From a53652f36ea271164c395ccf22e300039312b317 Mon Sep 17 00:00:00 2001
From: Rachael Alexanderson <madame-rachelle@users.noreply.github.com>
Date: Fri, 20 Dec 2019 03:04:56 -0500
Subject: [PATCH] - implement vid_scalemode = 6 - sets absolute minimum scaling
 to fill entire screen - useful for speeding up software rendering

---
 src/rendering/r_videoscale.cpp | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/rendering/r_videoscale.cpp b/src/rendering/r_videoscale.cpp
index 493fd122a..fa5b33723 100644
--- a/src/rendering/r_videoscale.cpp
+++ b/src/rendering/r_videoscale.cpp
@@ -27,7 +27,7 @@
 #include "v_video.h"
 #include "templates.h"
 
-#define NUMSCALEMODES 6
+#define NUMSCALEMODES 7
 
 extern bool setsizeneeded;
 
@@ -61,6 +61,33 @@ namespace
 		bool isScaled43;
 		bool isCustom;
 	};
+
+	float v_MinimumToFill()
+	{
+		// sx = screen x dimension, sy = same for y
+		float sx = (float)screen->GetClientWidth(), sy = (float)screen->GetClientHeight();
+		static float lastsx = 0., lastsy = 0., result = 0.;
+		if (lastsx != sx || lastsy != sy)
+		{
+			if (sx <= 0. || sy <= 0.)
+				return 1.; // prevent x/0 error
+			// set absolute minimum scale to fill the entire screen but get as close to 640x400 as possible
+			float ssx = 640. / sx, ssy = 400. / sy;
+			result = (ssx < ssy) ? ssy : ssx;
+			lastsx = sx;
+			lastsy = sy;
+		}
+		return result;
+	}
+	inline uint32_t v_mfillX()
+	{
+		return screen ? (uint32_t)((float)screen->GetClientWidth() * v_MinimumToFill()) : 640;
+	}
+	inline uint32_t v_mfillY()
+	{
+		return screen ? (uint32_t)((float)screen->GetClientHeight() * v_MinimumToFill()) : 400;
+	}
+
 	v_ScaleTable vScaleTable[NUMSCALEMODES] =
 	{
 		//	isValid,	isLinear,	GetScaledWidth(),									            	GetScaledHeight(),										        	isScaled43, isCustom
@@ -68,8 +95,9 @@ namespace
 		{ true,			true,		[](uint32_t Width)->uint32_t { return Width; },			        [](uint32_t Height)->uint32_t { return Height; },	        		false,  	false   },	// 1  - Native (Linear)
 		{ true,			false,		[](uint32_t Width)->uint32_t { return 640; },		            	[](uint32_t Height)->uint32_t { return 400; },			        	true,   	false   },	// 2  - 640x400 (formerly 320x200)
 		{ true,			true,		[](uint32_t Width)->uint32_t { return 960; },		            	[](uint32_t Height)->uint32_t { return 600; },				        true,   	false   },	// 3  - 960x600 (formerly 640x400)
-		{ true,			true,		[](uint32_t Width)->uint32_t { return 1280; },		            	[](uint32_t Height)->uint32_t { return 800; },	        			true,   	false   },	// 4  - 1280x800		
+		{ true,			true,		[](uint32_t Width)->uint32_t { return 1280; },		            	[](uint32_t Height)->uint32_t { return 800; },	        			true,   	false   },	// 4  - 1280x800
 		{ true,			true,		[](uint32_t Width)->uint32_t { return vid_scale_customwidth; },	[](uint32_t Height)->uint32_t { return vid_scale_customheight; },	true,   	true    },	// 5  - Custom
+		{ true,			true,		[](uint32_t Width)->uint32_t { return v_mfillX(); },				[](uint32_t Height)->uint32_t { return v_mfillY(); },				false,		false   },	// 6  - Minimum Scale to Fill Entire Screen
 	};
 	bool isOutOfBounds(int x)
 	{