/* Simple program:  Move N sprites around on the screen as fast as possible */

#include <stdlib.h>

#include <stdio.h>

#include <time.h>

#include "SDL_events.h"

#include "SDL_video.h"

#define WINDOW_WIDTH    640

#define WINDOW_HEIGHT   480

#define NUM_SPRITES     100

#define MAX_SPEED       1

static SDL_Texture *sprite;

static SDL_Rect positions[NUM_SPRITES];

static SDL_Rect velocities[NUM_SPRITES];

static int sprite_w, sprite_h;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */

static void

quit(int rc)

{

    exit(rc);

}

int

LoadSprite(char *file)

{

    SDL_Surface *temp;

    /* Load the sprite image */

    temp = SDL_LoadBMP(file);

    if (temp == NULL) {

        fprintf(stderr, "Couldn't load %s: %s", file, SDL_GetError());

        return (-1);

    }

    sprite_w = temp->w;

    sprite_h = temp->h;

    /* Set transparent pixel as the pixel at (0,0) */

    if (temp->format->palette) {

        SDL_SetColorKey(temp, SDL_TRUE, *(Uint8 *) temp->pixels);

    } else {

        switch (temp->format->BitsPerPixel) {

        case 15:

            SDL_SetColorKey(temp, SDL_TRUE,

                            (*(Uint16 *) temp->pixels) & 0x00007FFF);

            break;

        case 16:

            SDL_SetColorKey(temp, SDL_TRUE, *(Uint16 *) temp->pixels);

            break;

        case 24:

            SDL_SetColorKey(temp, SDL_TRUE,

                            (*(Uint32 *) temp->pixels) & 0x00FFFFFF);

            break;

        case 32:

            SDL_SetColorKey(temp, SDL_TRUE, *(Uint32 *) temp->pixels);

            break;

        }

    }

    /* Create textures from the image */

    sprite = SDL_CreateTextureFromSurface(0, temp);

    if (!sprite) {

        SDL_SetColorKey(temp, 0, 0);

        sprite = SDL_CreateTextureFromSurface(0, temp);

    }

    if (!sprite) {

        fprintf(stderr, "Couldn't create texture: %s\n", SDL_GetError());

        SDL_FreeSurface(temp);

        return (-1);

    }

    SDL_FreeSurface(temp);

    /* We're ready to roll. :) */

    return (0);

}

void

MoveSprites(SDL_Window * window, SDL_Texture * sprite)

{

    int i;

    int window_w = WINDOW_WIDTH;

    int window_h = WINDOW_HEIGHT;

    SDL_Rect *position, *velocity;

    /* Draw a gray background */

    SDL_SetRenderDrawColor(0xA0, 0xA0, 0xA0, 0xFF);

    SDL_RenderClear();

    /* Move the sprite, bounce at the wall, and draw */

    for (i = 0; i < NUM_SPRITES; ++i) {

        position = &positions[i];

        velocity = &velocities[i];

        position->x += velocity->x;

        if ((position->x < 0) || (position->x >= (window_w - sprite_w))) {

            velocity->x = -velocity->x;

            position->x += velocity->x;

        }

        position->y += velocity->y;

        if ((position->y < 0) || (position->y >= (window_h - sprite_h))) {

            velocity->y = -velocity->y;

            position->y += velocity->y;

        }

        /* Blit the sprite onto the screen */

        SDL_RenderCopy(sprite, NULL, position);

    }

    /* Update the screen! */

    SDL_RenderPresent();

}

int

main(int argc, char *argv[])

{

    SDL_Window *window;

    int i, done;

    SDL_Event event;

    window = SDL_CreateWindow("Happy Smileys",

                              SDL_WINDOWPOS_UNDEFINED,

                              SDL_WINDOWPOS_UNDEFINED,

                              WINDOW_WIDTH, WINDOW_HEIGHT,

                              SDL_WINDOW_SHOWN);

    if (!window) {

        quit(2);

    }

    if (LoadSprite("icon.bmp") < 0) {

        quit(2);

    }

    /* Initialize the sprite positions */

    srand(time(NULL));

    for (i = 0; i < NUM_SPRITES; ++i) {

        positions[i].x = rand() % (WINDOW_WIDTH - sprite_w);

        positions[i].y = rand() % (WINDOW_HEIGHT - sprite_h);

        positions[i].w = sprite_w;

        positions[i].h = sprite_h;

        velocities[i].x = 0;

        velocities[i].y = 0;

        while (!velocities[i].x && !velocities[i].y) {

            velocities[i].x = (rand() % (MAX_SPEED * 2 + 1)) - MAX_SPEED;

            velocities[i].y = (rand() % (MAX_SPEED * 2 + 1)) - MAX_SPEED;

        }

    }

    /* Main render loop */

    done = 0;

    while (!done) {

        /* Check for events */

        while (SDL_PollEvent(&event)) {

            if (event.type == SDL_QUIT || event.type == SDL_KEYDOWN) {

                done = 1;

            }

        }

        MoveSprites(window, sprite);

    }

    quit(0);

}

/* vi: set ts=4 sw=4 expandtab: */