74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
#ifdef _WIN32
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#include <windows.h>
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#endif
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#include <GL/glut.h>
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#include <stdlib.h>
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#include <stdio.h>
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void display(void)
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{
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glClear(GL_COLOR_BUFFER_BIT);
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glFlush();
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}
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void reshape(int w, int h)
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{
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glViewport (0, 0, (GLsizei) w, (GLsizei) h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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gluPerspective (45.0, (GLfloat) w/(GLfloat) h, 1.0, 100.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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}
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void mouse(int button, int state, int x, int y)
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{
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GLint viewport[4];
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GLdouble mvmatrix[16], projmatrix[16];
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GLint realy; /* OpenGL y coordinate position */
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GLdouble wx, wy, wz; /* returned world x, y, z coords */
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switch (button) {
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case GLUT_LEFT_BUTTON:
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if (state == GLUT_DOWN) {
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glGetIntegerv (GL_VIEWPORT, viewport);
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glGetDoublev (GL_MODELVIEW_MATRIX, mvmatrix);
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glGetDoublev (GL_PROJECTION_MATRIX, projmatrix);
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/* note viewport[3] is height of window in pixels */
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realy = viewport[3] - (GLint) y - 1;
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printf ("Coordinates at cursor are (%4d, %4d)\n",
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x, realy);
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gluUnProject ((GLdouble) x, (GLdouble) realy, 0.0,
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mvmatrix, projmatrix, viewport, &wx, &wy, &wz);
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printf ("World coords at z=0.0 are (%f, %f, %f)\n",
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wx, wy, wz);
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gluUnProject ((GLdouble) x, (GLdouble) realy, 1.0,
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mvmatrix, projmatrix, viewport, &wx, &wy, &wz);
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printf ("World coords at z=1.0 are (%f, %f, %f)\n",
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wx, wy, wz);
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}
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break;
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case GLUT_RIGHT_BUTTON:
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if (state == GLUT_DOWN)
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exit(0);
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break;
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default:
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break;
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}
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}
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int main(int argc, char** argv)
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{
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glutInit(&argc, argv);
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glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
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glutInitWindowSize (500, 500);
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glutInitWindowPosition (100, 100);
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glutCreateWindow (argv[0]);
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glutDisplayFunc(display);
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glutReshapeFunc(reshape);
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glutMouseFunc(mouse);
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glutMainLoop();
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return EXIT_SUCCESS;
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}
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