From b9dd67a0912291afb73ec0faa287b718c1f9a041 Mon Sep 17 00:00:00 2001
From: Miloslav Ciz <drummyfish@disroot.org>
Date: Tue, 3 Jan 2023 20:49:27 +0100
Subject: [PATCH] Add z-buffer mod

---
 README.md              |  2 ++
 mods/full_zbuffer.diff | 78 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 mods/full_zbuffer.diff

diff --git a/README.md b/README.md
index 2d16eda..428152b 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,8 @@ everywhere, made for the benefit of all living beings*
 
 ![](media/3screens.png)
 
+**NOTE: for a more consoomerist experience there are now mods in the mod directory with which you may rice the game.**
+
 This game got some attention on 4chan: [1](https://archive.li/Yzcwt), [2](https://archive.li/xY4ia), [3](https://archive.li/tFWrL).
 
 - [why this game is special](#why-this-game-is-special)
diff --git a/mods/full_zbuffer.diff b/mods/full_zbuffer.diff
new file mode 100644
index 0000000..9a3ec2f
--- /dev/null
+++ b/mods/full_zbuffer.diff
@@ -0,0 +1,78 @@
+This mod adds full z-buffer that mostly fixes the incorrect sprite visibility,
+however RAM consumption increases quite a bit. Note that visiblity inaccuracies
+may still occur as e.g. floor depth is not accurate and isn't used, but the game
+generally looks much better. By drummyfish, released under CC0 1.0, public
+domain.
+
+diff --git a/constants.h b/constants.h
+index 956baa0..da72f24 100644
+--- a/constants.h
++++ b/constants.h
+@@ -352,7 +352,7 @@
+   #define SFG_FONT_SIZE_BIG 1
+ #endif
+ 
+-#define SFG_Z_BUFFER_SIZE SFG_GAME_RESOLUTION_X
++#define SFG_Z_BUFFER_SIZE (SFG_GAME_RESOLUTION_X * SFG_GAME_RESOLUTION_Y)
+ 
+ /**
+   Step in which walls get higher, in raycastlib units.
+diff --git a/game.h b/game.h
+index 24285cb..f8ef257 100755
+--- a/game.h
++++ b/game.h
+@@ -951,6 +951,14 @@ void SFG_pixelFunc(RCL_PixelInfo *pixel)
+       :
+       SFG_TRANSPARENT_COLOR;
+ 
++    uint8_t *zValue = SFG_game.zBuffer +
++      pixel->position.y * SFG_GAME_RESOLUTION_X + pixel->position.x;
++  
++    uint8_t zDistance = SFG_RCLUnitToZBuffer(pixel->depth);
++
++    if (*zValue >= zDistance)
++      *zValue = zDistance;
++
+     shadow = pixel->hit.direction >> 1;
+   }
+   else // floor/ceiling
+@@ -1216,29 +1224,25 @@ void SFG_drawScaledSprite(
+ 
+   for (int16_t x = x0, u = u0; x <= x1; ++x, ++u)
+   {
+-    if (SFG_game.zBuffer[x] >= zDistance)
++    for (int16_t y = y0, v = v0; y <= y1; ++y, ++v)
+     {
+-      int8_t columnTransparent = 1;
++      uint8_t color =
++        SFG_getTexel(image,SFG_game.spriteSamplingPoints[u],
++          SFG_game.spriteSamplingPoints[v]);
+ 
+-      for (int16_t y = y0, v = v0; y <= y1; ++y, ++v)
++      if (color != SFG_TRANSPARENT_COLOR)
+       {
+-        uint8_t color =
+-          SFG_getTexel(image,SFG_game.spriteSamplingPoints[u],
+-            SFG_game.spriteSamplingPoints[v]);
+-
+-        if (color != SFG_TRANSPARENT_COLOR)
+-        {
+ #if SFG_DIMINISH_SPRITES
+-          color = palette_minusValue(color,minusValue);
++        color = palette_minusValue(color,minusValue);
+ #endif 
+-          columnTransparent = 0;
++        uint8_t *zValue = SFG_game.zBuffer + y * SFG_GAME_RESOLUTION_X + x;
+ 
++        if (*zValue >= zDistance)
++        {       
+           SFG_setGamePixel(x,y,color);
++          *zValue = zDistance;
+         }
+       }
+-
+-      if (!columnTransparent)
+-        SFG_game.zBuffer[x] = zDistance;
+     }
+   }
+ }