c++ - OpenGL 错误。运行时立方体顶点位置错误？

Question

我正在创建 Minecraft 的新手版本克隆。首先，我想渲染一个立方体并向所有面添加特定的纹理。我创建了一个 Block 类，它包含来自输​​入的顶点，并有一个名为 RenderBlock 的输出函数来渲染带有附加纹理的“ block ”。

这是输入 8 个数组的函数，代表 block 的 8 个顶点的 8 个坐标。

void Block::SetVertices(float UL[],float UR[],float ZR[],float ZL[],float UL2[],float           UR2[],float ZR2[],float ZL2[])
{
  Front_Square[1][1]=UL[1];
  Front_Square[1][2]=UL[2];
  Front_Square[1][3]=UL[3];
  std::cout << "Front Top Left Coordinates" << std::endl;    
  std::cout << Front_Square[1][1] << ","<<Front_Square[1][2] << "," << Front_Square[1][3] << std::endl;
  Front_Square[2][1]=UR[1];
  Front_Square[2][2]=UR[2];
  Front_Square[2][3]=UR[3];
  std::cout << "Front Top Right Coordinates" << std::endl;    
  std::cout << Front_Square[2][1] << ","<<Front_Square[2][2] << "," << Front_Square[2][3] << std::endl;
  Front_Square[3][1]=ZR[1];
  Front_Square[3][2]=ZR[2];
  Front_Square[3][3]=ZR[3];
  std::cout << "Front Bottom Right Coordinates" << std::endl;    
  std::cout << Front_Square[3][1] << ","<<Front_Square[3][2] << "," << Front_Square[3][3] << std::endl;
  Front_Square[4][1]=ZL[1];
  Front_Square[4][2]=ZL[2];
  Front_Square[4][3]=ZL[3];
  std::cout << "Front Bottom Left Coordinates" << std::endl;    
  std::cout << Front_Square[4][1] << ","<<Front_Square[4][2] << "," << Front_Square[4][3] << std::endl;
  //--------------BACK SQUARE------------------------------------------------------------------------------------------------------------------------//  
  Back_Square[1][1]=UL2[1];
  Back_Square[1][2]=UL2[2];
  Back_Square[1][3]=UL2[3];

  Back_Square[2][1]=UR2[1];
  Back_Square[2][2]=UR2[2];
  Back_Square[2][3]=UR2[3];

  Back_Square[3][1]=ZR2[1];
  Back_Square[3][2]=ZR2[2];
  Back_Square[3][3]=ZR2[3];

  Back_Square[4][1]=ZL2[1];
  Back_Square[4][2]=ZL2[2];
  Back_Square[4][3]=ZL2[3]; 
};

这里是渲染 block 的函数。

void Block::RenderBlock(const char*SideTexture)
{
 glEnable(GL_TEXTURE_2D);
 Tex[1]=loadTexture(SideTexture); 
 glBindTexture(GL_TEXTURE_2D, Tex[1]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);  
 glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(Front_Square[1][1],Front_Square[1][2],Front_Square[1][3]);//FTL
glTexCoord2f(1.0f, 1.0f); glVertex3f(Front_Square[2][1],Front_Square[2][2],Front_Square[2][3]);//FTR
glTexCoord2f(1.0f, 0.0f); glVertex3f(Front_Square[3][1],Front_Square[3][2],Front_Square[3][3]);//FBR
glTexCoord2f(0.0f, 0.0f); glVertex3f(Front_Square[4][1],Front_Square[4][2],Front_Square[4][3]);//FBL
     glEnd();

    glBindTexture(GL_TEXTURE_2D, Tex[1]);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(Back_Square[1][1],Back_Square[1][2],Back_Square[1][3]);//BTL
glTexCoord2f(1.0f, 1.0f); glVertex3f(Back_Square[2][1],Back_Square[2][2],Back_Square[2][3]);//BTR
glTexCoord2f(1.0f, 0.0f); glVertex3f(Back_Square[3][1],Back_Square[3][2],Back_Square[3][3]);//BBR
glTexCoord2f(0.0f, 0.0f); glVertex3f(Back_Square[4][1],Back_Square[4][2],Back_Square[4][3]);//BBL
     glEnd();


    glBindTexture(GL_TEXTURE_2D, Tex[1]);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(Back_Square[1][1],Back_Square[1][2],Back_Square[1][3]);//BTL
glTexCoord2f(1.0f, 1.0f); glVertex3f(Front_Square[1][1],Front_Square[1][2],Front_Square[1][3]);//FTL
glTexCoord2f(1.0f, 0.0f); glVertex3f(Front_Square[4][1],Front_Square[4][2],Front_Square[4][3]);//FBL
glTexCoord2f(0.0f, 0.0f); glVertex3f(Back_Square[4][1],Back_Square[4][2],Back_Square[4][3]);//BBL
     glEnd();

    glBindTexture(GL_TEXTURE_2D, Tex[1]);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(Back_Square[2][1],Back_Square[2][2],Back_Square[2][3]);//BTR
glTexCoord2f(1.0f, 1.0f); glVertex3f(Front_Square[2][1],Front_Square[2][2],Front_Square[2][3]);//FTR
glTexCoord2f(1.0f, 0.0f); glVertex3f(Front_Square[3][1],Front_Square[3][2],Front_Square[3][3]);//FBR
glTexCoord2f(0.0f, 0.0f); glVertex3f(Back_Square[3][1],Back_Square[3][2],Back_Square[3][3]);//BBR
     glEnd();

     glBindTexture(GL_TEXTURE_2D, Tex[1]);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(Back_Square[4][1],Back_Square[4][2],Back_Square[4][3]);//BBL
glTexCoord2f(1.0f, 1.0f); glVertex3f(Back_Square[3][1],Back_Square[3][2],Back_Square[3][3]);//BBR
glTexCoord2f(1.0f, 0.0f); glVertex3f(Front_Square[3][1],Front_Square[3][2],Front_Square[3][3]);//FBR
glTexCoord2f(0.0f, 0.0f); glVertex3f(Front_Square[4][1],Front_Square[4][2],Front_Square[4][3]);//FBL
     glEnd();

    glBindTexture(GL_TEXTURE_2D, Tex[1]);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glBegin(GL_QUADS);
glTexCoord2f(0.0f, 1.0f); glVertex3f(Back_Square[1][1],Back_Square[1][2],Back_Square[1][3]);//BTL
glTexCoord2f(1.0f, 1.0f); glVertex3f(Back_Square[2][1],Back_Square[2][2],Back_Square[2][3]);//BTR
glTexCoord2f(1.0f, 0.0f); glVertex3f(Front_Square[2][1],Front_Square[2][2],Front_Square[2][3]);//FTR
glTexCoord2f(0.0f, 0.0f); glVertex3f(Front_Square[1][1],Front_Square[1][2],Front_Square[1][3]);//FTL
     glEnd();
    glDisable(GL_TEXTURE_2D);
     };

2 个数组用于方 block 泥土和草地污垢

float TL[] = {0.0f,-1.0f,1.0f,0.0f};
float TR[] = {0.0f,1.0f,1.0f,0.0f};
float BR[] = {0.0f,1.0f,-1.0f,0.0f};
float BL[] = {0.0f,-1.0f,-1.0f,0.0f};
float TL2[] = {0.0f,-1.0f,1.0f,-2.0f};
float TR2[] = {0.0f,1.0f,1.0f,-2.0f};
float BR2[] = {0.0f,1.0f,-1.0f,-2.0f};
float BL2[] = {0.0f,-1.0f,-1.0f,-2.0f}

草

float DTL[] = {0.0f,-1.0f,1.0f+Grass_XChan,0.0f};
float DTR[] = {0.0f,1.0f,1.0f+Grass_XChan,0.0f};
float DBR[] = {0.0f,1.0f,-1.0f+Grass_XChan,0.0f};
float DBL[] = {0.0f,-1.0f,-1.0f+Grass_XChan,0.0f};
float DTL2[] = {0.0f,-1.0f,1.0f+Grass_XChan,-2.0f};
float DTR2[] = {0.0f,1.0f,1.0f+Grass_XChan,-2.0f};
float DBR2[] = {0.0f,1.0f,-1.0f+Grass_XChan,-2.0f};
float DBL2[] = {0.0f,-1.0f,-1.0f+Grass_XChan,-2.0f};

抱歉代码太长。如果你想看的话，这里是 Main.cpp。

#include <GL/glut.h>
#include <iostream>
#include <assert.h>
#include <fstream>
#include "block.h"
using namespace std;
float positionX = 0.0f;
float positionY = 0.0f;
float positionZ = -4.0f;
float angle = 0.0f;
float RotX=0.01f;
float RotY=0.0f;
float RotZ=0.0f;
float Grass_XChan=2.0f;
float Grass_ZChan=-2.0f;
bool Render = true;
Block Dirt;
Block Grass;
float TL[] = {0.0f,-1.0f,1.0f,0.0f};
float TR[] = {0.0f,1.0f,1.0f,0.0f};
float BR[] = {0.0f,1.0f,-1.0f,0.0f};
float BL[] = {0.0f,-1.0f,-1.0f,0.0f};
float TL2[] = {0.0f,-1.0f,1.0f,-2.0f};
float TR2[] = {0.0f,1.0f,1.0f,-2.0f};
float BR2[] = {0.0f,1.0f,-1.0f,-2.0f};
float BL2[] = {0.0f,-1.0f,-1.0f,-2.0f};

float DTL[] = {0.0f,-1.0f,1.0f+Grass_XChan,0.0f};
float DTR[] = {0.0f,1.0f,1.0f+Grass_XChan,0.0f};
float DBR[] = {0.0f,1.0f,-1.0f+Grass_XChan,0.0f};
float DBL[] = {0.0f,-1.0f,-1.0f+Grass_XChan,0.0f};
float DTL2[] = {0.0f,-1.0f,1.0f+Grass_XChan,-2.0f};
float DTR2[] = {0.0f,1.0f,1.0f+Grass_XChan,-2.0f};
float DBR2[] = {0.0f,1.0f,-1.0f+Grass_XChan,-2.0f};
float DBL2[] = {0.0f,-1.0f,-1.0f+Grass_XChan,-2.0f};
void display(void)
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glTranslatef(positionX, positionY, positionZ);
  glPushMatrix();
  glRotatef(angle,RotX,RotY,RotZ);
  Dirt.RenderBlock("C:/Users/Progr_Anim/Desktop/textures/DirtBottom.bmp");
  Grass.RenderBlock("C:/Users/Progr_Anim/Desktop/textures/GrassTop.bmp");

  glPopMatrix();
  glutSwapBuffers();
   }
  //-------------------------------------------------------------------------------------------------------------------------------------------
    void HandleResize(int w, int h) {
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45.0, (float)w / (float)h, 1.0, 200.0);
   }
   void Camera(unsigned char key,int x,int y)
   {
   switch(key)
 {
  case 'w':
       positionZ += 0.08f;
       break;
  case 's':
       positionZ -= 0.08f;
       break;
  case 'a':
       positionX += 0.08f;
       break;
  case 'd':
       positionX -= 0.08f;
       break;
  case 'c':
       if(angle>=360.0f)
       {
       angle=0.0f;                
       }
       angle+=5.0f;
       break;
  case '1':
       angle = 0.0f;
       RotX=1.0f;
       RotY=0.0f;
       RotZ=0.0f;
       break;
  case '2':
       angle = 0.0f;
       RotX=0.0f;
       RotY=1.0f;
       RotZ=0.0f;
       break;
  case '3':
       angle = 0.0f;
       RotX=0.0f;
       RotY=0.0f;
       RotZ=1.0f;
       break;
  case 'q':
       exit(0);
       break;
     }     
  }
 int main(int argc, char** argv)
 {
   Dirt.SetVertices(TL,TR,BR,BL,TL2,TR2,BR2,BL2);
   Grass.SetVertices(DTL,DTR,DBR,DBL,DTL2,DTR2,DBR2,DBL2);
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
   //Create Window
   glutInitWindowSize(640,480);
   glutCreateWindow("Love");
   glEnable(GL_DEPTH_TEST);
   glEnable(GL_COLOR_MATERIAL);
   glutDisplayFunc(display);
   glutReshapeFunc(HandleResize);
   glutKeyboardFunc(Camera);
   glutIdleFunc(display);
   glutMainLoop();
     return 0;
    }

这是带有旋转立方体的视频，顶部是草方 block ，底部是泥土方 block 。 Link

Answer 1

我要赌一下这里的答案，因为我认为帖子中的信息不够。

这段代码中的数组被当作第 0 个元素不存在一样使用，并且使用的数组定义在前面有一个额外的零作为填充。

但是有些数组没有在此处的代码中定义，必须在别处声明，可能带有大小。我猜测这个大小对于 1 索引数组是错误的。

即back_square 和 front_square 可能声明如下:

float back_square[4][3];

而不是:

float back_square[5][4];

这就是它们的使用方式。

结果将是未定义的行为，在这种情况下可能是顶点的覆盖，折叠立方体的一个角。

无论哪种方式，我都强烈建议不要以这种方式使用数组，并习惯从零开始的事情。