我正在编写Pong游戏编码，但在创建对象时遇到了麻烦。我有工作代码，但它没有包含类或任何对象，因为它是面向对象编程类，我需要修复它。但是，现在我收到了一堆不同的错误消息（它在100之后停止显示）。他们中的大多数似乎正在处理我没有正确创建对象。
我从来没有使用过C ++中的对象（可能应该这样做，但是因为这个原因而一直在为这个课程搞砸并获得积分），但是由于这个学期正在逐渐减少，我真的需要做好在这个项目上。
更新 我已经设法摆脱了大多数错误，但仍然有一些让我难过。我编辑了我的代码以反映我所做的更改并更新了错误列表。
这是我的代码：
我的标题文件：
#include "stdafx.h"
#include <string>
#include <Windows.h>
#include <iostream>
//#include <conio.h>
#include <sstream>
#include <math.h>
//#include <gl\gl.h>
//#include <gl\glu.h>
#include "GL/freeglut.h"
#pragma comment(lib, "Opengl32.lib")
#define VK_W 0x57
#define VK_S 0x53
using namespace std;
class Pong {
public:
Pong();
std::string int2str;
void drawText(float x, float y, std::string text);
void drawPaddle(float x, float y, float width, float height);
void draw();
void enable2D(int width, int height);
void keyboard();
void vec2_norm(float& x, float &y);
void updateBall();
void gameOverCheck();
void update(int value);
//window size and update rate
int width;
int height;
int interval; // 60 frames per-second
//scoring
int p1Score; //Player 1's score
int p2Score; //Player 2's score
int winner;
//the paddles
int paddleWidth;
int paddleHeight;
int paddleSpeed;
float paddleLeftX;
float paddleLeftY;
float paddleRightX;
float paddleRightY;
//the ball
float ballPositionX;
float ballPositionY;
float ballDirectionX;
float ballDirectionY;
int ballSize;
int ballSpeed;
};
我的.cpp文件：
#include "stdafx.h"
#include "PongGame.h"
#include <string>
#include <Windows.h>
#include <iostream>
//#include <conio.h>
#include <sstream>
#include <math.h>
//#include <gl\gl.h>
//#include <gl\glu.h>
#include "GL/freeglut.h"
#pragma comment(lib, "Opengl32.lib")
#define VK_W 0x57
#define VK_S 0x53
using namespace std;
Pong pong;
Pong::Pong() {
width = 500;
height = 300;
interval = 1000/60;
p1Score = 0;
p2Score = 0;
winner = 0;
paddleWidth = 10;
paddleHeight = 80;
paddleSpeed = 3;
paddleLeftX = 10.0f;
paddleLeftY = 50.0f;
paddleRightX = width - paddleWidth - 10;
paddleRightY = 50;
ballPositionX = width / 2;
ballPositionY = height / 2;
ballDirectionX = -1.0f;
ballDirectionY = 0.0f;
ballSize = 8;
ballSpeed = 3;
}
std::string int2str(int x) { //used to convert an integer to a string
std::stringstream ss;
ss << x;
return ss.str( );
}
void drawText(float x, float y, std::string text) {
glRasterPos2f(x, y);
glutBitmapString(GLUT_BITMAP_8_BY_13, (const unsigned char*)text.c_str());
}
void drawPaddle(float x, float y, float width, float height) {
glBegin(GL_QUADS);
glVertex2f(x, y);
glVertex2f(x + width, y);
glVertex2f(x + width, y + height);
glVertex2f(x, y + height);
glEnd();
}
void draw() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
//draws the paddles
drawPaddle(pong.paddleLeftX, pong.paddleLeftY, pong.paddleWidth, pong.paddleHeight);
drawPaddle(pong.paddleRightX, pong.paddleRightY, pong.paddleWidth, pong.paddleHeight);
//draws the ball
drawPaddle(pong.ballPositionX - pong.ballSize / 2, pong.ballPositionY- pong.ballSize / 2, pong.ballSize, pong.ballSize);
//draws the score at the top center of the screen
drawText(pong.width / 2 - 10, pong.height - 15, int2str(pong.p1Score) + ":" + int2str(pong.p2Score));
glutSwapBuffers();
}
void enable2D(int width, int height) {
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0f, width, 0.0f, height, 0.0f, 1.0f);
glMatrixMode (GL_MODELVIEW);
glLoadIdentity();
}
void keyboard() { //allows teh paddles to be controled from the keyboard
//moves left paddle (player 1)
if (GetAsyncKeyState(VK_W))
pong.paddleLeftY += pong.paddleSpeed; //move paddle up with "W" key
if (GetAsyncKeyState(VK_S))
pong.paddleLeftY -= pong.paddleSpeed; //move paddle down with "S" key
//moves right paddle (player 2)
if (GetAsyncKeyState(VK_UP))
pong.paddleRightY += pong.paddleSpeed; //move paddle up with "up" arrow
if (GetAsyncKeyState(VK_DOWN))
pong.paddleRightY -= pong.paddleSpeed; //move paddle down with "down" arrow
}
void vec2_norm(float& x, float &y) {
float length = sqrt((x * x) + (y * y));
if(length != 0.0f) {
length = 1.0f / length;
x *= length;
y *= length;
}
}
void updateBall() { //allows teh ball to move
pong.ballPositionX += pong.ballDirectionX * pong.ballSpeed;
pong.ballPositionY += pong.ballDirectionY * pong.ballSpeed;
if(pong.ballPositionX < pong.paddleLeftX + pong.paddleWidth && pong.ballPositionX > pong.paddleLeftX && pong.ballPositionY < pong.paddleLeftY + pong.paddleHeight && pong.ballPositionY > pong.paddleLeftY) { //if ball is hit by player 1's paddle
float t = ((pong.ballPositionY - pong.paddleLeftY) / pong.paddleHeight) - 0.5f;
pong.ballDirectionX = fabs(pong.ballDirectionX);
pong.ballDirectionY = t;
}
if (pong.ballPositionX > pong.paddleRightX && pong.ballPositionX < pong.paddleRightX + pong.paddleWidth && pong.ballPositionY < pong.paddleRightY + pong.paddleHeight && pong.ballPositionY > pong.paddleRightY) { //if ball is hit by player 2's paddle
float t = ((pong.ballPositionY - pong.paddleRightY) / pong.paddleHeight) - 0.5f;
pong.ballDirectionX = -fabs(pong.ballDirectionX);
pong.ballDirectionY = t;
}
if (pong.ballPositionX < 0) { //if ball hits the top wall
++pong.p2Score;
pong.ballPositionX = pong.width / 2;
pong.ballPositionY = pong.height / 2;
pong.ballDirectionX = fabs(pong.ballDirectionX);
pong.ballDirectionY = 0;
}
if (pong.ballPositionX > pong.width) { //if ball hits the right wall
++pong.p1Score;
pong.ballPositionX = pong.width / 2;
pong.ballPositionY = pong.height / 2;
pong.ballDirectionX = -fabs(pong.ballDirectionX);
pong.ballDirectionY = 0;
}
if (pong.ballPositionY > pong.height) { //ball hits top wall
pong.ballDirectionY = -fabs(pong.ballDirectionY);
}
if (pong.ballPositionY < 0) { //ball hits bottom wall
pong.ballDirectionY = fabs(pong.ballDirectionY);
}
vec2_norm(pong.ballDirectionX, pong.ballDirectionY);
}
void gameOverCheck() {
const int maxScore = 10;
if(pong.p1Score == maxScore) {
cout << "Player 1 Wins!" << endl;
pong.winner = 1;
}
else if(pong.p2Score == maxScore) {
cout << "Player 2 Wins!" << endl;
pong.winner = 2;
}
}
void update(int value) {
keyboard();
if(pong.winner == 0) {
updateBall();
glutTimerFunc(pong.interval, update, 0);
glutPostRedisplay();
gameOverCheck();
}
}
我的主要档案：
//PongGameTest.cpp
#include "stdafx.h"
#include "PongGame.h"
#include <string>
#include <Windows.h>
#include <iostream>
//#include <conio.h>
#include <sstream>
#include <math.h>
//#include <gl\gl.h>
//#include <gl\glu.h>
#include "GL/freeglut.h"
#pragma comment(lib, "Opengl32.lib")
#define VK_W 0x57
#define VK_S 0x53
using namespace std;
int _tmain(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(500, 200);
glutCreateWindow("Pong");
glutDisplayFunc(pong.draw);
glutTimerFunc(pong.interval, pong.update, 0);
pong.enable2D(pong..width, pong.height);
glColor3f(1.0f, 0.0f, 0.0f);
glutMainLoop();
return 0;
}
我确信你们都会讨厌我，但这是我编译时遇到的错误：
1> PongGameTest.cpp
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(25): error C2065: 'pong' : undeclared identifier
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(25): error C2228: left of '.draw' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(26): error C2065: 'pong' : undeclared identifier
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(26): error C2228: left of '.interval' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(26): error C2065: 'pong' : undeclared identifier
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(26): error C2228: left of '.update' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(28): error C2065: 'pong' : undeclared identifier
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(28): error C2228: left of '.enable2D' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(28): error C2065: 'pong' : undeclared identifier
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(28): error C2059: syntax error : '.'
1>c:\users\hitechredneck\desktop\fall 2014\object-oriented programming\game\ponggame\ponggame\ponggametest.cpp(29): error C2228: left of '.glColor3f' must have class/struct/union
1> type is ''unknown-type''
我很清楚没有人会阅读所有这些消息（我知道我肯定不会）但是你可以浏览它们，看看你是否可以弄清楚我做错了什么？就像我说的那样，我几乎100％肯定他们中的许多人都不能正确地创建对象并正确使用它的成员。
答案 0 :(得分：5)
1
Pong Pong;
是非法的：您不能声明类型名称为标识符的对象。这可能是Pong pong。
2
Pong::enable2D()
是非法的：enable2D不是静态函数，而是成员（每个实例）函数，因此您可以通过对象调用它，例如pong.enable2D();。< / p>
3
extern Pong pong; // in the header
Pong pong; // and both of these in the source
Pong Pong;
这绝对是错误的。你想做什么？无论全局与否，您都无法声明Pong类型为Pong的对象，如上所述（1）。你也许不想在main函数中使用全局但只是一个自动变量。
错误C2143：语法错误：缺少＆＃39;;＆＃39;之前＆＃39;。＆＃39;
如果编译器没有标识符声明，它将无法接受令牌.，而是期待;。
错误C2248：＆＃39; Pong :: height＆＃39; ：无法访问在课程中声明的私人成员＆＃39; Pong＆＃39;
这与C ++编译器错误一样清晰。
请阅读a good C++ beginner book并解决此类后勤问题。互联网不是一个好老师，它是一个很好的参考图书馆，但它不能代替一本好书。