From 9fe24cb1e7b2cb9b77ff1a6ce4b0ba9bf052f347 Mon Sep 17 00:00:00 2001
From: StapleButter <thetotalworm@gmail.com>
Date: Tue, 9 May 2017 22:22:52 +0200
Subject: [PATCH] latch 3D registers upon VBlank

(fixes the last bugs in Gericom's train game)
---
 src/GPU3D.cpp       | 44 +++++++++++++++++++++++++++++++++++---------
 src/GPU3D.h         | 14 +++++++++-----
 src/GPU3D_Soft.cpp  | 12 ++++++------
 src/wx/Platform.cpp |  2 +-
 4 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/src/GPU3D.cpp b/src/GPU3D.cpp
index 0f700d96..4d9eca3c 100644
--- a/src/GPU3D.cpp
+++ b/src/GPU3D.cpp
@@ -60,7 +60,16 @@
 //
 // viewport Y coordinates are upside-down
 //
-// clear color/depth/bitmap/etc registers (04000350/04000354) are double-buffered
+// several registers are latched upon VBlank, the renderer uses the latched registers
+// latched registers include:
+// DISP3DCNT
+// alpha test ref value
+// fog color, offset, density table
+// toon table
+// edge table
+// clear attributes
+//
+// TODO: check how DISP_1DOT_DEPTH works and whether it's latched
 
 
 namespace GPU3D
@@ -153,16 +162,27 @@ FIFO<CmdFIFOEntry>* CmdPIPE;
 u32 NumCommands, CurCommand, ParamCount, TotalParams;
 
 u32 DispCnt;
-u8 AlphaRefVal;
-u8 AlphaRef;
+u8 AlphaRefVal, AlphaRef;
 
 u16 ToonTable[32];
 u16 EdgeTable[8];
 
-u32 FogColor;
-u32 FogOffset;
+u32 FogColor, FogOffset;
 u8 FogDensityTable[32];
 
+u32 ClearAttr1, ClearAttr2;
+
+u32 RenderDispCnt;
+u8 RenderAlphaRef;
+
+u16 RenderToonTable[32];
+u16 RenderEdgeTable[8];
+
+u32 RenderFogColor, RenderFogOffset;
+u8 RenderFogDensityTable[32];
+
+u32 RenderClearAttr1, RenderClearAttr2;
+
 u32 GXStat;
 
 u32 ExecParams[32];
@@ -241,9 +261,6 @@ Vertex* RenderVertexRAM;
 Polygon* RenderPolygonRAM;
 u32 RenderNumPolygons;
 
-u32 ClearAttr1, ClearAttr2;
-u32 RenderClearAttr1, RenderClearAttr2;
-
 u32 FlushRequest;
 u32 FlushAttributes;
 
@@ -1790,7 +1807,16 @@ void VBlank()
         RenderPolygonRAM = CurPolygonRAM;
         RenderNumPolygons = NumPolygons;
 
-        // TODO: find out which other registers are latched for rendering
+        RenderDispCnt = DispCnt;
+        RenderAlphaRef = AlphaRef;
+
+        memcpy(RenderEdgeTable, EdgeTable, 8*2);
+        memcpy(RenderToonTable, ToonTable, 32*2);
+
+        RenderFogColor = FogColor;
+        RenderFogOffset = FogOffset;
+        memcpy(RenderFogDensityTable, FogDensityTable, 32);
+
         RenderClearAttr1 = ClearAttr1;
         RenderClearAttr2 = ClearAttr2;
 
diff --git a/src/GPU3D.h b/src/GPU3D.h
index fdb85f8c..ae246589 100644
--- a/src/GPU3D.h
+++ b/src/GPU3D.h
@@ -65,12 +65,16 @@ typedef struct
 
 } Polygon;
 
-extern u32 DispCnt;
-extern u8 AlphaRef;
-extern s32 Viewport[4];
-extern u32 RenderClearAttr1, RenderClearAttr2;
+extern u32 RenderDispCnt;
+extern u8 RenderAlphaRef;
 
-extern u16 ToonTable[32];
+extern u16 RenderToonTable[32];
+extern u16 RenderEdgeTable[8];
+
+extern u32 RenderFogColor, RenderFogOffset;
+extern u8 RenderFogDensityTable[32];
+
+extern u32 RenderClearAttr1, RenderClearAttr2;
 
 bool Init();
 void DeInit();
diff --git a/src/GPU3D_Soft.cpp b/src/GPU3D_Soft.cpp
index 55dd9061..67d797d1 100644
--- a/src/GPU3D_Soft.cpp
+++ b/src/GPU3D_Soft.cpp
@@ -549,14 +549,14 @@ u32 RenderPixel(Polygon* polygon, u8 vr, u8 vg, u8 vb, s16 s, s16 t)
 
     if (blendmode == 2)
     {
-        u16 tooncolor = ToonTable[vr >> 1];
+        u16 tooncolor = RenderToonTable[vr >> 1];
 
         vr = (tooncolor << 1) & 0x3E; if (vr) vr++;
         vg = (tooncolor >> 4) & 0x3E; if (vg) vg++;
         vb = (tooncolor >> 9) & 0x3E; if (vb) vb++;
     }
 
-    if ((DispCnt & (1<<0)) && (((polygon->TexParam >> 26) & 0x7) != 0))
+    if ((RenderDispCnt & (1<<0)) && (((polygon->TexParam >> 26) & 0x7) != 0))
     {
         u8 tr, tg, tb;
 
@@ -609,7 +609,7 @@ u32 RenderPixel(Polygon* polygon, u8 vr, u8 vg, u8 vb, s16 s, s16 t)
         a = polyalpha;
     }
 
-    if ((blendmode == 2) && (DispCnt & (1<<1)))
+    if ((blendmode == 2) && (RenderDispCnt & (1<<1)))
     {
         r += vr;
         g += vg;
@@ -968,7 +968,7 @@ void RenderPolygon(Polygon* polygon)
 
             // alpha test
             // TODO: check alpha test when blending is disabled
-            if (alpha <= AlphaRef) continue;
+            if (alpha <= RenderAlphaRef) continue;
 
             if (alpha == 31)
             {
@@ -1001,7 +1001,7 @@ void RenderPolygon(Polygon* polygon)
                 u32 dstcolor = ColorBuffer[pixeladdr];
                 u32 dstalpha = dstcolor >> 24;
 
-                if ((dstalpha > 0) && (DispCnt & (1<<3)))
+                if ((dstalpha > 0) && (RenderDispCnt & (1<<3)))
                 {
                     u32 srcR = color & 0x3F;
                     u32 srcG = (color >> 8) & 0x3F;
@@ -1039,7 +1039,7 @@ void RenderFrame(Vertex* vertices, Polygon* polygons, int npolys)
 {
     u32 polyid = RenderClearAttr1 & 0x3F000000;
 
-    if (DispCnt & (1<<14))
+    if (RenderDispCnt & (1<<14))
     {
         u8 xoff = (RenderClearAttr2 >> 16) & 0xFF;
         u8 yoff = (RenderClearAttr2 >> 24) & 0xFF;
diff --git a/src/wx/Platform.cpp b/src/wx/Platform.cpp
index 8bcbb7ed..482b886f 100644
--- a/src/wx/Platform.cpp
+++ b/src/wx/Platform.cpp
@@ -17,7 +17,7 @@
 */
 
 #include <stdio.h>
-#include "Platform.h"
+#include "../Platform.h"
 
 
 namespace Platform