Anarch/mods/particle_effects.diff

diff --git a/game.h b/game.h
index 991058d..328ed68 100755
--- a/game.h
+++ b/game.h
@@ -339,6 +339,15 @@ typedef struct
 
 #define SFG_MENU_ITEM_NONE 255
 
+typedef struct
+{
+  uint8_t dieIn;        ///< Double frames left to live.
+  uint8_t color;
+  uint8_t height;       ///< Floor h. under part., in RCL_UNITS_PER_SQUARE / 4s.
+  uint16_t position[3];
+  int8_t velocity[3];   ///< Velocity, simply added to position each frame.
+} SFG_Particle;
+
 /*
   GLOBAL VARIABLES
 ===============================================================================
@@ -453,6 +462,9 @@ struct
   uint8_t floorColor;
   uint8_t ceilingColor;
 
+  SFG_Particle particles[SFG_MAX_PARTICLES];
+  uint16_t particleCount;
+
   SFG_DoorRecord doorRecords[SFG_MAX_DOORS];
   uint8_t doorRecordCount;
   uint8_t checkedDoorIndex; ///< Says which door are currently being checked.
@@ -1312,6 +1324,79 @@ RCL_Unit SFG_floorHeightAt(int16_t x, int16_t y)
   return SFG_TILE_FLOOR_HEIGHT(tile) * SFG_WALL_HEIGHT_STEP - doorHeight;
 }
 
+/**
+  Emits new particle in the particle system, velocity is in 1/16ths of a square
+  per second.
+*/
+void SFG_emitParticle(uint8_t timeToLive, uint8_t color, RCL_Unit position[3],
+  int8_t velocity[3])
+{
+  if (timeToLive == 0)
+    return;
+
+  SFG_Particle *p = SFG_currentLevel.particles;
+
+  if (SFG_currentLevel.particleCount >= SFG_MAX_PARTICLES)
+    p += SFG_game.frame % SFG_currentLevel.particleCount; // replace random
+  else
+  { // append new particle
+    p += SFG_currentLevel.particleCount;
+    SFG_currentLevel.particleCount++;
+  }
+
+  p->height = SFG_floorHeightAt(
+    position[0] / RCL_UNITS_PER_SQUARE,
+    position[1] / RCL_UNITS_PER_SQUARE) / (RCL_UNITS_PER_SQUARE / 4);
+
+  p->dieIn = timeToLive;
+  p->color = color;
+
+  for (uint8_t i = 0; i < 3; ++i)
+  {
+    p->position[i] = position[i];
+
+    int16_t v = velocity[i];
+
+    v = (v * (RCL_UNITS_PER_SQUARE / 16)) / SFG_FPS;
+
+    if (v < -128)
+      v = -128;
+    else if (v > 127)
+      v = 127;
+
+    p->velocity[i] = v;
+  }
+}
+
+void SFG_explodeParticles(RCL_Unit position[3], uint8_t speed, uint8_t count,
+  uint16_t randomSeed, uint8_t color, uint8_t timeToLive, uint8_t allowDown)
+{
+  while (count)
+  {
+    int8_t v[3];
+    uint8_t randomAxis = randomSeed % 3;
+    uint8_t randomizedSpeed = speed - 2 + count % 4;
+
+    // select random point on a speed x speed x speed cube:
+    for (uint8_t i = 0; i < 3; ++i)
+    {
+      randomSeed = randomSeed * 123 + 10;
+      
+      v[i] = (i == randomAxis) ?
+        (((randomSeed / 32) % 2) ? -1 * randomizedSpeed : randomizedSpeed) :
+        ((randomSeed % (randomizedSpeed * 2)) - randomizedSpeed);
+    }
+
+    if (!allowDown && v[2] < 0)
+      v[2] *= -1;   
+
+    SFG_emitParticle(timeToLive + (timeToLive > 127 ? -1 * (randomSeed % 32) : 
+     (randomSeed % 32)),color,position,v);
+
+    count--;
+  }
+}
+
 /**
   Like SFG_floorCollisionHeightAt, but takes into account colliding items on
   the map, so the squares that have these items are higher. The former function
@@ -1662,6 +1747,8 @@ void SFG_setAndInitLevel(uint8_t levelNumber)
     }
   } 
 
+  SFG_currentLevel.particleCount = 0;
+
   SFG_currentLevel.timeStart = SFG_game.frameTime; 
   SFG_currentLevel.frameStart = SFG_game.frame;
 
@@ -2000,18 +2087,24 @@ void SFG_monsterChangeHealth(SFG_MonsterRecord *monster, int8_t healthAdd)
   if (healthAdd < 0)
   {
     // play hurt sound
+
+    RCL_Unit pos[3];
+
+    pos[0] = SFG_MONSTER_COORD_TO_RCL_UNITS(monster->coords[0]);
+    pos[1] = SFG_MONSTER_COORD_TO_RCL_UNITS(monster->coords[1]);
+    pos[2] = SFG_floorHeightAt(SFG_MONSTER_COORD_TO_SQUARES(monster->coords[0]),
+      SFG_MONSTER_COORD_TO_SQUARES(monster->coords[1]));
+
+    uint8_t volume = SFG_distantSoundVolume(pos[0],pos[1],pos[2]);
     
-    uint8_t volume = SFG_distantSoundVolume( 
-      SFG_MONSTER_COORD_TO_RCL_UNITS(monster->coords[0]),
-      SFG_MONSTER_COORD_TO_RCL_UNITS(monster->coords[1]),
-      SFG_floorHeightAt(
-        SFG_MONSTER_COORD_TO_SQUARES(monster->coords[0]),
-        SFG_MONSTER_COORD_TO_SQUARES(monster->coords[1])));
-    
-      SFG_playGameSound(5,volume);
+    SFG_playGameSound(5,volume);
     
     if (monster->health == 0)
+    {
       SFG_playGameSound(2,volume);
+      SFG_explodeParticles(pos,25,SFG_MAX_PARTICLES / 3,SFG_game.frame + pos[0],
+        52,255,0);
+    }
   }
 }
 
@@ -2222,6 +2315,14 @@ void SFG_createExplosion(RCL_Unit x, RCL_Unit y, RCL_Unit z)
         i--;
       }
     }
+
+  RCL_Unit pos[3];
+  pos[0] = x;
+  pos[1] = y;
+  pos[2] = z;
+
+  SFG_explodeParticles(pos,43,(SFG_MAX_PARTICLES * 3) / 2,
+    SFG_game.frame + x + y,191,150,1);
 }
 
 void SFG_createDust(RCL_Unit x, RCL_Unit y, RCL_Unit z)
@@ -2242,6 +2343,14 @@ void SFG_createDust(RCL_Unit x, RCL_Unit y, RCL_Unit z)
     RCL_nonZero(SFG_GET_PROJECTILE_FRAMES_TO_LIVE(SFG_PROJECTILE_DUST) / 2);
 
   SFG_createProjectile(dust);
+
+  RCL_Unit pos[3];
+  pos[0] = x;
+  pos[1] = y;
+  pos[2] = z;
+
+  SFG_explodeParticles(pos,30,SFG_MAX_PARTICLES / 3,SFG_game.frame + x + y,5,
+    5,1);
 }
 
 void SFG_getMonsterWorldPosition(SFG_MonsterRecord *monster, RCL_Unit *x,
@@ -2645,6 +2754,31 @@ void SFG_updateLevel(void)
       }
     }
 
+    if (!eliminate && ((SFG_game.frame % (SFG_FPS / 20 + 1)) == 0) &&
+      (p->type == SFG_PROJECTILE_FIREBALL || p->type == SFG_PROJECTILE_PLASMA))
+    {
+      // rocket and plasma emit particles as they fly  
+      int8_t vel[3];
+      uint8_t col = 95;
+
+      vel[0] = 0;
+      vel[1] = 0;
+
+      if (p->type == SFG_PROJECTILE_PLASMA)
+      {
+        col = 207;
+
+        vel[0] = p->direction[1] / 32;
+        vel[1] = p->direction[0] / 32;
+        vel[(SFG_game.frame % 8) == 0] *= -1;
+        vel[2] = (pos[0] % 3 + pos[1] % 2) * 4;
+      }
+      else
+        vel[2] = 8;
+
+      SFG_emitParticle(30,col - p->doubleFramesToLive / 4  ,pos,vel);
+    }
+
     if (p->doubleFramesToLive == 0) // no more time to live?
     {
       eliminate = 1;
@@ -2974,6 +3108,93 @@ void SFG_updateLevel(void)
       }
     }
   }
+
+  // update particles:
+
+  SFG_Particle *p = SFG_currentLevel.particles;
+  uint8_t evenFrame = SFG_game.frame % 2;
+
+  if (SFG_currentLevel.particleCount > 0)
+  {
+    // check visibility of one random particle
+    SFG_Particle *p = SFG_currentLevel.particles +
+      (SFG_game.frame % SFG_currentLevel.particleCount);
+
+    RCL_Vector2D particlePos;
+
+    particlePos.x = p->position[0];
+    particlePos.y = p->position[1];
+
+    if (RCL_castRay3D(
+      SFG_player.camera.position,
+      SFG_player.camera.height,
+      particlePos,
+      p->position[2],
+      SFG_floorHeightAt,
+      SFG_ceilingHeightAt,
+      SFG_game.visibilityRayConstraints
+      ) < (7 * RCL_UNITS_PER_SQUARE) / 8)
+      p->dieIn = 0; // particle out of sight: just kill it
+  }
+
+  for (int i = 0; i < SFG_currentLevel.particleCount; ++i)
+  {
+    if (p->dieIn != 0)
+    {
+      if (evenFrame)
+        p->dieIn--;
+
+      RCL_Unit height = p->height;
+      height *= RCL_UNITS_PER_SQUARE / 4;
+
+      uint8_t squareX = p->position[0] / RCL_UNITS_PER_SQUARE,
+              squareY = p->position[1] / RCL_UNITS_PER_SQUARE;
+
+      p->position[0] += p->velocity[0];
+      p->position[1] += p->velocity[1];
+
+      if (squareX != p->position[0] / RCL_UNITS_PER_SQUARE ||
+          squareY != p->position[1] / RCL_UNITS_PER_SQUARE)
+      {
+        // particle changed square, handle change in floor height
+
+        RCL_Unit newHeight = SFG_floorHeightAt(
+          p->position[0] / RCL_UNITS_PER_SQUARE,
+          p->position[1] / RCL_UNITS_PER_SQUARE);
+
+        if (p->position[2] >= newHeight)
+        {
+          p->height = newHeight / (RCL_UNITS_PER_SQUARE / 4);
+          height = newHeight;
+        }
+        else
+        {
+          p->position[0] -= p->velocity[0];
+          p->position[1] -= p->velocity[1];
+          p->velocity[0] = 0;
+          p->velocity[1] = 0;
+        }
+      }
+
+      if (p->velocity[2] > 0 || p->position[2] >= -1 * p->velocity[2])
+        p->position[2] += p->velocity[2];
+
+      if (p->position[2] < height)
+        p->position[2] = height;
+
+      if (evenFrame && p->velocity[2] > -30)
+        p->velocity[2] -= (RCL_UNITS_PER_SQUARE / 16) / SFG_FPS  ; // gravity
+    }
+    else
+    {
+      SFG_currentLevel.particleCount--;
+
+      if (SFG_currentLevel.particleCount > 0)
+        *p = SFG_currentLevel.particles[SFG_currentLevel.particleCount];
+    }
+
+    p++;
+  }
 }
 
 /**
@@ -3591,6 +3812,24 @@ void SFG_gameStepPlaying(void)
         default:                         sound = 0; break;
       }
 
+      if (SFG_player.weapon == SFG_WEAPON_SHOTGUN ||
+        SFG_player.weapon == SFG_WEAPON_MACHINE_GUN)
+      {
+        // spawn bullet shell:
+        RCL_Unit shellP[3];
+        int8_t shellV[3];
+
+        shellP[0] = SFG_player.camera.position.x;
+        shellP[1] = SFG_player.camera.position.y;
+        shellP[2] = SFG_player.camera.height;
+
+        shellV[0] = SFG_player.direction.x / 16 - SFG_player.direction.y / 32;
+        shellV[1] = SFG_player.direction.y / 16 + SFG_player.direction.x / 32;
+        shellV[2] = 2;
+
+        SFG_emitParticle(255,20,shellP,shellV);
+      }
+
       if (sound != 255)
         SFG_playGameSound(sound,255);
 
@@ -3769,6 +4008,14 @@ void SFG_gameStepPlaying(void)
     SFG_processEvent(SFG_EVENT_VIBRATE,0);
     SFG_processEvent(SFG_EVENT_PLAYER_DIES,0);
     SFG_setGameState(SFG_GAME_STATE_LOSE);
+  
+    RCL_Unit pos[3];
+    pos[0] = SFG_player.camera.position.x + (SFG_player.direction.x * 2) / 3;
+    pos[1] = SFG_player.camera.position.y + (SFG_player.direction.y * 2) / 3;
+    pos[2] = SFG_player.camera.height;
+
+    // blood:
+    SFG_explodeParticles(pos,8,(SFG_MAX_PARTICLES * 2) / 3,123,175,255,0);
   }
 #endif
 }
@@ -4860,6 +5107,36 @@ void SFG_draw(void)
             p.depth);  
     }
 
+    // particles:
+
+    SFG_Particle *particle = SFG_currentLevel.particles;
+
+    for (int i = 0; i < SFG_currentLevel.particleCount; ++i)
+    {
+      RCL_Vector2D worldPosition;
+
+      worldPosition.x = particle->position[0];
+      worldPosition.y = particle->position[1];
+
+      RCL_PixelInfo p =
+        RCL_mapToScreen(worldPosition,particle->position[2],SFG_player.camera);
+
+      p.position.x *= SFG_RAYCASTING_SUBSAMPLE;
+
+      if (p.depth > 127 &&
+        p.position.x >= 0 &&
+        p.position.x < (SFG_GAME_RESOLUTION_X - SFG_PARTICLE_SIZE) &&
+        p.position.y >= 0 &&
+        p.position.y < (SFG_GAME_RESOLUTION_Y - SFG_PARTICLE_SIZE))
+      {
+        for (int y = p.position.y; y < p.position.y + SFG_PARTICLE_SIZE; ++y)
+          for (int x = p.position.x; x < p.position.x + SFG_PARTICLE_SIZE; ++x)
+            SFG_setGamePixel(x,y,particle->color);
+      }
+
+      particle++;
+    }
+
 #if SFG_HEADBOB_ENABLED
     // after rendering sprites subtract back the head bob offset
     SFG_player.camera.height -= headBobOffset;
diff --git a/settings.h b/settings.h
index a0d8c1f..2155369 100644
--- a/settings.h
+++ b/settings.h
@@ -457,6 +457,20 @@
   #define SFG_FORCE_SINGLE_ITEM_MENU 0
 #endif
 
+/**
+  Maximum number of particles for the game's particle system.
+*/
+#ifndef SFG_MAX_PARTICLES
+  #define SFG_MAX_PARTICLES 64
+#endif
+
+/**
+  Particle size in pixels, for particle system.
+*/
+#ifndef SFG_PARTICLE_SIZE
+  #define SFG_PARTICLE_SIZE 4
+#endif
+
 //------ developer/debug settings ------
 
 /**