第1页 / 共14页
第2页 / 共14页
第3页 / 共14页
第4页 / 共14页
第5页 / 共14页
第6页 / 共14页
第7页 / 共14页
第8页 / 共14页
OpenGL B样条曲线.doc
实验八
曲线绘制
一、实验目的
1、掌握 Bezier 曲线的绘制；
2、掌握 B 样条曲线的绘制。
二、实验要求
1、通过菜单完成两种曲线的绘制:
1. Bezier 曲线（三次或四次）
2. B 样条曲线（二次或三次）
3. 退出
2、任意绘制带有曲线的二维图形或三维图形。
三、实验代码
Bezier
#include
#include
#include
static GLfloat v[4][2];
static GLfloat width = 600, height = 600;
static GLfloat mousex;
static GLfloat mousey;
static int count = 0;
void Init(){
glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
//设置背景颜色
}
void Reshape(GLsizei w, GLsizei h){
glViewport(0, 0, w, h);
width = w;
height = h;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, w, 0, h, -1.0, 1.0);
glutPostRedisplay();
}
void bezier(GLfloat vv[4][2], int i){
if (i == 0){
glColor3f(0.0, 0.0, 0.0);
glBegin(GL_LINE_STRIP);
glVertex2i(vv[0][0], vv[0][1]);
glVertex2i(vv[1][0], vv[1][1]);
glVertex2i(vv[2][0], vv[2][1]);
glVertex2i(vv[3][0], vv[3][1]);
glEnd();
}
else{
i--;
int j;
GLfloat l[4][2];
GLfloat r[4][2];
for (j = 0;j<2;j++){
l[0][j] = vv[0][j];
r[3][j] = vv[3][j];
l[1][j] = (vv[0][j] + vv[1][j]) / 2;
r[2][j] = (vv[2][j] + vv[3][j]) / 2;
l[2][j] = (l[1][j] + (vv[1][j] + vv[2][j]) / 2) / 2;
r[1][j] = (r[2][j] + (vv[1][j] + vv[2][j]) / 2) / 2;
l[3][j] = (l[2][j] + r[1][j]) / 2;
r[0][j] = l[3][j];
}
bezier(l, i);
bezier(r, i);
}
}
void mydisplay(){
glClearColor(1.0, 1.0, 1.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
if (count>1){
glBegin(GL_LINES);
glColor3f(0.0, 1.0, 0.0);
glVertex2f(v[0][0], v[0][1]);
glColor3f(0.0, 0.0, 1.0);
glVertex2f(v[1][0], v[1][1]);
glEnd();
}
if (count>2){
glBegin(GL_LINES);
glColor3f(1.0, 1.0, 0.0);
glVertex2f(v[1][0], v[1][1]);
glColor3f(0.0, 0.0, 1.0);
glVertex2f(v[2][0], v[2][1]);
glEnd();
}
if (count>3){
glBegin(GL_LINES);
glColor3f(1.0, 0.0, 1.0);
glVertex2f(v[2][0], v[2][1]);
glColor3f(0.0, 0.0, 1.0);
glVertex2f(v[3][0], v[3][1]);
glEnd();
}
if ((count>0) && (count<4)){
glBegin(GL_LINES);
glColor3f(0.6, 0.4, 0.7);
glVertex2f(v[count - 1][0], v[count - 1][1]);
glColor3f(0.0, 0.0, 1.0);
glVertex2f(mousex, mousey);
glEnd();
}
else if (count == 4){
GLint vv[4][2];
for (int i = 0;i<4;i++){
vv[i][0] = v[i][0];
vv[i][1] = v[i][1];
}
bezier(v, 5);
}
glutSwapBuffers();
glFlush();
}
void mymouse(int button, int state, int xx, int yy)
{
if ((button == GLUT_LEFT_BUTTON) && (state == GLUT_DOWN))
{
if (count<4)
{
v[count][0] = xx;
v[count][1] = height - yy;
glutPostRedisplay();
count++;
}
}
if ((button == GLUT_RIGHT_BUTTON) && (state == GLUT_DOWN))
count = 0;
glutPostRedisplay();
{
}
}
void mypassive(int xx, int yy)
{
}
mousex = xx;
mousey = height - yy;
if ((count>0) && (count<4)) glutPostRedisplay();
int main(int argc, char** argv)
{
}
glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
glutInitWindowSize(680, 680);
glutInitWindowPosition(340,-340);
glutInit(&argc, argv);
glutCreateWindow("Bezier");
glutDisplayFunc(mydisplay);
glutReshapeFunc(Reshape);
glutMouseFunc(mymouse);
glutPassiveMotionFunc(mypassive);
glutMainLoop();
return 0;
B 样条曲线
#include
#include
#include
#include
#include
using namespace std;
bool mouseRightIsDown = false;
void Init() {
glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
//设置背景颜色
}
void Reshape(int w, int h)
//两个参数：窗口被移动后大小
{
}
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0, w, h, 0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
struct Point
{
int x, y;
Point() {};
Point(int tx, int ty)
{
}
x = tx;
y = ty;
};
vector p;
double getRatio(double t, double a, double b, double c, double d)
{
}
return a * pow(t, 3) + b * pow(t, 2) + c * t + d;
double caculateSquarDistance(Point a, Point b)
{
}
return (a.x - b.x)*(a.x - b.x) + (a.y - b.y)*(a.y - b.y);
int getIndexNearByMouse(int x, int y)
{
double precision = 200;
int index = -1;
double Min;
for (int i = 0; i < p.size(); i++)
{
double dis = caculateSquarDistance(p[i], Point(x, y));
if (dis < precision)
{
if (index == -1)
{
}
index = i;
Min = dis;
else if (dis < Min)
{
}
index = i;
Min = dis;
}
}
return index;
}
void Blines(Point a, Point b, Point c, Point d)
{
int n = 500;
double derta = 1.0 / n;
glPointSize(2);
glColor3f(0.0, 1.0, 0.0);
glBegin(GL_LINE_STRIP);
for (int i = 0; i <= n; i++)
{
double t = derta * i;
double ratio[4];
ratio[0] = getRatio(t, -1, 3, -3, 1);
ratio[1] = getRatio(t, 3, -6, 0, 4);
ratio[2] = getRatio(t, -3, 3, 3, 1);
ratio[3] = getRatio(t, 1, 0, 0, 0);
double x = 0, y = 0;
x += ratio[0] * a.x + ratio[1] * b.x + ratio[2] * c.x + ratio[3] * d.x;
y += ratio[0] * a.y + ratio[1] * b.y + ratio[2] * c.y + ratio[3] * d.y;
x /= 6.0;
y /= 6.0;
glVertex2d(x, y);
}
glEnd();
}
void myDisplay()
{
glClear(GL_COLOR_BUFFER_BIT);
glPointSize(5);
glColor3f(0.0, 0.0, 1.0);
glBegin(GL_POINTS);
for (int i = 0; i < p.size(); i++)
glVertex2d(p[i].x, p[i].y);
glEnd();
//画线
glLineWidth(2);
glColor3f(1.0, 1.0, 0.0);
glBegin(GL_LINE_STRIP);
for (int i = 0; i < p.size(); i++)
glVertex2d(p[i].x, p[i].y);
glEnd();
if (p.size() >= 4)
for (int i = 0; i < p.size() - 3; i++)
Blines(p[i], p[i + 1], p[i + 2], p[i + 3]);
glFlush();
}
void keyboard(unsigned char key, int x, int y)
{
}
if (key == GLUT_KEY_LEFT)
exit(0);
if (key == GLUT_KEY_RIGHT)
//退格键
{
}
int index = getIndexNearByMouse(x, y);
if (index == -1)
return;
p.erase(p.begin() + index);
glutPostRedisplay();
void mouse(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
{
}
Point t(x, y);
p.push_back(t);
glutPostRedisplay();
if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
mouseRightIsDown = true;
if (button == GLUT_RIGHT_BUTTON && state == GLUT_UP)
mouseRightIsDown = false;
}
void motion(int x, int y)
{
}
if (mouseRightIsDown)
{
}
int index = getIndexNearByMouse(x, y);
if (index == -1)
return;
p[index].x = x;
p[index].y = y;
glutPostRedisplay();
int main(int argc, char *argv[])
{
glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
glutInitWindowSize(680, 680);
glutInitWindowPosition(340, -340);
glutInit(&argc, argv);
glutCreateWindow("B");
Init();
glutDisplayFunc(myDisplay);
glutReshapeFunc(Reshape);
glutMouseFunc(mouse);
glutMotionFunc(motion);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;
}
曲线图：
#include
#include
#include
#include
#include
相关推荐
2023年江西萍乡中考道德与法治真题及答案.doc
2012年重庆南川中考生物真题及答案.doc
2013年江西师范大学地理学综合及文艺理论基础考研真题.doc
2020年四川甘孜小升初语文真题及答案I卷.doc
2020年注册岩土工程师专业基础考试真题及答案.doc
2023-2024学年福建省厦门市九年级上学期数学月考试题及答案.doc
2021-2022学年辽宁省沈阳市大东区九年级上学期语文期末试题及答案.doc
2022-2023学年北京东城区初三第一学期物理期末试卷及答案.doc
2018上半年江西教师资格初中地理学科知识与教学能力真题及答案.doc
2012年河北国家公务员申论考试真题及答案-省级.doc
2020-2021学年江苏省扬州市江都区邵樊片九年级上学期数学第一次质量检测试题及答案.doc
2022下半年黑龙江教师资格证中学综合素质真题及答案.doc
