From a75c38eda98fa2689593eb7dc2fccb9826798595 Mon Sep 17 00:00:00 2001
From: Fabian Greffrath <fabian@greffrath.com>
Date: Wed, 14 Dec 2022 10:05:54 +0100
Subject: [PATCH] Crosshair lock fixes (#844)

* draw crosshair before weapon sprites to make sure they don't overlap

* prevent tracking targets out of view

* restrict crosshair coordinates to view window

* Gosh, widescreen

* fix up signs
---
 src/hu_stuff.c | 11 ++++-------
 src/hu_stuff.h |  1 +
 src/r_things.c | 31 ++++++++++++++++++-------------
 3 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/src/hu_stuff.c b/src/hu_stuff.c
index f88d5dba..da0780d7 100644
--- a/src/hu_stuff.c
+++ b/src/hu_stuff.c
@@ -42,6 +42,7 @@
 #include "p_map.h" // crosshair (linetarget)
 #include "m_misc2.h"
 #include "m_swap.h"
+#include "r_main.h"
 
 // global heads up display controls
 
@@ -1087,11 +1088,11 @@ static void HU_UpdateCrosshair(void)
 
 void HU_UpdateCrosshairLock(int x, int y)
 {
-  crosshair.x += x;
-  crosshair.y += y;
+  crosshair.x = ((viewwindowx + x) >> hires) - WIDESCREENDELTA;
+  crosshair.y = ((viewwindowy + y) >> hires);
 }
 
-static void HU_DrawCrosshair(void)
+void HU_DrawCrosshair(void)
 {
   if (plr->playerstate != PST_LIVE ||
       automapactive ||
@@ -1724,10 +1725,6 @@ void HU_Drawer(void)
   
   // display the interactive buffer for chat entry
   HUlib_drawIText(&w_chat);
-
-  // display crosshair
-  if (hud_crosshair)
-    HU_DrawCrosshair();
 }
 
 // [FG] draw Time widget on intermission screen
diff --git a/src/hu_stuff.h b/src/hu_stuff.h
index 98c3f2c4..dd038b39 100644
--- a/src/hu_stuff.h
+++ b/src/hu_stuff.h
@@ -108,6 +108,7 @@ extern crosstarget_t hud_crosshair_target;
 extern boolean hud_crosshair_lockon;
 extern mobj_t *crosshair_target;
 void HU_UpdateCrosshairLock(int x, int y);
+void HU_DrawCrosshair(void);
 
 extern int hud_crosshair_color;
 extern int hud_crosshair_target_color;
diff --git a/src/r_things.c b/src/r_things.c
index 6b2d9df6..f9e8d218 100644
--- a/src/r_things.c
+++ b/src/r_things.c
@@ -452,7 +452,7 @@ boolean flipcorpses = false;
 void R_ProjectSprite (mobj_t* thing)
 {
   fixed_t   gzt;               // killough 3/27/98
-  fixed_t   tx;
+  fixed_t   tx, txc;
   fixed_t   xscale;
   int       x1;
   int       x2;
@@ -549,18 +549,7 @@ void R_ProjectSprite (mobj_t* thing)
       flip = !flip;
     }
 
-  // [Alaux] Lock crosshair on target
-  if (STRICTMODE(hud_crosshair_lockon) && thing == crosshair_target)
-  {
-    HU_UpdateCrosshairLock
-    (
-      FixedMul(tx, xscale >> hires) >> FRACBITS,
-      (FixedMul(viewz - (interpz + crosshair_target->height/2), xscale >> hires) >> FRACBITS)
-      + (viewplayer->lookdir / MLOOKUNIT + viewplayer->recoilpitch)
-    );
-
-    crosshair_target = NULL; // Don't update it again until next tic
-  }
+  txc = tx; // [FG] sprite center coordinate
 
   // calculate edges of the shape
   // [crispy] fix sprite offsets for mirrored sprites
@@ -655,6 +644,18 @@ void R_ProjectSprite (mobj_t* thing)
       vis->colormap[1] = fullcolormap;
     }
   vis->brightmap = R_BrightmapForSprite(thing->sprite);
+
+  // [Alaux] Lock crosshair on target
+  if (STRICTMODE(hud_crosshair_lockon) && thing == crosshair_target)
+  {
+    HU_UpdateCrosshairLock
+    (
+      BETWEEN(0, viewwidth  - 1, (centerxfrac + FixedMul(txc, xscale)) >> FRACBITS),
+      BETWEEN(0, viewheight - 1, (centeryfrac + FixedMul(viewz - interpz - crosshair_target->height/2, xscale)) >> FRACBITS)
+    );
+
+    crosshair_target = NULL; // Don't update it again until next tic
+  }
 }
 
 //
@@ -865,6 +866,10 @@ void R_DrawPlayerSprites(void)
   mfloorclip = screenheightarray;
   mceilingclip = negonearray;
 
+  // display crosshair
+  if (hud_crosshair)
+    HU_DrawCrosshair();
+
   // add all active psprites
   for (i=0, psp=viewplayer->psprites; i<NUMPSPRITES; i++,psp++)
     if (psp->state)