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我正在创建一个名为 Square 的类和函数来计算 x、y、z 位置以创建 4 个顶点以在 OpenGL 中渲染一个正方形。

错误

8       [Error] expected constructor, destructor, or type conversion before '.' token
8       [Error] expected `,' or `;' before '.' token
9       [Error] expected constructor, destructor, or type conversion before '.' token
9       [Error] expected `,' or `;' before '.' token

这是main.cpp

#include <GL/glut.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include "Square2D.h"
SquareD Love;
Love.SetOrigin(0.0f,0.0f,0.0f);
Love.CalcVert(2.0f);

void Display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW); //Switch to the drawing perspective
glLoadIdentity(); //Reset the drawing perspective
Love.RenderSquare();
glTranslatef(0.0f,0.0f,-5.0f);
glutSwapBuffers();
};

void reshape(int w, int h) 
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); //Reset the camera
gluPerspective(45.0,(double)w/(double)h,1.0,200.0);
}
int main(int argc, char** argv)
{
//Init
glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
//Create Window
glutInitWindowSize(640,480);
    glutInitWindowPosition(40,40);
    glutCreateWindow("OpenGLUT Shapes");
//OpenGL Enables for effects
glEnable(GL_DEPTH_TEST);
    glEnable(GL_COLOR_MATERIAL);
//Functions
glutDisplayFunc(Display);
glutReshapeFunc(reshape);
//Main OpenGL loop
glutMainLoop();
//Return success//C++ requirement
return 0;
}

这是 SquareD 类的头文件

#ifndef XYZSQUARE_H
#define XYZSQUARE_H
// No description
class SquareD
{
public:
    // class constructor
    SquareD();
    // class destructor
    ~SquareD();

    void SetOrigin(float X,float Y,float Z);
    void RenderSquare();
    void CalcVert(float lenght);

    private:
    float TL_X,TL_Y,TL_Z;
    float TR_X,TR_Y,TR_Z;
    float BL_X,BL_Y,BL_Z;
    float BR_X,BR_Y,BR_Z;
    float Lenght;
    float OriginX,OriginY,OriginZ;
    };
    #endif // SQUARE_H

SquareD 类的 .cpp 文件

#include <GL/glut.h>
#include "Square2D.h" // class's header file
// class constructor
SquareD::SquareD()
{
// insert your code here
}
// class destructor
SquareD::~SquareD()
{
// insert your code here
}
void SquareD::SetOrigin(float X,float Y,float Z)
{
    OriginX=X;//X
    OriginY=Y;//Y
    OriginZ=Z;//Z
};
void SquareD::CalcVert(float lenght)
{
 Lenght=lenght/2;
 //Left Front
 TL_X =OriginX-Lenght;//X
 TL_Y =OriginY;       //Y
 TL_Z =OriginZ+Lenght;//Z
 //Right Front
 TR_X =OriginX+Lenght;//X
 TR_Y =OriginY;       //Y
 TR_Z =OriginZ+Lenght;//Z
 //Left Back
 BL_X =OriginX-Lenght;//X
 BL_Y =OriginY;       //Y
 BL_Z =OriginZ-Lenght;//Z
 //Right Back
 BR_X =OriginX+Lenght;//X
 BR_Y=OriginY;       //Y
 BR_Z=OriginZ-Lenght;//Z
};
void SquareD::RenderSquare()
{
     glVertex3f(TL_X,TL_Y,TL_Z);
 glVertex3f(TR_X,TR_Y,TR_Z);
 glVertex3f(BL_X,BL_Y,BL_Z);
 glVertex3f(BR_X,BR_Y,BR_Z);
};

是什么导致了错误，为什么？

4

1 回答 1

1

您的代码中有几个问题。

首先，你不能调用这样的函数（断章取义）。如果您在 main 中调用函数，那么它将起作用：

int main()
{
  Love.SetOrigin(0.0f,0.0f,0.0f);
  Love.CalcVert(2.0f);
  // rest of code
  // ...
}

其次，您需要在渲染时调用glBegin/ ：glEnd

void SquareD::RenderSquare()
{
  glBegin( GL_QUADS );
     glVertex3f(TL_X,TL_Y,TL_Z);
     glVertex3f(TR_X,TR_Y,TR_Z);
     glVertex3f(BL_X,BL_Y,BL_Z);
     glVertex3f(BR_X,BR_Y,BR_Z);
  glEnd();
};

如果您正确计算了顶点，并且正确设置了视口，并且正确设置了休息，您应该会看到一个正方形。

于 2012-12-20T07:13:27.587 回答