From c5e4de9542dfcdedc3021cc3e6dedae3278c8736 Mon Sep 17 00:00:00 2001
From: Sour <mesenemu@gmail.com>
Date: Thu, 7 Feb 2019 19:45:17 -0500
Subject: [PATCH] Video: Precalculate brightness/etc for the palette instead of
 manually applying it to each pixel

---
 Core/DefaultVideoFilter.cpp | 68 +++++++++++++++++++------------------
 Core/DefaultVideoFilter.h   |  3 +-
 2 files changed, 37 insertions(+), 34 deletions(-)

diff --git a/Core/DefaultVideoFilter.cpp b/Core/DefaultVideoFilter.cpp
index 174ae6a4..aa173024 100644
--- a/Core/DefaultVideoFilter.cpp
+++ b/Core/DefaultVideoFilter.cpp
@@ -50,22 +50,48 @@ void DefaultVideoFilter::OnBeforeApplyFilter()
 	}
 	_pictureSettings = currentSettings;
 	_needToProcess = _pictureSettings.Hue != 0 || _pictureSettings.Saturation != 0 || _pictureSettings.Brightness || _pictureSettings.Contrast;
+
+	if(_needToProcess) {
+		double y, i, q;
+		uint32_t* originalPalette = _console->GetSettings()->GetRgbPalette();
+
+		for(int pal = 0; pal < 512; pal++) {
+			uint32_t pixelOutput = originalPalette[pal];
+			double redChannel = ((pixelOutput & 0xFF0000) >> 16) / 255.0;
+			double greenChannel = ((pixelOutput & 0xFF00) >> 8) / 255.0;
+			double blueChannel = (pixelOutput & 0xFF) / 255.0;
+
+			//Apply brightness, contrast, hue & saturation
+			RgbToYiq(redChannel, greenChannel, blueChannel, y, i, q);
+			y *= _pictureSettings.Contrast * 0.5f + 1;
+			y += _pictureSettings.Brightness * 0.5f;
+			YiqToRgb(y, i, q, redChannel, greenChannel, blueChannel);
+
+			int r = std::min(255, (int)(redChannel * 255));
+			int g = std::min(255, (int)(greenChannel * 255));
+			int b = std::min(255, (int)(blueChannel * 255));
+
+			_calculatedPalette[pal] = 0xFF000000 | (r << 16) | (g << 8) | b;
+		}
+	} else {
+		memcpy(_calculatedPalette, _console->GetSettings()->GetRgbPalette(), sizeof(_calculatedPalette));
+	}
 }
 
 void DefaultVideoFilter::DecodePpuBuffer(uint16_t *ppuOutputBuffer, uint32_t* outputBuffer, bool displayScanlines)
 {
 	uint32_t* out = outputBuffer;
 	OverscanDimensions overscan = GetOverscan();
-	double scanlineIntensity = 1.0 - _console->GetSettings()->GetPictureSettings().ScanlineIntensity;
+	uint8_t scanlineIntensity = (uint8_t)((1.0 - _console->GetSettings()->GetPictureSettings().ScanlineIntensity) * 255);
 	for(uint32_t i = overscan.Top, iMax = 240 - overscan.Bottom; i < iMax; i++) {
 		if(displayScanlines && (i + overscan.Top) % 2 == 0) {
 			for(uint32_t j = overscan.Left, jMax = 256 - overscan.Right; j < jMax; j++) {
-				*out = ProcessIntensifyBits(ppuOutputBuffer[i * 256 + j], scanlineIntensity);
+				*out = ApplyScanlineEffect(ppuOutputBuffer[i * 256 + j], scanlineIntensity);
 				out++;
 			}
 		} else {
 			for(uint32_t j = overscan.Left, jMax = 256 - overscan.Right; j < jMax; j++) {
-				*out = ProcessIntensifyBits(ppuOutputBuffer[i * 256 + j]);
+				*out = _calculatedPalette[ppuOutputBuffer[i * 256 + j]];
 				out++;
 			}
 		}
@@ -91,37 +117,13 @@ void DefaultVideoFilter::YiqToRgb(double y, double i, double q, double &r, doubl
 	b = std::max(0.0, std::min(1.0, (y + _yiqToRgbMatrix[4] * i + _yiqToRgbMatrix[5] * q)));
 }
 
-uint32_t DefaultVideoFilter::ProcessIntensifyBits(uint16_t ppuPixel, double scanlineIntensity)
+uint32_t DefaultVideoFilter::ApplyScanlineEffect(uint16_t ppuPixel, uint8_t scanlineIntensity)
 {
-	uint32_t pixelOutput = _console->GetSettings()->GetRgbPalette()[ppuPixel & 0x1FF];
+	uint32_t pixelOutput = _calculatedPalette[ppuPixel];
 
-	if(_needToProcess || scanlineIntensity < 1.0) {
-		//Incorrect emphasis bit implementation, but will do for now.
-		double redChannel = ((pixelOutput & 0xFF0000) >> 16) / 255.0;
-		double greenChannel = ((pixelOutput & 0xFF00) >> 8) / 255.0;
-		double blueChannel = (pixelOutput & 0xFF) / 255.0;
+	uint8_t r = ((pixelOutput & 0xFF0000) >> 16) * scanlineIntensity / 255;
+	uint8_t g = ((pixelOutput & 0xFF00) >> 8) * scanlineIntensity / 255;
+	uint8_t b = (pixelOutput & 0xFF) * scanlineIntensity / 255;
 
-		//Apply brightness, contrast, hue & saturation
-		if(_needToProcess) {
-			double y, i, q;
-			RgbToYiq(redChannel, greenChannel, blueChannel, y, i, q);
-			y *= _pictureSettings.Contrast * 0.5f + 1;
-			y += _pictureSettings.Brightness * 0.5f;
-			YiqToRgb(y, i, q, redChannel, greenChannel, blueChannel);
-		}
-
-		if(scanlineIntensity < 1.0) {
-			redChannel *= scanlineIntensity;
-			greenChannel *= scanlineIntensity;
-			blueChannel *= scanlineIntensity;
-		}
-
-		int r = std::min(255, (int)(redChannel * 255));
-		int g = std::min(255, (int)(greenChannel * 255));
-		int b = std::min(255, (int)(blueChannel * 255));
-
-		return 0xFF000000 | (r << 16) | (g << 8) | b;
-	} else {
-		return pixelOutput;
-	}
+	return 0xFF000000 | (r << 16) | (g << 8) | b;
 }
\ No newline at end of file
diff --git a/Core/DefaultVideoFilter.h b/Core/DefaultVideoFilter.h
index d53a54f5..4d3c44c7 100644
--- a/Core/DefaultVideoFilter.h
+++ b/Core/DefaultVideoFilter.h
@@ -7,6 +7,7 @@ class DefaultVideoFilter : public BaseVideoFilter
 {
 private:
 	double _yiqToRgbMatrix[6];
+	uint32_t _calculatedPalette[512];
 	PictureSettings _pictureSettings;
 	bool _needToProcess = false;
 
@@ -17,7 +18,7 @@ private:
 
 protected:
 	void DecodePpuBuffer(uint16_t *ppuOutputBuffer, uint32_t* outputBuffer, bool displayScanlines);
-	uint32_t ProcessIntensifyBits(uint16_t ppuPixel, double scanlineIntensity = 1.0);
+	uint32_t ApplyScanlineEffect(uint16_t ppuPixel, uint8_t scanlineIntensity);
 	void OnBeforeApplyFilter();
 
 public: