我已經開始學習OpenGL並設法使用頂點緩衝對象創建一個旋轉立方體。但是,當我編譯我的代碼時,gcc發出以下警告:如何修復以下gcc警告?
|| sdlogl.c: In function ‘initGL’:
sdlogl.c|48| warning: implicit declaration of function ‘glGenBuffers’
sdlogl.c|50| warning: implicit declaration of function ‘glBindBuffer’
sdlogl.c|51| warning: implicit declaration of function ‘glBufferData’
我該如何解決這些警告?
這是我的代碼:
#include <SDL/SDL.h>
#include <SDL/SDL_opengl.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glext.h>
SDL_Surface *surface;
float rquad=0.0f;
GLuint vertexBuffer,colorBuffer;
float vert[]={
1, 1, 1, 1, 1,-1, -1, 1,-1, -1, 1, 1,
1,-1, 1, 1,-1,-1, -1,-1,-1, -1,-1, 1,
1, 1, 1, 1,-1, 1, 1,-1,-1, 1, 1,-1,
-1, 1, 1, -1,-1, 1, -1,-1,-1, -1, 1,-1,
1, 1, 1, -1, 1, 1, -1,-1, 1, 1,-1, 1,
1, 1,-1, -1, 1,-1, -1,-1,-1, 1,-1,-1
};
float colors[]={
1,0,0, 1,0,0, 1,0,0, 1,0,0,
0,1,0, 0,1,0, 0,1,0, 0,1,0,
0,0,1, 0,0,1, 0,0,1, 0,0,1,
1,1,0, 1,1,0, 1,1,0, 1,1,0,
1,0,1, 1,0,1, 1,0,1, 1,0,1,
0,1,1, 0,1,1, 0,1,1, 0,1,1
};
Uint32 timerfunc(Uint32 interval,void* param){
rquad+=0.8f;
return interval;
}
void initGL(){
glViewport(0,0,640,480);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45,640.0/480.0,0.1,100);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glShadeModel(GL_SMOOTH);
glClearColor(0,0,0,0);
glClearDepth(1);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glGenBuffers(1,&vertexBuffer);
glGenBuffers(1,&colorBuffer);
glBindBuffer(GL_ARRAY_BUFFER,vertexBuffer);
glBufferData(GL_ARRAY_BUFFER,72*sizeof(float),vert,
GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER,colorBuffer);
glBufferData(GL_ARRAY_BUFFER,72*sizeof(float),colors,
GL_STATIC_DRAW);
}
void drawGLScene(){
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0,0,-6);
glRotatef(rquad,1,1,0.5);
glBindBuffer(GL_ARRAY_BUFFER,vertexBuffer);
glVertexPointer(3,GL_FLOAT,0,0);
glBindBuffer(GL_ARRAY_BUFFER,colorBuffer);
glColorPointer(3,GL_FLOAT,0,0);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glDrawArrays(GL_QUADS,0,24);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_COLOR_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER,0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,0);
SDL_GL_SwapBuffers();
}
int main(int argc, char** argv){
int videoFlags=0;
videoFlags|=SDL_OPENGL;
videoFlags|=SDL_GL_DOUBLEBUFFER;
videoFlags|=SDL_HWPALETTE;
videoFlags|=SDL_HWSURFACE;
videoFlags|=SDL_HWACCEL;
int done=0;
SDL_Event event;
const SDL_VideoInfo* videoInfo;
SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER);
videoInfo=SDL_GetVideoInfo();
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1);
SDL_WM_SetCaption("Hello OpenGL!",NULL);
surface=SDL_SetVideoMode(640,480,32,videoFlags);
initGL();
SDL_AddTimer(10,timerfunc,NULL);
while(!done){
while(SDL_PollEvent(&event)){
if(event.type==SDL_QUIT){
done=1;
}
}
drawGLScene();
}
SDL_Quit();
return 0;
}
此外,我使用下面的命令編譯我的代碼:gcc sdlogl.c -g -Wall -lSDL -lGL -lGLU
我的印象是GLEE不像GLEW那樣積極維護。這是不正確的?此外,使用GLEW歸結爲包括以及,不是嗎? –
ssell
@ssell:必須使用glewInit()爲每個創建的渲染上下文初始化GLEW。我並沒有及時瞭解GLEW和GLEE的維護狀態,因爲我的3D引擎使用了我自己的擴展包裝器;特別是我使用LoadLibrary/dlopen動態加載opengl32.dll或libGL.so,主要是爲了能夠檢測到正確安裝的OpenGL。同樣在X11上,這段代碼檢查libGL.so是否與連接的DISPLAY相匹配,如果不匹配則發出警告;擴展包裝只是這個的一小部分。 – datenwolf
啊,我忘記了爲每個上下文調用glewInit()。 – ssell