From 6a5ab0edc0b79ffe93831ec4266a82ecf7fd7245 Mon Sep 17 00:00:00 2001
From: Randy Heit <rheit@zdoom.fake>
Date: Fri, 25 Sep 2009 02:27:48 +0000
Subject: [PATCH] - Fixed: FMultiPatchTexture::CopyTrueColorPixels() should
 clear the buffer   first before drawing into it if the copy op passed to it
 is OP_OVERWRITE.   FTexture::FillBuffer() sets this to erase whatever texture
 might have been   in the space it is going into.

SVN r1874 (trunk)
---
 docs/rh-log.txt                    |  6 ++++++
 src/textures/bitmap.cpp            | 14 ++++++++++++++
 src/textures/bitmap.h              |  1 +
 src/textures/multipatchtexture.cpp |  7 ++++++-
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index ac304a52d7..a5bee140ab 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,3 +1,9 @@
+September 24, 2009
+- Fixed: FMultiPatchTexture::CopyTrueColorPixels() should clear the buffer
+  first before drawing into it if the copy op passed to it is OP_OVERWRITE.
+  FTexture::FillBuffer() sets this to erase whatever texture might have been
+  in the space it is going into.
+
 September 22, 2009
 - Added a technique to try and minimize input lag with vsync enabled: Two
   surfaces are alternately locked for read-only access each frame, forcing
diff --git a/src/textures/bitmap.cpp b/src/textures/bitmap.cpp
index 913aa507e7..f1d78c478d 100644
--- a/src/textures/bitmap.cpp
+++ b/src/textures/bitmap.cpp
@@ -477,3 +477,17 @@ void FBitmap::CopyPixelData(int originx, int originy, const BYTE * patch, int sr
 	}
 }
 
+//===========================================================================
+//
+// Clear buffer
+//
+//===========================================================================
+void FBitmap::Zero()
+{
+	BYTE *buffer = data;
+	for (int y = 0; y < Height; ++y)
+	{
+		memset(buffer, 0, Width*4);
+		buffer += Pitch;
+	}
+}
diff --git a/src/textures/bitmap.h b/src/textures/bitmap.h
index 04bd580cd8..35bdf62a21 100644
--- a/src/textures/bitmap.h
+++ b/src/textures/bitmap.h
@@ -116,6 +116,7 @@ public:
 		return data;
 	}
 
+	void Zero();
 
 	virtual void CopyPixelDataRGB(int originx, int originy, const BYTE *patch, int srcwidth, 
 								int srcheight, int step_x, int step_y, int rotate, int ct, FCopyInfo *inf = NULL);
diff --git a/src/textures/multipatchtexture.cpp b/src/textures/multipatchtexture.cpp
index 4b9bd5e1b6..66c5276a3d 100644
--- a/src/textures/multipatchtexture.cpp
+++ b/src/textures/multipatchtexture.cpp
@@ -550,7 +550,12 @@ int FMultiPatchTexture::CopyTrueColorPixels(FBitmap *bmp, int x, int y, int w, i
 	if (w < 0 || w > Width) w = Width;
 	if (h < 0 || h > Height) h = Height;
 
-	for(int i=0;i<NumParts;i++)
+	if (inf->op == OP_OVERWRITE)
+	{
+		bmp->Zero();
+	}
+
+	for(int i = 0; i < NumParts; i++)
 	{
 		int ret = -1;