gallium: new pgon-mode.c test

A two-triangle strip is drawn such that the first tri is front-facing and
the second tri is back-facing.  Use different front/back polygon modes.

progs/trivial/Makefile

@@ -39,6 +39,7 @@ SOURCES = \
 	linestrip-stipple-wide.c \
 	linestrip-stipple.c \
 	linestrip.c \
+	pgon-mode.c \
 	point-clip.c \
 	point-param.c \
 	point-sprite.c \

progs/trivial/pgon-mode.c

@@ -0,0 +1,136 @@
+/**
+ * Test glPolygonMode.
+ * A tri-strip w/ two tris is drawn so that the first tri is front-facing
+ * but the second tri is back-facing.
+ * Set glPolygonMode differently for the front/back faces
+ *
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+
+static int Win;
+static GLfloat Zrot = 0;
+static GLboolean FrontFillBackUnfilled = GL_TRUE;
+static GLboolean Lines = GL_TRUE;
+
+
+static void
+Draw(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   if (FrontFillBackUnfilled) {
+      if (Lines) {
+         printf("FrontMode = FILL, BackMode = LINE\n");
+         glPolygonMode(GL_BACK, GL_LINE);
+      }
+      else {
+         printf("FrontMode = FILL, BackMode = POINT\n");
+         glPolygonMode(GL_BACK, GL_POINT);
+      }
+      glPolygonMode(GL_FRONT, GL_FILL);
+   }
+   else {
+      if (Lines) {
+         printf("FrontMode = LINE, BackMode = FILL\n");
+         glPolygonMode(GL_FRONT, GL_LINE);
+      }
+      else {
+         printf("FrontMode = POINT, BackMode = FILL\n");
+         glPolygonMode(GL_FRONT, GL_POINT);
+      }
+      glPolygonMode(GL_BACK, GL_FILL);
+   }
+
+   glPushMatrix();
+   glRotatef(Zrot, 0, 0, 1);
+
+   glBegin(GL_TRIANGLE_STRIP);
+   glVertex2f(-1, 0);
+   glVertex2f( 1, 0);
+   glVertex2f(0,  1);
+   glVertex2f(0, -1);
+   glEnd();
+
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0, 0.0, -15.0);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+   const GLfloat step = 3.0;
+   (void) x;
+   (void) y;
+   switch (key) {
+   case 'p':
+      FrontFillBackUnfilled = !FrontFillBackUnfilled;
+      break;
+   case 'l':
+      Lines = !Lines;
+      break;
+   case 'z':
+      Zrot -= step;
+      break;
+   case 'Z':
+      Zrot += step;
+      break;
+   case 27:
+      glutDestroyWindow(Win);
+      exit(0);
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+Init(void)
+{
+   printf("GL_RENDERER = %s\n", (char*) glGetString(GL_RENDERER));
+
+   glLineWidth(3.0);
+   glPointSize(3.0);
+
+   glColor4f(1, 1, 1, 0.8);
+   glEnable(GL_BLEND);
+   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+   printf("Press 'p' to toggle polygon mode\n");
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(400, 400);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   Win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutDisplayFunc(Draw);
+   Init();
+   glutMainLoop();
+   return 0;
+}