1 files changed, 23 insertions, 21 deletions

diff --git a/src/blitter/32bpp_anim.cpp b/src/blitter/32bpp_anim.cpp
index 532ad23cc..578d85f18 100644
--- a/src/blitter/32bpp_anim.cpp
+++ b/src/blitter/32bpp_anim.cpp
@@ -22,7 +22,7 @@ static FBlitter_32bppAnim iFBlitter_32bppAnim;
 
 Blitter_32bppAnim::~Blitter_32bppAnim()
 {
-	free(this->anim_buf);
+	free(this->anim_alloc);
 }
 
 template <BlitterMode mode>
@@ -39,8 +39,7 @@ inline void Blitter_32bppAnim::Draw(const Blitter::BlitterParams *bp, ZoomLevel
 	}
 
 	Colour *dst = (Colour *)bp->dst + bp->top * bp->pitch + bp->left;
-	assert(_screen.pitch == this->anim_buf_pitch); // precondition for translating 'bp->dst' into an 'anim_buf' offset below.
-	uint16 *anim = this->anim_buf + ((uint32 *)bp->dst - (uint32 *)_screen.dst_ptr) + bp->top * this->anim_buf_pitch + bp->left;
+	uint16 *anim = this->anim_buf + this->ScreenToAnimOffset((uint32 *)bp->dst) + bp->top * this->anim_buf_pitch + bp->left;
 
 	const byte *remap = bp->remap; // store so we don't have to access it via bp everytime
 
@@ -280,8 +279,7 @@ void Blitter_32bppAnim::DrawColourMappingRect(void *dst, int width, int height,
 	}
 
 	Colour *udst = (Colour *)dst;
-	assert(_screen.pitch == this->anim_buf_pitch); // precondition for translating 'dst' into an 'anim_buf' offset below.
-	uint16 *anim = this->anim_buf + ((uint32 *)dst - (uint32 *)_screen.dst_ptr);
+	uint16 *anim = this->anim_buf + this->ScreenToAnimOffset((uint32 *)dst);
 
 	if (pal == PALETTE_TO_TRANSPARENT) {
 		do {
@@ -319,8 +317,8 @@ void Blitter_32bppAnim::SetPixel(void *video, int x, int y, uint8 colour)
 
 	/* Set the colour in the anim-buffer too, if we are rendering to the screen */
 	if (_screen_disable_anim) return;
-	assert(_screen.pitch == this->anim_buf_pitch); // precondition for translating 'video' into an 'anim_buf' offset below.
-	this->anim_buf[((uint32 *)video - (uint32 *)_screen.dst_ptr) + x + y * this->anim_buf_pitch] = colour | (DEFAULT_BRIGHTNESS << 8);
+
+	this->anim_buf[this->ScreenToAnimOffset((uint32 *)video) + x + y * this->anim_buf_pitch] = colour | (DEFAULT_BRIGHTNESS << 8);
 }
 
 void Blitter_32bppAnim::DrawRect(void *video, int width, int height, uint8 colour)
@@ -332,8 +330,7 @@ void Blitter_32bppAnim::DrawRect(void *video, int width, int height, uint8 colou
 	}
 
 	Colour colour32 = LookupColourInPalette(colour);
-	assert(_screen.pitch == this->anim_buf_pitch); // precondition for translating 'video' into an 'anim_buf' offset below.
-	uint16 *anim_line = ((uint32 *)video - (uint32 *)_screen.dst_ptr) + this->anim_buf;
+	uint16 *anim_line = this->ScreenToAnimOffset((uint32 *)video) + this->anim_buf;
 
 	do {
 		Colour *dst = (Colour *)video;
@@ -357,8 +354,7 @@ void Blitter_32bppAnim::CopyFromBuffer(void *video, const void *src, int width,
 	assert(video >= _screen.dst_ptr && video <= (uint32 *)_screen.dst_ptr + _screen.width + _screen.height * _screen.pitch);
 	Colour *dst = (Colour *)video;
 	const uint32 *usrc = (const uint32 *)src;
-	assert(_screen.pitch == this->anim_buf_pitch); // precondition for translating 'video' into an 'anim_buf' offset below.
-	uint16 *anim_line = ((uint32 *)video - (uint32 *)_screen.dst_ptr) + this->anim_buf;
+	uint16 *anim_line = this->ScreenToAnimOffset((uint32 *)video) + this->anim_buf;
 
 	for (; height > 0; height--) {
 		/* We need to keep those for palette animation. */
@@ -401,8 +397,7 @@ void Blitter_32bppAnim::CopyToBuffer(const void *video, void *dst, int width, in
 
 	if (this->anim_buf == NULL) return;
 
-	assert(_screen.pitch == this->anim_buf_pitch); // precondition for translating 'video' into an 'anim_buf' offset below.
-	const uint16 *anim_line = ((const uint32 *)video - (uint32 *)_screen.dst_ptr) + this->anim_buf;
+	const uint16 *anim_line = this->ScreenToAnimOffset((const uint32 *)video) + this->anim_buf;
 
 	for (; height > 0; height--) {
 		memcpy(udst, src, width * sizeof(uint32));
@@ -485,18 +480,22 @@ void Blitter_32bppAnim::PaletteAnimate(const Palette &palette)
 	Colour *dst = (Colour *)_screen.dst_ptr;
 
 	/* Let's walk the anim buffer and try to find the pixels */
+	const int width = this->anim_buf_width;
+	const int pitch_offset = _screen.pitch - width;
+	const int anim_pitch_offset = this->anim_buf_pitch - width;
 	for (int y = this->anim_buf_height; y != 0 ; y--) {
-		for (int x = this->anim_buf_width; x != 0 ; x--) {
-			uint colour = GB(*anim, 0, 8);
+		for (int x = width; x != 0 ; x--) {
+			uint16 value = *anim;
+			uint8 colour = GB(value, 0, 8);
 			if (colour >= PALETTE_ANIM_START) {
 				/* Update this pixel */
-				*dst = this->AdjustBrightness(LookupColourInPalette(colour), GB(*anim, 8, 8));
+				*dst = this->AdjustBrightness(LookupColourInPalette(colour), GB(value, 8, 8));
 			}
 			dst++;
 			anim++;
 		}
-		dst += _screen.pitch - this->anim_buf_width;
-		anim += this->anim_buf_pitch - this->anim_buf_width;
+		dst += pitch_offset;
+		anim += anim_pitch_offset;
 	}
 
 	/* Make sure the backend redraws the whole screen */
@@ -513,10 +512,13 @@ void Blitter_32bppAnim::PostResize()
 	if (_screen.width != this->anim_buf_width || _screen.height != this->anim_buf_height ||
 			_screen.pitch != this->anim_buf_pitch) {
 		/* The size of the screen changed; we can assume we can wipe all data from our buffer */
-		free(this->anim_buf);
+		free(this->anim_alloc);
 		this->anim_buf_width = _screen.width;
 		this->anim_buf_height = _screen.height;
-		this->anim_buf_pitch = _screen.pitch;
-		this->anim_buf = CallocT<uint16>(this->anim_buf_height * this->anim_buf_pitch);
+		this->anim_buf_pitch = (_screen.width + 7) & ~7;
+		this->anim_alloc = CallocT<uint16>(this->anim_buf_pitch * this->anim_buf_height + 8);
+
+		/* align buffer to next 16 byte boundary */
+		this->anim_buf = reinterpret_cast<uint16 *>((reinterpret_cast<uintptr_t>(this->anim_alloc) + 0xF) & (~0xF));
 	}
 }