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         gdouble y = 0.875;
  36
  37         /* Setup view */
  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         glClearColor(0.5, 0.5, 1.0, 1.0);
  45         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  46
  47         /* Draw white background rectangle */
  48         glEnable(GL_COLOR_MATERIAL);
  49         glDisable(GL_TEXTURE_2D);
  50         glColor3f(1.0, 1.0, 1.0);
  51         glBegin(GL_QUADS);
  52         glVertex3f(-0.25, -0.75, 0.0);
  53         glVertex3f(-0.25,  0.75, 0.0);
  54         glVertex3f( 0.25,  0.75, 0.0);
  55         glVertex3f( 0.25, -0.75, 0.0);
  56         glEnd();
  57
  58         /* Clear background for GL_ONE */
  59         glEnable(GL_COLOR_MATERIAL);
  60         glDisable(GL_TEXTURE_2D);
  61         glColor4f(0.0, 0.0, 0.0, 0.0);
  62         glBegin(GL_QUADS);
  63         glVertex3f(-0.75,  0.0, 0.0);
  64         glVertex3f(-0.75,  0.5, 0.0);
  65         glVertex3f( 0.75,  0.5, 0.0);
  66         glVertex3f( 0.75,  0.0, 0.0);
  67         glEnd();
  68
  69         /* Setup for textures */
  70         glEnable(GL_TEXTURE_2D);
  71         glEnable(GL_BLEND);
  72         glColor4f(1.0, 1.0, 1.0, 1.0);
  73         glDisable(GL_COLOR_MATERIAL);
  74         glBlendFunc(GL_ONE, GL_ONE);
  75
  76         /* Left */
  77         glBindTexture(GL_TEXTURE_2D, texl);
  78         glBegin(GL_QUADS);
  79         glTexCoord2f( 0.0, y);     glVertex3f(-0.75,  0.0, 0.0);
  80         glTexCoord2f( 0.0, 1.0);   glVertex3f(-0.75,  0.5, 0.0);
  81         glTexCoord2f( 2.0, 1.0);   glVertex3f( 0.75,  0.5, 0.0);
  82         glTexCoord2f( 2.0, y);     glVertex3f( 0.75,  0.0, 0.0);
  83         glEnd();
  84
  85         /* Right */
  86         glBindTexture(GL_TEXTURE_2D, texr);
  87         glBegin(GL_QUADS);
  88         glTexCoord2f(-1.0, y);     glVertex3f(-0.75, 0.0, 0.0);
  89         glTexCoord2f(-1.0, 1.0);   glVertex3f(-0.75, 0.5, 0.0);
  90         glTexCoord2f( 1.0, 1.0);   glVertex3f( 0.75, 0.5, 0.0);
  91         glTexCoord2f( 1.0, y);     glVertex3f( 0.75, 0.0, 0.0);
  92         glEnd();
  93
  94         /* Bottom */
  95         glBlendFunc(GL_ONE, GL_ZERO);
  96         glBindTexture(GL_TEXTURE_2D, tex);
  97         glBegin(GL_QUADS);
  98         glTexCoord2f( 0.0, 0.0);   glVertex3f(-0.75, -0.5, 0.0);
  99         glTexCoord2f( 0.0, 1.0-y); glVertex3f(-0.75, -0.0, 0.0);
 100         glTexCoord2f( 1.0, 1.0-y); glVertex3f( 0.75, -0.0, 0.0);
 101         glTexCoord2f( 1.0, 0.0);   glVertex3f( 0.75, -0.5, 0.0);
 102         glEnd();
 103
 104         /* Flush */
 105         GdkGLDrawable *gldrawable = gdk_gl_drawable_get_current();
 106         if (gdk_gl_drawable_is_double_buffered(gldrawable))
 107                 gdk_gl_drawable_swap_buffers(gldrawable);
 108         else
 109                 glFlush();
 110         return FALSE;
 111 }
 112 gboolean on_configure(GtkWidget *drawing, GdkEventConfigure *event, gpointer _)
 113 {
 114         glViewport(0, 0,
 115                 drawing->allocation.width,
 116                 drawing->allocation.height);
 117         return FALSE;
 118 }
 119
 120 guint load_tex(gchar *filename)
 121 {
 122         GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file(filename, NULL);
 123         guchar    *pixels = gdk_pixbuf_get_pixels(pixbuf);
 124         int        width  = gdk_pixbuf_get_width(pixbuf);
 125         int        height = gdk_pixbuf_get_height(pixbuf);
 126         int        alpha  = gdk_pixbuf_get_has_alpha(pixbuf);
 127         guint      tex;
 128         glGenTextures(1, &tex);
 129         glBindTexture(GL_TEXTURE_2D, tex);
 130         glTexImage2D(GL_TEXTURE_2D, 0, 4, width, height, 0,
 131                         (alpha ? GL_RGBA : GL_RGB), GL_UNSIGNED_BYTE, pixels);
 132         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 133         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 134
 135         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
 136         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
 137         g_object_unref(pixbuf);
 138         return tex;
 139 }
 140
 141 int main(int argc, char **argv)
 142 {
 143         gtk_init(&argc, &argv);
 144
 145         GtkWidget   *window   = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 146         GtkWidget   *drawing  = gtk_drawing_area_new();
 147         GdkGLConfig *glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(
 148                         GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
 149                         GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA));
 150         g_signal_connect(window,  "destroy",         G_CALLBACK(gtk_main_quit), NULL);
 151         g_signal_connect(window,  "key-press-event", G_CALLBACK(on_key_press),  NULL);
 152         g_signal_connect(drawing, "expose-event",    G_CALLBACK(on_expose),     NULL);
 153         g_signal_connect(drawing, "configure-event", G_CALLBACK(on_configure),  NULL);
 154         gtk_widget_set_gl_capability(drawing, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
 155         gtk_container_add(GTK_CONTAINER(window), drawing);
 156         gtk_widget_show_all(window);
 157
 158         /* OpenGL setup */
 159         GdkGLContext  *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(drawing));
 160         GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(drawing));
 161         gdk_gl_drawable_gl_begin(gldrawable, glcontext);
 162
 163         /* Load texture */
 164         texl = load_tex("texls.png");
 165         texr = load_tex("texrs.png");
 166         tex  = load_tex("tex.png");
 167
 168         gtk_main();
 169
 170         gdk_gl_drawable_gl_end(gldrawable);
 171 }