计算机图形学6——3D scene roaming(三维场景漫游)

核心代码有：
前进操作：

	void move_up(void){P0.x=P0.x+step*v.x;P0.y=P0.y+step*v.y;P0.z=P0.z+step*v.z;}

左旋转操作：

	void turn_left(void){u.x=u.x*cos(turn_a)-n.x*sin(turn_a);u.y=u.y*cos(turn_a)-n.y*sin(turn_a);u.z=u.z*cos(turn_a)-n.z*sin(turn_a);n.x=u.x*sin(turn_a)+n.x*cos(turn_a);n.y=u.y*sin(turn_a)+n.y*cos(turn_a);n.z=u.z*sin(turn_a)+n.z*cos(turn_a);}

完整代码如下：

// ====== Computer Graphics Experiment #8 ======
// |             3D scene roaming              |
// =============================================
//
// Requirement:
// (1) Implement translation and rotation of view reference frame
// (2) Change smooth shading to flat shading and observe the effects
// (3) Carefully read and understand the rest of the source code#include <windows.h>
#include <GL/glut.h>
#include <math.h>#define PI 3.14159265// 3D vector class
class CVector3D
{
public:float x, y, z;// ConstructorsCVector3D(void) {x=0.0; y=0.0; z=0.0;}CVector3D(float x0, float y0, float z0){x=x0; y=y0; z=z0;}
};
/*view_frame.u=CVector3D(0.0, 1.0, 0.0);view_frame.v=CVector3D(0.0, 0.0, 1.0);view_frame.n=CVector3D(1.0, 0.0, 0.0);*/
// View reference frame class
class CViewFrame
{
public:float step; // step sizefloat turn_a; // turn anglefloat pitch_a; // pitch anglefloat roll_a; // roll angleCVector3D P0; // View reference pointCVector3D u; // unit vector in xv directionCVector3D v; // unit vector in yv directionCVector3D n; // unit vector in zv directionvoid move_up(void){P0.x=P0.x+step*v.x;P0.y=P0.y+step*v.y;P0.z=P0.z+step*v.z;}void move_down(void){P0.x=P0.x-step*v.x;P0.y=P0.y-step*v.y;P0.z=P0.z-step*v.z;}void move_left(void){P0.x=P0.x-step*u.x;P0.y=P0.y-step*u.y;P0.z=P0.z-step*u.z;}void move_right(void){P0.x=P0.x+step*u.x;P0.y=P0.y+step*u.y;P0.z=P0.z+step*u.z;}void move_forward(void){P0.x=P0.x-step*n.x;P0.y=P0.y-step*n.y;P0.z=P0.z-step*n.z;}void move_backward(void){P0.x=P0.x+step*n.x;P0.y=P0.y+step*n.y;P0.z=P0.z+step*n.z;}void turn_left(void){u.x=u.x*cos(turn_a)-n.x*sin(turn_a);u.y=u.y*cos(turn_a)-n.y*sin(turn_a);u.z=u.z*cos(turn_a)-n.z*sin(turn_a);n.x=u.x*sin(turn_a)+n.x*cos(turn_a);n.y=u.y*sin(turn_a)+n.y*cos(turn_a);n.z=u.z*sin(turn_a)+n.z*cos(turn_a);}void turn_right(void){u.x=u.x*cos(turn_a)+n.x*sin(turn_a);u.y=u.y*cos(turn_a)+n.y*sin(turn_a);u.z=u.z*cos(turn_a)+n.z*sin(turn_a);n.x=-u.x*sin(turn_a)+n.x*cos(turn_a);n.y=-u.y*sin(turn_a)+n.y*cos(turn_a);n.z=-u.z*sin(turn_a)+n.z*cos(turn_a);}void look_up(void){v.x=v.x*cos(pitch_a)+n.x*sin(pitch_a);v.y=v.y*cos(pitch_a)+n.y*sin(pitch_a);v.z=v.z*cos(pitch_a)+n.z*sin(pitch_a);n.x=-v.x*sin(pitch_a)+n.x*cos(pitch_a);n.y=-v.y*sin(pitch_a)+n.y*cos(pitch_a);n.z=-v.z*sin(pitch_a)+n.z*cos(pitch_a);}void look_down(void){v.x=v.x*cos(pitch_a)-n.x*sin(pitch_a);v.y=v.y*cos(pitch_a)-n.y*sin(pitch_a);v.z=v.z*cos(pitch_a)-n.z*sin(pitch_a);n.x=v.x*sin(pitch_a)+n.x*cos(pitch_a);n.y=v.y*sin(pitch_a)+n.y*cos(pitch_a);n.z=v.z*sin(pitch_a)+n.z*cos(pitch_a);}void roll_left(void){u.x=u.x*cos(roll_a)+v.x*sin(roll_a);u.y=u.y*cos(roll_a)+v.y*sin(roll_a);u.z=u.z*cos(roll_a)+v.z*sin(roll_a);v.x=-u.x*sin(roll_a)+v.x*cos(roll_a);v.y=-u.y*sin(roll_a)+v.y*cos(roll_a);v.z=-u.z*sin(roll_a)+v.z*cos(roll_a);}void roll_right(void){u.x=u.x*cos(roll_a)-v.x*sin(roll_a);u.y=u.y*cos(roll_a)-v.y*sin(roll_a);u.z=u.z*cos(roll_a)-v.z*sin(roll_a);v.x=u.x*sin(roll_a)+v.x*cos(roll_a);v.y=u.y*sin(roll_a)+v.y*cos(roll_a);v.z=u.z*sin(roll_a)+v.z*cos(roll_a);}
};CViewFrame view_frame;// Initialization function
void init(void)
{static GLfloat light_ambient[] = { 0.01, 0.01, 0.01, 1.0 };static GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };static GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };glClearColor (0.0, 0.0, 0.0, 0.0);glShadeModel (GL_SMOOTH); // Set shading model// Set light source properties for light source #0glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);glEnable(GL_LIGHTING); // Enable lightingglEnable(GL_LIGHT0); // Enable light source #0glEnable(GL_DEPTH_TEST); // Enable depth buffer testglEnable(GL_NORMALIZE); // Enable auto normalizationglEnable(GL_CULL_FACE); // Enable face culling// Set initial properties for view reference frameview_frame.P0=CVector3D(500.0, 0.0, 100.0);view_frame.u=CVector3D(0.0, 1.0, 0.0);view_frame.v=CVector3D(0.0, 0.0, 1.0);view_frame.n=CVector3D(1.0, 0.0, 0.0);view_frame.step=2;view_frame.turn_a=PI/18;view_frame.pitch_a=PI/18;view_frame.roll_a=PI/18;
}// Function to draw chess board on xy plane
void draw_chess_board(float sx, float sy, float sz, int nx, int ny)
// sx, sy, sz: size of the chess board
// nx, ny: Number of chess grids in x and y direction
{static GLfloat mat1_color[] = { 0.8, 0.8, 0.8, 1.0 };static GLfloat mat2_color[] = { 0.2, 0.2, 0.2, 1.0 };int i, j, iflag, jflag;float x, y, dx, dy;float *pcolor;dx=sx/(float)nx;dy=sy/(float)ny;for (i=0; i<nx; ++i){iflag=i%2;x=(i+0.5)*dx-0.5*sx;for (j=0; j<ny; ++j){jflag=j%2;y=(j+0.5)*dy-0.5*sy;if (iflag==jflag) pcolor=mat1_color;else pcolor=mat2_color;glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, pcolor);glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, pcolor);glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 64.0);glPushMatrix();glTranslatef(x, y, 0.0);glScalef(dx, dy, sz);glutSolidCube(1.0);glPopMatrix();}}}// Function to draw chess pieces
void draw_chess_piece(float sx, float sy, float sz, int nx, int ny)
// sx, sy, sz: size of the chess board
// nx, ny: Number of chess grids in x and y direction
{static GLfloat mat_color[4][4] = {{ 1.0, 0.0, 0.0, 1.0 },{ 0.0, 1.0, 0.0, 1.0 },{ 0.0, 0.0, 1.0, 1.0 },{ 1.0, 1.0, 0.0, 1.0 }};float x, y, dx, dy, size;dx=sx/(float)nx;dy=sy/(float)ny;if (dx<dy) size=dx;else size=dy;//glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);// Draw a sphereglMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_color[0]);glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_color[0]);glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 64.0);x=(0+0.5)*dx-0.5*sx;y=(2+0.5)*dy-0.5*sy;glPushMatrix();glTranslatef(x, y, 0.5*(sz+size));glutSolidSphere(0.5*size, 10, 10);glPopMatrix();// Draw a torusglMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_color[1]);glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_color[1]);glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 64.0);x=(1+0.5)*dx-0.5*sx;y=(0+0.5)*dy-0.5*sy;glPushMatrix();glTranslatef(x, y, 0.5*(sz+size));glRotatef(-90, 1.0, 0.0, 0.0);glutSolidTorus(0.1*size, 0.4*size, 10, 20);glPopMatrix();// Draw a coneglMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_color[2]);glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_color[2]);glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 64.0);x=(2+0.5)*dx-0.5*sx;y=(1+0.5)*dy-0.5*sy;glPushMatrix();glTranslatef(x, y, 0.5*sz);glutSolidCone(0.4*size, size, 10, 5);glPopMatrix();// Draw a rectangular solidglMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_color[3]);glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_color[3]);glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 64.0);x=(3+0.5)*dx-0.5*sx;y=(3+0.5)*dy-0.5*sy;glPushMatrix();glTranslatef(x, y, 0.5*(sz+0.9*size));glScalef(0.9*dx, 0.9*dy, 0.9*size);glutSolidCube(1.0);glPopMatrix();//glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
}// Display callback function
void display(void)
{static GLfloat light_pos[4]={200.0, 200.0, 200.0, 1.0};// Clear frame buffer and depth bufferglClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glPushMatrix(); //Save current ModelView matrix// Set viewing transformation matrixCVector3D look_at;look_at.x=view_frame.P0.x-view_frame.n.x;look_at.y=view_frame.P0.y-view_frame.n.y;look_at.z=view_frame.P0.z-view_frame.n.z;gluLookAt(view_frame.P0.x, view_frame.P0.y, view_frame.P0.z,look_at.x, look_at.y, look_at.z,view_frame.v.x, view_frame.v.y, view_frame.v.z);// Set light source positionglLightfv(GL_LIGHT0, GL_POSITION, light_pos);// Draw the scenedraw_chess_board(400.0, 400.0, 40.0, 4, 4);draw_chess_piece(400.0, 400.0, 40.0, 4, 4);glPopMatrix(); //Restore ModelView matrixglutSwapBuffers(); // Swap front and back buffer
}// Reshape callback function
void reshape (int w, int h)
{float wsize=500.0;// Set viewport as the entire program windowglViewport (0, 0, w, h);// Set symmetric perspective projectionglMatrixMode (GL_PROJECTION);glLoadIdentity ();gluPerspective(60.0, (float)w/(float)h, 10.0, 100000.0);// Reset modelview transformation matrix to identityglMatrixMode (GL_MODELVIEW);glLoadIdentity ();
}// Keyboard callback function
void keyboard (unsigned char key, int x, int y)
{switch (key){case 27:exit(0); break;case 'w':view_frame.move_forward();glutPostRedisplay(); break;case 's'://move backwardview_frame.move_backward();glutPostRedisplay(); break;case 'a'://move leftview_frame.move_left();glutPostRedisplay(); break;case 'd'://move rightview_frame.move_right();glutPostRedisplay(); break;case 'q'://roll leftview_frame.roll_left();glutPostRedisplay(); break;case 'e'://roll rightview_frame.roll_right();glutPostRedisplay(); break;}
}// Special key callback function
void special_key(int key, int x, int y)
{switch (key){case GLUT_KEY_LEFT:view_frame.turn_left();glutPostRedisplay(); break;case GLUT_KEY_RIGHT://turn rightview_frame.turn_right();glutPostRedisplay(); break;case GLUT_KEY_UP://look upview_frame.look_up();glutPostRedisplay(); break;case GLUT_KEY_DOWN://look downview_frame.look_down();glutPostRedisplay(); break;case GLUT_KEY_PAGE_UP://move upview_frame.move_up();glutPostRedisplay(); break;case GLUT_KEY_PAGE_DOWN://move downview_frame.move_down();glutPostRedisplay(); break;}
}// Main program
int main(int argc, char* argv[])
{glutInit(&argc, argv);glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);glutInitWindowSize (500, 300);glutInitWindowPosition (50, 50);glutCreateWindow ("3D Scene Roaming");init();glutDisplayFunc(display);glutReshapeFunc(reshape);glutKeyboardFunc(keyboard);glutSpecialFunc(special_key);glutMainLoop();return 0;
}