From 4843890c565bc54d67d65a01610f81eb3875d996 Mon Sep 17 00:00:00 2001
From: DS <ds.desour@proton.me>
Date: Thu, 15 Feb 2024 19:38:23 +0100
Subject: [PATCH] Inline g/setPixel in imageCleanTransparent (#14323)

---
 src/client/imagefilters.cpp | 60 ++++++++++++++++++++++++++-----------
 1 file changed, 43 insertions(+), 17 deletions(-)

diff --git a/src/client/imagefilters.cpp b/src/client/imagefilters.cpp
index ed8483fcfaa9..320af1fc8e80 100644
--- a/src/client/imagefilters.cpp
+++ b/src/client/imagefilters.cpp
@@ -65,20 +65,27 @@ class Bitmap {
 	}
 };
 
-/* Fill in RGB values for transparent pixels, to correct for odd colors
- * appearing at borders when blending.  This is because many PNG optimizers
- * like to discard RGB values of transparent pixels, but when blending then
- * with non-transparent neighbors, their RGB values will show up nonetheless.
- *
- * This function modifies the original image in-place.
- *
- * Parameter "threshold" is the alpha level below which pixels are considered
- * transparent. Should be 127 when the texture is used with ALPHA_CHANNEL_REF,
- * 0 when alpha blending is used.
- */
-void imageCleanTransparent(video::IImage *src, u32 threshold)
+template <bool IS_A8R8G8B8>
+static void imageCleanTransparentWithInlining(video::IImage *src, u32 threshold)
 {
-	core::dimension2d<u32> dim = src->getDimension();
+	void *const src_data = src->getData();
+	const core::dimension2d<u32> dim = src->getDimension();
+
+	auto get_pixel = [src, src_data, dim](u32 x, u32 y) -> video::SColor {
+		if constexpr (IS_A8R8G8B8) {
+			return reinterpret_cast<u32 *>(src_data)[y*dim.Width + x];
+		} else {
+			return src->getPixel(x, y);
+		}
+	};
+	auto set_pixel = [src, src_data, dim](u32 x, u32 y, video::SColor color) {
+		if constexpr (IS_A8R8G8B8) {
+			u32 *dest = &reinterpret_cast<u32 *>(src_data)[y*dim.Width + x];
+			*dest = color.color;
+		} else {
+			src->setPixel(x, y, color);
+		}
+	};
 
 	Bitmap bitmap(dim.Width, dim.Height);
 
@@ -86,7 +93,7 @@ void imageCleanTransparent(video::IImage *src, u32 threshold)
 	// Note: loop y around x for better cache locality.
 	for (u32 ctry = 0; ctry < dim.Height; ctry++)
 	for (u32 ctrx = 0; ctrx < dim.Width; ctrx++) {
-		if (src->getPixel(ctrx, ctry).getAlpha() > threshold)
+		if (get_pixel(ctrx, ctry).getAlpha() > threshold)
 			bitmap.set(ctrx, ctry);
 	}
 
@@ -125,7 +132,7 @@ void imageCleanTransparent(video::IImage *src, u32 threshold)
 
 			// Add RGB values weighted by alpha IF the pixel is opaque, otherwise
 			// use full weight since we want to propagate colors.
-			video::SColor d = src->getPixel(sx, sy);
+			video::SColor d = get_pixel(sx, sy);
 			u32 a = d.getAlpha() <= threshold ? 255 : d.getAlpha();
 			ss += a;
 			sr += a * d.getRed();
@@ -135,11 +142,11 @@ void imageCleanTransparent(video::IImage *src, u32 threshold)
 
 		// Set pixel to average weighted by alpha
 		if (ss > 0) {
-			video::SColor c = src->getPixel(ctrx, ctry);
+			video::SColor c = get_pixel(ctrx, ctry);
 			c.setRed(sr / ss);
 			c.setGreen(sg / ss);
 			c.setBlue(sb / ss);
-			src->setPixel(ctrx, ctry, c);
+			set_pixel(ctrx, ctry, c);
 			newmap.set(ctrx, ctry);
 		}
 	}
@@ -154,6 +161,25 @@ void imageCleanTransparent(video::IImage *src, u32 threshold)
 	}
 }
 
+/* Fill in RGB values for transparent pixels, to correct for odd colors
+ * appearing at borders when blending.  This is because many PNG optimizers
+ * like to discard RGB values of transparent pixels, but when blending then
+ * with non-transparent neighbors, their RGB values will show up nonetheless.
+ *
+ * This function modifies the original image in-place.
+ *
+ * Parameter "threshold" is the alpha level below which pixels are considered
+ * transparent. Should be 127 when the texture is used with ALPHA_CHANNEL_REF,
+ * 0 when alpha blending is used.
+ */
+void imageCleanTransparent(video::IImage *src, u32 threshold)
+{
+	if (src->getColorFormat() == video::ECF_A8R8G8B8)
+		imageCleanTransparentWithInlining<true>(src, threshold);
+	else
+		imageCleanTransparentWithInlining<false>(src, threshold);
+}
+
 /* Scale a region of an image into another image, using nearest-neighbor with
  * anti-aliasing; treat pixels as crisp rectangles, but blend them at boundaries
  * to prevent non-integer scaling ratio artifacts.  Note that this may cause