PSP: clarify and fix up display code

Also added support for stretching images, and fixed up displaying of large images as well as PNG files

svn-id: r53454

3 files changed, 134 insertions, 111 deletions

diff --git a/backends/platform/psp/display_client.cpp b/backends/platform/psp/display_client.cpp
index 916b6c1aae..9d4f573e28 100644
--- a/backends/platform/psp/display_client.cpp
+++ b/backends/platform/psp/display_client.cpp
@@ -347,7 +347,6 @@ void Buffer::copyFromRect(const byte *buf, uint32 pitch, int destX, int destY, u
 			PspMemory::fastCopy(dst, buf, _pixelFormat.pixelsToBytes(recHeight * recWidth));
 	} else {
 		do {
-			//memcpy(dst, buf, recWidthInBytes);
 			if (_pixelFormat.swapRB)
 				PspMemorySwap::fastSwap(dst, buf, recWidthInBytes, _pixelFormat);
 			else
@@ -379,45 +378,45 @@ void Buffer::copyToArray(byte *dst, int pitch) {
 	} while (--h);
 }
 
-/* We can size the buffer either by texture size (multiple of 2^n) or source size. The GU can
-	really handle both, but is supposed to get only 2^n size buffers */
 void Buffer::setSize(uint32 width, uint32 height, HowToSize textureOrSource/*=kSizeByTextureSize*/) {
 	DEBUG_ENTER_FUNC();
-	PSP_DEBUG_PRINT("w[%u], h[%u], %s\n", width, height, textureOrSource ? "size by source" : "size by texture");
-
+	
+	// We can size the buffer either by texture size (multiple of 2^n) or source size.
+	// At higher sizes, increasing the texture size to 2^n is a waste of space. At these sizes kSizeBySourceSize should be used.
+	
 	_sourceSize.width = width;
 	_sourceSize.height = height;
 
-	_textureSize.width = scaleUpToPowerOfTwo(width);
+	_textureSize.width = scaleUpToPowerOfTwo(width);		// can only scale up to 512
 	_textureSize.height = scaleUpToPowerOfTwo(height);
-
+	
 	if (textureOrSource == kSizeByTextureSize) {
 		_width = _textureSize.width;
 		_height = _textureSize.height;
-	} else { /* kSizeBySourceSize */
-		_width = _sourceSize.width;
+	} else { // sizeBySourceSize
+		_width =  _sourceSize.width;
 		_height = _sourceSize.height;
+		
+		// adjust allocated width to be divisible by 32. 
+		// The GU can only handle multiples of 16 bytes. A 4 bit image x 32 will give us 16 bytes
+		// We don't necessarily know the depth of the pixels here. So just make it divisible by 32.
+		uint32 checkDiv = _width & 31;
+		if (checkDiv)
+			_width += 32 - checkDiv;
 	}
+	
+	PSP_DEBUG_PRINT("width[%u], height[%u], texW[%u], texH[%u], sourceW[%d], sourceH[%d] %s\n", _width, _height, _textureSize.width, _textureSize.height, _sourceSize.width, _sourceSize.height, textureOrSource ? "size by source" : "size by texture");
 }
 
-/* Scale a dimension (width/height) up to power of 2 for the texture */
+// Scale a dimension (width/height) up to power of 2 for the texture
+// Will only go up to 512 since that's the maximum PSP texture size
 uint32 Buffer::scaleUpToPowerOfTwo(uint32 size) {
 
-	uint32 textureDimension = 0;
-	if (size <= 16)
-		textureDimension = 16;
-	else if (size <= 32)
-		textureDimension = 32;
-	else if (size <= 64)
-		textureDimension = 64;
-	else if (size <= 128)
-		textureDimension = 128;
-	else if (size <= 256)
-		textureDimension = 256;
-	else
-		textureDimension = 512;
+	uint32 textureDimension = 16;
+	while (size > textureDimension && textureDimension < 512)
+		textureDimension <<= 1;
 
-	PSP_DEBUG_PRINT("power of 2 = %u\n", textureDimension);
+	PSP_DEBUG_PRINT("size[%u]. power of 2[%u]\n", size, textureDimension);
 
 	return textureDimension;
 }
@@ -540,51 +539,41 @@ void GuRenderer::render() {
 	DEBUG_ENTER_FUNC();
 	PSP_DEBUG_PRINT("Buffer[%p] Palette[%p]\n", _buffer->getPixels(), _palette->getRawValues());
 
-	setMaxTextureOffsetByIndex(0, 0);
-
 	guProgramDrawBehavior();
 
 	if (_buffer->hasPalette())
 		guLoadPalette();
 
 	guProgramTextureFormat();
-	guLoadTexture();
-
-	Vertex *vertices = guGetVertices();
-	fillVertices(vertices);
-
-	guDrawVertices(vertices);
-
-	if (_buffer->getSourceWidth() > 512) {
-		setMaxTextureOffsetByIndex(1, 0);
 
-		guLoadTexture();
-
-		vertices = guGetVertices();
-		fillVertices(vertices);
-
-		guDrawVertices(vertices);
+	// Loop over patches of 512x512 pixel textures and draw them
+	for (uint32 j = 0; j < _buffer->getSourceHeight(); j += 512) {
+		_textureLoadOffset.y = j;
+		
+		for (uint32 i = 0; i < _buffer->getSourceWidth(); i += 512) {
+			_textureLoadOffset.x = i;
+			
+			guLoadTexture();
+			Vertex *vertices = guGetVertices();
+			fillVertices(vertices);
+
+			guDrawVertices(vertices);
+		}
 	}
 }
 
-inline void GuRenderer::setMaxTextureOffsetByIndex(uint32 x, uint32 y) {
-	DEBUG_ENTER_FUNC();
-	const uint32 maxTextureSizeShift = 9; /* corresponds to 512 = max texture size*/
-
-	_maxTextureOffset.x = x << maxTextureSizeShift; /* x times 512 */
-	_maxTextureOffset.y = y << maxTextureSizeShift; /* y times 512 */
-}
-
 inline void GuRenderer::guProgramDrawBehavior() {
 	DEBUG_ENTER_FUNC();
-	PSP_DEBUG_PRINT("blending[%s] colorTest[%s] reverseAlpha[%s] keyColor[%u]\n", _blending ? "on" : "off", _colorTest ? "on" : "off", _alphaReverse ? "on" : "off", _keyColor);
+	PSP_DEBUG_PRINT("blending[%s] colorTest[%s] reverseAlpha[%s] keyColor[%u]\n", 
+		_blending ? "on" : "off", _colorTest ? "on" : "off", 
+		_alphaReverse ? "on" : "off", _keyColor);
 
 	if (_blending) {
 		sceGuEnable(GU_BLEND);
 
-		if (_alphaReverse)	// Reverse the alpha value (0 is 1)
+		if (_alphaReverse)	// Reverse the alpha value (ie. 0 is 1) easier to do in some cases
 			sceGuBlendFunc(GU_ADD, GU_ONE_MINUS_SRC_ALPHA, GU_SRC_ALPHA, 0, 0);
-		else	// Normal alpha values
+		else				// Normal alpha values
 			sceGuBlendFunc(GU_ADD, GU_SRC_ALPHA, GU_ONE_MINUS_SRC_ALPHA, 0, 0);
 
 	} else
@@ -592,7 +581,9 @@ inline void GuRenderer::guProgramDrawBehavior() {
 
 	if (_colorTest) {
 		sceGuEnable(GU_COLOR_TEST);
-		sceGuColorFunc(GU_NOTEQUAL, _keyColor, 0x00ffffff);
+		sceGuColorFunc(GU_NOTEQUAL, 	// show only colors not equal to this color
+					   _keyColor, 
+					   0x00ffffff);		// match everything but alpha
 	} else
 		sceGuDisable(GU_COLOR_TEST);
 }
@@ -613,7 +604,8 @@ inline void GuRenderer::guLoadPalette() {
 	PSP_DEBUG_PRINT("bpp[%d], pixelformat[%d], mask[%x]\n", _buffer->getBitsPerPixel(), _palette->getPixelFormat(), mask);
 
 	sceGuClutMode(convertToGuPixelFormat(_palette->getPixelFormat()), 0, mask, 0);
-	sceGuClutLoad(_palette->getNumOfEntries() >> 3, _palette->getRawValues());
+	sceGuClutLoad(_palette->getNumOfEntries() >> 3, 	// it's in batches of 8 for some reason
+				  _palette->getRawValues());
 }
 
 inline void GuRenderer::guProgramTextureFormat() {
@@ -659,7 +651,17 @@ inline uint32 GuRenderer::convertToGuPixelFormat(PSPPixelFormat::Type format) {
 inline void GuRenderer::guLoadTexture() {
 	DEBUG_ENTER_FUNC();
 
-	sceGuTexImage(0, _buffer->getTextureWidth(), _buffer->getTextureHeight(), _buffer->getWidth(), _buffer->getPixels() + _buffer->_pixelFormat.pixelsToBytes(_maxTextureOffset.x));
+	byte *startPoint = _buffer->getPixels();
+	if (_textureLoadOffset.x)
+		startPoint += _buffer->_pixelFormat.pixelsToBytes(_textureLoadOffset.x);
+	if (_textureLoadOffset.y) 
+		startPoint += _buffer->getWidthInBytes() * _textureLoadOffset.y;
+	
+	sceGuTexImage(0, 
+				_buffer->getTextureWidth(), 	// texture width (must be power of 2)
+				_buffer->getTextureHeight(), 	// texture height (must be power of 2)
+				_buffer->getWidth(),			// width of a line of the image (to get to the next line)
+				startPoint);					// where to start reading
 }
 
 inline Vertex *GuRenderer::guGetVertices() {
@@ -677,40 +679,40 @@ void GuRenderer::fillVertices(Vertex *vertices) {
 	uint32 outputWidth = _displayManager->getOutputWidth();
 	uint32 outputHeight = _displayManager->getOutputHeight();
 
-	float textureStartX, textureStartY, textureEndX, textureEndY;
-
 	// Texture adjustments for eliminating half-pixel artifacts from scaling
 	// Not necessary if we don't scale
-	float textureAdjustment = 0.0f;
+	float textureFix = 0.0f;
 	if (_useGlobalScaler &&
-	        (_displayManager->getScaleX() != 1.0f || _displayManager->getScaleX() != 1.0f))
-		textureAdjustment = 0.5f;
-
-	textureStartX = textureAdjustment + _offsetInBuffer.x; //debug
-	textureStartY = textureAdjustment + _offsetInBuffer.y;
-	// We subtract maxTextureOffset because our shifted texture starts at 512 and will go to 640
-	textureEndX = _offsetInBuffer.x + _drawSize.width - textureAdjustment - _maxTextureOffset.x;
-	textureEndY = _offsetInBuffer.y + _drawSize.height - textureAdjustment;
-
+	        (_displayManager->getScaleX() != 1.0f || _displayManager->getScaleY() != 1.0f))
+			textureFix = 0.5f;
+
+	// These coordinates describe an area within the texture. ie. we already loaded a square of texture,
+	// now the coordinates within it are 0 to the edge of the area of the texture we want to draw
+	float textureStartX = textureFix + _offsetInBuffer.x;
+	float textureStartY = textureFix + _offsetInBuffer.y;	
+	// even when we draw one of several textures, we use the whole drawsize of the image. The GU 
+	// will draw what it can with the texture it has and scale it properly for us.
+	float textureEndX = -textureFix +  _offsetInBuffer.x + _drawSize.width  - _textureLoadOffset.x;
+	float textureEndY = -textureFix +  _offsetInBuffer.y + _drawSize.height - _textureLoadOffset.y;
 	// For scaling to the final image size, calculate the gaps on both sides
 	uint32 gapX = _useGlobalScaler ? (PSP_SCREEN_WIDTH - outputWidth) >> 1 : 0;
 	uint32 gapY = _useGlobalScaler ? (PSP_SCREEN_HEIGHT - outputHeight) >> 1 : 0;
 
 	// Save scaled offset on screen
-	float scaledOffsetOnScreenX = scaleSourceToOutputX(_offsetOnScreen.x);
-	float scaledOffsetOnScreenY = scaleSourceToOutputY(_offsetOnScreen.y);
-
-	float imageStartX, imageStartY, imageEndX, imageEndY;
+	float scaledOffsetOnScreenX = scaleSourceToOutput(true, _offsetOnScreen.x);
+	float scaledOffsetOnScreenY = scaleSourceToOutput(false, _offsetOnScreen.y);
 
-	imageStartX = gapX + scaledOffsetOnScreenX + (scaleSourceToOutputX(_maxTextureOffset.x));
-	imageStartY = gapY + scaledOffsetOnScreenY;
+	float imageStartX = gapX + scaledOffsetOnScreenX + (scaleSourceToOutput(true, stretch(true, _textureLoadOffset.x)));
+	float imageStartY = gapY + scaledOffsetOnScreenY + (scaleSourceToOutput(false, stretch(false, _textureLoadOffset.y)));
 
+	float imageEndX, imageEndY;
+	
 	if (_fullScreen) { // shortcut
 		imageEndX = PSP_SCREEN_WIDTH - gapX + scaledOffsetOnScreenX;
 		imageEndY = PSP_SCREEN_HEIGHT - gapY + scaledOffsetOnScreenY; // needed for screen shake
 	} else { /* !fullScreen */
-		imageEndX = imageStartX + scaleSourceToOutputX(_drawSize.width);
-		imageEndY = imageStartY + scaleSourceToOutputY(_drawSize.height);
+		imageEndX = gapX + scaledOffsetOnScreenX + scaleSourceToOutput(true, stretch(true, _drawSize.width));
+		imageEndY = gapY + scaledOffsetOnScreenY + scaleSourceToOutput(false, stretch(false, _drawSize.height));
 	}
 
 	vertices[0].u = textureStartX;
@@ -729,8 +731,8 @@ void GuRenderer::fillVertices(Vertex *vertices) {
 	PSP_DEBUG_PRINT("ImageStart:   X[%f] Y[%f] ImageEnd:   X[%.1f] Y[%.1f]\n", imageStartX, imageStartY, imageEndX, imageEndY);
 }
 
-/* Scale the input X offset to appear in proper position on the screen */
-inline float GuRenderer::scaleSourceToOutputX(float offset) {
+/* Scale the input X/Y offset to appear in proper position on the screen */
+inline float GuRenderer::scaleSourceToOutput(bool x, float offset) {
 	float result;
 
 	if (!_useGlobalScaler)
@@ -738,28 +740,22 @@ inline float GuRenderer::scaleSourceToOutputX(float offset) {
 	else if (!offset)
 		result = 0.0f;
 	else
-		result = offset * _displayManager->getScaleX();
+		result = x ? offset * _displayManager->getScaleX() : offset * _displayManager->getScaleY();
 
 	return result;
 }
 
-/* Scale the input Y offset to appear in proper position on the screen */
-inline float GuRenderer::scaleSourceToOutputY(float offset) {
-	float result;
-
-	if (!_useGlobalScaler)
-		result = offset;
-	else if (!offset)
-		result = 0.0f;
-	else
-		result = offset * _displayManager->getScaleY();
-
-	return result;
+/* Scale the input X/Y offset to appear in proper position on the screen */
+inline float GuRenderer::stretch(bool x, float size) {
+	if (!_stretch)
+		return size;
+	return (x ? size * _stretchX : size * _stretchY);
 }
 
 inline void GuRenderer::guDrawVertices(Vertex *vertices) {
 	DEBUG_ENTER_FUNC();
 
+	// This function shouldn't need changing. The '32' here refers to floating point vertices.
 	sceGuDrawArray(GU_SPRITES, GU_TEXTURE_32BITF | GU_VERTEX_32BITF | GU_TRANSFORM_2D, 2, 0, vertices);
 }
 
diff --git a/backends/platform/psp/display_client.h b/backends/platform/psp/display_client.h
index feec477282..005fc76c7c 100644
--- a/backends/platform/psp/display_client.h
+++ b/backends/platform/psp/display_client.h
@@ -174,8 +174,13 @@ protected:
 class GuRenderer {
 public:
 	// Constructors
-	GuRenderer() : _useGlobalScaler(false), _buffer(0), _palette(0), _blending(false), _alphaReverse(false), _colorTest(false), _keyColor(0), _fullScreen(false) {}
-	GuRenderer(Buffer *buffer, Palette *palette) : _useGlobalScaler(false), _buffer(buffer), _palette(palette), _blending(false), _alphaReverse(false), _colorTest(false), _keyColor(0), _fullScreen(false) {}
+	GuRenderer() : _useGlobalScaler(false), _buffer(0), _palette(0), 
+					_blending(false), _alphaReverse(false), _colorTest(false), 
+					_keyColor(0), _fullScreen(false), _stretch(false), _stretchX(1.0f), _stretchY(1.0f) {}
+	GuRenderer(Buffer *buffer, Palette *palette) : 
+					_useGlobalScaler(false), _buffer(buffer), _palette(palette), 
+					_blending(false), _alphaReverse(false), _colorTest(false), 
+					_keyColor(0), _fullScreen(false), _stretch(false), _stretchX(1.0f), _stretchY(1.0f) {}
 	static void setDisplayManager(DisplayManager *dm) { _displayManager = dm; } // Called by the Display Manager
 
 	// Setters
@@ -190,8 +195,7 @@ public:
 	}
 	void setBuffer(Buffer *buffer) { _buffer = buffer; }
 	void setPalette(Palette *palette) { _palette = palette; }
-	void setMaxTextureOffsetByIndex(uint32 x, uint32 y);	// For drawing multiple textures
-	void setOffsetOnScreen(uint32 x, uint32 y) { _offsetOnScreen.x = x; _offsetOnScreen.y = y; }
+	void setOffsetOnScreen(int x, int y) { _offsetOnScreen.x = x; _offsetOnScreen.y = y; }
 	void setOffsetInBuffer(uint32 x, uint32 y) { _offsetInBuffer.x = x; _offsetInBuffer.y = y; }
 	void setColorTest(bool value) { _colorTest = value; }
 	void setKeyColor(uint32 value) { _keyColor = _buffer->_pixelFormat.convertTo32BitColor(value); }
@@ -199,6 +203,8 @@ public:
 	void setAlphaReverse(bool value) { _alphaReverse = value; }
 	void setFullScreen(bool value) { _fullScreen = value; }		// Shortcut for rendering
 	void setUseGlobalScaler(bool value) { _useGlobalScaler = value; }	// Scale to screen
+	void setStretch(bool active) { _stretch = active; }
+	void setStretchXY(float x, float y) { _stretchX = x; _stretchY = y; }
 
 	static void cacheInvalidate(void *pointer, uint32 size);
 
@@ -216,11 +222,11 @@ protected:
 	void guDrawVertices(Vertex *vertices);
 
 	uint32 convertToGuPixelFormat(PSPPixelFormat::Type format);
-	float scaleSourceToOutputX(float offset);
-	float scaleSourceToOutputY(float offset);
+	float scaleSourceToOutput(bool x, float offset);
+	float stretch(bool x, float size);
 
 	friend class MasterGuRenderer;
-	Point _maxTextureOffset;		///> For rendering textures > 512 pixels
+	Point _textureLoadOffset;		///> For rendering textures > 512 pixels
 	Point _offsetOnScreen;			///> Where on screen to draw
 	Point _offsetInBuffer;			///> Where in the texture to draw
 	bool _useGlobalScaler;			///> Scale to the output size on screen
@@ -233,6 +239,8 @@ protected:
 	bool _colorTest;
 	uint32 _keyColor;				///> Color to test against for color test. in 32 bits.
 	bool _fullScreen;				///> Speeds up for fullscreen rendering
+	bool _stretch;					///> Whether zooming is activated
+	float _stretchX, _stretchY;
 };
 
 #endif /* PSP_SCREEN_H */
diff --git a/backends/platform/psp/png_loader.cpp b/backends/platform/psp/png_loader.cpp
index 978db3eaf9..64a89af5f9 100644
--- a/backends/platform/psp/png_loader.cpp
+++ b/backends/platform/psp/png_loader.cpp
@@ -29,13 +29,19 @@
 #include "backends/platform/psp/display_client.h"
 #include "backends/platform/psp/png_loader.h"
 
+//#define __PSP_DEBUG_FUNCS__	/* For debugging function calls */
+//#define __PSP_DEBUG_PRINT__	/* For debug printouts */
+
+#include "backends/platform/psp/trace.h"
+
 PngLoader::Status PngLoader::allocate() {
+	DEBUG_ENTER_FUNC();
 	if (!findImageDimensions()) {
 		PSP_ERROR("failed to get image dimensions\n");
 		return BAD_FILE;
 	}
 
-	PSP_DEBUG_PRINT("width[%d], height[%d], paletteSize[%d], bitDepth[%d]\n", _width, _height, _paletteSize, _bitDepth);
+	
 	_buffer->setSize(_width, _height, _sizeBy);
 
 	if (_paletteSize) {	// 8 or 4-bit image
@@ -60,7 +66,7 @@ PngLoader::Status PngLoader::allocate() {
 		PSP_ERROR("failed to allocate buffer\n");
 		return OUT_OF_MEMORY;
 	}
-	if (!_palette->allocate()) {
+	if (_buffer->hasPalette() && !_palette->allocate()) {
 		PSP_ERROR("failed to allocate palette\n");
 		return OUT_OF_MEMORY;
 	}
@@ -68,6 +74,7 @@ PngLoader::Status PngLoader::allocate() {
 }
 
 bool PngLoader::load() {
+	DEBUG_ENTER_FUNC();
 	// Try to load the image
 	_file->seek(0);	// Go back to start
 
@@ -98,6 +105,7 @@ void PngLoader::libReadFunc(png_structp pngPtr, png_bytep data, png_size_t lengt
 }
 
 bool PngLoader::basicImageLoad() {
+	DEBUG_ENTER_FUNC();
 	_pngPtr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 	if (!_pngPtr)
 		return false;
@@ -130,11 +138,11 @@ bool PngLoader::basicImageLoad() {
 bool PngLoader::findImageDimensions() {
 	DEBUG_ENTER_FUNC();
 
-	if (!basicImageLoad())
-		return false;
+	bool status = basicImageLoad(); 
 
+	PSP_DEBUG_PRINT("width[%d], height[%d], paletteSize[%d], bitDepth[%d], rowBytes[%d]\n", _width, _height, _paletteSize, _bitDepth, _infoPtr->rowbytes);
 	png_destroy_read_struct(&_pngPtr, &_infoPtr, png_infopp_NULL);
-	return true;
+	return status;
 }
 
 //
@@ -143,11 +151,11 @@ bool PngLoader::findImageDimensions() {
 bool PngLoader::loadImageIntoBuffer() {
 	DEBUG_ENTER_FUNC();
 
-	if (!basicImageLoad())
+	if (!basicImageLoad()) {
+		png_destroy_read_struct(&_pngPtr, &_infoPtr, png_infopp_NULL);
 		return false;
-
-	// Strip off 16 bit channels. Not really needed but whatever
-	png_set_strip_16(_pngPtr);
+	}	
+	png_set_strip_16(_pngPtr);		// Strip off 16 bit channels in case they occur
 
 	if (_paletteSize) {
 		// Copy the palette
@@ -163,10 +171,23 @@ bool PngLoader::loadImageIntoBuffer() {
 		if (png_get_valid(_pngPtr, _infoPtr, PNG_INFO_tRNS))
 			png_set_tRNS_to_alpha(_pngPtr);		// Convert trans channel to alpha for 32 bits
 
-		png_set_filler(_pngPtr, 0xff, PNG_FILLER_AFTER);	// Filler for alpha?
+		//png_set_filler(_pngPtr, 0xff, PNG_FILLER_AFTER);	// Filler for alpha if none exists
+		png_set_add_alpha(_pngPtr, 0xff, PNG_FILLER_AFTER);		// Filler for alpha if none exists
 	}
 
-	unsigned char *line = (unsigned char*) malloc(_infoPtr->rowbytes);
+	uint32 rowBytes = png_get_rowbytes(_pngPtr, _infoPtr);
+	uint32 channels = png_get_channels(_pngPtr, _infoPtr);
+	
+	// there seems to be a bug in libpng where it doesn't increase the rowbytes or the channel even after we add the
+	// alpha channel
+	if (channels == 3 && (rowBytes / _width) == 3) {
+		channels = 4;
+		rowBytes = _width * channels;		
+	}	
+	
+	PSP_DEBUG_PRINT("rowBytes[%d], channels[%d]\n", rowBytes, channels);
+	
+	unsigned char *line = (unsigned char*) malloc(rowBytes);
 	if (!line) {
 		png_destroy_read_struct(&_pngPtr, png_infopp_NULL, png_infopp_NULL);
 		PSP_ERROR("Couldn't allocate line\n");
@@ -175,11 +196,9 @@ bool PngLoader::loadImageIntoBuffer() {
 
 	for (size_t y = 0; y < _height; y++) {
 		png_read_row(_pngPtr, line, png_bytep_NULL);
-		_buffer->copyFromRect(line, _infoPtr->rowbytes, 0, y, _width, 1);	// Copy into buffer
+		_buffer->copyFromRect(line, rowBytes, 0, y, _width, 1);	// Copy into buffer
 	}
-
 	free(line);
-
 	png_read_end(_pngPtr, _infoPtr);
 	png_destroy_read_struct(&_pngPtr, &_infoPtr, png_infopp_NULL);