SDL/GL tutorials: Compilation is an ugly word...

Some Guy · 2002-02-04T21:36:13

You've probably guessed it already: This Guy has compile problems with some code. Yeah, I'm that Guy. Some Guy. =) Anyway, I tried to compile the base code (slightly modified) from the SDL version of the tutorials. I tried to compile it with Mesa and gcc, mind you. Here's something like what I wrote (I actually had no comments except for a description header at the top of the file, and had many tabs for good allignment, but no other changes; this version is copied from Molofee's source code.): #ifdef WIN32 #define WIN32_LEAN_AND_MEAN #include <windows.h> #endif #if defined(__APPLE__) && defined(__MACH__) #include <OpenGL/gl.h> // Header File For The OpenGL32 Library #include <OpenGL/glu.h> // Header File For The GLu32 Library #else #include <GL/gl.h> // Header File For The OpenGL32 Library #include <GL/glu.h> // Header File For The GLu32 Library #endif #include <SDL/SDL.h> //(Some Guy) Changed this from "SDL.h" int done; void InitGL (int w, int h); void DrawGLScene(); void CheckEvents(); //a function I added (Some Guy) /* A general OpenGL initialization function. Sets all of the initial parameters. */ void InitGL(int Width, int Height) // We call this right after our OpenGL window is created. { glViewport(0, 0, Width, Height); glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black glClearDepth(1.0); // Enables Clearing Of The Depth Buffer glDepthFunc(GL_LESS); // The Type Of Depth Test To Do glEnable(GL_DEPTH_TEST); // Enables Depth Testing glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading glMatrixMode(GL_PROJECTION); glLoadIdentity(); // Reset The Projection Matrix gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f); // Calculate The Aspect Ratio Of The Window glMatrixMode(GL_MODELVIEW); } /* The main drawing function. */ void DrawGLScene() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer glLoadIdentity(); // Reset The View glTranslatef(-1.5f,0.0f,-6.0f); // Move Left 1.5 Units And Into The Screen 6.0 // draw a triangle glBegin(GL_POLYGON); // start drawing a polygon glVertex3f( 0.0f, 1.0f, 0.0f); // Top glVertex3f( 1.0f,-1.0f, 0.0f); // Bottom Right glVertex3f(-1.0f,-1.0f, 0.0f); // Bottom Left glEnd(); // we're done with the polygon glTranslatef(3.0f,0.0f,0.0f); // Move Right 3 Units // draw a square (quadrilateral) glBegin(GL_QUADS); // start drawing a polygon (4 sided) glVertex3f(-1.0f, 1.0f, 0.0f); // Top Left glVertex3f( 1.0f, 1.0f, 0.0f); // Top Right glVertex3f( 1.0f,-1.0f, 0.0f); // Bottom Right glVertex3f(-1.0f,-1.0f, 0.0f); // Bottom Left glEnd(); // done with the polygon // swap buffers to display, since we're double buffered. SDL_GL_SwapBuffers(); } void CheckEvents() { SDL_Event event; while ( SDL_PollEvent(&event) ) { if ( event.type == SDL_QUIT ) { done = 1; } if ( event.type == SDL_KEYDOWN ) { if ( event.key.keysym.sym == SDLK_ESCAPE ) { done = 1; } } }//end while(SDL_PollEvent...) } int main(int argc, char **argv) { /* Initialize SDL for video output */ if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) { fprintf(stderr, "Unable to initialize SDL: %s\n", SDL_GetError()); exit(1); } /* Create a 640x480 OpenGL screen */ if ( SDL_SetVideoMode(640, 480, 0, SDL_OPENGL) == NULL ) { fprintf(stderr, "Unable to create OpenGL screen: %s\n", SDL_GetError()); SDL_Quit(); exit(2); } /* Set the title bar in environments that support it */ SDL_WM_SetCaption("Jeff Molofee's GL Code Tutorial ... NeHe '99", NULL); /* Loop, drawing and checking events */ InitGL(640, 480); done = 0; while ( ! done ) { DrawGLScene(); CheckEvents(); } SDL_Quit(); return 1; } Now, basically this is my slightly modified version of Molofee's source code released with the SDL tutorials. I simply made the variable done into a global variable, rather than a local one, and added a function called CheckEvents(), which is called towards the end of main(). I also changed #include "SDL.h" to #include <SDL/SDL.h>, because the former wouldn't compile on my Linux system. Apparently, gcc doesn't like something about this. I narrowed the error messages down, but a few remain like (off the top of my head): In function main(...) 'exit' undeclared (first use this function) In function InitGL(...) 'glViewPort' undeclared (first use this function) That last one really bothers me. And here's what I wrote to compile it, in case you want to know: $ gcc main.cpp -o first Should work, but why isn't it finding either of these functions in the headers? Edited by - Some Guy on February 2, 2002 10:20:35 PM

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Started by Some Guy February 02, 2002 09:18 PM

9 comments, last by Some Guy 23 years ago

Some Guy

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February 04, 2002 09:36 PM

Okay, this is what I last entered:


g++ main.cpp -o first -L/usr/X11/lib `sdl-config --cflags --libs` -lGL -lGLU

This is based on what everyone here has told me, and... it still didn''t work. <:{

I get this big loooooooooong error message that repeatedly says "undefined reference" which tells me that the linker is not doing it''s job, or there''s an API problem that I''ll never understand.

I have SDL and the development libraries installed, and I still can''t understand what is going on. Please help.

I am running Mandrake Linux 8.1 with SDL v1.2.3 and Mesa.

SDL/GL tutorials: Compilation is an ugly word...

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SDL/GL tutorials: Compilation is an ugly word...

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