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

#include "SDL.h"

#ifdef __MACOS__
#define HAVE_OPENGL
#endif

#ifdef HAVE_OPENGL

#include "SDL_opengl.h"

/* Undefine this if you want a flat cube instead of a rainbow cube */
#define SHADED_CUBE

/* Define this to be the name of the logo image to use with -logo */
#define LOGO_FILE	"icon.bmp"

static SDL_Surface *global_image = NULL;
static GLuint global_texture = 0;
static GLuint cursor_texture = 0;

/**********************************************************************/

void
HotKey_ToggleFullScreen (void)
{
    SDL_Surface *screen;

    screen = SDL_GetVideoSurface ();
    if (SDL_WM_ToggleFullScreen (screen)) {
        printf ("Toggled fullscreen mode - now %s\n",
                (screen->flags & SDL_FULLSCREEN) ? "fullscreen" : "windowed");
    } else {
        printf ("Unable to toggle fullscreen mode\n");
    }
}

void
HotKey_ToggleGrab (void)
{
    SDL_GrabMode mode;

    printf ("Ctrl-G: toggling input grab!\n");
    mode = SDL_WM_GrabInput (SDL_GRAB_QUERY);
    if (mode == SDL_GRAB_ON) {
        printf ("Grab was on\n");
    } else {
        printf ("Grab was off\n");
    }
    mode = SDL_WM_GrabInput (!mode);
    if (mode == SDL_GRAB_ON) {
        printf ("Grab is now on\n");
    } else {
        printf ("Grab is now off\n");
    }
}

void
HotKey_Iconify (void)
{
    printf ("Ctrl-Z: iconifying window!\n");
    SDL_WM_IconifyWindow ();
}

int
HandleEvent (SDL_Event * event)
{
    int done;

    done = 0;
    switch (event->type) {
    case SDL_ACTIVEEVENT:
        /* See what happened */
        printf ("app %s ", event->active.gain ? "gained" : "lost");
        if (event->active.state & SDL_APPACTIVE) {
            printf ("active ");
        } else if (event->active.state & SDL_APPMOUSEFOCUS) {
            printf ("mouse ");
        } else if (event->active.state & SDL_APPINPUTFOCUS) {
            printf ("input ");
        }
        printf ("focus\n");
        break;


    case SDL_KEYDOWN:
        if (event->key.keysym.sym == SDLK_ESCAPE) {
            done = 1;
        }
        if ((event->key.keysym.sym == SDLK_g) &&
            (event->key.keysym.mod & KMOD_CTRL)) {
            HotKey_ToggleGrab ();
        }
        if ((event->key.keysym.sym == SDLK_z) &&
            (event->key.keysym.mod & KMOD_CTRL)) {
            HotKey_Iconify ();
        }
        if ((event->key.keysym.sym == SDLK_RETURN) &&
            (event->key.keysym.mod & KMOD_ALT)) {
            HotKey_ToggleFullScreen ();
        }
        printf ("key '%s' pressed\n", SDL_GetKeyName (event->key.keysym.sym));
        break;
    case SDL_QUIT:
        done = 1;
        break;
    }
    return (done);
}

void
SDL_GL_Enter2DMode ()
{
    SDL_Surface *screen = SDL_GetVideoSurface ();

    /* Note, there may be other things you need to change,
       depending on how you have your OpenGL state set up.
     */
    glPushAttrib (GL_ENABLE_BIT);
    glDisable (GL_DEPTH_TEST);
    glDisable (GL_CULL_FACE);
    glEnable (GL_TEXTURE_2D);

    /* This allows alpha blending of 2D textures with the scene */
    glEnable (GL_BLEND);
    glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    glViewport (0, 0, screen->w, screen->h);

    glMatrixMode (GL_PROJECTION);
    glPushMatrix ();
    glLoadIdentity ();

    glOrtho (0.0, (GLdouble) screen->w, (GLdouble) screen->h, 0.0, 0.0, 1.0);

    glMatrixMode (GL_MODELVIEW);
    glPushMatrix ();
    glLoadIdentity ();

    glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
}

void
SDL_GL_Leave2DMode ()
{
    glMatrixMode (GL_MODELVIEW);
    glPopMatrix ();

    glMatrixMode (GL_PROJECTION);
    glPopMatrix ();

    glPopAttrib ();
}

/* Quick utility function for texture creation */
static int
power_of_two (int input)
{
    int value = 1;

    while (value < input) {
        value <<= 1;
    }
    return value;
}

GLuint
SDL_GL_LoadTexture (SDL_Surface * surface, GLfloat * texcoord)
{
    GLuint texture;
    int w, h;
    SDL_Surface *image;
    SDL_Rect area;
    Uint32 saved_flags;
    Uint8 saved_alpha;

    /* Use the surface width and height expanded to powers of 2 */
    w = power_of_two (surface->w);
    h = power_of_two (surface->h);
    texcoord[0] = 0.0f;         /* Min X */
    texcoord[1] = 0.0f;         /* Min Y */
    texcoord[2] = (GLfloat) surface->w / w;     /* Max X */
    texcoord[3] = (GLfloat) surface->h / h;     /* Max Y */

    image = SDL_CreateRGBSurface (SDL_SWSURFACE, w, h, 32,
#if SDL_BYTEORDER == SDL_LIL_ENDIAN     /* OpenGL RGBA masks */
                                  0x000000FF,
                                  0x0000FF00, 0x00FF0000, 0xFF000000
#else
                                  0xFF000000,
                                  0x00FF0000, 0x0000FF00, 0x000000FF
#endif
        );
    if (image == NULL) {
        return 0;
    }

    /* Save the alpha blending attributes */
    saved_flags = surface->flags & (SDL_SRCALPHA | SDL_RLEACCELOK);
    saved_alpha = surface->format->alpha;
    if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA) {
        SDL_SetAlpha (surface, 0, 0);
    }

    /* Copy the surface into the GL texture image */
    area.x = 0;
    area.y = 0;
    area.w = surface->w;
    area.h = surface->h;
    SDL_BlitSurface (surface, &area, image, &area);

    /* Restore the alpha blending attributes */
    if ((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA) {
        SDL_SetAlpha (surface, saved_flags, saved_alpha);
    }

    /* Create an OpenGL texture for the image */
    glGenTextures (1, &texture);
    glBindTexture (GL_TEXTURE_2D, texture);
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexImage2D (GL_TEXTURE_2D,
                  0,
                  GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->pixels);
    SDL_FreeSurface (image);    /* No longer needed */

    return texture;
}

void
DrawLogoCursor (void)
{
    static GLfloat texMinX, texMinY;
    static GLfloat texMaxX, texMaxY;
    static int w, h;
    int x, y;

    if (!cursor_texture) {
        SDL_Surface *image;
        GLfloat texcoord[4];

        /* Load the image (could use SDL_image library here) */
        image = SDL_LoadBMP (LOGO_FILE);
        if (image == NULL) {
            return;
        }
        w = image->w;
        h = image->h;

        /* Convert the image into an OpenGL texture */
        cursor_texture = SDL_GL_LoadTexture (image, texcoord);

        /* Make texture coordinates easy to understand */
        texMinX = texcoord[0];
        texMinY = texcoord[1];
        texMaxX = texcoord[2];
        texMaxY = texcoord[3];

        /* We don't need the original image anymore */
        SDL_FreeSurface (image);

        /* Make sure that the texture conversion is okay */
        if (!cursor_texture) {
            return;
        }
    }

    /* Move the image around */
    SDL_GetMouseState (&x, &y);
    x -= w / 2;
    y -= h / 2;

    /* Show the image on the screen */
    SDL_GL_Enter2DMode ();
    glBindTexture (GL_TEXTURE_2D, cursor_texture);
    glBegin (GL_TRIANGLE_STRIP);
    glTexCoord2f (texMinX, texMinY);
    glVertex2i (x, y);
    glTexCoord2f (texMaxX, texMinY);
    glVertex2i (x + w, y);
    glTexCoord2f (texMinX, texMaxY);
    glVertex2i (x, y + h);
    glTexCoord2f (texMaxX, texMaxY);
    glVertex2i (x + w, y + h);
    glEnd ();
    SDL_GL_Leave2DMode ();
}

void
DrawLogoTexture (void)
{
    static GLfloat texMinX, texMinY;
    static GLfloat texMaxX, texMaxY;
    static int x = 0;
    static int y = 0;
    static int w, h;
    static int delta_x = 1;
    static int delta_y = 1;

    SDL_Surface *screen = SDL_GetVideoSurface ();

    if (!global_texture) {
        SDL_Surface *image;
        GLfloat texcoord[4];

        /* Load the image (could use SDL_image library here) */
        image = SDL_LoadBMP (LOGO_FILE);
        if (image == NULL) {
            return;
        }
        w = image->w;
        h = image->h;

        /* Convert the image into an OpenGL texture */
        global_texture = SDL_GL_LoadTexture (image, texcoord);

        /* Make texture coordinates easy to understand */
        texMinX = texcoord[0];
        texMinY = texcoord[1];
        texMaxX = texcoord[2];
        texMaxY = texcoord[3];

        /* We don't need the original image anymore */
        SDL_FreeSurface (image);

        /* Make sure that the texture conversion is okay */
        if (!global_texture) {
            return;
        }
    }

    /* Move the image around */
    x += delta_x;
    if (x < 0) {
        x = 0;
        delta_x = -delta_x;
    } else if ((x + w) > screen->w) {
        x = screen->w - w;
        delta_x = -delta_x;
    }
    y += delta_y;
    if (y < 0) {
        y = 0;
        delta_y = -delta_y;
    } else if ((y + h) > screen->h) {
        y = screen->h - h;
        delta_y = -delta_y;
    }

    /* Show the image on the screen */
    SDL_GL_Enter2DMode ();
    glBindTexture (GL_TEXTURE_2D, global_texture);
    glBegin (GL_TRIANGLE_STRIP);
    glTexCoord2f (texMinX, texMinY);
    glVertex2i (x, y);
    glTexCoord2f (texMaxX, texMinY);
    glVertex2i (x + w, y);
    glTexCoord2f (texMinX, texMaxY);
    glVertex2i (x, y + h);
    glTexCoord2f (texMaxX, texMaxY);
    glVertex2i (x + w, y + h);
    glEnd ();
    SDL_GL_Leave2DMode ();
}

int
RunGLTest (int argc, char *argv[],
           int logo, int logocursor, int slowly, int bpp, float gamma,
           int noframe, int fsaa, int sync, int accel)
{
    int i;
    int rgb_size[3];
    int w = 640;
    int h = 480;
    int done = 0;
    int frames;
    Uint32 start_time, this_time;
    float color[8][3] = { {1.0, 1.0, 0.0},
    {1.0, 0.0, 0.0},
    {0.0, 0.0, 0.0},
    {0.0, 1.0, 0.0},
    {0.0, 1.0, 1.0},
    {1.0, 1.0, 1.0},
    {1.0, 0.0, 1.0},
    {0.0, 0.0, 1.0}
    };
    float cube[8][3] = { {0.5, 0.5, -0.5},
    {0.5, -0.5, -0.5},
    {-0.5, -0.5, -0.5},
    {-0.5, 0.5, -0.5},
    {-0.5, 0.5, 0.5},
    {0.5, 0.5, 0.5},
    {0.5, -0.5, 0.5},
    {-0.5, -0.5, 0.5}
    };
    Uint32 video_flags;
    int value;

    if (SDL_Init (SDL_INIT_VIDEO) < 0) {
        fprintf (stderr, "Couldn't initialize SDL: %s\n", SDL_GetError ());
        exit (1);
    }

    /* See if we should detect the display depth */
    if (bpp == 0) {
        if (SDL_GetVideoInfo ()->vfmt->BitsPerPixel <= 8) {
            bpp = 8;
        } else {
            bpp = 16;           /* More doesn't seem to work */
        }
    }

    /* Set the flags we want to use for setting the video mode */
    video_flags = SDL_OPENGL;
    for (i = 1; argv[i]; ++i) {
        if (strcmp (argv[i], "-fullscreen") == 0) {
            video_flags |= SDL_FULLSCREEN;
        }
    }

    if (noframe) {
        video_flags |= SDL_NOFRAME;
    }

    /* Initialize the display */
    switch (bpp) {
    case 8:
        rgb_size[0] = 3;
        rgb_size[1] = 3;
        rgb_size[2] = 2;
        break;
    case 15:
    case 16:
        rgb_size[0] = 5;
        rgb_size[1] = 5;
        rgb_size[2] = 5;
        break;
    default:
        rgb_size[0] = 8;
        rgb_size[1] = 8;
        rgb_size[2] = 8;
        break;
    }
    SDL_GL_SetAttribute (SDL_GL_RED_SIZE, rgb_size[0]);
    SDL_GL_SetAttribute (SDL_GL_GREEN_SIZE, rgb_size[1]);
    SDL_GL_SetAttribute (SDL_GL_BLUE_SIZE, rgb_size[2]);
    SDL_GL_SetAttribute (SDL_GL_DEPTH_SIZE, 16);
    SDL_GL_SetAttribute (SDL_GL_DOUBLEBUFFER, 1);
    if (fsaa) {
        SDL_GL_SetAttribute (SDL_GL_MULTISAMPLEBUFFERS, 1);
        SDL_GL_SetAttribute (SDL_GL_MULTISAMPLESAMPLES, fsaa);
    }
    if (accel) {
        SDL_GL_SetAttribute (SDL_GL_ACCELERATED_VISUAL, 1);
    }
    if (sync) {
        SDL_GL_SetAttribute (SDL_GL_SWAP_CONTROL, 1);
    } else {
        SDL_GL_SetAttribute (SDL_GL_SWAP_CONTROL, 0);
    }
    if (SDL_SetVideoMode (w, h, bpp, video_flags) == NULL) {
        fprintf (stderr, "Couldn't set GL mode: %s\n", SDL_GetError ());
        SDL_Quit ();
        exit (1);
    }

    printf ("Screen BPP: %d\n", SDL_GetVideoSurface ()->format->BitsPerPixel);
    printf ("\n");
    printf ("Vendor     : %s\n", glGetString (GL_VENDOR));
    printf ("Renderer   : %s\n", glGetString (GL_RENDERER));
    printf ("Version    : %s\n", glGetString (GL_VERSION));
    printf ("Extensions : %s\n", glGetString (GL_EXTENSIONS));
    printf ("\n");

    SDL_GL_GetAttribute (SDL_GL_RED_SIZE, &value);
    printf ("SDL_GL_RED_SIZE: requested %d, got %d\n", rgb_size[0], value);
    SDL_GL_GetAttribute (SDL_GL_GREEN_SIZE, &value);
    printf ("SDL_GL_GREEN_SIZE: requested %d, got %d\n", rgb_size[1], value);
    SDL_GL_GetAttribute (SDL_GL_BLUE_SIZE, &value);
    printf ("SDL_GL_BLUE_SIZE: requested %d, got %d\n", rgb_size[2], value);
    SDL_GL_GetAttribute (SDL_GL_DEPTH_SIZE, &value);
    printf ("SDL_GL_DEPTH_SIZE: requested %d, got %d\n", bpp, value);
    SDL_GL_GetAttribute (SDL_GL_DOUBLEBUFFER, &value);
    printf ("SDL_GL_DOUBLEBUFFER: requested 1, got %d\n", value);
    if (fsaa) {
        SDL_GL_GetAttribute (SDL_GL_MULTISAMPLEBUFFERS, &value);
        printf ("SDL_GL_MULTISAMPLEBUFFERS: requested 1, got %d\n", value);
        SDL_GL_GetAttribute (SDL_GL_MULTISAMPLESAMPLES, &value);
        printf ("SDL_GL_MULTISAMPLESAMPLES: requested %d, got %d\n", fsaa,
                value);
    }
    if (accel) {
        SDL_GL_GetAttribute (SDL_GL_ACCELERATED_VISUAL, &value);
        printf ("SDL_GL_ACCELERATED_VISUAL: requested 1, got %d\n", value);
    }
    if (sync) {
        SDL_GL_GetAttribute (SDL_GL_SWAP_CONTROL, &value);
        printf ("SDL_GL_SWAP_CONTROL: requested 1, got %d\n", value);
    }

    /* Set the window manager title bar */
    SDL_WM_SetCaption ("SDL GL test", "testgl");

    /* Set the gamma for the window */
    if (gamma != 0.0) {
        SDL_SetGamma (gamma, gamma, gamma);
    }

    glViewport (0, 0, w, h);
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();

    glOrtho (-2.0, 2.0, -2.0, 2.0, -20.0, 20.0);

    glMatrixMode (GL_MODELVIEW);
    glLoadIdentity ();

    glEnable (GL_DEPTH_TEST);

    glDepthFunc (GL_LESS);

    glShadeModel (GL_SMOOTH);

    /* Loop until done. */
    start_time = SDL_GetTicks ();
    frames = 0;
    while (!done) {
        GLenum gl_error;
        char *sdl_error;
        SDL_Event event;

        /* Do our drawing, too. */
        glClearColor (0.0, 0.0, 0.0, 1.0);
        glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glBegin (GL_QUADS);

#ifdef SHADED_CUBE
        glColor3fv (color[0]);
        glVertex3fv (cube[0]);
        glColor3fv (color[1]);
        glVertex3fv (cube[1]);
        glColor3fv (color[2]);
        glVertex3fv (cube[2]);
        glColor3fv (color[3]);
        glVertex3fv (cube[3]);

        glColor3fv (color[3]);
        glVertex3fv (cube[3]);
        glColor3fv (color[4]);
        glVertex3fv (cube[4]);
        glColor3fv (color[7]);
        glVertex3fv (cube[7]);
        glColor3fv (color[2]);
        glVertex3fv (cube[2]);

        glColor3fv (color[0]);
        glVertex3fv (cube[0]);
        glColor3fv (color[5]);
        glVertex3fv (cube[5]);
        glColor3fv (color[6]);
        glVertex3fv (cube[6]);
        glColor3fv (color[1]);
        glVertex3fv (cube[1]);

        glColor3fv (color[5]);
        glVertex3fv (cube[5]);
        glColor3fv (color[4]);
        glVertex3fv (cube[4]);
        glColor3fv (color[7]);
        glVertex3fv (cube[7]);
        glColor3fv (color[6]);
        glVertex3fv (cube[6]);

        glColor3fv (color[5]);
        glVertex3fv (cube[5]);
        glColor3fv (color[0]);
        glVertex3fv (cube[0]);
        glColor3fv (color[3]);
        glVertex3fv (cube[3]);
        glColor3fv (color[4]);
        glVertex3fv (cube[4]);

        glColor3fv (color[6]);
        glVertex3fv (cube[6]);
        glColor3fv (color[1]);
        glVertex3fv (cube[1]);
        glColor3fv (color[2]);
        glVertex3fv (cube[2]);
        glColor3fv (color[7]);
        glVertex3fv (cube[7]);
#else /* flat cube */
        glColor3f (1.0, 0.0, 0.0);
        glVertex3fv (cube[0]);
        glVertex3fv (cube[1]);
        glVertex3fv (cube[2]);
        glVertex3fv (cube[3]);

        glColor3f (0.0, 1.0, 0.0);
        glVertex3fv (cube[3]);
        glVertex3fv (cube[4]);
        glVertex3fv (cube[7]);
        glVertex3fv (cube[2]);

        glColor3f (0.0, 0.0, 1.0);
        glVertex3fv (cube[0]);
        glVertex3fv (cube[5]);
        glVertex3fv (cube[6]);
        glVertex3fv (cube[1]);

        glColor3f (0.0, 1.0, 1.0);
        glVertex3fv (cube[5]);
        glVertex3fv (cube[4]);
        glVertex3fv (cube[7]);
        glVertex3fv (cube[6]);

        glColor3f (1.0, 1.0, 0.0);
        glVertex3fv (cube[5]);
        glVertex3fv (cube[0]);
        glVertex3fv (cube[3]);
        glVertex3fv (cube[4]);

        glColor3f (1.0, 0.0, 1.0);
        glVertex3fv (cube[6]);
        glVertex3fv (cube[1]);
        glVertex3fv (cube[2]);
        glVertex3fv (cube[7]);
#endif /* SHADED_CUBE */

        glEnd ();

        glMatrixMode (GL_MODELVIEW);
        glRotatef (5.0, 1.0, 1.0, 1.0);

        /* Draw 2D logo onto the 3D display */
        if (logo) {
            DrawLogoTexture ();
        }
        if (logocursor) {
            DrawLogoCursor ();
        }

        SDL_GL_SwapBuffers ();

        /* Check for error conditions. */
        gl_error = glGetError ();

        if (gl_error != GL_NO_ERROR) {
            fprintf (stderr, "testgl: OpenGL error: %d\n", gl_error);
        }

        sdl_error = SDL_GetError ();

        if (sdl_error[0] != '\0') {
            fprintf (stderr, "testgl: SDL error '%s'\n", sdl_error);
            SDL_ClearError ();
        }

        /* Allow the user to see what's happening */
        if (slowly) {
            SDL_Delay (20);
        }

        /* Check if there's a pending event. */
        while (SDL_PollEvent (&event)) {
            done = HandleEvent (&event);
        }
        ++frames;
    }

    /* Print out the frames per second */
    this_time = SDL_GetTicks ();
    if (this_time != start_time) {
        printf ("%2.2f FPS\n",
                ((float) frames / (this_time - start_time)) * 1000.0);
    }

    if (global_image) {
        SDL_FreeSurface (global_image);
        global_image = NULL;
    }
    if (global_texture) {
        glDeleteTextures (1, &global_texture);
        global_texture = 0;
    }
    if (cursor_texture) {
        glDeleteTextures (1, &cursor_texture);
        cursor_texture = 0;
    }

    /* Destroy our GL context, etc. */
    SDL_Quit ();
    return (0);
}

int
main (int argc, char *argv[])
{
    int i, logo, logocursor = 0;
    int numtests;
    int bpp = 0;
    int slowly;
    float gamma = 0.0;
    int noframe = 0;
    int fsaa = 0;
    int accel = 0;
    int sync = 0;

    logo = 0;
    slowly = 0;
    numtests = 1;
    for (i = 1; argv[i]; ++i) {
        if (strcmp (argv[i], "-twice") == 0) {
            ++numtests;
        }
        if (strcmp (argv[i], "-logo") == 0) {
            logo = 1;
        }
        if (strcmp (argv[i], "-logocursor") == 0) {
            logocursor = 1;
        }
        if (strcmp (argv[i], "-slow") == 0) {
            slowly = 1;
        }
        if (strcmp (argv[i], "-bpp") == 0) {
            bpp = atoi (argv[++i]);
        }
        if (strcmp (argv[i], "-gamma") == 0) {
            gamma = (float) atof (argv[++i]);
        }
        if (strcmp (argv[i], "-noframe") == 0) {
            noframe = 1;
        }
        if (strcmp (argv[i], "-fsaa") == 0) {
            ++fsaa;
        }
        if (strcmp (argv[i], "-accel") == 0) {
            ++accel;
        }
        if (strcmp (argv[i], "-sync") == 0) {
            ++sync;
        }
        if (strncmp (argv[i], "-h", 2) == 0) {
            printf
                ("Usage: %s [-twice] [-logo] [-logocursor] [-slow] [-bpp n] [-gamma n] [-noframe] [-fsaa] [-fullscreen]\n",
                 argv[0]);
            exit (0);
        }
    }
    for (i = 0; i < numtests; ++i) {
        RunGLTest (argc, argv, logo, logocursor, slowly, bpp, gamma,
                   noframe, fsaa, sync, accel);
    }
    return 0;
}

#else /* HAVE_OPENGL */

int
main (int argc, char *argv[])
{
    printf ("No OpenGL support on this system\n");
    return 1;
}

#endif /* HAVE_OPENGL */