C ++:从openGL去除摩尔纹效果 [英] C++: Removing Moire effect from openGL

问题描述

我绘制的图案具有详细的像素，并且经常会遇到莫尔效应.我不擅长着色，我不确定着色器是否可以解决此问题.我还没有找到任何基本的，可理解的和完整的着色器示例.大多数教程网站都从中间开始一个程序，省略了头文件包括的内容！

这是我代码的MWE.是否可以减轻或消除莫尔效应?

  #include< cmath>#include< vector>#ifdef __APPLE__#include< GLUT/glut.h>#别的#include< GL/glut.h>#万一const int w = 640，h = 480;浮动cam_angle = 0.0f;无效的init(){GLfloat LightAmbient [] = {0.2f，0.2f，0.2f，1.0f};GLfloat LightDiffuse [] = {0.5f，0.5f，0.5f，1.0f};GLfloat LightPosition [] = {5.0f，5.0f，-10.0f，1.0f};glClearColor(0.0，0.0，0.0，0.0);glShadeModel(GL_SMOOTH);glEnable(GL_DEPTH_TEST);glLightfv(GL_LIGHT1，GL_AMBIENT，LightAmbient);glLightfv(GL_LIGHT1，GL_DIFFUSE，LightDiffuse);glLightfv(GL_LIGHT1，GL_POSITION，LightPosition);glEnable(GL_LIGHT1);}无效的onDisplay(){glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glClearColor(1.0f，1.0f，1.0f，1.0f);glMatrixMode(GL_PROJECTION);glLoadIdentity();gluPerspective(90，float(w)/float(h)，0.01，10000);glMatrixMode(GL_MODELVIEW);glLoadIdentity();const double pi = 3.1415926;double cam_x = 2.0 * cos(pi/4.0)* cos(cam_angle);;double cam_y = 2.0 * sin(pi/4.0)* cos(cam_angle);;double cam_z = 2.0 * sin(cam_angle);gluLookAt(cam_x，cam_y，cam_z，0，0，0，0，0，1);结构Point3D{x，y，z的两倍；无符号字符r，g，b，a = 255;};for(双倍r = 0.5; r <= 1.0; r + = 0.03){std :: vector< Point3D>点for(int i = 0; i <1000; i ++){double theta = double(i)/1000.0*pi*2.0;Point3D p;p.x = r * sin(theta);p.y = r * cos(theta);p.z = r;p.r = 128；p.g = 200；p.b = 50；points.push_back(p);}//画glPushMatrix();glColor3ub(255,255,255);glEnableClientState(GL_VERTEX_ARRAY);glEnableClientState(GL_COLOR_ARRAY);glVertexPointer(3，GL_DOUBLE，sizeof(Point3D)，& points [0] .x);glColorPointer(4，GL_UNSIGNED_BYTE，sizeof(Point3D)，& points [0] .r);//glPointSize(3.0);glLineWidth(2.0);glDrawArrays(GL_LINE_STRIP，0，int(points.size()));glDisableClientState(GL_VERTEX_ARRAY);glDisableClientState(GL_COLOR_ARRAY);glPopMatrix();}glFlush();glutSwapBuffers();}void Timer(int/*值*/){cam_angle + = 0.01f;glutPostRedisplay();//100毫秒glutTimerFunc(100，计时器，0);}int main(int argc，char ** argv){glutInit(& argc，argv);glutInitWindowSize(w，h);glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);glutInitWindowPosition(100，100);glutCreateWindow(我的窗口")；glBlendFunc(GL_SRC_ALPHA，GL_ONE_MINUS_SRC_ALPHA);glEnable(GL_BLEND);在里面();glutDisplayFunc(onDisplay);计时器(0);glutMainLoop();返回0;} 

解决方案

如果使用

带有 GLUT_MULTISAMPLE :

另请参见 GLUT + OpenGL多采样抗锯齿(MSAA) >

I draw patterns which have detailed pixels and they often face with Moire effect. I am not good at shading and I am not sure if this problem will be solved by shaders. I have not found any basic, understandable and complete example of shaders. Most of the tutorial websites start a program from the middle omitting the header file includes!

This is a MWE of my code. Is it possible to mitigate or remove the Moire effect from it?

#include <cmath>
#include <vector>

#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

const int w=640,h=480;
float cam_angle=0.0f;

void init()
{
    GLfloat LightAmbient[] = { 0.2f, 0.2f, 0.2f, 1.0f };
    GLfloat LightDiffuse[] = { 0.5f, 0.5f, 0.5f, 1.0f };
    GLfloat LightPosition[] = { 5.0f, 5.0f, -10.0f, 1.0f };

    glClearColor(0.0, 0.0, 0.0, 0.0);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_DEPTH_TEST);
    glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient);
    glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse);
    glLightfv(GL_LIGHT1, GL_POSITION, LightPosition);
    glEnable(GL_LIGHT1);
}

void onDisplay()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective (90, float(w)/float(h), 0.01, 10000);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    const double pi=3.1415926;
    double cam_x=2.0*cos(pi/4.0)*cos(cam_angle);;
    double cam_y=2.0*sin(pi/4.0)*cos(cam_angle);;
    double cam_z=2.0*sin(cam_angle);
    gluLookAt(cam_x, cam_y, cam_z,  0, 0, 0, 0, 0, 1);

    struct Point3D
    {
        double x, y, z;
        unsigned char r, g, b, a=255;
    };

    for(double r=0.5;r<=1.0;r+=0.03)
    {
        std::vector<Point3D> points;
        for(int i=0;i<1000;i++)
        {
            double theta=double(i)/1000.0*pi*2.0;
            Point3D p;
            p.x=r*sin(theta);
            p.y=r*cos(theta);
            p.z=r;
            p.r=128;
            p.g=200;
            p.b=50;
            points.push_back(p);
        }
    // draw
        glPushMatrix();
        glColor3ub(255,255,255);
        glEnableClientState( GL_VERTEX_ARRAY );
        glEnableClientState( GL_COLOR_ARRAY );
        glVertexPointer(3, GL_DOUBLE, sizeof(Point3D), &points[0].x );
        glColorPointer( 4, GL_UNSIGNED_BYTE, sizeof(Point3D), &points[0].r );
        // glPointSize( 3.0 );
        glLineWidth(2.0);
        glDrawArrays( GL_LINE_STRIP, 0, int(points.size()) );
        glDisableClientState( GL_VERTEX_ARRAY );
        glDisableClientState( GL_COLOR_ARRAY );
        glPopMatrix();
    }

    glFlush();
    glutSwapBuffers();
}

void Timer(int /*value*/)
{
    cam_angle+=0.01f;
    glutPostRedisplay();
    // 100 milliseconds
    glutTimerFunc(100, Timer, 0);
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitWindowSize (w, h);
    glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
    glutInitWindowPosition (100, 100);
    glutCreateWindow ("my window");
    glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_BLEND);

    init();
    glutDisplayFunc(onDisplay);
    Timer(0);
    glutMainLoop();

    return 0;
}

解决方案

If you use Multisampling, then the result will be significantly improved:

glutSetOption(GLUT_MULTISAMPLE, 8);
glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE | GLUT_MULTISAMPLE);

without GLUT_MULTISAMPLE:

with GLUT_MULTISAMPLE:

See also the answer to GLUT + OpenGL multisampling anti aliasing (MSAA)

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