| /** |
| * 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; |
| } |