/*
* This code was created by Jeff Molofee '99
* (ported to Linux/SDL by Ti Leggett '01)
*
* If you've found this code useful, please let me know.
*
* Visit Jeff at http://nehe.gamedev.net/
*
* or for port-specific comments, questions, bugreports etc.
* email to leggett@eecs.tulane.edu
*/
#include <stdio.h>
#include <stdlib.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include "SDL.h"
/* screen width, height, and bit depth */
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
#define SCREEN_BPP 16
/* Define our booleans */
#define TRUE 1
#define FALSE 0
/* This is our SDL surface */
SDL_Surface *surface;
/* function to release/destroy our resources and restoring the old desktop */
void Quit( int returnCode )
{
/* clean up the window */
SDL_Quit( );
/* and exit appropriately */
exit( returnCode );
}
/* function to reset our viewport after a window resize */
int resizeWindow( int width, int height )
{
/* Height / width ration */
GLfloat ratio;
/* Protect against a divide by zero */
if ( height == 0 )
height = 1;
ratio = ( GLfloat )width / ( GLfloat )height;
/* Setup our viewport. */
glViewport( 0, 0, ( GLsizei )width, ( GLsizei )height );
/* change to the projection matrix and set our viewing volume. */
glMatrixMode( GL_PROJECTION );
glLoadIdentity( );
/* Set our perspective */
gluPerspective( 45.0f, ratio, 0.1f, 100.0f );
/* Make sure we're chaning the model view and not the projection */
glMatrixMode( GL_MODELVIEW );
/* Reset The View */
glLoadIdentity( );
return( TRUE );
}
/* function to handle key press events */
void handleKeyPress( SDL_keysym *keysym )
{
switch ( keysym->sym )
{
case SDLK_ESCAPE:
/* ESC key was pressed */
Quit( 0 );
break;
case SDLK_F1:
/* F1 key was pressed
* this toggles fullscreen mode
*/
SDL_WM_ToggleFullScreen( surface );
break;
default:
break;
}
return;
}
/* general OpenGL initialization function */
int initGL( GLvoid )
{
/* Enable smooth shading */
glShadeModel( GL_SMOOTH );
/* Set the background black */
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
/* Depth buffer setup */
glClearDepth( 1.0f );
/* Enables Depth Testing */
glEnable( GL_DEPTH_TEST );
/* The Type Of Depth Test To Do */
glDepthFunc( GL_LEQUAL );
/* Really Nice Perspective Calculations */
glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
return( TRUE );
}
/* Here goes our drawing code */
int drawGLScene( GLvoid )
{
/* rotational vars for the triangle and quad, respectively */
static GLfloat rtri, rquad;
/* These are to calculate our fps */
static GLint T0 = 0;
static GLint Frames = 0;
/* Clear The Screen And The Depth Buffer */
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
/* Move Left 1.5 Units And Into The Screen 6.0 */
glLoadIdentity();
glTranslatef( -1.5f, 0.0f, -6.0f );
/* Rotate The Triangle On The Y axis ( NEW ) */
glRotatef( rtri, 0.0f, 1.0f, 0.0f );
glBegin( GL_TRIANGLES ); /* Drawing Using Triangles */
glColor3f( 1.0f, 0.0f, 0.0f ); /* Red */
glVertex3f( 0.0f, 1.0f, 0.0f ); /* Top Of Triangle (Front) */
glColor3f( 0.0f, 1.0f, 0.0f ); /* Green */
glVertex3f( -1.0f, -1.0f, 1.0f ); /* Left Of Triangle (Front) */
glColor3f( 0.0f, 0.0f, 1.0f ); /* Blue */
glVertex3f( 1.0f, -1.0f, 1.0f ); /* Right Of Triangle (Front) */
glColor3f( 1.0f, 0.0f, 0.0f ); /* Red */
glVertex3f( 0.0f, 1.0f, 0.0f ); /* Top Of Triangle (Right) */
glColor3f( 0.0f, 0.0f, 1.0f ); /* Blue */
glVertex3f( 1.0f, -1.0f, 1.0f ); /* Left Of Triangle (Right) */
glColor3f( 0.0f, 1.0f, 0.0f ); /* Green */
glVertex3f( 1.0f, -1.0f, -1.0f ); /* Right Of Triangle (Right) */
glColor3f( 1.0f, 0.0f, 0.0f ); /* Red */
glVertex3f( 0.0f, 1.0f, 0.0f ); /* Top Of Triangle (Back) */
glColor3f( 0.0f, 1.0f, 0.0f ); /* Green */
glVertex3f( 1.0f, -1.0f, -1.0f ); /* Left Of Triangle (Back) */
glColor3f( 0.0f, 0.0f, 1.0f ); /* Blue */
glVertex3f( -1.0f, -1.0f, -1.0f ); /* Right Of Triangle (Back) */
glColor3f( 1.0f, 0.0f, 0.0f ); /* Red */
glVertex3f( 0.0f, 1.0f, 0.0f ); /* Top Of Triangle (Left) */
glColor3f( 0.0f, 0.0f, 1.0f ); /* Blue */
glVertex3f( -1.0f, -1.0f, -1.0f ); /* Left Of Triangle (Left) */
glColor3f( 0.0f, 1.0f, 0.0f ); /* Green */
glVertex3f( -1.0f, -1.0f, 1.0f ); /* Right Of Triangle (Left) */
glEnd( ); /* Finished Drawing The Triangle */
/* Move Right 3 Units */
glLoadIdentity( );
glTranslatef( 1.5f, 0.0f, -6.0f );
/* Rotate The Quad On The X axis ( NEW ) */
glRotatef( rquad, 1.0f, 0.0f, 0.0f );
/* Set The Color To Blue One Time Only */
glColor3f( 0.5f, 0.5f, 1.0f);
glBegin( GL_QUADS ); /* Draw A Quad */
glColor3f( 0.0f, 1.0f, 0.0f ); /* Set The Color To Green */
glVertex3f( 1.0f, 1.0f, -1.0f ); /* Top Right Of The Quad (Top) */
glVertex3f( -1.0f, 1.0f, -1.0f ); /* Top Left Of The Quad (Top) */
glVertex3f( -1.0f, 1.0f, 1.0f ); /* Bottom Left Of The Quad (Top) */
glVertex3f( 1.0f, 1.0f, 1.0f ); /* Bottom Right Of The Quad (Top) */
glColor3f( 1.0f, 0.5f, 0.0f ); /* Set The Color To Orange */
glVertex3f( 1.0f, -1.0f, 1.0f ); /* Top Right Of The Quad (Botm) */
glVertex3f( -1.0f, -1.0f, 1.0f ); /* Top Left Of The Quad (Botm) */
glVertex3f( -1.0f, -1.0f, -1.0f ); /* Bottom Left Of The Quad (Botm) */
glVertex3f( 1.0f, -1.0f, -1.0f ); /* Bottom Right Of The Quad (Botm) */
glColor3f( 1.0f, 0.0f, 0.0f ); /* Set The Color To Red */
glVertex3f( 1.0f, 1.0f, 1.0f ); /* Top Right Of The Quad (Front) */
glVertex3f( -1.0f, 1.0f, 1.0f ); /* Top Left Of The Quad (Front) */
glVertex3f( -1.0f, -1.0f, 1.0f ); /* Bottom Left Of The Quad (Front) */
glVertex3f( 1.0f, -1.0f, 1.0f ); /* Bottom Right Of The Quad (Front) */
glColor3f( 1.0f, 1.0f, 0.0f ); /* Set The Color To Yellow */
glVertex3f( 1.0f, -1.0f, -1.0f ); /* Bottom Left Of The Quad (Back) */
glVertex3f( -1.0f, -1.0f, -1.0f ); /* Bottom Right Of The Quad (Back) */
glVertex3f( -1.0f, 1.0f, -1.0f ); /* Top Right Of The Quad (Back) */
glVertex3f( 1.0f, 1.0f, -1.0f ); /* Top Left Of The Quad (Back) */
glColor3f( 0.0f, 0.0f, 1.0f ); /* Set The Color To Blue */
glVertex3f( -1.0f, 1.0f, 1.0f ); /* Top Right Of The Quad (Left) */
glVertex3f( -1.0f, 1.0f, -1.0f ); /* Top Left Of The Quad (Left) */
glVertex3f( -1.0f, -1.0f, -1.0f ); /* Bottom Left Of The Quad (Left) */
glVertex3f( -1.0f, -1.0f, 1.0f ); /* Bottom Right Of The Quad (Left) */
glColor3f( 1.0f, 0.0f, 1.0f ); /* Set The Color To Violet */
glVertex3f( 1.0f, 1.0f, -1.0f ); /* Top Right Of The Quad (Right) */
glVertex3f( 1.0f, 1.0f, 1.0f ); /* Top Left Of The Quad (Right) */
glVertex3f( 1.0f, -1.0f, 1.0f ); /* Bottom Left Of The Quad (Right) */
glVertex3f( 1.0f, -1.0f, -1.0f ); /* Bottom Right Of The Quad (Right) */
glEnd( ); /* Done Drawing The Quad */
/* Draw it to the screen */
SDL_GL_SwapBuffers( );
/* Gather our frames per second */
Frames++;
{
GLint t = SDL_GetTicks();
if (t - T0 >= 5000) {
GLfloat seconds = (t - T0) / 1000.0;
GLfloat fps = Frames / seconds;
printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps);
T0 = t;
Frames = 0;
}
}
/* Increase The Rotation Variable For The Triangle ( NEW ) */
rtri += 0.2f;
/* Decrease The Rotation Variable For The Quad ( NEW ) */
rquad -=0.15f;
return( TRUE );
}
int main( int argc, char **argv )
{
/* Flags to pass to SDL_SetVideoMode */
int videoFlags;
/* main loop variable */
int done = FALSE;
/* used to collect events */
SDL_Event event;
/* this holds some info about our display */
const SDL_VideoInfo *videoInfo;
/* whether or not the window is active */
int isActive = TRUE;
/* initialize SDL */
if ( SDL_Init( SDL_INIT_VIDEO ) < 0 )
{
fprintf( stderr, "Video initialization failed: %s\n",
SDL_GetError( ) );
Quit( 1 );
}
/* Fetch the video info */
videoInfo = SDL_GetVideoInfo( );
if ( !videoInfo )
{
fprintf( stderr, "Video query failed: %s\n",
SDL_GetError( ) );
Quit( 1 );
}
/* the flags to pass to SDL_SetVideoMode */
videoFlags = SDL_OPENGL; /* Enable OpenGL in SDL */
videoFlags |= SDL_GL_DOUBLEBUFFER; /* Enable double buffering */
videoFlags |= SDL_HWPALETTE; /* Store the palette in hardware */
videoFlags |= SDL_RESIZABLE; /* Enable window resizing */
/* This checks to see if surfaces can be stored in memory */
if ( videoInfo->hw_available )
videoFlags |= SDL_HWSURFACE;
else
videoFlags |= SDL_SWSURFACE;
/* This checks if hardware blits can be done */
if ( videoInfo->blit_hw )
videoFlags |= SDL_HWACCEL;
/* Sets up OpenGL double buffering */
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
/* get a SDL surface */
surface = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP,
videoFlags );
/* Verify there is a surface */
if ( !surface )
{
fprintf( stderr, "Video mode set failed: %s\n", SDL_GetError( ) );
Quit( 1 );
}
/* initialize OpenGL */
initGL( );
/* resize the initial window */
resizeWindow( SCREEN_WIDTH, SCREEN_HEIGHT );
/* wait for events */
while ( !done )
{
/* handle the events in the queue */
while ( SDL_PollEvent( &event ) )
{
switch( event.type )
{
case SDL_ACTIVEEVENT:
/* Something's happend with our focus
* If we lost focus or we are iconified, we
* shouldn't draw the screen
*/
if ( event.active.gain == 0 )
isActive = FALSE;
else
isActive = TRUE;
break;
case SDL_VIDEORESIZE:
/* handle resize event */
surface = SDL_SetVideoMode( event.resize.w,
event.resize.h,
16, videoFlags );
if ( !surface )
{
fprintf( stderr, "Could not get a surface after resize: %s\n", SDL_GetError( ) );
Quit( 1 );
}
resizeWindow( event.resize.w, event.resize.h );
break;
case SDL_KEYDOWN:
/* handle key presses */
handleKeyPress( &event.key.keysym );
break;
case SDL_QUIT:
/* handle quit requests */
done = TRUE;
break;
default:
break;
}
}
/* draw the scene */
if ( isActive )
drawGLScene( );
}
/* clean ourselves up and exit */
Quit( 0 );
/* Should never get here */
return( 0 );
}
