使用评估器使用 opengl 的插值曲线

问题描述

这段代码几乎可以工作，但问题是它留下了最后一个控制点，就像它不存在一样。我找不到错误，我不知道为什么，我检查了很多次转换矩阵和转换后的控制点，但没有

#include <GL/glew.h>
#include <GL/freeglut.h>
#include <stdio.h>
#include <math.h>

// Begin globals.
static int numVal = 0;

// Final control points.
static float controlPoints[4][3] =
{
    {-30.0,0.0,0.0},{ -10.0,20.0,{10.0,-20.0,{30.0,0.0}
};



//Matrix multiplication Mb^-1 * Mi
static float conversion[4][4] =
{
    {1.0,{-0.8333,3.0,-1.5,0.3333},{0.3333,-0.8333},{0.0,1.0}
};


//End globals

//Control point conversion for evaluator
void convertcp(float ctrlpoints[4][3]){
    int i,j,k;
    float tot = 0.0;
    for(i = 0; i < 4;i++){
        for(j = 0;j < 4;j++){
            ctrlpoints[i][j] = 0;
            for(k = 0; k < 3;k++){
                ctrlpoints[i][j] += conversion[i][k] * controlPoints[k][j];
            }
        }
    }
}

// End globals.

// Initialization routine.
void setup(void){glClearColor(1.0,1.0,0.0);}


// Drawing routine.
void drawScene(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glColor3f(0.0,0.0);

    int indx;
    float ctrlpoints[4][3];
    convertcp(ctrlpoints);


    // Draw the control polygon in light gray.
    glColor3f(0.7,0.7,0.7);
    glBegin(GL_LINE_STRIP);
    for (indx = 0; indx < 4; indx++)
        glVertex3fv(controlPoints[indx]);
    glEnd();

    // Specify and enable the Bezier curve.
    glMap1f(GL_MAP1_VERTEX_3,3,4,&ctrlpoints[0][0]);
    glEnable(GL_MAP1_VERTEX_3);

    // Draw the Bezier curve by defining a sample grid and evaluating on it.
    glColor3f(0.0,0.0);
    glMapGrid1f(100,1.0);
    glEvalMesh1(GL_LINE,100);
    // Draw the Bezier control points as dots.
    glPointSize(5.0);
    glColor3f(0.0,0.0);
    glBegin(GL_POINTS);
    for (indx = 0; indx < 4; indx++)
        glVertex3fv(controlPoints[indx]);
    glEnd();

    // Highlight selected control point,glColor3f(1.0,0.0);
    glBegin(GL_POINTS);
    glVertex3fv(controlPoints[numVal]);
    glEnd();

    glutSwapBuffers();
    glutPostRedisplay();
}

// OpenGL window reshape routine.
void resize(int w,int h)
{
    glViewport(0,w,h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-50.0,50.0,-50.0,-1.0,1.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

// Keyboard input processing routine.
void keyInput(unsigned char key,int x,int y)
{
    switch (key)
    {
    case 27:
        exit(0);
        break;
    case ' ':
        if (numVal < 3) numVaL++;
            else numVal = 0;
        glutPostRedisplay();
        break;
    default:
        break;
    }
}

// Callback routine for non-ASCII key entry.
void specialKeyInput(int key,int y)
{

    if(key == gluT_KEY_UP) controlPoints[numVal][2] += 1.0;
    if(key == gluT_KEY_DOWN) controlPoints[numVal][2] -= 1.0;
    if(key == gluT_KEY_LEFT) controlPoints[numVal][0] -= 1.0;
    if(key == gluT_KEY_RIGHT) controlPoints[numVal][0] += 1.0;
    glutPostRedisplay();
}

// Routine to output interaction instructions to the console window.
void printInteraction(void)
{
    printf("Interaction:\n");
    printf("Press space to select a control point.\n");
    printf("Press the arrow keys to move the selected control point.\n");
}

// Main routine.
int main(int argc,char **argv)
{
    glutinit(&argc,argv);

    glutinitContextVersion(4,3);
    glutinitContextProfile(gluT_COMPATIBILITY_PROFILE);

    glutinitdisplayMode(gluT_DOUBLE | gluT_RGBA);
    glutinitwindowSize(500,500);
    glutinitwindowPosition(100,100);
    glutCreateWindow("Interpolating Curves");
    glutdisplayFunc(drawScene);
    glutReshapeFunc(resize);
    glutKeyboardFunc(keyInput);
    glutSpecialFunc(specialKeyInput);

    glewExperimental = GL_TRUE;
    glewInit();

    setup();

    glutMainLoop();
}

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

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