handle changed VCount+threaded rasteriser more gracefully

src/GPU.cpp

@@ -1061,6 +1061,12 @@ void FinishFrame(u32 lines)
     AssignFramebuffers();
 
     TotalScanlines = lines;
+
+    if (GPU3D::AbortFrame)
+    {
+        GPU3D::RestartFrame();
+        GPU3D::AbortFrame = false;
+    }
 }
 
 void StartScanline(u32 line)
@@ -1180,6 +1186,7 @@ void SetVCount(u16 val)
     // 3D engine seems to give up on the current frame in that situation, repeating the last two scanlines
     // TODO: also check the various DMA types that can be involved
 
+    GPU3D::AbortFrame |= NextVCount != val;
     NextVCount = val;
 }
 

src/GPU3D.cpp

@@ -275,6 +275,8 @@ u32 FlushAttributes;
 
 std::unique_ptr<GPU3D::Renderer3D> CurrentRenderer = {};
 
+bool AbortFrame;
+
 bool Init()
 {
     return true;
@@ -380,6 +382,8 @@ void Reset()
     ResetRenderingState();
 
     RenderXPos = 0;
+
+    AbortFrame = false;
 }
 
 void DoSavestate(Savestate* file)
@@ -621,6 +625,8 @@ void DoSavestate(Savestate* file)
 
     file->Bool32(&UseShininessTable);
     file->VarArray(ShininessTable, 128*sizeof(u8));
+
+    file->Bool32(&AbortFrame);
 }
 
 
@@ -2611,27 +2617,34 @@ u32 ScrolledLine[256];
 
 u32* GetLine(int line)
 {
-    u32* rawline = CurrentRenderer->GetLine(line);
-
-    if (RenderXPos == 0) return rawline;
-
-    // apply X scroll
-
-    if (RenderXPos & 0x100)
+    if (!AbortFrame)
     {
-        int i = 0, j = RenderXPos;
-        for (; j < 512; i++, j++)
-            ScrolledLine[i] = 0;
-        for (j = 0; i < 256; i++, j++)
-            ScrolledLine[i] = rawline[j];
+        u32* rawline = CurrentRenderer->GetLine(line);
+
+        if (RenderXPos == 0) return rawline;
+
+        // apply X scroll
+
+        if (RenderXPos & 0x100)
+        {
+            int i = 0, j = RenderXPos;
+            for (; j < 512; i++, j++)
+                ScrolledLine[i] = 0;
+            for (j = 0; i < 256; i++, j++)
+                ScrolledLine[i] = rawline[j];
+        }
+        else
+        {
+            int i = 0, j = RenderXPos;
+            for (; j < 256; i++, j++)
+                ScrolledLine[i] = rawline[j];
+            for (; i < 256; i++)
+                ScrolledLine[i] = 0;
+        }
     }
     else
     {
-        int i = 0, j = RenderXPos;
-        for (; j < 256; i++, j++)
-            ScrolledLine[i] = rawline[j];
-        for (; i < 256; i++)
-            ScrolledLine[i] = 0;
+        memset(ScrolledLine, 0, 256*4);
     }
 
     return ScrolledLine;

src/GPU3D.h

@@ -97,6 +97,8 @@ extern u16 RenderXPos;
 extern std::array<Polygon*,2048> RenderPolygonRAM;
 extern u32 RenderNumPolygons;
 
+extern bool AbortFrame;
+
 extern u64 Timestamp;
 
 bool Init();