From 0284d635d2fd6693e64a47436992d3681453ed72 Mon Sep 17 00:00:00 2001
From: Flyinghead <raphael.jean@gmail.com>
Date: Mon, 16 Jul 2018 16:28:48 +0200
Subject: [PATCH] Upscale rendered-to textures

Increase the size of RTT textures by a given integer factor. Defaults to
1.
This gives much better quality textures, particularly visible when used
fullscreen for transition or pause screens.
---
 core/nullDC.cpp          | 1 +
 core/rend/gles/gles.cpp  | 7 +++++++
 core/rend/gles/gltex.cpp | 7 +++++++
 core/types.h             | 1 +
 4 files changed, 16 insertions(+)

diff --git a/core/nullDC.cpp b/core/nullDC.cpp
index c1bbeb748..9b3dec0f5 100755
--- a/core/nullDC.cpp
+++ b/core/nullDC.cpp
@@ -313,6 +313,7 @@ void LoadSettings()
 	settings.rend.WideScreen		= cfgLoadInt("config","rend.WideScreen",0);
 	settings.rend.ShowFPS			= cfgLoadInt("config", "rend.ShowFPS", 0);
 	settings.rend.RenderToTextureBuffer = cfgLoadInt("config", "rend.RenderToTextureBuffer", 0);
+	settings.rend.RenderToTextureUpscale = cfgLoadInt("config", "rend.RenderToTextureUpscale", 1);
 	settings.rend.TranslucentPolygonDepthMask = cfgLoadInt("config", "rend.TranslucentPolygonDepthMask", 0);
 	settings.rend.ModifierVolumes	= cfgLoadInt("config","rend.ModifierVolumes",1);
 	settings.rend.Clipping			= cfgLoadInt("config","rend.Clipping",1);
diff --git a/core/rend/gles/gles.cpp b/core/rend/gles/gles.cpp
index 8ee55d670..e113365f1 100755
--- a/core/rend/gles/gles.cpp
+++ b/core/rend/gles/gles.cpp
@@ -1754,6 +1754,13 @@ bool RenderFrame()
 			width *= dc2s_scale_h;
 			height *= dc2s_scale_h;
 		}
+		else if (settings.rend.RenderToTextureUpscale > 1 && !settings.rend.RenderToTextureBuffer)
+		{
+			min_x *= settings.rend.RenderToTextureUpscale;
+			min_y *= settings.rend.RenderToTextureUpscale;
+			width *= settings.rend.RenderToTextureUpscale;
+			height *= settings.rend.RenderToTextureUpscale;
+		}
 
 		glScissor(min_x, min_y, width, height);
 		glcache.Enable(GL_SCISSOR_TEST);
diff --git a/core/rend/gles/gltex.cpp b/core/rend/gles/gltex.cpp
index b3767eea2..91556c08f 100644
--- a/core/rend/gles/gltex.cpp
+++ b/core/rend/gles/gltex.cpp
@@ -434,6 +434,13 @@ void BindRTT(u32 addy, u32 fbw, u32 fbh, u32 channels, u32 fmt)
 	while (fbw2 < fbw)
 		fbw2 *= 2;
 
+	if (settings.rend.RenderToTextureUpscale > 1 && !settings.rend.RenderToTextureBuffer)
+	{
+		fbw *= settings.rend.RenderToTextureUpscale;
+		fbh *= settings.rend.RenderToTextureUpscale;
+		fbw2 *= settings.rend.RenderToTextureUpscale;
+		fbh2 *= settings.rend.RenderToTextureUpscale;
+	}
 	// Get the currently bound frame buffer object. On most platforms this just gives 0.
 	//glGetIntegerv(GL_FRAMEBUFFER_BINDING, &m_i32OriginalFbo);
 
diff --git a/core/types.h b/core/types.h
index 0c62273a3..c81c7c21d 100644
--- a/core/types.h
+++ b/core/types.h
@@ -617,6 +617,7 @@ struct settings_t
 		bool WideScreen;
 		bool ShowFPS;
 		bool RenderToTextureBuffer;
+		int RenderToTextureUpscale;
 		bool TranslucentPolygonDepthMask;
 		bool ModifierVolumes;
 		bool Clipping;