117 lines
2.2 KiB
C
117 lines
2.2 KiB
C
/**
|
|
* Test frustum/user clipping w/ glPolygonMode LINE/POINT.
|
|
*
|
|
* The bottom/left and bottom/right verts are outside the frustum and clipped.
|
|
* The top vertex is clipped by a user clipping plane.
|
|
*
|
|
* A filled gray reference triangle is shown underneath the points/lines.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <GL/glut.h>
|
|
|
|
|
|
static int win;
|
|
|
|
|
|
static void
|
|
ColorTri(void)
|
|
{
|
|
glBegin(GL_TRIANGLES);
|
|
glColor3f(1, 0, 0); glVertex3f(-1.5, -0.8, 0.0);
|
|
glColor3f(0, 1, 0); glVertex3f( 1.5, -0.8, 0.0);
|
|
glColor3f(0, 0, 1); glVertex3f( 0.0, 0.9, 0.0);
|
|
glEnd();
|
|
}
|
|
|
|
|
|
static void
|
|
GrayTri(void)
|
|
{
|
|
glColor3f(0.3, 0.3, 0.3);
|
|
glBegin(GL_TRIANGLES);
|
|
glVertex3f(-1.5, -0.8, 0.0);
|
|
glVertex3f( 1.5, -0.8, 0.0);
|
|
glVertex3f( 0.0, 0.9, 0.0);
|
|
glEnd();
|
|
}
|
|
|
|
|
|
static void
|
|
Draw(void)
|
|
{
|
|
static const GLdouble plane[4] = { 0, -1.0, 0, 0.5 };
|
|
|
|
glClear(GL_COLOR_BUFFER_BIT);
|
|
|
|
glPointSize(13.0);
|
|
glLineWidth(5.0);
|
|
|
|
glClipPlane(GL_CLIP_PLANE0, plane);
|
|
glEnable(GL_CLIP_PLANE0);
|
|
|
|
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
|
|
GrayTri();
|
|
|
|
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
|
|
ColorTri();
|
|
|
|
glPolygonMode(GL_FRONT_AND_BACK, GL_POINT);
|
|
ColorTri();
|
|
|
|
glutSwapBuffers();
|
|
}
|
|
|
|
|
|
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, -1.0, 1.0);
|
|
glMatrixMode(GL_MODELVIEW);
|
|
}
|
|
|
|
|
|
static void
|
|
Key(unsigned char key, int x, int y)
|
|
{
|
|
if (key == 27) {
|
|
glutDestroyWindow(win);
|
|
exit(0);
|
|
}
|
|
else {
|
|
glutPostRedisplay();
|
|
}
|
|
}
|
|
|
|
|
|
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);
|
|
}
|
|
|
|
|
|
int
|
|
main(int argc, char **argv)
|
|
{
|
|
glutInitWindowSize(300, 300);
|
|
glutInit(&argc, argv);
|
|
glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
|
|
win = glutCreateWindow(*argv);
|
|
if (!win) {
|
|
return 1;
|
|
}
|
|
Init();
|
|
glutReshapeFunc(Reshape);
|
|
glutKeyboardFunc(Key);
|
|
glutDisplayFunc(Draw);
|
|
glutMainLoop();
|
|
return 0;
|
|
}
|