ACME-1195 : WIP : Lazy evaluate intermediate images in snapshot preview so perf is better in common cases, allow thumbnail to be computed from grabed frame (for SL Share), thumbnail display still buggy in SL Share

1 files changed, 38 insertions, 42 deletions

diff --git a/indra/llimage/llimage.cpp b/indra/llimage/llimage.cpp
index c8a05e1fae..18e08b94a6 100755
--- a/indra/llimage/llimage.cpp
+++ b/indra/llimage/llimage.cpp
@@ -449,18 +449,8 @@ void LLImageRaw::verticalFlip()
 void LLImageRaw::expandToPowerOfTwo(S32 max_dim, BOOL scale_image)
 {
 	// Find new sizes
-	S32 new_width = MIN_IMAGE_SIZE;
-	S32 new_height = MIN_IMAGE_SIZE;
-
-	while( (new_width < getWidth()) && (new_width < max_dim) )
-	{
-		new_width <<= 1;
-	}
-
-	while( (new_height < getHeight()) && (new_height < max_dim) )
-	{
-		new_height <<= 1;
-	}
+	S32 new_width  = expandDimToPowerOfTwo(getWidth(), max_dim);
+	S32 new_height = expandDimToPowerOfTwo(getHeight(), max_dim);
 
 	scale( new_width, new_height, scale_image );
 }
@@ -468,55 +458,61 @@ void LLImageRaw::expandToPowerOfTwo(S32 max_dim, BOOL scale_image)
 void LLImageRaw::contractToPowerOfTwo(S32 max_dim, BOOL scale_image)
 {
 	// Find new sizes
-	S32 new_width = max_dim;
-	S32 new_height = max_dim;
-
-	while( (new_width > getWidth()) && (new_width > MIN_IMAGE_SIZE) )
-	{
-		new_width >>= 1;
-	}
-
-	while( (new_height > getHeight()) && (new_height > MIN_IMAGE_SIZE) )
-	{
-		new_height >>= 1;
-	}
+	S32 new_width  = contractDimToPowerOfTwo(getWidth(), MIN_IMAGE_SIZE);
+	S32 new_height = contractDimToPowerOfTwo(getHeight(), MIN_IMAGE_SIZE);
 
 	scale( new_width, new_height, scale_image );
 }
 
-void LLImageRaw::biasedScaleToPowerOfTwo(S32 max_dim)
+// static
+S32 LLImageRaw::biasedDimToPowerOfTwo(S32 curr_dim, S32 max_dim)
 {
 	// Strong bias towards rounding down (to save bandwidth)
 	// No bias would mean THRESHOLD == 1.5f;
-	const F32 THRESHOLD = 1.75f; 
-
+	const F32 THRESHOLD = 1.75f;
+    
 	// Find new sizes
-	S32 larger_w = max_dim;	// 2^n >= mWidth
-	S32 smaller_w = max_dim;	// 2^(n-1) <= mWidth
-	while( (smaller_w > getWidth()) && (smaller_w > MIN_IMAGE_SIZE) )
+	S32 larger_dim  = max_dim;	// 2^n >= curr_dim
+	S32 smaller_dim = max_dim;	// 2^(n-1) <= curr_dim
+	while( (smaller_dim > curr_dim) && (smaller_dim > MIN_IMAGE_SIZE) )
 	{
-		larger_w = smaller_w;
-		smaller_w >>= 1;
+		larger_dim = smaller_dim;
+		smaller_dim >>= 1;
 	}
-	S32 new_width = ( (F32)getWidth() / smaller_w > THRESHOLD ) ? larger_w : smaller_w;
+	return ( ((F32)curr_dim / (F32)smaller_dim) > THRESHOLD ) ? larger_dim : smaller_dim;
+}
 
+// static
+S32 LLImageRaw::expandDimToPowerOfTwo(S32 curr_dim, S32 max_dim)
+{
+	S32 new_dim = MIN_IMAGE_SIZE;
+	while( (new_dim < curr_dim) && (new_dim < max_dim) )
+	{
+		new_dim <<= 1;
+	}
+    return new_dim;
+}
 
-	S32 larger_h = max_dim;	// 2^m >= mHeight
-	S32 smaller_h = max_dim;	// 2^(m-1) <= mHeight
-	while( (smaller_h > getHeight()) && (smaller_h > MIN_IMAGE_SIZE) )
+// static
+S32 LLImageRaw::contractDimToPowerOfTwo(S32 curr_dim, S32 min_dim)
+{
+	S32 new_dim = MAX_IMAGE_SIZE;
+	while( (new_dim > curr_dim) && (new_dim > min_dim) )
 	{
-		larger_h = smaller_h;
-		smaller_h >>= 1;
+		new_dim >>= 1;
 	}
-	S32 new_height = ( (F32)getHeight() / smaller_h > THRESHOLD ) ? larger_h : smaller_h;
+    return new_dim;
+}
 
+void LLImageRaw::biasedScaleToPowerOfTwo(S32 max_dim)
+{
+	// Find new sizes
+	S32 new_width  = biasedDimToPowerOfTwo(getWidth(),max_dim);
+	S32 new_height = biasedDimToPowerOfTwo(getHeight(),max_dim);
 
 	scale( new_width, new_height );
 }
 
-
-
-
 // Calculates (U8)(255*(a/255.f)*(b/255.f) + 0.5f).  Thanks, Jim Blinn!
 inline U8 LLImageRaw::fastFractionalMult( U8 a, U8 b )
 {