progs/xdemos/texture_from_pixmap.c

/*
 * Mesa 3-D graphics library
 * Version:  7.1
 * 
 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


/*
 * Test the GLX_EXT_texture_from_pixmap extension
 * Brian Paul
 * 19 May 2007
 */


#define GL_GLEXT_PROTOTYPES
#define GLX_GLXEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glx.h>
#include <X11/keysym.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>


static Display *
OpenDisplay(void)
{
   int screen;
   Display *dpy;
   const char *ext;

   dpy = XOpenDisplay(NULL);
   if (!dpy) {
      printf("Couldn't open default display!\n");
      exit(1);
   }

   screen = DefaultScreen(dpy);
   ext = glXQueryExtensionsString(dpy, screen);
   if (!strstr(ext, "GLX_EXT_texture_from_pixmap")) {
      printf("GLX_EXT_texture_from_pixmap not supported by GLX\n");
      exit(1);
   }

   return dpy;
}


static GLXFBConfig
ChoosePixmapFBConfig(Display *display)
{
   int screen = DefaultScreen(display);
   GLXFBConfig *fbconfigs;
   int i, nfbconfigs, value;
   float top, bottom;

   fbconfigs = glXGetFBConfigs(display, screen, &nfbconfigs);
   for (i = 0; i < nfbconfigs; i++) {

      glXGetFBConfigAttrib(display, fbconfigs[i], GLX_DRAWABLE_TYPE, &value);
      if (!(value & GLX_PIXMAP_BIT))
         continue;

      glXGetFBConfigAttrib(display, fbconfigs[i],
                           GLX_BIND_TO_TEXTURE_TARGETS_EXT, &value);
      if (!(value & GLX_TEXTURE_2D_BIT_EXT))
         continue;

      glXGetFBConfigAttrib(display, fbconfigs[i],
                           GLX_BIND_TO_TEXTURE_RGBA_EXT, &value);
      if (value == False) {
         glXGetFBConfigAttrib(display, fbconfigs[i],
                              GLX_BIND_TO_TEXTURE_RGB_EXT, &value);
         if (value == False)
            continue;
      }

      glXGetFBConfigAttrib(display, fbconfigs[i],
                           GLX_Y_INVERTED_EXT, &value);
      if (value == True) {
         top = 0.0f;
         bottom = 1.0f;
      }
      else {
         top = 1.0f;
         bottom = 0.0f;
      }

      break;
   }

   if (i == nfbconfigs) {
      printf("Unable to find FBconfig for texturing\n");
      exit(1);
   }

   return fbconfigs[i];
}


static GLXPixmap
CreatePixmap(Display *dpy, GLXFBConfig config, int w, int h, Pixmap *p)
{
   GLXPixmap gp;
   const int pixmapAttribs[] = {
      GLX_TEXTURE_TARGET_EXT, GLX_TEXTURE_2D_EXT,
      GLX_TEXTURE_FORMAT_EXT, GLX_TEXTURE_FORMAT_RGB_EXT,
      None
   };
   Window root = RootWindow(dpy, 0);

   *p = XCreatePixmap(dpy, root, w, h, 24);
   XSync(dpy, 0);
   gp = glXCreatePixmap(dpy, config, *p, pixmapAttribs);
   XSync(dpy, 0);

   return gp;
}


static void
DrawPixmapImage(Display *dpy, Pixmap pm, int w, int h)
{
   XGCValues gcvals;
   GC gc;

   gcvals.background = 0;
   gc = XCreateGC(dpy, pm, GCBackground, &gcvals);

   XSetForeground(dpy, gc, 0x0);
   XFillRectangle(dpy, pm, gc, 0, 0, w, h);

   XSetForeground(dpy, gc, 0xff0000);
   XFillRectangle(dpy, pm, gc, 0, 0, 50, 50);

   XSetForeground(dpy, gc, 0x00ff00);
   XFillRectangle(dpy, pm, gc, w - 50, 0, 50, 50);

   XSetForeground(dpy, gc, 0x0000ff);
   XFillRectangle(dpy, pm, gc, 0, h - 50, 50, 50);

   XSetForeground(dpy, gc, 0xffffff);
   XFillRectangle(dpy, pm, gc, h - 50, h - 50, 50, 50);

   XSetForeground(dpy, gc, 0xffff00);
   XSetLineAttributes(dpy, gc, 3, LineSolid, CapButt, JoinBevel);
   XDrawLine(dpy, pm, gc, 0, 0, w, h);
   XDrawLine(dpy, pm, gc, 0, h, w, 0);

   XFreeGC(dpy, gc);
}


static XVisualInfo *
ChooseWindowVisual(Display *dpy)
{
   int screen = DefaultScreen(dpy);
   XVisualInfo *visinfo;
   int attribs[] = {
      GLX_RGBA,
      GLX_RED_SIZE, 1,
      GLX_GREEN_SIZE, 1,
      GLX_BLUE_SIZE, 1,
      GLX_DOUBLEBUFFER,
      None
   };

   visinfo = glXChooseVisual(dpy, screen, attribs);
   if (!visinfo) {
      printf("Unable to find RGB, double-buffered visual\n");
      exit(1);
   }

   return visinfo;
}


static Window
CreateWindow(Display *dpy, XVisualInfo *visinfo,
             int width, int height, const char *name)
{
   int screen = DefaultScreen(dpy);
   Window win;
   XSetWindowAttributes attr;
   unsigned long mask;
   Window root;

   root = RootWindow(dpy, screen);

   /* window attributes */
   attr.background_pixel = 0;
   attr.border_pixel = 0;
   attr.colormap = XCreateColormap(dpy, root, visinfo->visual, AllocNone);
   attr.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
   mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;

   win = XCreateWindow(dpy, root, 0, 0, width, height,
		        0, visinfo->depth, InputOutput,
		        visinfo->visual, mask, &attr);
   if (win) {
      XSizeHints sizehints;
      sizehints.width  = width;
      sizehints.height = height;
      sizehints.flags = USSize;
      XSetNormalHints(dpy, win, &sizehints);
      XSetStandardProperties(dpy, win, name, name,
                              None, (char **)NULL, 0, &sizehints);

      XMapWindow(dpy, win);
   }
   return win;
}


static void
BindPixmapTexture(Display *dpy, GLXPixmap gp)
{
   GLuint texture;

   glGenTextures(1, &texture);
   glBindTexture(GL_TEXTURE_2D, texture);

   glXBindTexImageEXT(dpy, gp, GLX_FRONT_LEFT_EXT, NULL);

   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

   glEnable(GL_TEXTURE_2D);
   /*
     glXReleaseTexImageEXT (display, glxpixmap, GLX_FRONT_LEFT_EXT);
   */
}


static void
Resize(Window win, unsigned int width, unsigned int height)
{
   float sz = 1.5;
   glViewport(0, 0, width, height);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-sz, sz, -sz, sz, -1.0, 1.0);
   glMatrixMode(GL_MODELVIEW);
}


static void
Redraw(Display *dpy, Window win, float rot)
{
   glClearColor(0.25, 0.25, 0.25, 0.0);
   glClear(GL_COLOR_BUFFER_BIT);
   glPushMatrix();
   glRotatef(rot, 0, 0, 1);
   glRotatef(2.0 * rot, 1, 0, 0);

   glBegin(GL_QUADS);
   glTexCoord2d(0.0, 0.0);
   glVertex2f(-1, -1);
   glTexCoord2d(1.0, 0.0);
   glVertex2f( 1, -1);
   glTexCoord2d(1.0, 1.0);
   glVertex2d(1.0, 1.0);
   glTexCoord2d(0.0, 1.0);
   glVertex2f(-1.0, 1.0);
   glEnd();

   glPopMatrix();

   glXSwapBuffers(dpy, win);
}


static void
EventLoop(Display *dpy, Window win)
{
   GLfloat rot = 0.0;
   int anim = 0;
 
   while (1) {
      if (!anim || XPending(dpy) > 0) {
         XEvent event;
         XNextEvent(dpy, &event);

         switch (event.type) {
         case Expose:
            Redraw(dpy, win, rot);
            break;
         case ConfigureNotify:
            Resize(event.xany.window,
                   event.xconfigure.width,
                   event.xconfigure.height);
            break;
         case KeyPress:
            {
               char buf[100];
               KeySym keySym;
               XComposeStatus stat;
               XLookupString(&event.xkey, buf, sizeof(buf), &keySym, &stat);
               if (keySym == XK_Escape) {
                  return; /* exit */
               }
               else if (keySym == XK_r) {
                  rot += 1.0;
                  Redraw(dpy, win, rot);
               }
               else if (keySym == XK_a) {
                  anim = !anim;
               }
               else if (keySym == XK_R) {
                  rot -= 1.0;
                  Redraw(dpy, win, rot);
               }
            }
            break;
         default:
            ; /*no-op*/
         }
      }
      else {
         /* animate */
         rot += 1.0;
         Redraw(dpy, win, rot);
      }
   }
}



int
main(int argc, char *argv[])
{
   Display *dpy;
   GLXFBConfig pixmapConfig;
   XVisualInfo *windowVis;
   GLXPixmap gp;
   Window win;
   GLXContext ctx;
   Pixmap p;

   dpy = OpenDisplay();

   pixmapConfig = ChoosePixmapFBConfig(dpy);
   windowVis = ChooseWindowVisual(dpy);
   win = CreateWindow(dpy, windowVis, 500, 500, "Texture From Pixmap");

   gp = CreatePixmap(dpy, pixmapConfig, 512, 512, &p);
   DrawPixmapImage(dpy, p, 512, 512);

   ctx = glXCreateContext(dpy, windowVis, NULL, True);
   if (!ctx) {
      printf("Couldn't create GLX context\n");
      exit(1);
   }

   glXMakeCurrent(dpy, win, ctx);

   BindPixmapTexture(dpy, gp);

   EventLoop(dpy, win);

   return 0;
}