dos-vga-arena-shooter-game/game.c

#include <stddef.h>
#include <stdio.h>
#include <math.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>

#include "sprites.h"
#include "system/vga.h"
#include "system/keyboard.h"
#include "system/mouse_io.h"
#include "system/pc_stuff.h"

#include "bmpload.h"
#include "const.h"
#include "arena.h"
#include "movement.h"
#include "combat.h"

// TODO: centralize these outside of game.c
struct CompiledSpriteRender rabbit, mouse, bullet, enemy;
struct SpriteBounds bounds;

struct BMPImage spritesheetImage;
struct VGAColor vgaColors[256];

struct MouseStatus mouseStatus;

struct RabbitPosition rabbitPosition = {
  .rabbitPosition = { 60, 60 },
  .rabbitLimits = { { 20, 20 }, { 180, 180 } },
  .mousePosition = { 0, 0 },
  .rabbitVelocity = { 0, 0 },
  .mouseDotPosition = { 0, 0 }
};
struct EnemyPosition enemyPosition[ENEMY_MAX_COUNT];
struct BulletPosition rabbitBulletPosition[RABBIT_BULLET_LIMIT];
struct RabbitWeaponry rabbitWeaponry;

struct SpawnPointRange {
  int left, width;
  int top, height;
};

struct SpawnPointRange spawnPointRanges[1] = {
   { .left = 130, .width = 50, .top = 50, .height = 100 }
};


void setupRabbitBullets() {
  int i;

  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    rabbitBulletPosition[i].isActive = 0;
    rabbitBulletPosition[i].willBeInactive = 0;
  }

  rabbitWeaponry.cooldown = 0;
}

void setupEnemies() {
  int i;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    enemyPosition[i].isActive = 0;
    enemyPosition[i].willBeInactive = 0;
  }
}

void maybeSpawnEnemy() {
  char canSpawn;
  int i, availableEnemy;
  int spawnX, spawnY;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    if (!enemyPosition[i].isActive) {
      availableEnemy = i;
      canSpawn = 1;
      break;
    }
  }

  if (!canSpawn) return;

  spawnX = spawnPointRanges[0].left + rand() % spawnPointRanges[0].width;
  spawnY = spawnPointRanges[0].top + rand() % spawnPointRanges[0].height;

  enemyPosition[availableEnemy].isActive = 1;
  enemyPosition[availableEnemy].enemyPosition[0] = spawnX;
  enemyPosition[availableEnemy].enemyPosition[1] = spawnY;
  enemyPosition[availableEnemy].oldEnemyPosition[0] = spawnX;
  enemyPosition[availableEnemy].oldEnemyPosition[1] = spawnY;
}

void setupEnemySprites() {
  buildCompiledSprite(
    &sprite_enemy,
    &enemy,
    SPRITE_ENEMY_WIDTH,
    SPRITE_ENEMY_HEIGHT,
    SPRITE_ENEMY_OFFSET_X,
    SPRITE_ENEMY_OFFSET_Y
  );
}

void setupRabbitSprites() {
  buildCompiledSprite(
    &sprite_rabbit,
    &rabbit,
    SPRITE_RABBIT_WIDTH,
    SPRITE_RABBIT_HEIGHT,
    SPRITE_RABBIT_OFFSET_X,
    SPRITE_RABBIT_OFFSET_Y
  );

  buildCompiledSprite(
    &sprite_mouse,
    &mouse,
    SPRITE_MOUSE_WIDTH,
    SPRITE_MOUSE_HEIGHT,
    SPRITE_MOUSE_OFFSET_X,
    SPRITE_MOUSE_OFFSET_Y
  );

  buildCompiledSprite(
    &sprite_bullet,
    &bullet,
    SPRITE_BULLET_WIDTH,
    SPRITE_BULLET_HEIGHT,
    SPRITE_BULLET_OFFSET_X,
    SPRITE_BULLET_OFFSET_Y
  );
}

void renderMouse() {
  mouse.x = rabbitPosition.mousePosition[0];
  mouse.y = rabbitPosition.mousePosition[1];

  drawCompiledSprite(&mouse);
  drawPixel(rabbitPosition.mouseDotPosition[0], rabbitPosition.mouseDotPosition[1], 2);
}

void renderRabbit() {
  rabbit.x = rabbitPosition.rabbitPosition[0];
  rabbit.y = rabbitPosition.rabbitPosition[1];

  drawCompiledSprite(&rabbit);
}

void renderEnemies() {
  int i;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    if (!enemyPosition[i].isActive) continue;

    enemy.x = enemyPosition[i].enemyPosition[0];
    enemy.y = enemyPosition[i].enemyPosition[1];

    drawCompiledSprite(&enemy);
  }
}

void renderRabbitBullets() {
  char i;

  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    if (!rabbitBulletPosition[i].isActive) continue;

    bullet.x = rabbitBulletPosition[i].x;
    bullet.y = rabbitBulletPosition[i].y;

    drawCompiledSprite(&bullet);
  }
}

void drawOnlyMouseArena() {
  mouse.x = rabbitPosition.oldMousePosition[0];
  mouse.y = rabbitPosition.oldMousePosition[1];
  getSpriteBounds(&mouse, &bounds);
  drawOnlyArena(&bounds);

  bounds.top = rabbitPosition.oldMouseDotPosition[1];
  bounds.bottom = rabbitPosition.oldMouseDotPosition[1];
  bounds.left = rabbitPosition.oldMouseDotPosition[0];
  bounds.right = rabbitPosition.oldMouseDotPosition[0];
  drawOnlyArena(&bounds);
}

void drawOnlyRabbitArena() {
  rabbit.x = rabbitPosition.oldRabbitPosition[0];
  rabbit.y = rabbitPosition.oldRabbitPosition[1];
  getSpriteBounds(&rabbit, &bounds);
  drawOnlyArena(&bounds);
}

void drawOnlyEnemiesArena() {
  int i;

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    if (!enemyPosition[i].isActive) continue;

    enemy.x = enemyPosition[i].oldEnemyPosition[0];
    enemy.y = enemyPosition[i].oldEnemyPosition[1];
    getSpriteBounds(&enemy, &bounds);
    drawOnlyArena(&bounds);

    if (enemyPosition[i].willBeInactive) {
      enemyPosition[i].isActive = 0;
    }
  }
}

void drawOnlyRabbitBulletArena() {
  int i;
  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
    if (!rabbitBulletPosition[i].isActive) continue;

    bullet.x = rabbitBulletPosition[i].oldX;
    bullet.y = rabbitBulletPosition[i].oldY;
    getSpriteBounds(&bullet, &bounds);
    drawOnlyArena(&bounds);

    if (rabbitBulletPosition[i].willBeInactive) {
      rabbitBulletPosition[i].isActive = 0;
    }
  }
}

int setupGame() {
  FILE *fh;

  installKeyboardHandler();
  initializeDrawBuffer();

  fh = fopen("sprtsht.bmp", "rb");
  if (readBMPIntoNewMemory(fh, &spritesheetImage)) return 1;
  fclose(fh);

  spritesheetImage.transparentColor = 0;

  setupWallSprites();
  setupRabbitSprites();
  setupRabbitBullets();
  setupEnemySprites();

  setVideoMode(VIDEO_MODE_VGA_256);
  bmp256ColorPaletteToVGAColorPalette(&spritesheetImage, vgaColors);
  setVGAColors(vgaColors, 256);

  activateMouse(&mouseStatus);

  buildArena();
  clearArenaRedrawRequests();

  srand(time(NULL));

  return 0;
}

void handleMovement() {
  handleRabbitMovement(
    &rabbitPosition,
    &keyboardKeydownState
  );
  captureAndLimitMousePosition(
    &rabbitPosition,
    &mouseStatus
  );
  calculateTargetAngle(
    &rabbitPosition,
    &mouseStatus
  );
}

void handleCombat() {
  if (mouseStatus.leftButtonDown) {
    attemptToFireRabbitBullet(
      &rabbitPosition,
      &rabbitWeaponry,
      rabbitBulletPosition
    );
  }

  advanceRabbitBullets(
    rabbitBulletPosition,
    &rabbitWeaponry
  );

  buildCollisionGrids(
    rabbitBulletPosition,
    &rabbitPosition,
    enemyPosition
  );

  handleRabbitToEnemyCollisions(
    &rabbitPosition,
    enemyPosition
  );

  handleRabbitBulletToEnemyCollisions(
    rabbitBulletPosition,
    enemyPosition
  );
}

void handleRedraw() {
  drawOnlyRabbitArena();
  drawOnlyEnemiesArena();
  drawOnlyMouseArena();
  drawOnlyRabbitBulletArena();

  redrawArena();

  renderRabbit();
  renderEnemies();
  renderMouse();
  renderRabbitBullets();
}

/*
double speedCalcs[200];
int currentSpeedCalc = 0;
double averageSpeedCalc;
clock_t startTime;
*/

int main(void) {
  byte *drawBuffer;
  int keepRunning = 1;
  int i;

  if (setupGame()) return 1;

  drawBuffer = getDrawBuffer();

  for (i = 0; i < ENEMY_MAX_COUNT; ++i) {
    maybeSpawnEnemy();
  }

  while (keepRunning) {
    readMouse(&mouseStatus);
    populateKeyboardKeydownState();

    handleMovement();
    handleRedraw();
    handleCombat();

    waitStartVbl();
    copyDrawBufferToDisplay();
    waitEndVbl();

    if (keyboardKeydownState.KEY_ESC) { keepRunning = 0; }
  }

  freeBMP(&spritesheetImage);

  setVideoMode(VIDEO_MODE_80x25_TEXT);
  uninstallKeyboardHandler();

  /*
  averageSpeedCalc = 0;
  for (currentSpeedCalc = 0; currentSpeedCalc < 200; ++currentSpeedCalc) {
    averageSpeedCalc += speedCalcs[currentSpeedCalc];
  }

  averageSpeedCalc /= 200;

  fprintf(stderr, "average: %f\n", averageSpeedCalc);
  */

  return 0;
}