press 'f' to toggle front-face winding
diff --git a/progs/trivial/tri-cull.c b/progs/trivial/tri-cull.c
index af26cb0..2eead84 100644
--- a/progs/trivial/tri-cull.c
+++ b/progs/trivial/tri-cull.c
@@ -29,6 +29,7 @@
static GLenum doubleBuffer;
static GLint cullmode = 0;
+static GLenum front = GL_CCW; /* GL default */
static void cull(void)
{
@@ -76,11 +77,16 @@
static void Key(unsigned char key, int x, int y)
{
switch (key) {
- case 27:
- exit(1);
+ case 27:
+ exit(1);
case 'c':
cull();
break;
+ case 'f':
+ front = ((front == GL_CCW) ? GL_CW : GL_CCW);
+ glFrontFace(front);
+ printf("front face = %s\n", front == GL_CCW ? "GL_CCW" : "GL_CW");
+ break;
default:
return;
}
@@ -92,7 +98,7 @@
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_TRIANGLES);
- /* back-facing */
+ /* CCW / front-facing */
glColor3f(0,0,.7);
glVertex3f(-0.1, -0.9, -30.0);
glColor3f(.8,0,0);
@@ -100,7 +106,7 @@
glColor3f(0,.9,0);
glVertex3f(-0.9, 0.0, -30.0);
- /* front-facing */
+ /* CW / back-facing */
glColor3f(0,0,.7);
glVertex3f( 0.1, -0.9, -30.0);
glColor3f(.8,0,0);