1 files changed, 327 insertions, 0 deletions
diff --git a/progs/trivial/tri-viewport.c b/progs/trivial/tri-viewport.c
new file mode 100644
index 0000000000..3e52449b47
--- /dev/null
+++ b/progs/trivial/tri-viewport.c
@@ -0,0 +1,327 @@
+/*
+ * 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>
+
+GLenum doubleBuffer = 1;
+int win;
+static float tx = 0;
+static float ty = 0;
+static float tw = 0;
+static float th = 0;
+static float z = -5;
+
+
+static float win_width = 250;
+static float win_height = 250;
+static enum {
+   ORTHO,
+   FRUSTUM,
+   MODE_MAX
+} mode = ORTHO;
+
+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, 0.0);
+}
+
+static void Reshape(int width, int height)
+{
+   win_width = width;
+   win_height = height;
+   glutPostRedisplay();
+}
+
+
+static void Key(unsigned char key, int x, int y)
+{
+   switch (key) {
+   case 27:
+      exit(0);
+   case 'w':
+      tw += 1.0;
+      break;
+   case 'W':
+      tw -= 1.0;
+      break;
+   case 'h':
+      th += 1.0;
+      break;
+   case 'H':
+      th -= 1.0;
+      break;
+
+   case 'z':
+      z += 1.0;
+      break;
+   case 'Z':
+      z -= 1.0;
+      break;
+   case 'm':
+      mode++;
+      mode %= MODE_MAX;
+      break;
+   case ' ':
+      tw = th = tx = ty = 0;
+      z = -5;
+      mode = ORTHO;
+      break;
+   default:
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void Draw(void)
+{
+   int i;
+   float w = tw + win_width;
+   float h = th + win_height;
+
+   fprintf(stderr, "glViewport(%f %f %f %f)\n", tx, ty, w, h);
+   fprintf(stderr, "mode: %s\n", mode == FRUSTUM ? "FRUSTUM" : "ORTHO");
+   fprintf(stderr, "z: %f\n", z);
+   fflush(stderr);
+
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+
+   switch (mode) {
+   case FRUSTUM:
+      glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
+      break;
+   case ORTHO:
+   default:
+      glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
+      break;
+   }
+
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+
+
+   glClear(GL_COLOR_BUFFER_BIT); 
+
+
+   /***********************************************************************
+    * Should be clipped to be no larger than the triangles:
+    */
+   glViewport(tx, ty, w, h);
+
+   glBegin(GL_POLYGON);
+   glColor3f(1,1,0); 
+   glVertex3f(-100, -100, z);
+   glVertex3f(-100, 100, z);
+   glVertex3f(100, 100, z);
+   glVertex3f(100, -100, z);
+   glEnd();
+
+   glBegin(GL_POLYGON);
+   glColor3f(0,1,1); 
+   glVertex3f(-10, -10, z);
+   glVertex3f(-10, 10, z);
+   glVertex3f(10, 10, z);
+   glVertex3f(10, -10, z);
+   glEnd();
+
+   glBegin(GL_POLYGON);
+   glColor3f(1,0,0); 
+   glVertex3f(-2, -2, z);
+   glVertex3f(-2, 2, z);
+   glVertex3f(2, 2, z);
+   glVertex3f(2, -2, z);
+   glEnd();
+
+
+   glBegin(GL_POLYGON);
+   glColor3f(.5,.5,1); 
+   glVertex3f(-1, -1, z);
+   glVertex3f(-1, 1, z);
+   glVertex3f(1, 1, z);
+   glVertex3f(1, -1, z);
+   glEnd();
+
+   /***********************************************************************
+    */
+   glViewport(0, 0, win_width, win_height);
+   glBegin(GL_LINES);
+   glColor3f(1,1,0); 
+   glVertex3f(-1, 0, z);
+   glVertex3f(1, 0, z);
+
+   glVertex3f(0,  -1, z);
+   glVertex3f(0,  1, z);
+   glEnd();
+
+
+   /***********************************************************************
+    */
+   glViewport(tx, ty, w, h);
+   glBegin(GL_TRIANGLES);
+   glColor3f(1,0,0); 
+   glVertex3f(-1, -1, z);
+   glVertex3f(0, -1, z);
+   glVertex3f(-.5,  -.5, z);
+
+   glColor3f(1,1,1);
+   glVertex3f(0, -1, z);
+   glVertex3f(1, -1, z);
+   glVertex3f(.5,  -.5, z);
+
+   glVertex3f(-.5, -.5, z);
+   glVertex3f(.5, -.5, z);
+   glVertex3f(0,  0, z);
+
+
+   glColor3f(0,1,0); 
+   glVertex3f(1, 1, z);
+   glVertex3f(0, 1, z);
+   glVertex3f(.5,  .5, z);
+
+   glColor3f(1,1,1);
+   glVertex3f(0, 1, z);
+   glVertex3f(-1, 1, z);
+   glVertex3f(-.5,  .5, z);
+
+   glVertex3f(.5, .5, z);
+   glVertex3f(-.5, .5, z);
+   glVertex3f( 0,  0, z);
+
+   glEnd();
+
+
+   glViewport(0, 0, win_width, win_height);
+
+   glBegin(GL_LINES);
+   glColor3f(.5,.5,0); 
+   for (i = -10; i < 10; i++) {
+      float f = i / 10.0;
+
+      if (i == 0)
+         continue;
+
+      glVertex3f(-1, f, z);
+      glVertex3f(1, f, z);
+
+      glVertex3f(f, -1, z);
+      glVertex3f(f, 1, z);
+   }
+   glEnd();
+
+
+
+   glFlush();
+
+   if (doubleBuffer) {
+      glutSwapBuffers();
+   }
+}
+
+static GLenum Args(int argc, char **argv)
+{
+   GLint i;
+
+   if (getenv("VPX"))
+      tx = atof(getenv("VPX"));
+
+   if (getenv("VPY"))
+      ty = atof(getenv("VPY"));
+
+
+   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;
+}
+
+
+static void
+special(int k, int x, int y)
+{
+   switch (k) {
+   case GLUT_KEY_UP:
+      ty += 1.0;
+      break;
+   case GLUT_KEY_DOWN:
+      ty -= 1.0;
+      break;
+   case GLUT_KEY_LEFT:
+      tx -= 1.0;
+      break;
+   case GLUT_KEY_RIGHT:
+      tx += 1.0;
+      break;
+   default:
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+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);
+
+   win = glutCreateWindow(*argv);
+   if (!win) {
+      exit(1);
+   }
+
+   Init();
+
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key); 
+   glutSpecialFunc(special);
+   glutDisplayFunc(Draw);
+   glutMainLoop();
+   return 0;
+}