我有一个似乎很常见的问题，但我似乎无法在我的代码上下文中解决它。我最近开始了一门课，我被投入到C++和OpenGL中，没有C++的先验知识，所以请对我放轻松。这是我的 3 个文件，旨在打开一个 OpenGL 窗口;但是我遇到了一个很好的LNK2005错误：
我错误 LNK2005："public： static unsigned int JWindow：：id" （？id@JWindow@@2IA） 已在 Application.obj X：\School\comp2501\COMP2501Tutorial1\COMP2501Tutorial1\Main.obj COMP2501Tutorial1 中定义
似乎找不到我在哪里重新定义的东西来给我这个错误。
主.cpp
#include <windows.h> // Standard header for MS JWindows applications
#include <freeglut.h>
#include "Application.h"
#define KEY_ESCAPE 27
static GLfloat lightPos[] = { 1.0, 1.0, 1.0, 0.0 };
void drawCube(GLdouble x0, GLdouble x1, GLdouble y0, GLdouble y1, GLdouble z0, GLdouble z1) {/**/}
int main(int argc, char **argv) {
JWindow::create(640, 480, "Tutorial 1", 45.0f, 0.1f, 500.0f);
// initialize and run program
glutInit(&argc, argv); // GLUT initialization
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH); // Display Mode (RGBA color|two screen buffers| use depth buffer)
glutInitWindowSize(JWindow::width, JWindow::height); // set JWindow size
glutDisplayFunc(JWindow::display); // register display function
glutIdleFunc(JWindow::display); // register idle function
glutKeyboardFunc(JWindow::keyboard); // register keyboard function
glutCloseFunc(JWindow::close); // register close function
JWindow::initialize(); // intialization
glutMainLoop(); // run GLUT mainloop
}
应用.h
class JWindow{
public:
static void updateProjection();
static void render();
static void initialize();
static void timer(int);
static void display();
static void close();
static void create(int, int, char*, float, float, float);
static void keyboard(unsigned char, int, int);
static GLuint id;
static char* title;
static int width;
static int height;
static float fovAngle;
static float zNear;
static float zFar;
};
GLuint JWindow::id = 0;
char* JWindow::title = "JWindow";
int JWindow::width = 0;
int JWindow::height = 0;
float JWindow::fovAngle = 0.0f;
float JWindow::zNear = 0.0f;
float JWindow::zFar = 0.0f;
应用.cpp
#include <freeglut.h>
#include "Application.h"
#define KEY_ESCAPE 27
void JWindow::updateProjection()
{
glutSetWindow(JWindow::id); // tell opengl which JWindow you want to change
JWindow::height = (JWindow::height < 1) ? 1 : JWindow::height; // make sure we are not dividing by zero for the aspect
glViewport(0, 0, JWindow::width, JWindow::height); // set the viewport
glMatrixMode(GL_PROJECTION); // select projection matrix
glLoadIdentity(); // reset projection matrix
GLfloat aspect = (GLfloat)JWindow::width / JWindow::height; // calculate aspect ratio
gluPerspective(JWindow::fovAngle, aspect, JWindow::zNear, JWindow::zFar); // set up a perspective projection matrix
}
// Render data to the screen
void JWindow::render()
{
glClearColor(0.25f, 0.25f, 0.25f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen and Depth Buffer
glMatrixMode(GL_MODELVIEW); // Tell opengl we are working with the modelview matrix
glLoadIdentity(); // Set the modelview matrix to the identity matrix
gluLookAt(0.0f, 0.0f, 10.0f, //position
0.0f, 0.0f, 0.0f, //look at position
0.0f, 1.0f, 0.0f); //up vector
/*
glBegin(GL_TRIANGLES); // Send the following information as triangles
glColor4f(1.0f, 0.0f, 0.0f, 1.0f); // glColor4f(red,green,blue,alpha)
glVertex3f(-1.0f, -1.0f, 0.0f); // glVertex3f(x,y,z)
glColor4f(0.0f, 1.0f, 0.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 0.0f);
glColor4f(0.0f, 0.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, 0.0f);
glEnd(); // tell opengl we are done sending data
*/
//drawCube(-1, 1, -1, 1, -1, 1);
glutSolidTorus(1, 2, 10, 10);
glutSwapBuffers(); //works with GL_DOUBLE. use glFlush(); instead, if using GL_SINGLE
}
// Function called when timer ends
void JWindow::timer(int id) {
glutPostRedisplay(); // Tell GLUT to call it's glutDisplayFunc
}
// Set new timer and render
void JWindow::display(void)
{
glutTimerFunc(17, timer, 1); //Call timer function in at least 17 milliseconds
glutSetWindow(JWindow::id); //Tell glut which JWindow we are working on (only needed for multiple JWindows)
JWindow::render(); //Call our render function
}
//get keyboard input
void JWindow::keyboard(unsigned char key, int mousePositionX, int mousePositionY)
{
switch (key)
{
case KEY_ESCAPE:
glutExit(); //if ESC key is pressed, quit
break;
default:
break;
}
}
// callback function when glut ends
void JWindow::close()
{
//memory cleanup when program quits
}
void JWindow::initialize()
{
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glClearColor(0.0, 0.0, 0.0, 1.0);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glViewport(0, 0, JWindow::width, JWindow::height); // set the viewport
glMatrixMode(GL_PROJECTION); // select projection matrix
glLoadIdentity(); // reset projection matrix
GLfloat aspect = (GLfloat)JWindow::width / JWindow::height; // calculate aspect ratio
gluPerspective(JWindow::fovAngle, aspect, JWindow::zNear, JWindow::zFar); // set up a perspective projection matrix
}
void reshape(GLint newWidth, GLint newHeight) {
}
void JWindow::create(int w, int h, char* t, float fov, float n, float f){
JWindow::width = w;
JWindow::height = h;
JWindow::title = t;
JWindow::fovAngle = fov;
JWindow::zNear = n;
JWindow::zFar = f;
JWindow::id = glutCreateWindow(JWindow::title);
}
您应该将静态成员的初始化移动到Application.cpp文件中：
GLuint JWindow::id = 0;
char* JWindow::title = "JWindow";
int JWindow::width = 0;
int JWindow::height = 0;
float JWindow::fovAngle = 0.0f;
float JWindow::zNear = 0.0f;
float JWindow::zFar = 0.0f;
这些是静态成员的定义。如果将它们包含在多个翻译单元中（您已经完成），则有多个定义。