progs/trivial: add dlist-flat-tri.c

State-change functions which precede the first call to glEnd() in
a compiled list are vulnerable to not being executed when that list
is called.

In particular this can happen if a list is invoked from within a
begin/end pair, as in this example.

diff --git a/progs/trivial/Makefile b/progs/trivial/Makefile
index 0209c509503382e2f225b62998da7310fdd42e5a..ae750db22a633d4ea097a8bc9288b94fdbfb054f 100644 (file)
--- a/progs/trivial/Makefile
+++ b/progs/trivial/Makefile
@@ -19,6 +19,7 @@ SOURCES = \
        clear-random.c \
        clear.c \
        dlist-dangling.c \
+       dlist-flat-tri.c \
        dlist-tri-flat-tri.c \
        dlist-recursive-call.c \
        dlist-edgeflag-dangling.c \

diff --git a/progs/trivial/dlist-flat-tri.c b/progs/trivial/dlist-flat-tri.c
new file mode 100644 (file)
index 0000000..c3dd792
--- /dev/null
+++ b/progs/trivial/dlist-flat-tri.c
@@ -0,0 +1,171 @@
+/*
+ * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and
+ * its documentation for any purpose is hereby granted without fee, provided
+ * that (i) the above copyright notices and this permission notice appear in
+ * all copies of the software and related documentation, and (ii) the name of
+ * Silicon Graphics may not be used in any advertising or
+ * publicity relating to the software without the specific, prior written
+ * permission of Silicon Graphics.
+ *
+ * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
+ * ANY KIND,
+ * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
+ * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
+ * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
+ * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+ * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
+ * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+
+
+#define CI_OFFSET_1 16
+#define CI_OFFSET_2 32
+
+
+GLenum doubleBuffer;
+GLint list;
+
+static void Init(void)
+{
+   fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
+   fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
+   fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
+   fflush(stderr);
+
+   glClearColor(0.0, 0.0, 1.0, 0.0);
+
+   list = glGenLists(1);
+   glNewList(list, GL_COMPILE); 
+
+   /* XXX: this state-change will only be executed if list is called
+    * from outside a begin/end pair:
+    */
+   glShadeModel( GL_FLAT );
+   glBegin(GL_TRIANGLES);
+   glColor3f(0,0,.7);
+   glVertex3f( -0.9,  0.9, -30.0);
+   glColor3f(0,.9,0);
+   glVertex3f( -0.9, -0.9, -30.0);
+   glColor3f(.8,0,0);
+   glVertex3f(  0.9,  0.0, -30.0);
+   glEnd();
+
+   /* This statechange is potentially NOT redundant:
+    */
+   glShadeModel( GL_FLAT );
+   glBegin(GL_TRIANGLES);
+   glColor3f(0,1,0);
+   glVertex3f( -0.5,  0.5, -30.0);
+   glColor3f(0,0,1);
+   glVertex3f( -0.5, -0.5, -30.0);
+   glColor3f(1,0,0);
+   glVertex3f(  0.5,  0.0, -30.0);
+   glEnd();
+
+   glEndList();
+}
+
+static void Reshape(int width, int height)
+{
+
+    glViewport(0, 0, (GLint)width, (GLint)height);
+
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
+    glMatrixMode(GL_MODELVIEW);
+}
+
+static void Key(unsigned char key, int x, int y)
+{
+
+    switch (key) {
+      case 27:
+       exit(1);
+      default:
+       return;
+    }
+
+    glutPostRedisplay();
+}
+
+
+
+
+static void Draw(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT); 
+
+   glShadeModel( GL_SMOOTH );
+
+   glBegin(GL_TRIANGLES);
+
+   /* Note: call the list from inside a begin/end pair.  The end is
+    * provided by the display list...
+    */
+   glCallList(list);
+
+   glFlush();
+
+   if (doubleBuffer) {
+      glutSwapBuffers();
+   }
+}
+
+static GLenum Args(int argc, char **argv)
+{
+    GLint i;
+
+    doubleBuffer = GL_FALSE;
+
+    for (i = 1; i < argc; i++) {
+        if (strcmp(argv[i], "-sb") == 0) {
+           doubleBuffer = GL_FALSE;
+       } else if (strcmp(argv[i], "-db") == 0) {
+           doubleBuffer = GL_TRUE;
+       } else {
+           fprintf(stderr, "%s (Bad option).\n", argv[i]);
+           return GL_FALSE;
+       }
+    }
+    return GL_TRUE;
+}
+
+int main(int argc, char **argv)
+{
+    GLenum type;
+
+    glutInit(&argc, argv);
+
+    if (Args(argc, argv) == GL_FALSE) {
+       exit(1);
+    }
+
+    glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
+
+    type = GLUT_RGB | GLUT_ALPHA;
+    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
+    glutInitDisplayMode(type);
+
+    if (glutCreateWindow(*argv) == GL_FALSE) {
+       exit(1);
+    }
+
+    Init();
+
+    glutReshapeFunc(Reshape);
+    glutKeyboardFunc(Key);
+    glutDisplayFunc(Draw);
+    glutMainLoop();
+       return 0;
+}