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