main.c
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/* Simple program: Create a blank window, wait for keypress, quit.
Please see the SDL documentation for details on using the SDL API:
/Developer/Documentation/SDL/docs.html
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "SDL.h"
extern void Atlantis_Init ();
extern void Atlantis_Reshape (int w, int h);
extern void Atlantis_Animate ();
extern void Atlantis_Display ();
static SDL_Surface *gScreen;
static void initAttributes ()
{
// Setup attributes we want for the OpenGL context
int value;
// Don't set color bit sizes (SDL_GL_RED_SIZE, etc)
// Mac OS X will always use 8-8-8-8 ARGB for 32-bit screens and
// 5-5-5 RGB for 16-bit screens
// Request a 16-bit depth buffer (without this, there is no depth buffer)
value = 16;
SDL_GL_SetAttribute (SDL_GL_DEPTH_SIZE, value);
// Request double-buffered OpenGL
// The fact that windows are double-buffered on Mac OS X has no effect
// on OpenGL double buffering.
value = 1;
SDL_GL_SetAttribute (SDL_GL_DOUBLEBUFFER, value);
}
static void printAttributes ()
{
// Print out attributes of the context we created
int nAttr;
int i;
int attr[] = { SDL_GL_RED_SIZE, SDL_GL_BLUE_SIZE, SDL_GL_GREEN_SIZE,
SDL_GL_ALPHA_SIZE, SDL_GL_BUFFER_SIZE, SDL_GL_DEPTH_SIZE };
char *desc[] = { "Red size: %d bits\n", "Blue size: %d bits\n", "Green size: %d bits\n",
"Alpha size: %d bits\n", "Color buffer size: %d bits\n",
"Depth bufer size: %d bits\n" };
nAttr = sizeof(attr) / sizeof(int);
for (i = 0; i < nAttr; i++) {
int value;
SDL_GL_GetAttribute (attr[i], &value);
printf (desc[i], value);
}
}
static void createSurface (int fullscreen)
{
Uint32 flags = 0;
flags = SDL_OPENGL;
if (fullscreen)
flags |= SDL_FULLSCREEN;
// Create window
gScreen = SDL_SetVideoMode (640, 480, 0, flags);
if (gScreen == NULL) {
fprintf (stderr, "Couldn't set 640x480 OpenGL video mode: %s\n",
SDL_GetError());
SDL_Quit();
exit(2);
}
}
static void initGL ()
{
Atlantis_Init ();
Atlantis_Reshape (gScreen->w, gScreen->h);
}
static void drawGL ()
{
Atlantis_Animate ();
Atlantis_Display ();
}
static void mainLoop ()
{
SDL_Event event;
int done = 0;
int fps = 24;
int delay = 1000/fps;
int thenTicks = -1;
int nowTicks;
while ( !done ) {
/* Check for events */
while ( SDL_PollEvent (&event) ) {
switch (event.type) {
case SDL_MOUSEMOTION:
break;
case SDL_MOUSEBUTTONDOWN:
break;
case SDL_KEYDOWN:
/* Any keypress quits the app... */
case SDL_QUIT:
done = 1;
break;
default:
break;
}
}
// Draw at 24 hz
// This approach is not normally recommended - it is better to
// use time-based animation and run as fast as possible
drawGL ();
SDL_GL_SwapBuffers ();
// Time how long each draw-swap-delay cycle takes
// and adjust delay to get closer to target framerate
if (thenTicks > 0) {
nowTicks = SDL_GetTicks ();
delay += (1000/fps - (nowTicks-thenTicks));
thenTicks = nowTicks;
if (delay < 0)
delay = 1000/fps;
}
else {
thenTicks = SDL_GetTicks ();
}
SDL_Delay (delay);
}
}
int main(int argc, char *argv[])
{
// Init SDL video subsystem
if ( SDL_Init (SDL_INIT_VIDEO) < 0 ) {
fprintf(stderr, "Couldn't initialize SDL: %s\n",
SDL_GetError());
exit(1);
}
// Set GL context attributes
initAttributes ();
// Create GL context
createSurface (0);
// Get GL context attributes
printAttributes ();
// Init GL state
initGL ();
// Draw, get events...
mainLoop ();
// Cleanup
SDL_Quit();
return 0;
}