前言
最近我正在使用Code::Blocks编程C++，但在尝试编译包含freeglut的项目时遇到了问题。我使用的是Windows 8操作系统，并按照code::blocks wiki正确安装了freeglut。我还安装了git bash和mingw64。问题在于，我无法使用Code::Blocks或在gitbash中使用g++命令编译我的教授（使用freeglut的项目）编写的源代码。
main.cpp:
/* Copyright (c) Mark J. Kilgard, 1996. */
/* This program is freely distributable without licensing fees
and is provided without guarantee or warrantee expressed or
implied. This program is -not- in the public domain. */
#include "Graphics.h"
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
setColor(RED);
drawFilledTriangle(0,0,100,100,200,0);
setColor(BLUE);
drawFilledCircle(200,200,150);
glFlush(); /* Single buffered, so needs a flush. */
}
int main(int argc, char **argv)
{
graphicsSetup( argc, argv, &display);
glutMainLoop();
return 0;
}
Graphics.cpp
#include <iostream>
using namespace std;
#include "Graphics.h"
#include <cmath>
const double PI = acos(-1.0);
const double ANGLE_STEP = PI/180.0;
void keyboard(unsigned char key, int x, int y)
{
if (key == 27)
exit(1);
}
void clearWindow() {
glClear( GL_COLOR_BUFFER_BIT );
}
void setColor(ColorName name) {
switch(name) {
case WHITE: glColor3d(1.0, 1.0, 1.0); break;
case GREY: glColor3d(0.4, 0.4, 0.4); break;
case BLACK: glColor3d(0.0, 0.0, 0.0); break;
case RED: glColor3d(1.0, 0.0, 0.0); break;
case ORANGE: glColor3d(1.0, 0.5, 0.0); break;
case YELLOW: glColor3d(1.0, 1.0, 0.0); break;
case GREEN: glColor3d(0.0, 1.0, 0.0); break;
case FOREST_GREEN: glColor3d(0.0, 0.25, 0.0); break;
case BLUE: glColor3d(0.0, 0.0, 1.0); break;
case CYAN: glColor3d(0.0, 1.0, 1.0); break;
case MIDNIGHT_BLUE: glColor3d(0.0, 0.0, 0.25); break;
case PURPLE: glColor3d(0.5, 0.25, 0.0); break;
case MAGENTA: glColor3d(1.0, 0.0, 1.0); break;
case BROWN: glColor3d(0.36, 0.16, 0.1); break;
default: cerr << "Trying to set invalid color. Color unchanged" << endl;
}
}
void graphicsSetup(int argc, char *argv[], void (*display)()) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB);
if (! glutGet(GLUT_DISPLAY_MODE_POSSIBLE))
glutInitDisplayMode(GLUT_INDEX);
glutInitWindowPosition(50,50);
glutInitWindowSize(640, 480);
glutCreateWindow("single triangle");
glClearColor(1.0,1.0,1.0,0.0);
glutDisplayFunc(display);
// set "esc" key to end program
glutKeyboardFunc(keyboard);
// set coordinates to "normal"
glLoadIdentity();
glOrtho(0,640,0,480, 1, -1);
}
void drawTriangle(int x1, int y1, int x2, int y2, int x3, int y3) {
glBegin(GL_LINE_STRIP);
glVertex2i(x1,y1);
glVertex2i(x2,y2);
glVertex2i(x3,y3);
glVertex2i(x1,y1);
glEnd();
}
void drawFilledTriangle(int x1, int y1, int x2, int y2, int x3, int y3) {
glBegin(GL_POLYGON);
glVertex2i(x1,y1);
glVertex2i(x2,y2);
glVertex2i(x3,y3);
glVertex2i(x1,y1);
glEnd();
}
void drawLine(int x1, int y1, int x2, int y2) {
glBegin(GL_LINE_STRIP);
glVertex2i(x1,y1);
glVertex2i(x2,y2);
glEnd();
}
void drawBox(int x1, int y1, int x2, int y2) {
glBegin(GL_LINE_STRIP);
glVertex2i(x1,y1);
glVertex2i(x2,y1);
glVertex2i(x2,y2);
glVertex2i(x1,y2);
glVertex2i(x1,y1);
glEnd();
}
void drawFilledBox(int x1, int y1, int x2, int y2) {
glBegin(GL_POLYGON);
glVertex2i(x1,y1);
glVertex2i(x2,y1);
glVertex2i(x2,y2);
glVertex2i(x1,y2);
glVertex2i(x1,y1);
glEnd();
}
void drawCircle(int x, int y, int radius) {
double angle;
int X, Y;
glBegin(GL_LINE_STRIP);
for (angle=0;angle< 2.0*PI + ANGLE_STEP; angle += ANGLE_STEP) {
X = x + int(double(radius) * cos(angle));
Y = y + int(double(radius) * sin(angle));
glVertex2i(X,Y);
}
glEnd();
}
void drawFilledCircle(int x, int y, int radius) {
double angle;
int X0, Y0, X1, Y1;
glBegin(GL_TRIANGLES);
X1 = x + radius;
Y1 = y;
for (angle=0;angle< 2.0*PI + ANGLE_STEP; angle += ANGLE_STEP) {
X0 = X1;
Y0 = Y1;
X1 = x + int(double(radius) * cos(angle));
Y1 = y + int(double(radius) * sin(angle));
glVertex2i(x,y);
glVertex2i(X0,Y0);
glVertex2i(X1,Y1);
}
glEnd();
}
Graphics.h
#include <GL/glut.h>
// set the pre-defined colors
enum ColorName {
WHITE,
GREY,
BLACK,
RED,
ORANGE,
YELLOW,
GREEN,
FOREST_GREEN,
BLUE,
MIDNIGHT_BLUE,
CYAN,
PURPLE,
MAGENTA,
BROWN,
NUM_COLORS
};
void clearWindow();
void setColor(ColorName name);
void graphicsSetup(int argc, char *argv[], void (*display)());
// graphic object primatives
void drawTriangle(int x1, int y1,int x2,int y2,int x3,int y3);
void drawLine(int x1, int y1, int x2, int y2);
void drawBox(int x1, int y1, int x2, int y2); // x-y coords of upper-right and lower-left corners
void drawCircle(int x, int y, int radius);
// filled graphics primatives
void drawFilledTriangle(int x1, int y1,int x2,int y2,int x3,int y3);
void drawFilledBox(int x1, int y1, int x2, int y2);
void drawFilledCircle(int x, int y, int radius);
makefile
TARGET = test.exe
CXX = c:\usr\local\mingw32\bin\g++.exe
FILES = main.cpp Graphics.cpp
OBJS = $(FILES:.cpp=.o)
GINCS = -I/usr/local/include/GL
GLIBS = -L/usr/local/lib -lfreeglut -lglu32 -lopengl32 -Wl,--subsystem,windows
all: $(TARGET)
$(TARGET): $(OBJS)
$(CXX) -o $(TARGET) $(OBJS) $(GLIBS)
%.o: %.cpp
$(CXX) -c $< -o $@ $(GINCS)
clean:
del $(TARGET) $(OBJS)
在GIT中编译
我使用
cd命令进入包含main.cpp ; Graphics.cpp ; Graphics.h ; makefile的目录。然后我运行
make命令，虽然我已经将所有的 freeglut 库、头文件和二进制文件添加到了正确的目录下（C:\usr\local\mingw32(inlcude\,lib\,bin)），并且 GL\glut.h 文件也肯定存在……
$ make c:\usr\local\mingw32\bin\g++.exe -c main.cpp -o main.o -I/usr/local/include/GL In file included from main.cpp:7:0: Graphics.h:1:21: fatal error: GL/glut.h: No such file or directory compilation terminated. makefile:16: recipe for target 'main.o' failed make: *** [main.o] Error 1
在CODE::BLOCKS中编译
- 我在code::blocks中打开了
main.cpp; Graphics.h; Graphics.cpp。 - 选中main.cpp后，我点击“构建并运行”。我遇到了这个错误，除此之外好像什么也没有发生，但是现在项目目录中有一个main.o文件。
C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `_imp____glutInitWithExit@12' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `_imp____glutCreateWindowWithExit@8' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `_imp____glutCreateMenuWithExit@8' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `glClear@4' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `setColor(ColorName)' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `drawFilledTriangle(int, int, int, int, int, int)' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `setColor(ColorName)' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `drawFilledCircle(int, int, int)' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `glFlush@0' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `graphicsSetup(int, char**, void (*)())' C:\Users\Admin\Desktop\C++Projects\cosc1337.code\GraphicsLib\examples\ex4\main.o:main.cpp|| undefined reference to `_imp__glutMainLoop@0' === Build failed: 11 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===
- 当Graphics.cpp处于活动状态时，我执行“build and run”操作时会出现与之前相同的错误，但是Graphics.o文件被创建。
总结：
在使用code::blocks创建对象文件后，我可以使用gitbash运行makefile将它们链接起来，并创建一个可运行的test.exe，以查看我的位置，但我困惑和沮丧的是，我不能只使用code::blocks或只使用git，因为这样调整代码需要不合理长的时间才能令人满意，并且肯定会在以后引起问题。
编辑
我编写的所有其他程序以及“hello world”都可以在code::blocks和gitbash上无问题编译。
int main() {}，直到你可以在两种方式下可靠、一致地编译而不出错为止。只要你做不到这一点，你的系统就需要进行一些调整。然后逐渐尝试包含free glut等内容，直到你能够让它正常工作，并且如果你真的遇到了困难，请再次在SO上发布。 - Chris Beck