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, mask;
  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;
  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         /* Setup for textures */
  59         glEnable(GL_TEXTURE_2D);
  60         glEnable(GL_BLEND);
  61         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  62         glDisable(GL_COLOR_MATERIAL);
  63
  64         /* Setup mask */
  65         glActiveTexture(GL_TEXTURE1);
  66         glEnable(GL_TEXTURE_2D);
  67         glBindTexture(GL_TEXTURE_2D, mask);
  68         glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
  69
  70         glActiveTexture(GL_TEXTURE0);
  71         glEnable(GL_TEXTURE_2D);
  72         glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  73
  74         /* Left */
  75         glBindTexture(GL_TEXTURE_2D, texl);
  76         glBegin(GL_QUADS);
  77         glMultiTexCoord2f(GL_TEXTURE0,  0.0, y);     glMultiTexCoord2f(GL_TEXTURE1,  0.0, y);     glVertex3f(-0.75,  0.0, 0.0);
  78         glMultiTexCoord2f(GL_TEXTURE0,  0.0, 1.0);   glMultiTexCoord2f(GL_TEXTURE1,  0.0, 1.0);   glVertex3f(-0.75,  0.5, 0.0);
  79         glMultiTexCoord2f(GL_TEXTURE0,  2.0, 1.0);   glMultiTexCoord2f(GL_TEXTURE1,  2.0, 1.0);   glVertex3f( 0.75,  0.5, 0.0);
  80         glMultiTexCoord2f(GL_TEXTURE0,  2.0, y);     glMultiTexCoord2f(GL_TEXTURE1,  2.0, y);     glVertex3f( 0.75,  0.0, 0.0);
  81         glEnd();
  82
  83         /* Right */
  84         glBindTexture(GL_TEXTURE_2D, texr);
  85         glBegin(GL_QUADS);
  86         glMultiTexCoord2f(GL_TEXTURE0, -1.0, y);     glMultiTexCoord2f(GL_TEXTURE1, -1.0, y);     glVertex3f(-0.75, 0.0, 0.0);
  87         glMultiTexCoord2f(GL_TEXTURE0, -1.0, 1.0);   glMultiTexCoord2f(GL_TEXTURE1, -1.0, 1.0);   glVertex3f(-0.75, 0.5, 0.0);
  88         glMultiTexCoord2f(GL_TEXTURE0,  1.0, 1.0);   glMultiTexCoord2f(GL_TEXTURE1,  1.0, 1.0);   glVertex3f( 0.75, 0.5, 0.0);
  89         glMultiTexCoord2f(GL_TEXTURE0,  1.0, y);     glMultiTexCoord2f(GL_TEXTURE1,  1.0, y);     glVertex3f( 0.75, 0.0, 0.0);
  90         glEnd();
  91
  92         glActiveTexture(GL_TEXTURE1);
  93         glDisable(GL_TEXTURE_2D);
  94         glActiveTexture(GL_TEXTURE0);
  95
  96         /* Bottom */
  97         glBindTexture(GL_TEXTURE_2D, tex);
  98         glBegin(GL_QUADS);
  99         glTexCoord2f( 0.0, 0.0);   glVertex3f(-0.75, -0.5, 0.0);
 100         glTexCoord2f( 0.0, 1.0-y); glVertex3f(-0.75, -0.0, 0.0);
 101         glTexCoord2f( 1.0, 1.0-y); glVertex3f( 0.75, -0.0, 0.0);
 102         glTexCoord2f( 1.0, 0.0);   glVertex3f( 0.75, -0.5, 0.0);
 103         glEnd();
 104
 105         /* Flush */
 106         GdkGLDrawable *gldrawable = gdk_gl_drawable_get_current();
 107         if (gdk_gl_drawable_is_double_buffered(gldrawable))
 108                 gdk_gl_drawable_swap_buffers(gldrawable);
 109         else
 110                 glFlush();
 111         return FALSE;
 112 }
 113 gboolean on_configure(GtkWidget *drawing, GdkEventConfigure *event, gpointer _)
 114 {
 115         glViewport(0, 0,
 116                 drawing->allocation.width,
 117                 drawing->allocation.height);
 118         return FALSE;
 119 }
 120
 121 guint load_mask(void)
 122 {
 123         guint  tex  = 0;
 124         guint8 byte = 0xff;
 125
 126         glGenTextures(1, &tex);
 127         glBindTexture(GL_TEXTURE_2D, tex);
 128
 129         glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, 1, 1, 0,
 130                         GL_ALPHA, GL_UNSIGNED_BYTE, &byte);
 131
 132         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 133         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 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
 138         return tex;
 139 }
 140
 141 guint load_tex(gchar *filename)
 142 {
 143         GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file(filename, NULL);
 144         guchar    *pixels = gdk_pixbuf_get_pixels(pixbuf);
 145         int        width  = gdk_pixbuf_get_width(pixbuf);
 146         int        height = gdk_pixbuf_get_height(pixbuf);
 147         int        alpha  = gdk_pixbuf_get_has_alpha(pixbuf);
 148         guint      tex;
 149
 150         glGenTextures(1, &tex);
 151         glBindTexture(GL_TEXTURE_2D, tex);
 152         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0,
 153                         (alpha ? GL_RGBA : GL_RGB), GL_UNSIGNED_BYTE, pixels);
 154
 155         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 156         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 157
 158         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
 159         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 160
 161         g_object_unref(pixbuf);
 162         return tex;
 163 }
 164
 165 int main(int argc, char **argv)
 166 {
 167         gtk_init(&argc, &argv);
 168
 169         GtkWidget   *window   = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 170         GtkWidget   *drawing  = gtk_drawing_area_new();
 171         GdkGLConfig *glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(
 172                         GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
 173                         GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA));
 174         g_signal_connect(window,  "destroy",         G_CALLBACK(gtk_main_quit), NULL);
 175         g_signal_connect(window,  "key-press-event", G_CALLBACK(on_key_press),  NULL);
 176         g_signal_connect(drawing, "expose-event",    G_CALLBACK(on_expose),     NULL);
 177         g_signal_connect(drawing, "configure-event", G_CALLBACK(on_configure),  NULL);
 178         gtk_widget_set_gl_capability(drawing, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
 179         gtk_container_add(GTK_CONTAINER(window), drawing);
 180         gtk_widget_show_all(window);
 181
 182         /* OpenGL setup */
 183         GdkGLContext  *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(drawing));
 184         GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(drawing));
 185         gdk_gl_drawable_gl_begin(gldrawable, glcontext);
 186
 187         /* Load texture */
 188         mask = load_mask();
 189         texl = load_tex("texls.png");
 190         texr = load_tex("texrs.png");
 191         tex  = load_tex("tex.png");
 192
 193         gtk_main();
 194
 195         gdk_gl_drawable_gl_end(gldrawable);
 196 }