Add convex tessellation example

This tessellates a non-convex polygon such that it can be drawn
correctly.

diff --git a/examples/.gitignore b/examples/.gitignore
index 420b0215c1e8493c211a0f2651d6e5b50b75d2b4..0f06fc99c995b1190cfb86c66ccef301c8fa2a46 100644 (file)
--- a/examples/.gitignore
+++ b/examples/.gitignore
@@ -6,5 +6,6 @@ interp/interp
 plugin/teapot
 shader/shader
 sort/sort
+tess/convex
 tess/split
 tex/tex

diff --git a/examples/tess/convex.c b/examples/tess/convex.c
new file mode 100644 (file)
index 0000000..7d8451d
--- /dev/null
+++ b/examples/tess/convex.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2010 Andy Spencer <andy753421@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <math.h>
+#include <gtk/gtk.h>
+#include <gtk/gtkgl.h>
+#include <gdk/gdkkeysyms.h>
+#include <GL/gl.h>
+#include <GL/glu.h>
+
+guint tex, texl, texr;
+
+gboolean on_key_press(GtkWidget *widget, GdkEventKey *event, gpointer _)
+{
+       if (event->keyval == GDK_q)
+               gtk_main_quit();
+       return FALSE;
+}
+
+gboolean on_expose(GtkWidget *drawing, GdkEventExpose *event, gpointer _)
+{
+       glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+       glMatrixMode(GL_PROJECTION);
+       glLoadIdentity();
+       glOrtho(-1,1, -1,1, 10,-10);
+       glMatrixMode(GL_MODELVIEW);
+       glLoadIdentity();
+       glTranslatef(0, 0, -5);
+
+       glEnable(GL_COLOR_MATERIAL);
+       glDisable(GL_TEXTURE_2D);
+       glColor3f(1.0, 1.0, 1.0);
+
+       /* Create vertexes */
+       double verts[20][3];
+       for (int i = 0; i < G_N_ELEMENTS(verts); i++) {
+               float ang = 2*G_PI * i / G_N_ELEMENTS(verts);
+               verts[i][0] = sin(ang) * (i%2+0.5) * 0.6;
+               verts[i][1] = cos(ang) * (i%2+0.5) * 0.6;
+               verts[i][2] = 0;
+       }
+
+       /* Draw raw polygon */
+       glColor4f(0.5, 0.0, 0.0, 1.0);
+       GLUtesselator *tess = gluNewTess();
+       gluTessCallback(tess, GLU_TESS_BEGIN,  glBegin);
+       gluTessCallback(tess, GLU_TESS_VERTEX, glVertex3dv);
+       gluTessCallback(tess, GLU_TESS_END,    glEnd);
+       gluTessBeginPolygon(tess, NULL);
+       gluTessBeginContour(tess);
+       for (int i = 0; i < G_N_ELEMENTS(verts); i++)
+               gluTessVertex(tess, verts[i], verts[i]);
+       gluTessEndContour(tess);
+       gluTessEndPolygon(tess);
+       gluDeleteTess(tess);
+
+       /* Draw tesselated polygon */
+       //glColor4f(0.0, 0.0, 0.5, 1.0);
+       //glBegin(GL_POLYGON);
+       //for (int i = 0; i < G_N_ELEMENTS(verts); i++)
+       //      glVertex3dv(verts[i]);
+       //glEnd();
+
+       /* Draw outline */
+       glColor4f(0.8, 0.8, 0.8, 1.0);
+       glBegin(GL_LINE_LOOP);
+       for (int i = 0; i < G_N_ELEMENTS(verts); i++)
+               glVertex3dv(verts[i]);
+       glEnd();
+
+       /* Flush */
+       GdkGLDrawable *gldrawable = gdk_gl_drawable_get_current();
+       if (gdk_gl_drawable_is_double_buffered(gldrawable))
+               gdk_gl_drawable_swap_buffers(gldrawable);
+       else
+               glFlush();
+       return FALSE;
+}
+gboolean on_configure(GtkWidget *drawing, GdkEventConfigure *event, gpointer _)
+{
+       glViewport(0, 0,
+               drawing->allocation.width,
+               drawing->allocation.height);
+       return FALSE;
+}
+
+int main(int argc, char **argv)
+{
+       gtk_init(&argc, &argv);
+
+       GtkWidget   *window   = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+       GtkWidget   *drawing  = gtk_drawing_area_new();
+       GdkGLConfig *glconfig = gdk_gl_config_new_by_mode((GdkGLConfigMode)(
+                       GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
+                       GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA));
+       g_signal_connect(window,  "destroy",         G_CALLBACK(gtk_main_quit), NULL);
+       g_signal_connect(window,  "key-press-event", G_CALLBACK(on_key_press),  NULL);
+       g_signal_connect(drawing, "expose-event",    G_CALLBACK(on_expose),     NULL);
+       g_signal_connect(drawing, "configure-event", G_CALLBACK(on_configure),  NULL);
+       gtk_widget_set_gl_capability(drawing, glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE);
+       gtk_container_add(GTK_CONTAINER(window), drawing);
+       gtk_widget_show_all(window);
+
+       /* OpenGL setup */
+       GdkGLContext  *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(drawing));
+       GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(drawing));
+       gdk_gl_drawable_gl_begin(gldrawable, glcontext);
+
+       /* Go */
+       gtk_main();
+       gdk_gl_drawable_gl_end(gldrawable);
+}

diff --git a/examples/tess/mkfile b/examples/tess/mkfile
index 53cc1458483a297a47c26a619be95f89f76b1c6d..142ca46ac5a177526f8b8a34dd5d3424345508f0 100644 (file)
--- a/examples/tess/mkfile
+++ b/examples/tess/mkfile
@@ -1,5 +1,5 @@
 MKSHELL=/usr/lib/plan9/bin/rc
-PROGS=split
+PROGS=convex split
 PKGS=gtkglext-1.0
-default:V: split-run
+default:V: convex-run
 <$HOME/lib/mkcommon