From 1fe9ce3bf9f94bdd86edfda7e49e52c95c7f4643 Mon Sep 17 00:00:00 2001
From: Logan McNaughton <logan@bacoosta.com>
Date: Tue, 17 Apr 2018 12:38:24 -0600
Subject: [PATCH] Fix BAR Fog with N64 Depth Compare

---
 .../OpenGLContext/GLSL/glsl_ShaderStorage.h   |  2 +-
 .../GLSL/glsl_SpecialShadersFactory.cpp       | 51 +++++++++++++++----
 src/Graphics/OpenGLContext/opengl_GLInfo.cpp  |  3 +-
 3 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/src/Graphics/OpenGLContext/GLSL/glsl_ShaderStorage.h b/src/Graphics/OpenGLContext/GLSL/glsl_ShaderStorage.h
index 6a83d523..6c521dda 100644
--- a/src/Graphics/OpenGLContext/GLSL/glsl_ShaderStorage.h
+++ b/src/Graphics/OpenGLContext/GLSL/glsl_ShaderStorage.h
@@ -20,7 +20,7 @@ namespace glsl {
 		bool _saveCombinerKeys(const graphics::Combiners & _combiners) const;
 		bool _loadFromCombinerKeys(graphics::Combiners & _combiners);
 
-		const u32 m_formatVersion = 0x1FU;
+		const u32 m_formatVersion = 0x20U;
 		const u32 m_keysFormatVersion = 0x04;
 		const opengl::GLInfo & m_glinfo;
 		opengl::CachedUseProgram * m_useProgram;
diff --git a/src/Graphics/OpenGLContext/GLSL/glsl_SpecialShadersFactory.cpp b/src/Graphics/OpenGLContext/GLSL/glsl_SpecialShadersFactory.cpp
index 0e65f794..5ed68257 100644
--- a/src/Graphics/OpenGLContext/GLSL/glsl_SpecialShadersFactory.cpp
+++ b/src/Graphics/OpenGLContext/GLSL/glsl_SpecialShadersFactory.cpp
@@ -60,20 +60,51 @@ namespace glsl {
 				"uniform lowp usampler2D uTlutImage;\n"
 				"uniform sampler2D uDepthImage;		\n"
 				"uniform lowp vec4 uFogColor;								\n"
-				"OUT lowp vec4 fragColor;									\n"
+				;
+
+			if (config.frameBufferEmulation.N64DepthCompare != 0) {
+				if (_glinfo.imageTextures)
+					m_part += "layout(binding = 2, r32f) highp uniform restrict readonly image2D uDepthImageZ;		\n";
+
+				if (_glinfo.ext_fetch) {
+					m_part +=
+						"layout(location = 0) OUT lowp vec4 fragColor;	\n"
+						"layout(location = 1) inout highp vec4 depthZ;	\n"
+						;
+				} else
+					m_part += "OUT lowp vec4 fragColor;									\n";
+			} else
+				m_part += "OUT lowp vec4 fragColor;	\n";
+
+			m_part +=
 				"lowp float get_alpha()										\n"
 				"{															\n"
 				;
-			if (_glinfo.fetch_depth) {
-				m_part +=
-					"  highp float bufZ = gl_LastFragDepthARM;	\n"
-					;
+
+			if (config.frameBufferEmulation.N64DepthCompare == 0) {
+				if (_glinfo.fetch_depth) {
+					m_part +=
+						"  highp float bufZ = gl_LastFragDepthARM;	\n"
+						;
+				} else {
+					m_part +=
+						"  mediump ivec2 coord = ivec2(gl_FragCoord.xy);	\n"
+						"  highp float bufZ = texelFetch(uDepthImage,coord, 0).r;	\n"
+						;
+				}
 			} else {
-				m_part +=
-					"  mediump ivec2 coord = ivec2(gl_FragCoord.xy);	\n"
-					"  highp float bufZ = texelFetch(uDepthImage,coord, 0).r;	\n"
-					;
+				if (_glinfo.imageTextures) {
+					m_part +=
+						"  mediump ivec2 coord = ivec2(gl_FragCoord.xy);	\n"
+						"  highp float bufZ = imageLoad(uDepthImageZ,coord).r;	\n"
+						;
+				} else if (_glinfo.ext_fetch) {
+					m_part +=
+						"  highp float bufZ = depthZ.r;	\n"
+						;
+				}
 			}
+
 			m_part +=
 				"  highp int iZ = bufZ > 0.999 ? 262143 : int(floor(bufZ * 262143.0));\n"
 				"  mediump int y0 = clamp(iZ/512, 0, 511);					\n"
@@ -90,7 +121,7 @@ namespace glsl {
 				"}															\n"
 				;
 
-			if (_glinfo.fetch_depth)
+			if (config.frameBufferEmulation.N64DepthCompare == 0 && _glinfo.fetch_depth)
 				 m_part = "#extension GL_ARM_shader_framebuffer_fetch_depth_stencil : enable	\n" + m_part;
 		}
 	};
diff --git a/src/Graphics/OpenGLContext/opengl_GLInfo.cpp b/src/Graphics/OpenGLContext/opengl_GLInfo.cpp
index 387a86a5..15b39eb5 100644
--- a/src/Graphics/OpenGLContext/opengl_GLInfo.cpp
+++ b/src/Graphics/OpenGLContext/opengl_GLInfo.cpp
@@ -52,8 +52,7 @@ void GLInfo::init() {
 		imageTextures = (numericVersion >= 31);
 		msaa = numericVersion >= 31;
 	} else {
-		imageTextures = ((numericVersion >= 43) || (Utils::isExtensionSupported(*this, "GL_ARB_shader_image_load_store") &&
-				Utils::isExtensionSupported(*this, "GL_ARB_compute_shader")));
+		imageTextures = (numericVersion >= 42) || Utils::isExtensionSupported(*this, "GL_ARB_shader_image_load_store");
 		msaa = true;
 	}