update imageScaleNNAA, add OpenMP

gframe/image_manager.cpp

 #include "image_manager.h"
 #include "game.h"
 #include <thread>
+#ifdef _OPENMP
+#include <omp.h>
+#endif
 
 namespace ygo {
 
@@ -128,25 +131,27 @@ void ImageManager::ResizeTexture() {
 }
 // function by Warr1024, from https://github.com/minetest/minetest/issues/2419 , modified
 void imageScaleNNAA(irr::video::IImage *src, irr::video::IImage *dest) {
-	double sx, sy, minsx, maxsx, minsy, maxsy, area, ra, ga, ba, aa, pw, ph, pa;
-	irr::u32 dy, dx;
-	irr::video::SColor pxl;
+	const irr::core::dimension2d<irr::u32> srcDim = src->getDimension();
+	const irr::core::dimension2d<irr::u32> destDim = dest->getDimension();
 
-	// Cache rectsngle boundaries.
-	double sw = src->getDimension().Width * 1.0;
-	double sh = src->getDimension().Height * 1.0;
+	// Cache scale ratios.
+	const double rx = (double)srcDim.Width / destDim.Width;
+	const double ry = (double)srcDim.Height / destDim.Height;
 
-	// Walk each destination image pixel.
-	// Note: loop y around x for better cache locality.
-	irr::core::dimension2d<irr::u32> dim = dest->getDimension();
-	for(dy = 0; dy < dim.Height; dy++)
-		for(dx = 0; dx < dim.Width; dx++) {
+#pragma omp parallel
+{
+	double sx, sy, minsx, maxsx, minsy, maxsy, area, ra, ga, ba, aa, pw, ph, pa;
+	irr::video::SColor pxl, npxl;
 
+	// Walk each destination image pixel.
+#pragma omp for schedule(dynamic)
+	for(irr::s32 dy = 0; dy < destDim.Height; dy++) {
+		for(irr::s32 dx = 0; dx < destDim.Width; dx++) {
 			// Calculate floating-point source rectangle bounds.
-			minsx = dx * sw / dim.Width;
-			maxsx = minsx + sw / dim.Width;
-			minsy = dy * sh / dim.Height;
-			maxsy = minsy + sh / dim.Height;
+			minsx = dx * rx;
+			maxsx = minsx + rx;
+			minsy = dy * ry;
+			maxsy = minsy + ry;
 
 			// Total area, and integral of r, g, b values over that area,
 			// initialized to zero, to be summed up in next loops.
@@ -157,9 +162,8 @@ void imageScaleNNAA(irr::video::IImage *src, irr::video::IImage *dest) {
 			aa = 0;
 
 			// Loop over the integral pixel positions described by those bounds.
-			for(sy = floor(minsy); sy < maxsy; sy++)
+			for(sy = floor(minsy); sy < maxsy; sy++) {
 				for(sx = floor(minsx); sx < maxsx; sx++) {
-
 					// Calculate width, height, then area of dest pixel
 					// that's covered by this source pixel.
 					pw = 1;
@@ -183,21 +187,20 @@ void imageScaleNNAA(irr::video::IImage *src, irr::video::IImage *dest) {
 					ba += pa * pxl.getBlue();
 					aa += pa * pxl.getAlpha();
 				}
-
+			}
 			// Set the destination image pixel to the average color.
 			if(area > 0) {
-				pxl.setRed(ra / area + 0.5);
-				pxl.setGreen(ga / area + 0.5);
-				pxl.setBlue(ba / area + 0.5);
-				pxl.setAlpha(aa / area + 0.5);
+				npxl.set((irr::u32)(aa / area + 0.5),
+						 (irr::u32)(ra / area + 0.5),
+						 (irr::u32)(ga / area + 0.5),
+						 (irr::u32)(ba / area + 0.5));
 			} else {
-				pxl.setRed(0);
-				pxl.setGreen(0);
-				pxl.setBlue(0);
-				pxl.setAlpha(0);
+				npxl.set(0);
 			}
-			dest->setPixel(dx, dy, pxl);
+			dest->setPixel(dx, dy, npxl);
 		}
+	}
+} // end of parallel region
 }
 irr::video::ITexture* ImageManager::GetTextureFromFile(const char* file, irr::s32 width, irr::s32 height) {
 	if(mainGame->gameConf.use_image_scale) {

gframe/premake5.lua

@@ -5,6 +5,7 @@ project "YGOPro"
     kind "WindowedApp"
     cppdialect "C++14"
     rtti "Off"
+    openmp "On"
 
     files { "*.cpp", "*.h" }
     includedirs { "../ocgcore" }