
glUniformMatrix4fv(client->rotation, 1, GL_FALSE,
(GLfloat *) rotation);
glVertexAttribPointer(POS, 2, GL_FLOAT, GL_FALSE, 0, verts);
glVertexAttribPointer(COL, 3, GL_FLOAT, GL_FALSE, 0, colors);
glEnableVertexAttribArray(POS);
glEnableVertexAttribArray(COL);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableVertexAttribArray(POS);
glDisableVertexAttribArray(COL);
glFlush();
}
static void
frame_callback(void *data, struct wl_callback *callback, uint32_t time);
static const struct wl_callback_listener frame_listener = {
frame_callback
};
static void
frame_callback(void *data, struct wl_callback *callback, uint32_t time)
{
struct nested_client *client = data;
if (callback)
wl_callback_destroy(callback);
callback = wl_surface_frame(client->surface);
wl_callback_add_listener(callback, &frame_listener, client);
render_triangle(client, time);
eglSwapBuffers(client->egl_display, client->egl_surface);
}
static void
registry_handle_global(void *data, struct wl_registry *registry,
uint32_t name, const char *interface, uint32_t version)
{
struct nested_client *client = data;
if (strcmp(interface, "wl_compositor") == 0) {
client->compositor =
wl_registry_bind(registry, name,
&wl_compositor_interface, 1);
}
}
static void
registry_handle_global_remove(void *data, struct wl_registry *registry,
uint32_t name)
{
}
static const struct wl_registry_listener registry_listener = {
registry_handle_global,
registry_handle_global_remove
};
static struct nested_client *
nested_client_create(void)
{
static const EGLint context_attribs[] = {
EGL_CONTEXT_CLIENT_VERSION, 2,
EGL_NONE
};
static const EGLint config_attribs[] = {
EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
EGL_RED_SIZE, 1,
EGL_GREEN_SIZE, 1,
EGL_BLUE_SIZE, 1,
EGL_ALPHA_SIZE, 1,
EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
EGL_NONE
};
EGLint major, minor, n;
EGLBoolean ret;
struct nested_client *client;
client = malloc(sizeof *client);
if (client == NULL)
return NULL;
client->width = 250;
client->height = 250;
client->display = wl_display_connect(NULL);
client->registry = wl_display_get_registry(client->display);
wl_registry_add_listener(client->registry,
&registry_listener, client);
/* get globals */
wl_display_roundtrip(client->display);
client->egl_display = eglGetDisplay(client->display);
if (client->egl_display == NULL)
return NULL;
ret = eglInitialize(client->egl_display, &major, &minor);
if (!ret)
return NULL;
ret = eglBindAPI(EGL_OPENGL_ES_API);
if (!ret)
return NULL;
ret = eglChooseConfig(client->egl_display, config_attribs,
&client->egl_config, 1, &n);
if (!ret || n != 1)
return NULL;
client->egl_context = eglCreateContext(client->egl_display,
client->egl_config,
EGL_NO_CONTEXT,
context_attribs);
if (!client->egl_context)
return NULL;
client->surface = wl_compositor_create_surface(client->compositor);
client->native = wl_egl_window_create(client->surface,
client->width, client->height);
client->egl_surface =
eglCreateWindowSurface(client->egl_display,
client->egl_config,
client->native, NULL);
eglMakeCurrent(client->egl_display, client->egl_surface,
client->egl_surface, client->egl_context);
wl_egl_window_resize(client->native,
client->width, client->height, 0, 0);
frame_callback(client, NULL, 0);
return client;
}
static void
nested_client_destroy(struct nested_client *client)
{
eglMakeCurrent(client->egl_display,
EGL_NO_SURFACE, EGL_NO_SURFACE,
EGL_NO_CONTEXT);
wl_egl_window_destroy(client->native);
wl_surface_destroy(client->surface);
if (client->compositor)
wl_compositor_destroy(client->compositor);
wl_registry_destroy(client->registry);
wl_display_flush(client->display);
wl_display_disconnect(client->display);
}
int
main(int argc, char **argv)
{
struct nested_client *client;
int ret = 0;
if (getenv("WAYLAND_SOCKET") == NULL) {
fprintf(stderr,
"must be run by nested, don't run standalone\n");
return -1;
}
client = nested_client_create();
while (ret != -1)
ret = wl_display_dispatch(client->display);
nested_client_destroy(client);
return 0;
}