diff options
Diffstat (limited to 'progs/trivial/tri-point-line-clipped.c')
-rw-r--r-- | progs/trivial/tri-point-line-clipped.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/progs/trivial/tri-point-line-clipped.c b/progs/trivial/tri-point-line-clipped.c new file mode 100644 index 00000000000..f8c1015f5f4 --- /dev/null +++ b/progs/trivial/tri-point-line-clipped.c @@ -0,0 +1,116 @@ +/** + * 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; +} |