Rework buffer size allocations to only allocate as much space as is actually required.

desmume/src/frontend/windows/video.h

@@ -44,6 +44,7 @@ public:
 	int prescaleTotal;
 
 	size_t scratchBufferSize;
+	size_t rawBufferSize;
 	u8* srcBuffer;
 	size_t srcBufferSize;
 	u32 *buffer, *buffer_raw;
@@ -59,25 +60,35 @@ public:
 
 		prescaleTotal = prescaleHD;
 
-		const int kInflationFactor = 5; //the largest filter is going up 5x in each dimension
+		ResizeBuffers();
 
+		setfilter(currentfilter);
+	}
+
+	void ResizeBuffers()
+	{
 		// all these stupid video filters read outside of their buffer. let's allocate too much and hope it stays filled with black. geeze
 		const int kPadSize = 4;
 
-		size_t scratchBufferWidth = 256*kInflationFactor*prescaleHD + (kPadSize*2);
+		// raw buffer
-		size_t scratchBufferHeight = 192*2*prescaleHD*kInflationFactor + (kPadSize*2);
+		size_t rawBufferWidth = 256 * prescaleHD + (kPadSize * 2);
-		scratchBufferSize = scratchBufferWidth * scratchBufferHeight * 4;
+		size_t rawBufferHeight = 192 * 2 * prescaleHD + (kPadSize * 2);
+		rawBufferSize = rawBufferWidth * rawBufferHeight * 4;
+		buffer_raw = buffer = (u32*)malloc_alignedCacheLine(rawBufferSize);
 
-		//why are these the same size, anyway?
+		// display buffer
-		buffer_raw = buffer = (u32*)malloc_alignedCacheLine(scratchBufferSize);
+		size_t scratchBufferWidth = width + (kPadSize * 2);
+		size_t scratchBufferHeight = height + (kPadSize * 2);
+		scratchBufferSize = scratchBufferWidth * scratchBufferHeight * 4;
 		filteredbuffer = (u32*)malloc_alignedCacheLine(scratchBufferSize);
 
-		clear();
-
 		//move the buffer pointer inside it's padded area so that earlier reads won't go out of the buffer we allocated
-		buffer += (kPadSize*scratchBufferWidth + kPadSize)*4;
+		buffer += (kPadSize*rawBufferWidth + kPadSize) * 4;
 
-		setfilter(currentfilter);
+		// clean the new buffers
+		clear();
+		// prevent crashing when reducing the scaling
+		srcBufferSize = 0;
 	}
 
 	enum {
@@ -114,7 +125,7 @@ public:
 		//{
 		//	memset(srcBuffer, 0xFF, size() * 2);
 		//}
-		memset(buffer_raw, 0, scratchBufferSize);
+		memset(buffer_raw, 0, rawBufferSize);
 		memset(filteredbuffer, 0, scratchBufferSize);
 	}
 
@@ -170,6 +181,7 @@ public:
 
 		width *= prescaleHD;
 		height *= prescaleHD;
+		ResizeBuffers();
 	}
 
 	SSurface src;