图形学立方体旋转程序

立方体旋转程序 /* Rotating cube with color interpolation */ /* Demonstration of use of homogeneous coordinate transformations and simple data structure for representing cube from Chapter 4 */ /* Colors are assigned to the vertices */ /* cube is centered at orign*/ #include #include GLfloat vertices[][3] = {{-1.0,-1.0,-1.0},{1.0,-1.0,-1.0}, {1.0,1.0,-1.0}, {-1.0,1.0,-1.0}, {-1.0,-1.0,1.0}, {1.0,-1.0,1.0}, {1.0,1.0,1.0}, {-1.0,1.0,1.0}}; GLfloat colors[][3] = {{0.0,0.0,0.0},{1.0,0.0,0.0}, {1.0,1.0,0.0}, {0.0,1.0,0.0}, {0.0,0.0,1.0}, {1.0,0.0,1.0}, {1.0,1.0,1.0}, {0.0,1.0,1.0}}; void polygon(int a, int b, int c, int d) { /* draw a polygon via list of vertices */ glBegin(GL_POLYGON); glColor3fv(colors[a]); glVertex3fv(vertices[a]); glColor3fv(colors[b]); glVertex3fv(vertices[b]); glColor3fv(colors[c]); glVertex3fv(vertices[c]); glColor3fv(colors[d]); glVertex3fv(vertices[d]); glEnd(); } void colorcube(void) { /* map vertices to faces */ polygon(0,3,2,1); polygon(2,3,7,6); polygon(0,4,7,3); polygon(1,2,6,5); polygon(4,5,6,7); polygon(0,1,5,4); } static GLfloat theta[] = {0.0,0.0,0.0}; static GLint axis = 2; void display(void) { /* display callback, clear frame buffer and z buffer, rotate cube and draw, swap buffers */ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glRotatef(theta[0], 1.0, 0.0, 0.0); glRotatef(theta[1], 0.0, 1.0, 0.0); glRotatef(theta[2], 0.0, 0.0, 1.0); colorcube(); glFlush(); glutSwapBuffers(); } void spinCube() { /* Idle callback, spin cube 2 degrees about selected axis */ theta[axis] += 2.0; if( theta[axis] > 360.0 ) theta[axis] -= 360.0; /* display(); */ glutPostRedisplay(); } void mouse(int btn, int state, int x, int y) { /* mouse callback, selects an axis about which to rotate */ if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) axis = 0; if(btn==GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) axis = 1; if(btn==GLUT_RIGHT_BUTTON && state == GLUT