Floor rendering fix, from PsyDoom

Erick194 · Jun 5, 2020 · 07375ca · 07375ca
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commit 07375ca
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diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
@@ -105,6 +105,9 @@
       * Suggestion to create a code to increase the map limit to 255
          https://github.com/BodbDearg/PsyDoom/commit/78436a90bfb8e2318141c13bce2e9c8f313af814
 
+      * Floor rendering fix, from PsyDoom
+         https://github.com/BodbDearg/PsyDoom/commit/2a0250ca6b43d920706849d0d9018cc4656cb1f1
+
 * **[Fabien Sanglard](https://github.com/fabiensanglard)**
 
    * Article **[The Polygons of Doom: PSX](http://fabiensanglard.net/doom_psx/index.html)**

diff --git a/PSXDOOM/doomdef.h b/PSXDOOM/doomdef.h
@@ -3,18 +3,20 @@
 /* Fixes and Version Update Here*/
 // NEWS (PsyDoom) and ([GEC] Master Edition)
 #define SHOWFPS 1
-#define ENABLE_NIGHTMARE    1       // Originally Activated in the project [GEC] Master Edition
+#define ENABLE_NIGHTMARE    1       // Originally Activated in the project [GEC] Master Edition.
 #define ENABLE_MOREMAPS		1       // Enable the increase of map limits, important note you need to change the #define LASTLEVEL to the desired value the limit is up to 255.
-#define P_FNHF_UPDATE       1       // PsyDoom P_FindNextHighestFloor new code logic
+#define P_FNHF_UPDATE       1       // PsyDoom P_FindNextHighestFloor new code logic.
+
 
 //FIXES
-#define FIX_LINEDEFS_DELETION   1   // Fixes for the 'linedef deletion' bug. From PsyDoom
-#define RANGE_CHECKS    1           // Only if necessary to avoid alterations in the game
-#define FIX_ML_DONTDRAW 1           // Automap: fix a PSX DOOM bug where lines flagged with ML_DONTDRAW would draw when the computer map powerup is obtained. From PsyDoom
+#define FIX_LINEDEFS_DELETION   1   // Fixes for the 'linedef deletion' bug. From PsyDoom.
+#define RANGE_CHECKS    1           // Only if necessary to avoid alterations in the game.
+#define FIX_ML_DONTDRAW 1           // Automap: fix a PSX DOOM bug where lines flagged with ML_DONTDRAW would draw when the computer map powerup is obtained. From PsyDoom.
 #define FIX_PE_SKULL_LIMIT 1        // Fixes code error when limiting lost souls, converting Doom 2 pc function to PsxDoom (based on Jaguar Doom), code is incompatible, fixes based on repair done for Psx Final Doom.
+#define FIX_FLATSPANS   1           // Precision fix for large open maps, to prevent cracks at the right of the screen. From PsyDoom.
 
 //UPDATES
-#define GH_UPDATES  1               // Psx Doom Greatest Hits Updates
+#define GH_UPDATES  1               // Psx Doom Greatest Hits Updates.
 
 #define	VINT	int
 

diff --git a/PSXDOOM/r_phase2.c b/PSXDOOM/r_phase2.c
@@ -899,6 +899,12 @@ void R_Render_Plane(vleaf_t *vlf1, int zheight, psxobj_t *psxobj)
 	unsigned long *v_yy;
 	xpos_t *xtable;
 
+	#if FIX_FLATSPANS == 1
+        int origSpanR;
+        int origSpanUR;
+        int origSpanVR;
+    #endif
+
 	POLY_FT3 *planepoly = (POLY_FT3*) getScratchAddr(128);//1F800200
 
 	lf1 = vlf1->lf;
@@ -1126,12 +1132,34 @@ void R_Render_Plane(vleaf_t *vlf1, int zheight, psxobj_t *psxobj)
 				delta2 = ((vx2 - vx1) / linecnt);
 				delta3 = ((vy2 - vy1) / linecnt);
 
+				// From PsyDoom: precision fix to prevent cracks at the right side of the screen on large open maps like 'Tower Of Babel'.
+                // Store the coords where the last span should end, and use those for the right side of the last span instead of
+                // the somewhat truncated/imprecise stepped coords.
+                //
+                // TODO: make this tweak configurable according to user prefs.
+                #if FIX_FLATSPANS == 1
+                    origSpanR = x2;
+                    origSpanUR = vx2;
+                    origSpanVR = vy2;
+                #endif
+
 				for (j = 0; j < linecnt; j++)
 				{
 					x2 = (x1 + delta1);
 					vx2 = (vx1 + delta2);
 					vy2 = (vy1 + delta3);
 
+					// From PsyDoom: precision fix to prevent cracks at the right side of the screen on large open maps like 'Tower Of Babel'.
+                    // TODO: make this tweak configurable according to user prefs.
+                    #if FIX_FLATSPANS == 1
+                        if ((j + 1) >= linecnt)
+                        {
+                            x2 = origSpanR;
+                            vx2 = origSpanUR;
+                            vy2 = origSpanVR;
+                        }
+                    #endif
+
 					xpos = 0;
 					if ((vx1 < vx2) && (vx2 < 256) == 0)
 					{