Skip drawing invisible voxel sections

CREDITS.md

@@ -52,6 +52,7 @@ This page lists all the individual contributions to the project by their author.
   - MP saves support for quicksave command and savegame trigger action
   - Ported XNA CnCNet Client MP save handling
   - Retint fix toggle
+  - Voxel drawing invisible sections skip
 - **Uranusian (Thrifinesma)**:
   - Mind Control enhancement
   - Custom warhead splash list
@@ -532,6 +533,7 @@ This page lists all the individual contributions to the project by their author.
   - Fix a jumpjet crash related to voxel shadow drawing
   - Replace `BLOWFISH.DLL` using Red Alert source code
   - Adjust the dehardcoding of the 255 `OverlayType` limit to a different format
+  - Voxel drawing invisible sections skip
 - **CrimRecya**:
   - Fix `LimboKill` not working reliably
   - Allow using waypoints, area guard and attack move with aircraft

docs/Fixed-or-Improved-Logics.md

@@ -297,6 +297,7 @@ This page describes all ingame logics that are fixed or improved in Phobos witho
 - Allow the default value of `DefaultToGuardArea` to be defined by `[General] -> DefaultToGuardArea`.
 - Fixed the bug that cause technos teleport to cell 0,0 by ChronoSphere superweapon.
 - Fixed the bug that techno in attack move will move to target if it cannot attack it.
+- Voxel drawing code now skips sections that are invisible (have all zeros in the transform matrix main diagonal, meaning that the scale is 0% on all axes), thus increasing drawing performance for some voxels.
 
 ## Fixes / interactions with other extensions
 

docs/Whats-New.md

@@ -596,6 +596,7 @@ Vanilla fixes:
 - Fixed the issue where units recruited by a team with `AreTeamMembersRecruitable=false` cannot be recruited even if they have been liberated by that team (by TaranDahl)
 - Fixed the bug that cause technos teleport to cell 0,0 by ChronoSphere superweapon (by NetsuNegi)
 - Fixed the bug that techno in attack move will move to target if it cannot attack it (by NetsuNegi)
+- Voxel drawing code now skips sections that are invisible (have all zeros in the transform matrix main diagonal, meaning that the scale is 0% on all axes), thus increasing drawing performance for some voxels (by Kerbiter, ZivDero)
 
 Phobos fixes:
 - Fixed the bug that `AllowAirstrike=no` cannot completely prevent air strikes from being launched against it (by NetsuNegi)

src/Misc/Hooks.BugFixes.cpp

@@ -1,6 +1,7 @@
 #include <AircraftTrackerClass.h>
 #include <JumpjetLocomotionClass.h>
 #include <TunnelLocomotionClass.h>
+#include <FileFormats/HVA.h>
 
 #include <Ext/BuildingType/Body.h>
 #include <Ext/Techno/Body.h>
@@ -2716,7 +2717,7 @@ DEFINE_HOOK(0x5218C2, InfantryClass_UnmarkAllOccupationBits_ResetOwnerIdx, 0x6)
 	const auto pExt = CellExt::ExtMap.Find(pCell);
 	pExt->InfantryCount--;
 
-	// Vanilla check only the flag to decide if the InfantryOwnerIndex should be reset. 
+	// Vanilla check only the flag to decide if the InfantryOwnerIndex should be reset.
 	// But the tree take one of the flag bit. So if a infantry walk through a cell with a tree, the InfantryOwnerIndex won't be reset.
 	return (newFlag & 0x1C) == 0 || pExt->InfantryCount == 0 ? Reset : NoReset;
 }
@@ -3014,3 +3015,26 @@ DEFINE_HOOK(0x6EA870, TeamClass_LiberateMember_Start, 0x6)
 	pMember->RecruitableB = true;
 	return 0;
 }
+
+DEFINE_HOOK(0x706F64, TechnoClass_RenderVoxelObject_SkipInvisibleSections, 0x0)
+{
+	enum { SkipLayer = 0x706FDF };
+
+	GET(MotLib* const, pMotLib, EDI);
+
+	// stolen code
+	if (!pMotLib)
+		return 0x706FBD;
+
+	GET(int const, layer, EBX);
+	GET_STACK(unsigned int const, frame, STACK_OFFSET(0x13C, 0x18));
+
+	auto mtx = pMotLib->GetLayerMatrix(layer, frame);
+
+	if (mtx.row[0][0] == 0.0 || mtx.row[1][1] == 0.0 || mtx.row[2][2] == 0.0)
+		return SkipLayer;
+
+	// stolen code
+	R->EAX(frame);
+	return 0x706F6F;
+}