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OpenGL\SDL Simple App Source

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I have looked and coned3D nehes and other sites tuts for code that is a simple application ( no objects in the window, just a blank screen) made with Opengl and SDL, and couldn't find any exactly or close to how I canted it. I want to see source that is simple like that so it will be quick as possible so I can understand how OGL "glues" or "ties in" to SDL.Can somebody please type me ( not link, i've tried them) a simple source how I explained I wanted of a simple window with nothing but a color background. I apreciate it most highly!!! THANKS!!!! ~Mad_Koder

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Would someone please post a source because I only have a few hours, and by the time I can get on, the post will be dead before I can ask something in return if needed.

THANKS A BUNCH

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This is the example in the SDL documentation.

Initialisation
Initialising SDL to use OpenGL is not very different to initialising SDL
normally. There are three differences; you must pass SDL_OPENGL to
SDL_SetVideoMode, you must specify several GL attributes (depth buffer size,
framebuffer sizes) using SDL_GL_SetAttribute and finally, if you wish to use
double buffering you must specify it as a GL attribute, not by passing the
SDL_DOUBLEBUF flag to SDL_SetVideoMode.

Example 2-7. Initializing SDL with OpenGL

/* Information about the current video settings. */
const SDL_VideoInfo* info = NULL;
/* Dimensions of our window. */
int width = 0;
int height = 0;
/* Color depth in bits of our window. */
int bpp = 0;
/* Flags we will pass into SDL_SetVideoMode. */
int flags = 0;

/* First, initialize SDL's video subsystem. */
if( SDL_Init( SDL_INIT_VIDEO ) < 0 ) {
/* Failed, exit. */
fprintf( stderr, "Video initialization failed: %s\n",
SDL_GetError( ) );
quit_tutorial( 1 );
}

/* Let's get some video information. */
info = SDL_GetVideoInfo( );

if( !info ) {
/* This should probably never happen. */
fprintf( stderr, "Video query failed: %s\n",
SDL_GetError( ) );
quit_tutorial( 1 );
}

/*
* Set our width/height to 640/480 (you would
* of course let the user decide this in a normal
* app). We get the bpp we will request from
* the display. On X11, VidMode can't change
* resolution, so this is probably being overly
* safe. Under Win32, ChangeDisplaySettings
* can change the bpp.
*/

width = 640;
height = 480;
bpp = info->vfmt->BitsPerPixel;

/*
* Now, we want to setup our requested
* window attributes for our OpenGL window.
* We want *at least* 5 bits of red, green
* and blue. We also want at least a 16-bit
* depth buffer.
*
* The last thing we do is request a double
* buffered window. '1' turns on double
* buffering, '0' turns it off.
*
* Note that we do not use SDL_DOUBLEBUF in
* the flags to SDL_SetVideoMode. That does
* not affect the GL attribute state, only
* the standard 2D blitting setup.
*/

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );

/*
* We want to request that SDL provide us
* with an OpenGL window, in a fullscreen
* video mode.
*
* EXERCISE:
* Make starting windowed an option, and
* handle the resize events properly with
* glViewport.
*/

flags = SDL_OPENGL | SDL_FULLSCREEN;

/*
* Set the video mode
*/

if( SDL_SetVideoMode( width, height, bpp, flags ) == 0 ) {
/*
* This could happen for a variety of reasons,
* including DISPLAY not being set, the specified
* resolution not being available, etc.
*/

fprintf( stderr, "Video mode set failed: %s\n",
SDL_GetError( ) );
quit_tutorial( 1 );
}




And here is the full example in the docs. You should be able to pull the information out of this quite easily. Hope it helps.


/*
* SDL OpenGL Tutorial.
* (c) Michael Vance, 2000
* briareos@lokigames.com
*
* Distributed under terms of the LGPL.
*/


#include <SDL/SDL.h>
#include <GL/gl.h>
#include <GL/glu.h>

#include <stdio.h>
#include <stdlib.h>

static GLboolean should_rotate = GL_TRUE;

static void quit_tutorial( int code )
{
/*
* Quit SDL so we can release the fullscreen
* mode and restore the previous video settings,
* etc.
*/

SDL_Quit( );

/* Exit program. */
exit( code );
}

static void handle_key_down( SDL_keysym* keysym )
{

/*
* We're only interested if 'Esc' has
* been presssed.
*
* EXERCISE:
* Handle the arrow keys and have that change the
* viewing position/angle.
*/

switch( keysym->sym ) {
case SDLK_ESCAPE:
quit_tutorial( 0 );
break;
case SDLK_SPACE:
should_rotate = !should_rotate;
break;
default:
break;
}

}

static void process_events( void )
{
/* Our SDL event placeholder. */
SDL_Event event;

/* Grab all the events off the queue. */
while( SDL_PollEvent( &event ) ) {

switch( event.type ) {
case SDL_KEYDOWN:
/* Handle key presses. */
handle_key_down( &event.key.keysym );
break;
case SDL_QUIT:
/* Handle quit requests (like Ctrl-c). */
quit_tutorial( 0 );
break;
}

}

}

static void draw_screen( void )
{
/* Our angle of rotation. */
static float angle = 0.0f;

/*
* EXERCISE:
* Replace this awful mess with vertex
* arrays and a call to glDrawElements.
*
* EXERCISE:
* After completing the above, change
* it to use compiled vertex arrays.
*
* EXERCISE:
* Verify my windings are correct here ;).
*/

static GLfloat v0[] = { -1.0f, -1.0f, 1.0f };
static GLfloat v1[] = { 1.0f, -1.0f, 1.0f };
static GLfloat v2[] = { 1.0f, 1.0f, 1.0f };
static GLfloat v3[] = { -1.0f, 1.0f, 1.0f };
static GLfloat v4[] = { -1.0f, -1.0f, -1.0f };
static GLfloat v5[] = { 1.0f, -1.0f, -1.0f };
static GLfloat v6[] = { 1.0f, 1.0f, -1.0f };
static GLfloat v7[] = { -1.0f, 1.0f, -1.0f };
static GLubyte red[] = { 255, 0, 0, 255 };
static GLubyte green[] = { 0, 255, 0, 255 };
static GLubyte blue[] = { 0, 0, 255, 255 };
static GLubyte white[] = { 255, 255, 255, 255 };
static GLubyte yellow[] = { 0, 255, 255, 255 };
static GLubyte black[] = { 0, 0, 0, 255 };
static GLubyte orange[] = { 255, 255, 0, 255 };
static GLubyte purple[] = { 255, 0, 255, 0 };

/* Clear the color and depth buffers. */
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

/* We don't want to modify the projection matrix. */
glMatrixMode( GL_MODELVIEW );
glLoadIdentity( );

/* Move down the z-axis. */
glTranslatef( 0.0, 0.0, -5.0 );

/* Rotate. */
glRotatef( angle, 0.0, 1.0, 0.0 );

if( should_rotate ) {

if( ++angle > 360.0f ) {
angle = 0.0f;
}

}

/* Send our triangle data to the pipeline. */
glBegin( GL_TRIANGLES );

glColor4ubv( red );
glVertex3fv( v0 );
glColor4ubv( green );
glVertex3fv( v1 );
glColor4ubv( blue );
glVertex3fv( v2 );

glColor4ubv( red );
glVertex3fv( v0 );
glColor4ubv( blue );
glVertex3fv( v2 );
glColor4ubv( white );
glVertex3fv( v3 );

glColor4ubv( green );
glVertex3fv( v1 );
glColor4ubv( black );
glVertex3fv( v5 );
glColor4ubv( orange );
glVertex3fv( v6 );

glColor4ubv( green );
glVertex3fv( v1 );
glColor4ubv( orange );
glVertex3fv( v6 );
glColor4ubv( blue );
glVertex3fv( v2 );

glColor4ubv( black );
glVertex3fv( v5 );
glColor4ubv( yellow );
glVertex3fv( v4 );
glColor4ubv( purple );
glVertex3fv( v7 );

glColor4ubv( black );
glVertex3fv( v5 );
glColor4ubv( purple );
glVertex3fv( v7 );
glColor4ubv( orange );
glVertex3fv( v6 );

glColor4ubv( yellow );
glVertex3fv( v4 );
glColor4ubv( red );
glVertex3fv( v0 );
glColor4ubv( white );
glVertex3fv( v3 );

glColor4ubv( yellow );
glVertex3fv( v4 );
glColor4ubv( white );
glVertex3fv( v3 );
glColor4ubv( purple );
glVertex3fv( v7 );

glColor4ubv( white );
glVertex3fv( v3 );
glColor4ubv( blue );
glVertex3fv( v2 );
glColor4ubv( orange );
glVertex3fv( v6 );

glColor4ubv( white );
glVertex3fv( v3 );
glColor4ubv( orange );
glVertex3fv( v6 );
glColor4ubv( purple );
glVertex3fv( v7 );

glColor4ubv( green );
glVertex3fv( v1 );
glColor4ubv( red );
glVertex3fv( v0 );
glColor4ubv( yellow );
glVertex3fv( v4 );

glColor4ubv( green );
glVertex3fv( v1 );
glColor4ubv( yellow );
glVertex3fv( v4 );
glColor4ubv( black );
glVertex3fv( v5 );

glEnd( );

/*
* EXERCISE:
* Draw text telling the user that 'Spc'
* pauses the rotation and 'Esc' quits.
* Do it using vetors and textured quads.
*/


/*
* Swap the buffers. This this tells the driver to
* render the next frame from the contents of the
* back-buffer, and to set all rendering operations
* to occur on what was the front-buffer.
*
* Double buffering prevents nasty visual tearing
* from the application drawing on areas of the
* screen that are being updated at the same time.
*/

SDL_GL_SwapBuffers( );
}

static void setup_opengl( int width, int height )
{
float ratio = (float) width / (float) height;

/* Our shading model--Gouraud (smooth). */
glShadeModel( GL_SMOOTH );

/* Culling. */
glCullFace( GL_BACK );
glFrontFace( GL_CCW );
glEnable( GL_CULL_FACE );

/* Set the clear color. */
glClearColor( 0, 0, 0, 0 );

/* Setup our viewport. */
glViewport( 0, 0, width, height );

/*
* Change to the projection matrix and set
* our viewing volume.
*/

glMatrixMode( GL_PROJECTION );
glLoadIdentity( );
/*
* EXERCISE:
* Replace this with a call to glFrustum.
*/

gluPerspective( 60.0, ratio, 1.0, 1024.0 );
}

int main( int argc, char* argv[] )
{
/* Information about the current video settings. */
const SDL_VideoInfo* info = NULL;
/* Dimensions of our window. */
int width = 0;
int height = 0;
/* Color depth in bits of our window. */
int bpp = 0;
/* Flags we will pass into SDL_SetVideoMode. */
int flags = 0;

/* First, initialize SDL's video subsystem. */
if( SDL_Init( SDL_INIT_VIDEO ) < 0 ) {
/* Failed, exit. */
fprintf( stderr, "Video initialization failed: %s\n",
SDL_GetError( ) );
quit_tutorial( 1 );
}

/* Let's get some video information. */
info = SDL_GetVideoInfo( );

if( !info ) {
/* This should probably never happen. */
fprintf( stderr, "Video query failed: %s\n",
SDL_GetError( ) );
quit_tutorial( 1 );
}

/*
* Set our width/height to 640/480 (you would
* of course let the user decide this in a normal
* app). We get the bpp we will request from
* the display. On X11, VidMode can't change
* resolution, so this is probably being overly
* safe. Under Win32, ChangeDisplaySettings
* can change the bpp.
*/

width = 640;
height = 480;
bpp = info->vfmt->BitsPerPixel;

/*
* Now, we want to setup our requested
* window attributes for our OpenGL window.
* We want *at least* 5 bits of red, green
* and blue. We also want at least a 16-bit
* depth buffer.
*
* The last thing we do is request a double
* buffered window. '1' turns on double
* buffering, '0' turns it off.
*
* Note that we do not use SDL_DOUBLEBUF in
* the flags to SDL_SetVideoMode. That does
* not affect the GL attribute state, only
* the standard 2D blitting setup.
*/

SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 );
SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );

/*
* We want to request that SDL provide us
* with an OpenGL window, in a fullscreen
* video mode.
*
* EXERCISE:
* Make starting windowed an option, and
* handle the resize events properly with
* glViewport.
*/

flags = SDL_OPENGL | SDL_FULLSCREEN;

/*
* Set the video mode
*/

if( SDL_SetVideoMode( width, height, bpp, flags ) == 0 ) {
/*
* This could happen for a variety of reasons,
* including DISPLAY not being set, the specified
* resolution not being available, etc.
*/

fprintf( stderr, "Video mode set failed: %s\n",
SDL_GetError( ) );
quit_tutorial( 1 );
}

/*
* At this point, we should have a properly setup
* double-buffered window for use with OpenGL.
*/

setup_opengl( width, height );

/*
* Now we want to begin our normal app process--
* an event loop with a lot of redrawing.
*/

while( 1 ) {
/* Process incoming events. */
process_events( );
/* Draw the screen. */
draw_screen( );
}

/*
* EXERCISE:
* Record timings using SDL_GetTicks() and
* and print out frames per second at program
* end.
*/


/* Never reached. */
return 0;
}

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