Remove mulDiv255

That appears to be significantly slower in x86
JD557 · Nov 27, 2024 · cdb91f5 · cdb91f5
1 parent d6d2175
commit cdb91f5
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Showing 2 changed files with 15 additions and 23 deletions.
diff --git a/core/shared/src/main/scala/eu/joaocosta/minart/graphics/Blitter.scala b/core/shared/src/main/scala/eu/joaocosta/minart/graphics/Blitter.scala
@@ -104,9 +104,9 @@ private[graphics] object Blitter {
         val colorDest   = dest.unsafeGetPixel(destX, destY)
         val factor      = 255 - colorSource.a
         val color = Color(
-          Math.min(Color.mulDiv255(colorDest.r, factor) + colorSource.r, 255),
-          Math.min(Color.mulDiv255(colorDest.g, factor) + colorSource.g, 255),
-          Math.min(Color.mulDiv255(colorDest.b, factor) + colorSource.b, 255)
+          Math.min((colorDest.r * factor) / 255 + colorSource.r, 255),
+          Math.min((colorDest.g * factor) / 255 + colorSource.g, 255),
+          Math.min((colorDest.b * factor) / 255 + colorSource.b, 255)
         )
         dest.unsafePutPixel(destX, destY, color)
         dx += 1
@@ -254,9 +254,9 @@ private[graphics] object Blitter {
         val colorDest   = dest.unsafeGetPixel(destX, destY)
         val factor      = 255 - colorSource.a
         val color = Color(
-          Math.min(Color.mulDiv255(colorDest.r, factor) + colorSource.r, 255),
-          Math.min(Color.mulDiv255(colorDest.g, factor) + colorSource.g, 255),
-          Math.min(Color.mulDiv255(colorDest.b, factor) + colorSource.b, 255)
+          Math.min((colorDest.r * factor) / 255 + colorSource.r, 255),
+          Math.min((colorDest.g * factor) / 255 + colorSource.g, 255),
+          Math.min((colorDest.b * factor) / 255 + colorSource.b, 255)
         )
         dest.unsafePutPixel(destX, destY, color)
         dx += 1

diff --git a/core/shared/src/main/scala/eu/joaocosta/minart/graphics/Color.scala b/core/shared/src/main/scala/eu/joaocosta/minart/graphics/Color.scala
@@ -111,9 +111,9 @@ object Color {
       */
     def *(that: Color): Color =
       Color(
-        mulDiv255(color.r, that.r),
-        mulDiv255(color.g, that.g),
-        mulDiv255(color.b, that.b)
+        color.r * that.r / 255,
+        color.g * that.g / 255,
+        color.b * that.b / 255
       )
 
     /** Combines this with another color by multiplying each RGB value (on the [0.0, 1.0] range).
@@ -123,9 +123,9 @@ object Color {
       */
     def :*(that: Color): Color =
       Color(
-        mulDiv255(color.r, that.r),
-        mulDiv255(color.g, that.g),
-        mulDiv255(color.b, that.b),
+        color.r * that.r / 255,
+        color.g * that.g / 255,
+        color.b * that.b / 255,
         color.a
       )
 
@@ -136,9 +136,9 @@ object Color {
       */
     def *:(that: Color): Color =
       Color(
-        mulDiv255(color.r, that.r),
-        mulDiv255(color.g, that.g),
-        mulDiv255(color.b, that.b),
+        color.r * that.r / 255,
+        color.g * that.g / 255,
+        color.b * that.b / 255,
         that.a
       )
 
@@ -225,12 +225,4 @@ object Color {
     */
   def unapply(color: Color): Some[(Int, Int, Int)] =
     Some(color.r, color.g, color.b)
-
-  /** Computes (x * y) / 255
-    * Based on https://github.com/libsdl-org/SDL/blob/bbc9c75618fbc60583123e03f31f4e856f2654bf/src/video/SDL_blit.h#L524-L530
-    */
-  inline private[graphics] def mulDiv255(x: Int, y: Int): Int = {
-    val out = (x * y) + 1
-    (out + (out >> 8) >> 8)
-  }
 }