progs/xdemos/xfont.c

   1
   2 /*
   3  * Mesa 3-D graphics library
   4  *
   5  * Copyright (C) 1999  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /*
  27  * Example of using glXUseXFont().
  28  * 5 November 1999
  29  * Brian Paul
  30  */
  31
  32
  33 #include <GL/gl.h>
  34 #include <GL/glx.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39
  40 static const char *ProgramName = "xfont";
  41
  42 static const char *FontName = "fixed";
  43
  44 static GLuint FontBase = 0;
  45
  46
  47
  48 static void redraw( Display *dpy, Window w )
  49 {
  50    static const char *text = "This is glXUseXFont()";
  51
  52    glClear( GL_COLOR_BUFFER_BIT );
  53
  54    /* triangle */
  55    glColor3f( 0.2, 0.2, 1.0 );
  56    glBegin(GL_TRIANGLES);
  57    glVertex2f( 0, 0.8 );
  58    glVertex2f( -0.8, -0.7 );
  59    glVertex2f( 0.8, -0.7 );
  60    glEnd();
  61
  62    /* text */
  63    glColor3f( 1, 1, 1 );
  64    glRasterPos2f(-0.8, 0);
  65    glListBase(FontBase);
  66    glCallLists(strlen(text), GL_UNSIGNED_BYTE, (GLubyte *) text);
  67
  68    glXSwapBuffers( dpy, w );
  69 }
  70
  71
  72
  73 static void resize( unsigned int width, unsigned int height )
  74 {
  75    glViewport( 0, 0, width, height );
  76    glMatrixMode( GL_PROJECTION );
  77    glLoadIdentity();
  78    glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 );
  79 }
  80
  81
  82
  83 static void setup_font( Display *dpy )
  84 {
  85     XFontStruct *fontInfo;
  86     Font id;
  87     unsigned int first, last;
  88
  89     fontInfo = XLoadQueryFont(dpy, FontName);
  90     if (!fontInfo) {
  91         printf("Error: font %s not found\n", FontName);
  92         exit(0);
  93     }
  94
  95     id = fontInfo->fid;
  96     first = fontInfo->min_char_or_byte2;
  97     last = fontInfo->max_char_or_byte2;
  98
  99     FontBase = glGenLists((GLuint) last + 1);
 100     if (!FontBase) {
 101         printf("Error: unable to allocate display lists\n");
 102         exit(0);
 103     }
 104     glXUseXFont(id, first, last - first + 1, FontBase + first);
 105 }
 106
 107 static Window make_rgb_db_window( Display *dpy, int xpos, int ypos,
 108                                   unsigned int width, unsigned int height )
 109 {
 110    int attrib[] = { GLX_RGBA,
 111                     GLX_RED_SIZE, 1,
 112                     GLX_GREEN_SIZE, 1,
 113                     GLX_BLUE_SIZE, 1,
 114                     GLX_DOUBLEBUFFER,
 115                     None };
 116    int scrnum;
 117    XSetWindowAttributes attr;
 118    unsigned long mask;
 119    Window root;
 120    Window win;
 121    GLXContext ctx;
 122    XVisualInfo *visinfo;
 123
 124    scrnum = DefaultScreen( dpy );
 125    root = RootWindow( dpy, scrnum );
 126
 127    visinfo = glXChooseVisual( dpy, scrnum, attrib );
 128    if (!visinfo) {
 129       printf("Error: couldn't get an RGB, Double-buffered visual\n");
 130       exit(1);
 131    }
 132
 133    /* window attributes */
 134    attr.background_pixel = 0;
 135    attr.border_pixel = 0;
 136    attr.colormap = XCreateColormap( dpy, root, visinfo->visual, AllocNone);
 137    attr.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
 138    mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;
 139
 140    win = XCreateWindow( dpy, root, 0, 0, width, height,
 141                         0, visinfo->depth, InputOutput,
 142                         visinfo->visual, mask, &attr );
 143
 144    {
 145       XSizeHints sizehints;
 146       sizehints.x = xpos;
 147       sizehints.y = ypos;
 148       sizehints.width  = width;
 149       sizehints.height = height;
 150       sizehints.flags = USSize | USPosition;
 151       XSetNormalHints(dpy, win, &sizehints);
 152       XSetStandardProperties(dpy, win, ProgramName, ProgramName,
 153                               None, (char **)NULL, 0, &sizehints);
 154    }
 155
 156
 157    ctx = glXCreateContext( dpy, visinfo, NULL, True );
 158
 159    glXMakeCurrent( dpy, win, ctx );
 160
 161    return win;
 162 }
 163
 164
 165 static void event_loop( Display *dpy )
 166 {
 167    XEvent event;
 168
 169    while (1) {
 170       XNextEvent( dpy, &event );
 171
 172       switch (event.type) {
 173          case Expose:
 174             redraw( dpy, event.xany.window );
 175             break;
 176          case ConfigureNotify:
 177             resize( event.xconfigure.width, event.xconfigure.height );
 178             break;
 179          case KeyPress:
 180             exit(0);
 181          default:
 182             ;  /* no-op */
 183       }
 184    }
 185 }
 186
 187
 188
 189 int main( int argc, char *argv[] )
 190 {
 191    Display *dpy;
 192    Window win;
 193
 194    dpy = XOpenDisplay(NULL);
 195
 196    win = make_rgb_db_window( dpy, 0, 0, 300, 300 );
 197    setup_font( dpy );
 198
 199    glShadeModel( GL_FLAT );
 200    glClearColor( 0.5, 0.5, 1.0, 1.0 );
 201
 202    XMapWindow( dpy, win );
 203
 204    event_loop( dpy );
 205    return 0;
 206 }