Pileus Git - grits/blob - examples/tex/tex.c

   1 /*
   2  * Copyright (C) 2009-2010 Andy Spencer <andy753421@gmail.com>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <gtk/gtk.h>
  19 #include <gtk/gtkgl.h>
  20 #include <gdk/gdkkeysyms.h>
  21 #include <GL/gl.h>
  22 #include <GL/glu.h>
  23
  24 guint tex, texl, texr;
  25
  26 gboolean on_key_press(GtkWidget *widget, GdkEventKey *event, gpointer _)
  27 {
  28         if (event->keyval == GDK_q)
  29                 gtk_main_quit();
  30         return FALSE;
  31 }
  32
  33 gboolean on_expose(GtkWidget *drawing, GdkEventExpose *event, gpointer _)
  34 {
  35         glClearColor(0.5, 0.5, 1.0, 1.0);
  36         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  37
  38         glMatrixMode(GL_PROJECTION);
  39         glLoadIdentity();
  40         glOrtho(-1,1, -1,1, 10,-10);
  41         glMatrixMode(GL_MODELVIEW);
  42         glLoadIdentity();
  43         glTranslatef(0, 0, -5);
  44
  45         glEnable(GL_COLOR_MATERIAL);
  46         glDisable(GL_TEXTURE_2D);
  47         glColor3f(1.0, 1.0, 1.0);
  48         glBegin(GL_QUADS);
  49         glVertex3f(-0.25, -0.75, 0.0);
  50         glVertex3f(-0.25,  0.75, 0.0);
  51         glVertex3f( 0.25,  0.75, 0.0);
  52         glVertex3f( 0.25, -0.75, 0.0);
  53         glEnd();
  54
  55         /* Textures */
  56         glDisable(GL_COLOR_MATERIAL);
  57         glEnable(GL_TEXTURE_2D);
  58         glEnable(GL_BLEND);
  59
  60         gdouble y = 0.875;
  61
  62         /* Left */
  63         glBlendFunc(GL_ONE, GL_ZERO);
  64         glBindTexture(GL_TEXTURE_2D, texl);
  65         glBegin(GL_QUADS);
  66         glTexCoord2f(0.0, y); glVertex3f(-0.75,  0.0, 0.0);
  67         glTexCoord2f(0.0, 1.0); glVertex3f(-0.75,  0.5, 0.0);
  68         glTexCoord2f(2.0, 1.0); glVertex3f( 0.75,  0.5, 0.0);
  69         glTexCoord2f(2.0, y); glVertex3f( 0.75,  0.0, 0.0);
  70         glEnd();
  71
  72         /* Right */
  73         glBlendFunc(GL_ONE, GL_ONE);
  74         glBindTexture(GL_TEXTURE_2D, texr);
  75         glBegin(GL_QUADS);
  76         glTexCoord2f(-1.0, y); glVertex3f(-0.75, 0.0, 0.0);
  77         glTexCoord2f(-1.0, 1.0); glVertex3f(-0.75, 0.5, 0.0);
  78         glTexCoord2f( 1.0, 1.0); glVertex3f( 0.75, 0.5, 0.0);
  79         glTexCoord2f( 1.0, y); glVertex3f( 0.75, 0.0, 0.0);
  80         glEnd();
  81
  82         /* Bottom */
  83         glBlendFunc(GL_ONE, GL_ZERO);
  84         glBindTexture(GL_TEXTURE_2D, tex);
  85         glBegin(GL_QUADS);
  86         glTexCoord2f(0.0, 0.0); glVertex3f(-0.75, -0.5, 0.0);
  87         glTexCoord2f(0.0, 1.0-y); glVertex3f(-0.75, -0.0, 0.0);
  88         glTexCoord2f(1.0, 1.0-y); glVertex3f( 0.75, -0.0, 0.0);
  89         glTexCoord2f(1.0, 0.0); glVertex3f( 0.75, -0.5, 0.0);
  90         glEnd();
  91
  92
  93         /* Flush */
  94         GdkGLDrawable *gldrawable = gdk_gl_drawable_get_current();
  95         if (gdk_gl_drawable_is_double_buffered(gldrawable))
  96                 gdk_gl_drawable_swap_buffers(gldrawable);
  97         else
  98                 glFlush();
  99         return FALSE;
 100 }
 101 gboolean on_configure(GtkWidget *drawing, GdkEventConfigure *event, gpointer _)
 102 {
 103         glViewport(0, 0,
 104                 drawing->allocation.width,
 105                 drawing->allocation.height);
 106         return FALSE;
 107 }
 108
 109 guint load_tex(gchar *filename)
 110 {
 111         GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file(filename, NULL);
 112         guchar    *pixels = gdk_pixbuf_get_pixels(pixbuf);
 113         int        width  = gdk_pixbuf_get_width(pixbuf);
 114         int        height = gdk_pixbuf_get_height(pixbuf);
 115         int        alpha  = gdk_pixbuf_get_has_alpha(pixbuf);
 116         guint      tex;
 117         glGenTextures(1, &tex);
 118         glBindTexture(GL_TEXTURE_2D, tex);
 119         glTexImage2D(GL_TEXTURE_2D, 0, 4, width, height, 0,
 120                         (alpha ? GL_RGBA : GL_RGB), GL_UNSIGNED_BYTE, pixels);
 121         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 122         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 123
 124         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
 125         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
 126         g_object_unref(pixbuf);
 127         return tex;
 128 }
 129
 130 int main(int argc, char **argv)
 131 {
 132         gtk_init(&argc, &argv);
 133
 134         GtkWidget   *window   = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 135         GtkWidget   *drawing  = gtk_drawing_area_new();
 136         GdkGLConfig *glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(
 137                         GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
 138                         GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA));
 139         g_signal_connect(window,  "destroy",         G_CALLBACK(gtk_main_quit), NULL);
 140         g_signal_connect(window,  "key-press-event", G_CALLBACK(on_key_press),  NULL);
 141         g_signal_connect(drawing, "expose-event",    G_CALLBACK(on_expose),     NULL);
 142         g_signal_connect(drawing, "configure-event", G_CALLBACK(on_configure),  NULL);
 143         gtk_widget_set_gl_capability(drawing, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
 144         gtk_container_add(GTK_CONTAINER(window), drawing);
 145         gtk_widget_show_all(window);
 146
 147         /* OpenGL setup */
 148         GdkGLContext  *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(drawing));
 149         GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(drawing));
 150         gdk_gl_drawable_gl_begin(gldrawable, glcontext);
 151
 152         /* Load texture */
 153         texl = load_tex("texls.png");
 154         texr = load_tex("texrs.png");
 155         tex  = load_tex("tex.png");
 156
 157         gtk_main();
 158
 159         gdk_gl_drawable_gl_end(gldrawable);
 160 }