我试图用 Xlib、XF86VidMode 和 OpenGL 编写一些简单的图形。我有两个问题:
- Xlib 似乎没有 WM_TIMER 的等价物,所以我编写了一个 SIGALRM 处理程序,它发送消息以解除对消息循环的阻塞,但由于这种用法完全是线程不安全的,所以程序会在一段时间后挂起。因此我尝试在 xcb 中重新编码。
- XF86VidMode 使用起来很尴尬,我不喜欢结果,所以我改用 RandR。
完成上述操作后,事实证明 xcb 有相同的挂起,所以我无法编写阻塞消息循环。相反,我每隔一段时间就轮询一次,程序没有挂起,但是有一些令人讨厌的跳帧。
虽然我可以用 RandR 切换视频模式,但我想使用 xcb 版本,但它不起作用。我为 xcb 抄袭了@datenwolf 的一个示例,但不知何故 xcb_randr_get_screen_info_reply 不起作用。它应该返回一个指向结构的指针,该结构后跟一个屏幕尺寸数组(以毫米为单位的尺寸是错误的),然后是刷新率数据。刷新率数据是垃圾,大部分为零。我究竟做错了什么?
/*
gcc rrxcb.c -lxcb-randr -lxcb -lX11 -lX11-xcb -lGL -orrxcb
*/
#include <xcb/randr.h>
#include <stdio.h>
#include <X11/Xlib.h>
#include <X11/Xlib-xcb.h>
#include <xcb/xcb.h>
#include <GL/glx.h>
#include <unistd.h>
void screen_from_Xlib_Display(
Display * const display,
xcb_connection_t *connection,
int * const out_screen_num,
xcb_screen_t ** const out_screen)
{
xcb_screen_iterator_t screen_iter = xcb_setup_roots_iterator(xcb_get_setup(connection));
int screen_num = DefaultScreen(display);
while( screen_iter.rem && screen_num > 0 ) {
xcb_screen_next(&screen_iter);
--screen_num;
}
*out_screen_num = screen_num;
*out_screen = screen_iter.data;
}
int main()
{
Display *display;
xcb_connection_t *connection;
xcb_window_t win;
const int GLX_TRUE = True;
int attrib_list[] = {GLX_X_RENDERABLE,GLX_TRUE,
GLX_DRAWABLE_TYPE,GLX_WINDOW_BIT,
GLX_RENDER_TYPE,GLX_RGBA_BIT,
GLX_CONFIG_CAVEAT,GLX_NONE,
GLX_DOUBLEBUFFER,GLX_TRUE,
GLX_BUFFER_SIZE,32,
GLX_DEPTH_SIZE,24,
GLX_STENCIL_SIZE,8,
0};
GLXFBConfig *FBConfigs;
int nelements;
GLXFBConfig fb_config;
XVisualInfo *visual;
int visualID;
GLXContext context;
xcb_colormap_t colormap;
xcb_void_cookie_t create_color;
xcb_void_cookie_t create_win;
const uint32_t eventmask = XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS;
const uint32_t valuemask = XCB_CW_EVENT_MASK | XCB_CW_COLORMAP;
uint32_t valuelist[] = {eventmask,colormap};
xcb_randr_get_screen_info_cookie_t screen_info;
xcb_randr_get_screen_info_reply_t *reply;
int screen_num;
xcb_screen_t *screen;
xcb_generic_error_t *error;
xcb_randr_screen_size_t *sizes;
int sizes_length;
xcb_randr_refresh_rates_iterator_t rates_iter;
uint16_t *rates;
int rates_length;
int i;
/* Open Xlib Display */
display = XOpenDisplay(NULL);
printf("display = %p\n",display);
connection = XGetXCBConnection(display);
printf("connection = %p\n",connection);
XSetEventQueueOwner(display,XCBOwnsEventQueue);
win = xcb_generate_id(connection);
printf("win = %d\n",win);
screen_from_Xlib_Display(display,connection,&screen_num,&screen);
printf("screen_num = %d\n",screen_num);
printf("screen->root = %d\n",screen->root);
FBConfigs = glXChooseFBConfig(display,screen_num,attrib_list,
&nelements);
printf("FBConfig = %p\n",FBConfigs);
printf("nelements = %d\n",nelements);
fb_config = FBConfigs[0];
visual = glXGetVisualFromFBConfig(display,fb_config);
printf("visual = %p\n",visual);
visualID = visual->visualid;
printf("visualID = %d\n",visualID);
context = glXCreateNewContext(display,fb_config,GLX_RGBA_TYPE,
0,True);
printf("context = %p\n",context);
colormap = xcb_generate_id(connection);
printf("colormap = %d\n",colormap);
create_color = xcb_create_colormap_checked(connection,
XCB_COLORMAP_ALLOC_NONE,colormap,screen->root,visualID);
printf("create_color.sequence = %d\n",create_color.sequence);
error = xcb_request_check(connection,create_color);
printf("error = %p\n",error);
create_win = xcb_create_window_checked(connection,
XCB_COPY_FROM_PARENT,win, screen->root,0,0,640,480,2,
XCB_WINDOW_CLASS_INPUT_OUTPUT,visualID,valuemask,valuelist);
printf("create_win.sequence = %d\n",create_win.sequence);
error = xcb_request_check(connection,create_win);
printf("error = %p\n",error);
screen_info = xcb_randr_get_screen_info_unchecked(connection, screen->root);
printf("screen_info.sequence = %d\n",screen_info.sequence);
reply = xcb_randr_get_screen_info_reply(connection,screen_info,
NULL);
printf("reply = %p\n",reply);
printf("reply->response_type = %d\n",reply->response_type);
printf("reply->rotations = %d\n",reply->rotations);
printf("reply->sequence = %d\n",reply->sequence);
printf("reply->length = %d\n",reply->length);
printf("reply->nSizes = %d\n",reply->nSizes);
printf("reply->sizeID = %d\n",reply->sizeID);
printf("reply->rotation = %d\n",reply->rotation);
printf("reply->rate = %d\n",reply->rate);
printf("reply->nInfo = %d\n",reply->nInfo);
printf("reply+1 = %p\n",reply+1);
sizes = xcb_randr_get_screen_info_sizes(reply);
printf("sizes = %p\n",sizes);
sizes_length = xcb_randr_get_screen_info_sizes_length(reply);
printf("sizes_length = %d\n",sizes_length);
rates_iter = xcb_randr_get_screen_info_rates_iterator(reply);
printf("rates_iter.data = %p\n",rates_iter.data);
printf("rates_iter.rem = %d\n",rates_iter.rem);
printf("rates_iter.index = %d\n",rates_iter.index);
for( ; rates_iter.rem; xcb_randr_refresh_rates_next(&rates_iter))
{
rates = xcb_randr_refresh_rates_rates(rates_iter.data);
printf("rates = %p\n",rates);
rates_length =
xcb_randr_refresh_rates_rates_length(rates_iter.data);
printf("rates_length = %d\n",rates_length);
printf("rates[0] = %d\n",rates[0]);
/*
for(i = 0; i < rates_length; i++)
{
printf("%d%c",rates[i],(i==rates_length-1)?'\n':' ');
}
*/
}
for(i = 0; i < sizes_length; i++)
{
printf("%d %d %d %d %d\n",i,sizes[i].width,sizes[i].height,sizes[i].mwidth,sizes[i].mheight);
}
return 0;
}
所以我的输出是
display = 0x563687942010
connection = 0x563687943410
win = 54525954
screen_num = 0
screen->root = 241
FBConfig = 0x563687951b20
nelements = 8
visual = 0x563687951d30
visualID = 33
context = 0x563687951680
colormap = 54525956
create_color.sequence = 26
error = (nil)
create_win.sequence = 28
error = (nil)
screen_info.sequence = 31
reply = 0x563687abde30
reply->response_type = 1
reply->rotations = 63
reply->sequence = 31
reply->length = 36
reply->nSizes = 18
reply->sizeID = 1
reply->rotation = 1
reply->rate = 30
reply->nInfo = 53
reply+1 = 0x563687abde50
sizes = 0x563687abde50
sizes_length = 18
rates_iter.data = 0x563687abdee0
rates_iter.rem = 35
rates_iter.index = 176
rates = 0x563687abdee2
rates_length = 0
rates[0] = 0
rates = 0x563687abdee4
rates_length = 0
rates[0] = 0
rates = 0x563687abdee6
rates_length = 0
...
rates = 0x563687add7a8
rates_length = 0
rates[0] = 0
0 4096 2160 1872 1053
1 3840 2160 1872 1053
2 1920 1080 1872 1053
3 1680 1050 1872 1053
4 1600 900 1872 1053
5 1280 1024 1872 1053
6 1440 900 1872 1053
7 1366 768 1872 1053
8 1280 800 1872 1053
9 1152 864 1872 1053
10 1280 720 1872 1053
11 1024 768 1872 1053
12 832 624 1872 1053
13 800 600 1872 1053
14 720 576 1872 1053
15 720 480 1872 1053
16 640 480 1872 1053
17 720 400 1872 1053
谁能发现我做错了什么?