bullet -> enemy collision codepath works

combat.c

@@ -0,0 +1,149 @@
+#include <math.h>
+
+#include "game.h"
+
+#include "movement.h"
+#include "const.h"
+#include "system/vga.h"
+
+void attemptToFireRabbitBullet(
+  struct RabbitPosition *rabbitPosition,
+  struct RabbitWeaponry *rabbitWeaponry,
+  struct BulletPosition rabbitBulletPosition[]
+) {
+  int okToFire = 0, availableBullet, i;
+  signed char doubleVelocityX, doubleVelocityY;
+
+  if (rabbitWeaponry->cooldown > 0) return;
+
+  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
+    if (rabbitBulletPosition[i].isActive == 0) {
+      okToFire = 1;
+      availableBullet = i;
+      break;
+    }
+  }
+
+  if (!okToFire) return;
+
+  rabbitWeaponry->cooldown = RABBIT_BULLET_COOLDOWN;
+
+  doubleVelocityX = sin(rabbitPosition->mouseAngle * DEG2RAD) * (RABBIT_BULLET_VELOCITY * 2);
+  doubleVelocityY = -cos(rabbitPosition->mouseAngle * DEG2RAD) * (RABBIT_BULLET_VELOCITY * 2);
+
+  rabbitBulletPosition[availableBullet].isActive = 1;
+  rabbitBulletPosition[availableBullet].willBeInactive = 0;
+  rabbitBulletPosition[availableBullet].x = rabbitPosition->rabbitPosition[0];
+  rabbitBulletPosition[availableBullet].y = rabbitPosition->rabbitPosition[1] - RABBIT_BULLET_HEIGHT_START;
+  rabbitBulletPosition[availableBullet].oldX = rabbitBulletPosition[availableBullet].x;
+  rabbitBulletPosition[availableBullet].oldY = rabbitBulletPosition[availableBullet].y;
+
+  rabbitBulletPosition[availableBullet].velocityXSteps[0] = doubleVelocityX / RABBIT_BULLET_VELOCITY;
+  rabbitBulletPosition[availableBullet].velocityXSteps[1] = doubleVelocityX % RABBIT_BULLET_VELOCITY;
+
+  rabbitBulletPosition[availableBullet].velocityYSteps[0] = doubleVelocityY / RABBIT_BULLET_VELOCITY;
+  rabbitBulletPosition[availableBullet].velocityYSteps[1] = doubleVelocityY % RABBIT_BULLET_VELOCITY;
+
+  rabbitBulletPosition[availableBullet].velocityStep = 0;
+}
+
+void advanceRabbitBullets(
+  struct BulletPosition rabbitBulletPosition[],
+  struct RabbitWeaponry *rabbitWeaponry
+) {
+  int i;
+
+  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
+    if (!rabbitBulletPosition[i].isActive) continue;
+
+    rabbitBulletPosition[i].oldX = rabbitBulletPosition[i].x;
+    rabbitBulletPosition[i].oldY = rabbitBulletPosition[i].y;
+
+    rabbitBulletPosition[i].x += rabbitBulletPosition[i].velocityXSteps[rabbitBulletPosition[i].velocityStep];
+    rabbitBulletPosition[i].y += rabbitBulletPosition[i].velocityYSteps[rabbitBulletPosition[i].velocityStep];
+
+    if (rabbitBulletPosition[i].x < MOUSE_LIMIT_LEFT) rabbitBulletPosition[i].willBeInactive = 1;
+    if (rabbitBulletPosition[i].x >= MOUSE_LIMIT_RIGHT) rabbitBulletPosition[i].willBeInactive = 1;
+    if (rabbitBulletPosition[i].y < MOUSE_LIMIT_TOP) rabbitBulletPosition[i].willBeInactive = 1;
+    if (rabbitBulletPosition[i].y >= MOUSE_LIMIT_BOTTOM) rabbitBulletPosition[i].willBeInactive = 1;
+
+    rabbitBulletPosition[i].velocityStep = 1 - rabbitBulletPosition[i].velocityStep;
+  }
+
+  if (rabbitWeaponry->cooldown > 0) rabbitWeaponry->cooldown--;
+}
+
+struct CollisionDetection {
+  short int sourceSX, sourceSY, sourceEX, sourceEY;
+  short int targetSX, targetSY, targetEX, targetEY;
+};
+
+struct CollisionDetection collisionDetection;
+
+int isCollision() {
+  int result;
+
+  // first pass: are the hitboxes even close
+  result = !(
+    collisionDetection.sourceEY < collisionDetection.targetSY ||
+    collisionDetection.sourceEX < collisionDetection.targetSX ||
+    collisionDetection.targetEY < collisionDetection.sourceSY ||
+    collisionDetection.targetEX < collisionDetection.sourceSX
+  );
+
+  if (!result) return result;
+
+  // second pass: check against specific character shaped hitboxes
+  // these will be generated from the spritesheet generator
+
+  return result;
+}
+
+void populateSourceCollision(struct CompiledSpriteRender *sprite) {
+  getSpriteBounds(sprite, &bounds);
+
+  collisionDetection.sourceSX = bounds.left;
+  collisionDetection.sourceSY = bounds.top;
+  collisionDetection.sourceEX = bounds.right;
+  collisionDetection.sourceEY = bounds.bottom;
+}
+
+void populateTargetCollision(struct CompiledSpriteRender *sprite) {
+  getSpriteBounds(sprite, &bounds);
+
+  collisionDetection.targetSX = bounds.left;
+  collisionDetection.targetSY = bounds.top;
+  collisionDetection.targetEX = bounds.right;
+  collisionDetection.targetEY = bounds.bottom;
+}
+
+void handleRabbitBulletToEnemyCollisions(
+  struct BulletPosition rabbitBulletPosition[],
+  struct EnemyPosition enemyPosition[]
+) {
+  int bulletIdx, enemyIdx;
+
+  // to start: brute force items
+  // possible performance improvements:
+  // * horizontal sweep against enemies to rule out enemies to check
+  for (bulletIdx = 0; bulletIdx < RABBIT_BULLET_LIMIT; ++bulletIdx) {
+    if (!rabbitBulletPosition[bulletIdx].isActive) continue;
+    if (rabbitBulletPosition[bulletIdx].willBeInactive) continue;
+
+    populateSourceCollision(&bullet);
+
+    for (enemyIdx = 0; enemyIdx < ENEMY_MAX_COUNT; ++enemyIdx) {
+      if (!enemyPosition[enemyIdx].isActive) continue;
+      if (enemyPosition[enemyIdx].willBeInactive) continue;
+
+      populateTargetCollision(&enemy);
+
+      if (isCollision()) {
+        enemyPosition[enemyIdx].willBeInactive = 1;
+        rabbitBulletPosition[bulletIdx].willBeInactive = 1;
+        break;
+      }
+    }
+  }
+}
+

combat.h

@@ -0,0 +1,15 @@
+void attemptToFireRabbitBullet(
+  struct RabbitPosition*,
+  struct RabbitWeaponry*,
+  struct BulletPosition[]
+);
+
+void advanceRabbitBullets(
+  struct BulletPosition[],
+  struct RabbitWeaponry*
+);
+
+void handleRabbitBulletToEnemyCollisions(
+  struct BulletPosition[],
+  struct EnemyPosition[]
+);

game.c

@@ -14,11 +14,17 @@
 #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 CompiledSpriteRender rabbit, mouse, bullet, enemy;
+struct MouseStatus mouseStatus;
+
 struct RabbitPosition rabbitPosition = {
   .rabbitPosition = { 60, 60 },
   .rabbitLimits = { { 20, 20 }, { 180, 180 } },
@@ -26,12 +32,20 @@ struct RabbitPosition rabbitPosition = {
   .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 = 50, .width = 30, .top = 50, .height = 30 }
+};
+
+
 void setupRabbitBullets() {
   int i;
 
@@ -52,91 +66,6 @@ void setupEnemies() {
   }
 }
 
-void attemptToFireRabbitBullet() {
-  char okToFire = 0, availableBullet, i;
-  signed char doubleVelocityX, doubleVelocityY;
-
-  if (rabbitWeaponry.cooldown > 0) return;
-
-  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
-    if (rabbitBulletPosition[i].isActive == 0) {
-      okToFire = 1;
-      availableBullet = i;
-      break;
-    }
-  }
-
-  if (!okToFire) return;
-
-  rabbitWeaponry.cooldown = RABBIT_BULLET_COOLDOWN;
-
-  doubleVelocityX = sin(rabbitPosition.mouseAngle * DEG2RAD) * (RABBIT_BULLET_VELOCITY * 2);
-  doubleVelocityY = -cos(rabbitPosition.mouseAngle * DEG2RAD) * (RABBIT_BULLET_VELOCITY * 2);
-
-  rabbitBulletPosition[availableBullet].isActive = 1;
-  rabbitBulletPosition[availableBullet].willBeInactive = 0;
-  rabbitBulletPosition[availableBullet].x = rabbitPosition.rabbitPosition[0];
-  rabbitBulletPosition[availableBullet].y = rabbitPosition.rabbitPosition[1] - RABBIT_BULLET_HEIGHT_START;
-  rabbitBulletPosition[availableBullet].oldX = rabbitBulletPosition[availableBullet].x;
-  rabbitBulletPosition[availableBullet].oldY = rabbitBulletPosition[availableBullet].y;
-
-  rabbitBulletPosition[availableBullet].velocityXSteps[0] = doubleVelocityX / RABBIT_BULLET_VELOCITY;
-  rabbitBulletPosition[availableBullet].velocityXSteps[1] = doubleVelocityX % RABBIT_BULLET_VELOCITY;
-
-  rabbitBulletPosition[availableBullet].velocityYSteps[0] = doubleVelocityY / RABBIT_BULLET_VELOCITY;
-  rabbitBulletPosition[availableBullet].velocityYSteps[1] = doubleVelocityY % RABBIT_BULLET_VELOCITY;
-
-  rabbitBulletPosition[availableBullet].velocityStep = 0;
-}
-
-void advanceRabbitBullets() {
-  char i;
-  signed char velocityX, velocityY;
-
-  for (i = 0; i < RABBIT_BULLET_LIMIT; ++i) {
-    if (!rabbitBulletPosition[i].isActive) continue;
-
-    rabbitBulletPosition[i].oldX = rabbitBulletPosition[i].x;
-    rabbitBulletPosition[i].oldY = rabbitBulletPosition[i].y;
-
-    rabbitBulletPosition[i].x += rabbitBulletPosition[i].velocityXSteps[rabbitBulletPosition[i].velocityStep];
-    rabbitBulletPosition[i].y += rabbitBulletPosition[i].velocityYSteps[rabbitBulletPosition[i].velocityStep];
-
-    if (rabbitBulletPosition[i].x < MOUSE_LIMIT_LEFT) rabbitBulletPosition[i].willBeInactive = 1;
-    if (rabbitBulletPosition[i].x >= MOUSE_LIMIT_RIGHT) rabbitBulletPosition[i].willBeInactive = 1;
-    if (rabbitBulletPosition[i].y < MOUSE_LIMIT_TOP) rabbitBulletPosition[i].willBeInactive = 1;
-    if (rabbitBulletPosition[i].y >= MOUSE_LIMIT_BOTTOM) rabbitBulletPosition[i].willBeInactive = 1;
-
-    rabbitBulletPosition[i].velocityStep = 1 - rabbitBulletPosition[i].velocityStep;
-  }
-
-  if (rabbitWeaponry.cooldown > 0) rabbitWeaponry.cooldown--;
-}
-
-void detectPlayerBulletToEnemyCollisions() {
-  int bulletIdx, enemyIdx;
-
-  for (bulletIdx = 0; bulletIdx < RABBIT_BULLET_LIMIT; ++bulletIdx) {
-    if (!rabbitBulletPosition[bulletIdx].isActive) continue;
-
-    for (enemyIdx = 0; enemyIdx < ENEMY_MAX_COUNT; ++enemyIdx) {
-      if (!enemyPosition[enemyIdx].isActive) continue;
-
-      // bullets hit enemies if:
-      // * bulletY - bullet_height_start is within 3px of enemy base
-      // * 
-    }
-  }
-}
-
-struct SpawnPointRange {
-  int left, width;
-  int top, height;
-};
-
-struct SpawnPointRange spawnPointRanges[1] = {
-   { .left = 50, .width = 30, .top = 50, .height = 30 }
-};
 
 void maybeSpawnEnemy() {
   char canSpawn;
@@ -159,6 +88,8 @@ void maybeSpawnEnemy() {
   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() {
@@ -201,8 +132,6 @@ void setupRabbitSprites() {
   );
 }
 
-struct MouseStatus mouseStatus;
-
 void renderMouse() {
   mouse.x = rabbitPosition.mousePosition[0];
   mouse.y = rabbitPosition.mousePosition[1];
@@ -244,8 +173,6 @@ void renderRabbitBullets() {
   }
 }
 
-struct SpriteBounds bounds;
-
 void drawOnlyMouseArena() {
   mouse.x = rabbitPosition.oldMousePosition[0];
   mouse.y = rabbitPosition.oldMousePosition[1];
@@ -278,7 +205,7 @@ void drawOnlyEnemiesArena() {
     drawOnlyArena(&bounds);
 
     if (enemyPosition[i].willBeInactive) {
-      enemyPosition[i].willBeInactive = 0;
+      enemyPosition[i].isActive = 0;
     }
   }
 }
@@ -330,28 +257,7 @@ int setupGame() {
   return 0;
 }
 
-double speedCalcs[200];
+void handleMovement() {
-int currentSpeedCalc = 0;
-double averageSpeedCalc;
-clock_t startTime;
-
-// non cdecl is put params into eax, ebx, and ecx
-
-int main(void) {
-  byte *drawBuffer;
-  int keepRunning = 1;
-
-  void (*code)(byte *);
-
-  if (setupGame()) return 1;
-
-  drawBuffer = getDrawBuffer();
-
-  maybeSpawnEnemy();
-
-  while (keepRunning) {
-    readMouse(&mouseStatus);
-    populateKeyboardKeydownState();
   handleRabbitMovement(
     &rabbitPosition,
     &keyboardKeydownState
@@ -364,11 +270,29 @@ int main(void) {
     &rabbitPosition,
     &mouseStatus
   );
+}
 
-    if (mouseStatus.leftButtonDown) attemptToFireRabbitBullet();
+void handleCombat() {
+  if (mouseStatus.leftButtonDown) {
+    attemptToFireRabbitBullet(
+      &rabbitPosition,
+      &rabbitWeaponry,
+      rabbitBulletPosition
+    );
+  }
 
-    advanceRabbitBullets();
+  advanceRabbitBullets(
+    rabbitBulletPosition,
+    &rabbitWeaponry
+  );
 
+  handleRabbitBulletToEnemyCollisions(
+    rabbitBulletPosition,
+    enemyPosition
+  );
+}
+
+void handleRedraw() {
   drawOnlyRabbitArena();
   drawOnlyEnemiesArena();
   drawOnlyMouseArena();
@@ -380,11 +304,35 @@ int main(void) {
   renderEnemies();
   renderMouse();
   renderRabbitBullets();
+}
+
+/*
+double speedCalcs[200];
+int currentSpeedCalc = 0;
+double averageSpeedCalc;
+clock_t startTime;
+*/
+
+int main(void) {
+  byte *drawBuffer;
+  int keepRunning = 1;
+
+  if (setupGame()) return 1;
+
+  drawBuffer = getDrawBuffer();
+
+  maybeSpawnEnemy();
+
+  while (keepRunning) {
+    readMouse(&mouseStatus);
+    populateKeyboardKeydownState();
+
+    handleMovement();
+    handleCombat();
+    handleRedraw();
 
     waitStartVbl();
-
     copyDrawBufferToDisplay();
-
     waitEndVbl();
 
     if (keyboardKeydownState.KEY_ESC) { keepRunning = 0; }
@@ -395,6 +343,7 @@ int main(void) {
   setVideoMode(VIDEO_MODE_80x25_TEXT);
   uninstallKeyboardHandler();
 
+  /*
   averageSpeedCalc = 0;
   for (currentSpeedCalc = 0; currentSpeedCalc < 200; ++currentSpeedCalc) {
     averageSpeedCalc += speedCalcs[currentSpeedCalc];
@@ -403,6 +352,7 @@ int main(void) {
   averageSpeedCalc /= 200;
 
   fprintf(stderr, "average: %f\n", averageSpeedCalc);
+  */
 
   return 0;
 }

game.h

@@ -0,0 +1,4 @@
+#include "system/vga.h"
+
+extern struct CompiledSpriteRender rabbit, mouse, bullet, enemy;
+extern struct SpriteBounds bounds;

makefile

@@ -1,4 +1,4 @@
-obj = game.o bmpload.o arena.o movement.o sprites.o
+obj = game.o bmpload.o arena.o movement.o sprites.o combat.o
 
 all: system/system.lib game.exe .SYMBOLIC
 

test.asm

@@ -1,67 +0,0 @@
-#PUBLIC doAThing_
-#PUBLIC renderTopTile_
-PUBLIC renderFloorTile_
-
-.386
-.model flat,c
-
-.CODE
-doAThing_:
-  push ebp
-  mov ebp, esp
-
-  mov eax, [ebp + 8]
-
-  pop ebp
-  ret
-
-renderTopTile_:
-  push ebp
-  mov ebp, esp
-  push ebx
-
-  mov eax, [ebp + 8]
-  mov ebx, 20
-
-_renderNextLine:
-  mov DWORD PTR [eax], 02020202h
-  mov DWORD PTR [eax + 4], 02020202h
-  mov DWORD PTR [eax + 8], 02020202h
-  mov DWORD PTR [eax + 12], 02020202h
-  mov DWORD PTR [eax + 16], 02020202h
-
-  add eax, 320
-  dec ebx
-  cmp ebx, 0
-  jne _renderNextLine
-
-  pop ebx
-  pop ebp
-  ret
-
-renderFloorTile_:
-  push ebp
-  mov ebp, esp
-  push ebx
-
-  mov eax, [ebp + 8]
-  mov ebx, 20
-
-_renderNextFloorLine:
-  mov DWORD PTR [eax], 04040404h
-  mov DWORD PTR [eax + 4], 04040404h
-  mov DWORD PTR [eax + 8], 04040404h
-  mov DWORD PTR [eax + 12], 04040404h
-  mov DWORD PTR [eax + 16], 04040404h
-
-  add eax, 320
-  dec ebx
-  cmp ebx, 0
-  jne _renderNextFloorLine
-
-_done:
-  pop ebx
-  pop ebp
-  ret
-
-end