shooter.cpp

#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream.h>
#include "libs\w_mlib.h"    // Mouse-library
#include "libs\gfxlib.h"   // Gfx-header
#include "libs\imageio.h"

const short TRUE = 1;
const short FALSE = 0;
const short SHOT_DELAY = 10;
const short SHIP_WIDTH = 16;
const short SHIP_HEIGHT = 32;
const short SHIP_ANIMATION_TRESHOLD = 2;
const short BULLET_WIDTH = 4;
const short BULLET_HEIGHT = 3;
const short EXPLOSION_WIDTH = 16;
const short EXPLOSION_HEIGHT = 32;
const short ENEMY_WIDTH = 16;
const short ENEMY_HEIGHT = 25;


short smallestNumber(short a, short b);
short largestNumber(short a, short b);
void loadAssets();
void initBullets();
void initVgaGraphicsMode();
void initMouse();
short checkShotFired(short shotDelay, short curMouseX, short curMouseY);
short updateBullets(short shotDelay, short shotVelocity);
void clearShip(short curMouseX, short curMouseY, signed short deltaX, signed short deltaY);
void initEnemy();
void spawnEnemy();
void clearAndMoveEnemy();
void handlePlayerShipAnimation(short& freezeFrames, short& targetState, short& curState, signed short deltaX);

struct Bullet {
    short x;
    short y;
};

struct Enemy {
    short x;
    short y;
    short width;
    short height;
    short yVel;
    short numHits;
    short state;
    short frameDelay;
    short doFinalClear;
};

byte ship[5][512];
byte explosionFrames[4][512];
byte enemyShip[400];
byte bullet[12];
signed char palette[768];
Bullet bullets[20];
Enemy enemy;

int main(int argc, char *argv[])
{
    initBullets();
    loadAssets();
    initVgaGraphicsMode();
    initMouse();
    initEnemy();

    short curMouseX = MOUSE_X, curMouseY = MOUSE_Y;
    signed short deltaX = 0, deltaY = 0;
    short targetState = 2;
    short curState = 2;
    short freezeFrames = 0;

    short shotDelay = 0;
    short shotVelocity = 4;

    short xOffset = 0;
    short yOffset = 0;
    short quit = FALSE;
    short spawnNewEnemy = FALSE;

    while (quit == FALSE) {
        short key;

        shotDelay = checkShotFired(shotDelay, curMouseX, curMouseY);
        shotDelay = updateBullets(shotDelay, shotVelocity);

        // draw enemy ship
        if (enemy.y < 200 && enemy.state == 1) {
            clip_put_block(enemy.x, enemy.y, enemy.width, enemy.height, enemyShip);
        } else {
            if (enemy.state > 1 && enemy.state <= 5) {
                clip_put_block(enemy.x, enemy.y, enemy.width, enemy.height, explosionFrames[enemy.state - 2]);
                enemy.frameDelay--;
            }
            if (enemy.frameDelay == 0) {
                if (enemy.state == 5) {
                    enemy.state = 0;
                    enemy.doFinalClear = TRUE;
                }
                if (enemy.state > 0 && enemy.state < 5) {
                    enemy.state++;
                    enemy.frameDelay = 10;
                }
            }
        }

        // draw player ship
        put_block(curMouseX, curMouseY, SHIP_WIDTH, SHIP_HEIGHT, ship[curState]);

        wait_vbl();
        get_mouse_status();

        deltaX = MOUSE_X - curMouseX;
        deltaY = MOUSE_Y - curMouseY;

        clearShip(curMouseX, curMouseY, deltaX, deltaY);
        clearAndMoveEnemy();

        if (spawnNewEnemy) {
            spawnEnemy();
            spawnNewEnemy = FALSE;
        }

        curMouseX = MOUSE_X;
        curMouseY = MOUSE_Y;

        handlePlayerShipAnimation(freezeFrames, targetState, curState, deltaX);

        if (kbhit()) {
            key = getch();

            if (key == 27)      // ESC
                quit = TRUE;
            if (key == 32)      // SPACE
                spawnNewEnemy = TRUE;
            if (key == 97) {    // a
                enemy.state = 2;
                enemy.frameDelay = 10;
            }
        }
    }

    text_mode();
    reset_mouse();
}

short smallestNumber(short a, short b) {
    return a < b ? a : b;
}

short largestNumber(short a, short b) {
    return a > b ? a : b;
}

void loadAssets()
{
    pcxRead("bullets.pcx", bullet, palette, BULLET_WIDTH, BULLET_HEIGHT);
    pcxRead("eship.pcx", enemyShip, palette, ENEMY_WIDTH, ENEMY_HEIGHT);
    pcxRead("ship_ll.pcx", ship[0], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("ship_l.pcx", ship[1], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("ship.pcx", ship[2], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("ship_r.pcx", ship[3], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("ship_rr.pcx", ship[4], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("exp01.pcx", explosionFrames[0], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("exp02.pcx", explosionFrames[1], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("exp03.pcx", explosionFrames[2], palette, SHIP_WIDTH, SHIP_HEIGHT);
    pcxRead("exp04.pcx", explosionFrames[3], palette, SHIP_WIDTH, SHIP_HEIGHT);
}

void initBullets()
{
    for (short i = 0; i < 20; i++) {
        bullets[i].x = 0;
        bullets[i].y = 0;
    }
}

void initVgaGraphicsMode()
{
    mode_13h();
    set_pal(palette);
}

void initMouse()
{
    set_mouse_sens(20,16);
    xlimit_mouse(8,300);
    ylimit_mouse(167,167);
    get_mouse_status();
}

short checkShotFired(short shotDelay, short curMouseX, short curMouseY)
{
    if (shotDelay == 0 && BUTTON_STATE == 1)
    {
        short freeBulletSlot = -1;
        for (short i = 0; i < 20; i++) {
            if (bullets[i].y <= 0) {
                freeBulletSlot = i;
                break;
            }
        }
        if (freeBulletSlot >= 0) {
            bullets[freeBulletSlot].x = curMouseX + 6;
            bullets[freeBulletSlot].y = curMouseY - 4;
            shotDelay = SHOT_DELAY;
        }
    }
    return shotDelay;
}

short updateBullets(short shotDelay, short shotVelocity)
{
    if (shotDelay > 0) shotDelay--;
    for (short i = 0; i < 20; i++) {
        if (bullets[i].y > 0) {
            draw_box(bullets[i].x, bullets[i].y, BULLET_WIDTH, BULLET_HEIGHT, 0);
            bullets[i].y -= shotVelocity;
        }
        if (bullets[i].y > 0) {
            put_block(bullets[i].x, bullets[i].y, BULLET_WIDTH, BULLET_HEIGHT, bullet);
        }
    }
    return shotDelay;
}

void clearShip(short curMouseX, short curMouseY, signed short deltaX, signed short deltaY)
{
    short xOffset = 0,
        yOffset = 0;

    if (deltaX < 0) {
        xOffset = SHIP_WIDTH;
    }
    if (deltaY < 0) {
        yOffset = SHIP_HEIGHT;
    }

    draw_box(smallestNumber(curMouseX, MOUSE_X) + xOffset, curMouseY, abs(deltaX) + 1, SHIP_HEIGHT, 0);
    draw_box(curMouseX, smallestNumber(curMouseY, MOUSE_Y) + yOffset, SHIP_WIDTH, abs(deltaY) + 1, 0);
}

void initEnemy()
{
    enemy.x = 0;
    enemy.y = 200;
    enemy.width = ENEMY_WIDTH;
    enemy.height = ENEMY_HEIGHT;
    enemy.yVel = 2;
    enemy.numHits = 1;
}

void spawnEnemy()
{
    enemy.x = 100;
    enemy.y = -1 - ENEMY_HEIGHT;
    enemy.state = 1;
    enemy.frameDelay = 4;
    enemy.doFinalClear = FALSE;
}

void clearAndMoveEnemy()
{
    if (enemy.y >= 0 && enemy.y < 200 && enemy.state > 0) {
        draw_box(enemy.x, enemy.y, enemy.width, enemy.yVel, 0);
    }
    if (enemy.doFinalClear == TRUE) {
        draw_box(enemy.x, enemy.y, EXPLOSION_WIDTH, EXPLOSION_HEIGHT, 0);   
    }
    if (enemy.y < 200) enemy.y += enemy.yVel;
}

void handlePlayerShipAnimation(short& freezeFrames, short& targetState, short& curState, signed short deltaX)
{
    if (freezeFrames == 0) {
        if (abs(deltaX) >= SHIP_ANIMATION_TRESHOLD) {
            targetState = deltaX > 0 ? 0 : 4;
        } else {
            targetState = 2;
        }

        if (targetState != curState) {
            if (targetState < curState) curState--;
            if (targetState > curState) curState++;
            freezeFrames = 10;
        }
    }
    if (freezeFrames > 0) freezeFrames--;
}