Pileus Git - grits/blob - examples/tess/convex.c

   1 /*
   2  * Copyright (C) 2011 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 <math.h>
  19 #include <gtk/gtk.h>
  20 #include <gtk/gtkgl.h>
  21 #include <gdk/gdkkeysyms.h>
  22 #include <GL/gl.h>
  23 #include <GL/glu.h>
  24
  25 guint tex, texl, texr;
  26
  27 gboolean on_key_press(GtkWidget *widget, GdkEventKey *event, gpointer _)
  28 {
  29         if (event->keyval == GDK_KEY_q)
  30                 gtk_main_quit();
  31         return FALSE;
  32 }
  33
  34 gboolean on_expose(GtkWidget *drawing, GdkEventExpose *event, gpointer _)
  35 {
  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
  49         /* Create vertexes */
  50         double verts[20][3];
  51         for (int i = 0; i < G_N_ELEMENTS(verts); i++) {
  52                 float ang = 2*G_PI * i / G_N_ELEMENTS(verts);
  53                 verts[i][0] = sin(ang) * (i%2+0.5) * 0.6;
  54                 verts[i][1] = cos(ang) * (i%2+0.5) * 0.6;
  55                 verts[i][2] = 0;
  56         }
  57
  58         /* Draw raw polygon */
  59         glColor4f(0.5, 0.0, 0.0, 1.0);
  60         GLUtesselator *tess = gluNewTess();
  61         gluTessCallback(tess, GLU_TESS_BEGIN,  glBegin);
  62         gluTessCallback(tess, GLU_TESS_VERTEX, glVertex3dv);
  63         gluTessCallback(tess, GLU_TESS_END,    glEnd);
  64         gluTessBeginPolygon(tess, NULL);
  65         gluTessBeginContour(tess);
  66         for (int i = 0; i < G_N_ELEMENTS(verts); i++)
  67                 gluTessVertex(tess, verts[i], verts[i]);
  68         gluTessEndContour(tess);
  69         gluTessEndPolygon(tess);
  70         gluDeleteTess(tess);
  71
  72         /* Draw tesselated polygon */
  73         //glColor4f(0.0, 0.0, 0.5, 1.0);
  74         //glBegin(GL_POLYGON);
  75         //for (int i = 0; i < G_N_ELEMENTS(verts); i++)
  76         //      glVertex3dv(verts[i]);
  77         //glEnd();
  78
  79         /* Draw outline */
  80         glColor4f(0.8, 0.8, 0.8, 1.0);
  81         glBegin(GL_LINE_LOOP);
  82         for (int i = 0; i < G_N_ELEMENTS(verts); i++)
  83                 glVertex3dv(verts[i]);
  84         glEnd();
  85
  86         /* Flush */
  87         GdkGLDrawable *gldrawable = gdk_gl_drawable_get_current();
  88         if (gdk_gl_drawable_is_double_buffered(gldrawable))
  89                 gdk_gl_drawable_swap_buffers(gldrawable);
  90         else
  91                 glFlush();
  92         return FALSE;
  93 }
  94 gboolean on_configure(GtkWidget *drawing, GdkEventConfigure *event, gpointer _)
  95 {
  96         glViewport(0, 0,
  97                 drawing->allocation.width,
  98                 drawing->allocation.height);
  99         return FALSE;
 100 }
 101
 102 int main(int argc, char **argv)
 103 {
 104         gtk_init(&argc, &argv);
 105
 106         GtkWidget   *window   = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 107         GtkWidget   *drawing  = gtk_drawing_area_new();
 108         GdkGLConfig *glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(
 109                         GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
 110                         GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA));
 111         g_signal_connect(window,  "destroy",         G_CALLBACK(gtk_main_quit), NULL);
 112         g_signal_connect(window,  "key-press-event", G_CALLBACK(on_key_press),  NULL);
 113         g_signal_connect(drawing, "expose-event",    G_CALLBACK(on_expose),     NULL);
 114         g_signal_connect(drawing, "configure-event", G_CALLBACK(on_configure),  NULL);
 115         gtk_widget_set_gl_capability(drawing, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
 116         gtk_container_add(GTK_CONTAINER(window), drawing);
 117         gtk_widget_show_all(window);
 118
 119         /* OpenGL setup */
 120         GdkGLContext  *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(drawing));
 121         GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(drawing));
 122         gdk_gl_drawable_gl_begin(gldrawable, glcontext);
 123
 124         /* Go */
 125         gtk_main();
 126         gdk_gl_drawable_gl_end(gldrawable);
 127 }