我刚接触linux下编程，所以不懂，麻烦各位帮我看看是什么问题Q5B|/D
Q(^M&oH
程序代码|
K2spKW
"vII,VC|
#include <stdio.h> IuVv2WLp
F
#include <stdlib.h>
,c[9_O^1Jk
vS8KLinux伊甸园论坛#include <SDL.h>
%jtu7A2tj~1VFwww.linuxeden.com#include <SDL_image.h>\        pjW:Wv
u
#define DIR_UP 0www.linuxeden.comrt4?
~9W:F)@
#define DIR_LEFT 1v.?,rV9HG
#define DIR_DOWN 2;M1c,xD~{'V
#define DIR_RIGHT 3
R~!N#{4D#@SDL_Surface *screen;C[4P4`{1vM
typedef struct Sprite_t { G"^PEPYa
int width;www.linuxeden.com4?,Ro"w2KT,QnH
int height;
Jz@5g        v+jint x;3N8l-zWo        a(oTs
int y;(bHU7os
int ox;
z        [9MLvuh ?%Lint oy;ru!['AM^4p
int dir;.kw-q:j:|nw`
int subframe;
:d
qV|BS7owww.linuxeden.comint speed;www.linuxeden.comUx        O$S0qQL
int timer;
&S
A.n/@_Cint moving; //use to calculate subframe9Q&`3CE?3Y
SDL_Surface *image;
9c"Q%m_4]9K4v"ka}Sprite_t;
(A3v,{{        Ic*gtypedef enum GameState { A+gf _X ^
GAME_RUNNING,
Z/^-EiERGAME_OVER,
}"jz-]2hF}GameState;
Vz5@oBvg-pc2uvoid Init_SDL()
~%w?O0fA-H\Z!C{e
n@'?d
if ( SDL_Init( SDL_INIT_VIDEO) < 0 ) {!k{ s,[0J&C4?[U R%CB
fprintf(stderr,"Can't init SDL: %s\n",SDL_GetError());
i q-^
jI4iX0j8Xwww.linuxeden.comexit(1);:G^Xh5k4Hkl+_
}
ovk2Rb;bl&ggscreen = SDL_SetVideoMode(640, 480, 16, SDL_SWSURFACE);Linux伊甸园论坛0g9z.[$~9k/~
W1~
if ( screen == NULL ) {
~Z%j
i2UQ7o!Q)uqwww.linuxeden.comfprintf(stderr, "Error: %s\n",SDL_GetError());
cO:?9JZ.R"e6O
cKWexit(1);
-jjo,FcChLinux伊甸园论坛} ye'R9M1^v;^
atexit(SDL_Quit);$V%]l7EE3{,m        E.o|
}www.linuxeden.com        E
~{rC:]*^L/`
void DrawSprite(SDL_Surface *surface,Sprite_t *sprite)

tv#Z
?Hs(eP{
+zr dE4d`vs9R~www.linuxeden.comSDL_Rect src_rect,des_rect;-@#l
A!psTD
sprite->subframe=sprite->timer/4;
q2o1C@Esrc_rect.w=des_rect.w=sprite->width;Linux伊甸园论坛,\Yt+J9Cr8O
src_rect.h=des_rect.h=sprite->height; v0ZE%~,|;Gs5\eT        Oc
src_rect.x=sprite->subframe*sprite->width;
|;U#P)vPE6rbHsrc_rect.y=sprite->dir*sprite->height;
'@~HS:}5S0~U8edes_rect.x=sprite->x;
7k2i"Z
cV|%hXLinux伊甸园论坛des_rect.y=sprite->y;
Vl&xO8^www.linuxeden.com//Draw sprite to new position
Op.SUX
|zwww.linuxeden.comSDL_BlitSurface(sprite->image,&src_rect,surface,&des_rect);4WZ!B1|/x?_
}
Vy5F-g:HsxUvoid ClearSprite(SDL_Surface *surface,Sprite_t *sprite)
l5@QF#x
B7m{"H.qS4~M5D\!?        K6^2a
SDL_Rect mask;
!IR/V`        _"o6opmask.w=sprite->width;-D7m%l        B]3`}1JM
mask.h=sprite->height;

qR(?4ZZ7v%Y7Nmask.x=sprite->ox;
:y[Dx@C
xmask.y=sprite->oy;
L4U:|C4Ys^/_2hwww.linuxeden.com//Clear sprite from the old position|r4Rb
n n
SDL_FillRect(surface,&mask,SDL_MapRGB(surface->format,0,0,0));
-|'i
l5Qi*Xv*ewww.linuxeden.com}
D
E$PJ        fr+W{+Fwww.linuxeden.comUint32 TimeLeft() ,R[9r oS0C)PD
{www.linuxeden.com$OW vj8A4A y
static Uint32 next_time=0;0dq@*F/B
Uint32 now;8B1]"e9lTRY|f4v5D*n
now=SDL_GetTicks();
]JdU5LH/^6U}if(next_time<=now){
]x/n
?TpS        @ynext_time=now+30;
wY3m:gK+kpreturn(0);mSVsF
}
?K7jg,r:u
O-rcreturn(next_time-now);
j:F:K.Sao.}x,C+s}^/a
?0{\"hx)B!f8n
Lwmhy4NK
%y2b4w4},_h
int main()
mu5@lp^!V7o{

Q8[
H4N)^ EnPlGameState game_state;4r
MKi7]~i*x/\
Sprite_t tank;!Rp%F
C]t(S*R
SDL_Event event;

h#{N*eFLLinux伊甸园论坛Init_SDL();
6PA
x:U
Nl;GJwww.linuxeden.comtank.image=IMG_Load("tank.png");-Sz7XOI,I6Y
SDL_SetColorKey(tank.image,SDL_SRCCOLORKEY,SDL_MapRGB(tank.image->format,255,0,255));
z)JSj7X%^0ttank.image=SDL_DisplayFormat(tank.image);
adf}/Py,nLinux伊甸园论坛game_state=GAME_RUNNING;&ahklS;G2`
tank.dir=DIR_RIGHT;R{k+Xt
tank.width=32;
l.]w'YEK"i"o3Dtank.height=32;
b3wL~m5p4uM`tank.x=300;0u^C.M!C5o9~
tank.y=200;
"^kbt1V T;@tank.ox=tank.x;
&x,vOP.xbtank.oy=tank.y;www.linuxeden.comR6A5WoN
B&|U
xP
tank.moving=0;ti8Y9kr0JxO
tank.speed=3;
/e:hp}/jD,_tank.timer=0;Linux伊甸园论坛et;W[9^(d
while(game_state==GAME_RUNNING){
d)J
g/JX        ZyClearSprite(screen,&tank);)VZW%^bfh,Y!o&Y$oD
//Get Input
_Of4v,rwww.linuxeden.comSDL_PollEvent(&event);
5uMX1uSY+q1B }switch(event.type){
6mI^^neIwww.linuxeden.comcase SDL_KEYDOWN:
v
t;@3z2W_"F
Mswitch(event.key.keysym.sym){
.CPm        g
z#P$dDR0Hcase SDLK_ESCAPE:

p2on$JD)Ngame_state=GAME_OVER;+jc7x;I2?.P)O{m
break;"G{J(R0qCj4@Qb3i
case SDLK_UP:G!|$y%^"i
tank.dir=DIR_UP;
$Sx v2I)vk7Q["p OrLinux伊甸园论坛tank.y-=tank.speed;
+XSK@DBbreak;+{Yl$l-N(UFs'h
case SDLK_DOWN:Hm!p@a,\?
R
tank.dir=DIR_DOWN;www.linuxeden.coml;h+P:^J        u9l
tank.y+=tank.speed;{*E"gxd'ez(G[
break;
![+ajzPt:Ncase SDLK_LEFT:Linux伊甸园论坛Y{;~$v?j)IF
tank.dir=DIR_LEFT;{3i;]8C1P:e
tank.x-=tank.speed;

W%hH[\5h)Owww.linuxeden.combreak;
1D#Y.X,R9GOLinux伊甸园论坛case SDLK_RIGHT:
uF6I}"U,~        Btank.dir=DIR_RIGHT;
0QW*Q(|a
wtank.x+=tank.speed;
K3u'[
[*T
S?www.linuxeden.combreak;Linux伊甸园论坛uj
s6D{
G
default:
bz        i+QJ&pbreak;
t        h5u CO
^
eE}Linux伊甸园论坛 [&Q^
Zn'Y
case SDL_KEYUP: -_2j/\/sZU-x#b
break;
kAPE
a8E)Q
default:
`?s0[2c3rR(]
ubreak;
_4t3l#l1|h0w)?}
bjl r`1qu(EN
Cwww.linuxeden.com{5O        T!zG?QP
DrawSprite(screen,&tank);

a|PK}6w+awww.linuxeden.comtank.ox=tank.x;Linux伊甸园论坛t7F(IUbN
tank.oy=tank.y;
r/G+rW+LSDL_UpdateRect(screen,0,0,0,0);
Oz3M9g2j?tsSDL_Delay(TimeLeft());

Hn'HRStank.timer++;
3D)p-\%dZ `-q7{tank.timer%=8;
1S'NmPV5fLinux伊甸园论坛}
SNZ$U*e
?        `amSDL_FreeSurface(tank.image);Linux伊甸园论坛R%I'Je,y        S9N8`
}
9u@j.?4@.@-yLinux伊甸园论坛9_td
O^"x5?M4h
编译的时候提示 6[N+]t^axi        N1W
/tmp/ccCxlEey.o(.text+0xlf8):in function 'main';
0K3J:WZFTX0tswww.linuxeden.comtest.c:undefined reference to 'IMG_Load'7D c
fz:lB
collect2:ld 返回 1'B$]$S%Vr
是不是tank.image=IMG_Load("tank.png");这句有问题？+S*p3j%]2n} T1x
请各位指点以下我该怎么改，谢谢

是个坦克游戏程序吧，IMG_Load（）函数定义了没有？好像是没定义啊