+/* Copyright © 2013, Intel Corporation
+ *
+ * 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 THE
+ * AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
+
+/* Perform some simple drawing via OpenGL as follows:
+ *
+ * 1. Using GLX to construct an OpenGL context
+ * 2. By directly linking with libGL.so
+ * 3. By directly calling OpenGL functions
+ */
+
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glx.h>
+
+#include "util.h"
+
+static void
+set_2d_projection (int width, int height)
+{
+ glMatrixMode (GL_PROJECTION);
+ glLoadIdentity ();
+ glOrtho (0, width, height, 0, 0, 1);
+ glMatrixMode (GL_MODELVIEW);
+}
+
+static void
+paint_rgb_using_clear (double r, double g, double b)
+{
+ glClearColor(r, g, b, 1.0);
+ glClear(GL_COLOR_BUFFER_BIT);
+}
+
+static void
+draw (Display *dpy, Window window, int width, int height)
+{
+ int i;
+ int visual_attr[] = {
+ GLX_RGBA,
+ GLX_RED_SIZE, 8,
+ GLX_GREEN_SIZE, 8,
+ GLX_BLUE_SIZE, 8,
+ GLX_ALPHA_SIZE, 8,
+ GLX_DOUBLEBUFFER,
+ GLX_DEPTH_SIZE, 24,
+ GLX_STENCIL_SIZE, 8,
+ GLX_X_VISUAL_TYPE, GLX_DIRECT_COLOR,
+ None
+ };
+
+ /* Window and context setup. */
+ XVisualInfo *visual_info = glXChooseVisual(dpy, 0, visual_attr);
+ GLXContext ctx = glXCreateContext(dpy, visual_info, NULL, True);
+ glXMakeCurrent(dpy, window, ctx);
+
+ glViewport(0, 0, width, height);
+
+ set_2d_projection (width, height);
+
+/* Simply count through some colors, frame by frame. */
+#define RGB(frame) (((frame+1)/4) % 2), (((frame+1)/2) % 2), ((frame+1) % 2)
+
+ int frame = 0;
+ for (i = 0; i < 2; i++) {
+ /* Frame: Draw a solid (magenta) frame */
+ paint_rgb_using_clear (RGB(frame));
+ glXSwapBuffers (dpy, window);
+ frame++;
+
+ /* Frame: Draw a solid (yellow) frame */
+ paint_rgb_using_clear (RGB(frame));
+ glXSwapBuffers (dpy, window);
+ frame++;
+
+ /* Frame: Draw a solid (cyan) frame */
+ paint_rgb_using_clear (RGB(frame));
+ glXSwapBuffers (dpy, window);
+ frame++;
+ }
+
+ /* Cleanup */
+ glXDestroyContext (dpy, ctx);
+}
+
+static void
+handle_events(Display *dpy, Window window)
+{
+ XEvent xev;
+ int width = 0;
+ int height = 0;
+
+ XNextEvent (dpy, &xev);
+
+ while (1) {
+ XNextEvent (dpy, &xev);
+ switch (xev.type) {
+ case ConfigureNotify:
+ width = xev.xconfigure.width;
+ height = xev.xconfigure.height;
+ break;
+ case Expose:
+ if (xev.xexpose.count == 0) {
+ draw (dpy, window, width, height);
+ return;
+ }
+ break;
+ }
+ }
+}
+
+int
+main (void)
+{
+ Display *dpy;
+ Window window;
+
+ util_init_display_window (&dpy, &window);
+
+ handle_events (dpy, window);
+
+ util_fini_display_window (dpy, window);
+
+ return 0;
+}