Question

基于opengl计算机图形学beize曲线绘制代码 c++ 2631822046@qq.com

Answer 1

#include <gl/glut.h>

// OpenGL 编程指南
// 示例程序12-1 具有4个控制点的Bézier曲线

GLfloat ctrlpoints[4][3] = {
{ -4.0, -4, 0}, { -2, 4, 0},
{2, -4, 0}, {4, 4, 0}
};

void init(void)
{
glClearColor(0,0,0,0);
glShadeModel(GL_FLAT);
glMap1f(GL_MAP1_VERTEX_3,0,1,3,4,&ctrlpoints[0][0]);
glEnable(GL_MAP1_VERTEX_3);
}

void display(void)
{
int i;
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1,1,1);
glBegin(GL_LINE_STRIP);
for(i=0;i<=30;i++)glEvalCoord1f((GLfloat)i/30);
glEnd();
/* The following code displays the control points as dots. */
glPointSize(5);
glColor3f(1,1,0);
glBegin(GL_POINTS);
for(i=0;i<4;i++)glVertex3fv(&ctrlpoints[i][0]);
glEnd();
glFlush();
}

void reshape(int w, int h)
{
glViewport(0,0,w,h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if(w<=h)
glOrtho(-5,5,-5*h/(GLfloat)w,5*h/(GLfloat)w,-5,5);
else
glOrtho(-5*w/(GLfloat)h,5*w/(GLfloat)h,-5,5,-5,5);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

int main(int argc, char** argv)
{
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutInitWindowSize(500,500);
glutInitWindowPosition(100,100);
glutCreateWindow(argv[0]);
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}

Answer 2

#include <GL/glaux.h>
#include <GL/gl.h>
#include <GL/glu.h>
#pragma comment (lib, "opengl32.lib")
#pragma comment (lib, "glu32.lib")
#pragma comment (lib, "glaux.lib")
void myinit(void);
void CALLBACK myReshape(GLsizei w, GLsizei h);
void CALLBACK display(void);

GLfloat ctrlpoints[4][3] = {
{ -4.0, -4.0, 0.0}, { -2.0, 4.0, 0.0},
{2.0, -4.0, 0.0}, {4.0, 4.0, 0.0}};

void myinit(void)
{
glClearColor(0.0, 0.0, 0.0, 1.0);
glMap1f(GL_MAP1_VERTEX_3, 0.0, 1.0, 3, 4, &ctrlpoints[0][0]);
glEnable(GL_MAP1_VERTEX_3);
glShadeModel(GL_FLAT);
}

void CALLBACK display(void)
{
int i;

glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 1.0, 1.0);
glBegin(GL_LINE_STRIP);
for (i = 0; i <= 30; i++)
glEvalCoord1f((GLfloat) i/30.0);
glEnd();

/* 显示控制点 */
glPointSize(5.0);
glColor3f(1.0, 1.0, 0.0);
glBegin(GL_POINTS);
for (i = 0; i < 4; i++)
glVertex3fv(&ctrlpoints[i][0]);
glEnd();
glFlush();
}

void CALLBACK myReshape(GLsizei w, GLsizei h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
glOrtho(-5.0, 5.0, -5.0*(GLfloat)h/(GLfloat)w,
5.0*(GLfloat)h/(GLfloat)w, -5.0, 5.0);
else
glOrtho(-5.0*(GLfloat)w/(GLfloat)h,
5.0*(GLfloat)w/(GLfloat)h, -5.0, 5.0, -5.0, 5.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

void main(void )
{
auxInitDisplayMode (AUX_SINGLE | AUX_RGBA);
auxInitPosition (0, 0, 500, 500);
auxInitWindow ("Bezier Curves");
myinit();
auxReshapeFunc (myReshape);
auxMainLoop(display);
}