GS/HW: Only enable depth writes/floor calculation if depth is output

bin/resources/shaders/dx11/tfx.fx

@@ -71,6 +71,7 @@
 #define PS_DITHER 0
 #define PS_DITHER_ADJUST 0
 #define PS_ZCLAMP 0
+#define PS_ZFLOOR 0
 #define PS_SCANMSK 0
 #define PS_AUTOMATIC_LOD 0
 #define PS_MANUAL_LOD 0
@@ -138,7 +139,7 @@ struct PS_OUTPUT
 #endif
 #endif
 #endif
-#if PS_ZCLAMP
+#if PS_ZCLAMP || PS_ZFLOOR
 	float depth : SV_Depth;
 #endif
 };
@@ -1209,8 +1210,16 @@ PS_OUTPUT ps_main(PS_INPUT input)
 
 #endif // PS_DATE != 1/2
 
+#if PS_ZFLOOR
+float depth_value = floor(input.p.z * exp2(32.0f)) * exp2(-32.0f);
+#else
+float depth_value = input.p.z;
+#endif
+
 #if PS_ZCLAMP
-	output.depth = min(input.p.z, MaxDepthPS);
+	output.depth = min(depth_value, MaxDepthPS);
+#elif PS_ZFLOOR
+	output.depth = depth_value;
 #endif
 
 	return output;

bin/resources/shaders/opengl/tfx_fs.glsl

@@ -1143,7 +1143,16 @@ void ps_main()
 	#endif
 #endif
 
-#if PS_ZCLAMP
-	gl_FragDepth = min(gl_FragCoord.z, MaxDepthPS);
+#if PS_ZFLOOR
+float depth_value = floor(gl_FragCoord.z * exp2(32.0f)) * exp2(-32.0f);
+#else
+float depth_value = gl_FragCoord.z;
 #endif
+	
+#if PS_ZCLAMP
+	gl_FragDepth = min(depth_value, MaxDepthPS);
+#elif PS_ZFLOOR
+	gl_FragDepth = depth_value;
+#endif
+
 }

bin/resources/shaders/vulkan/tfx.glsl

@@ -288,6 +288,7 @@ void main()
 #define PS_DITHER 0
 #define PS_DITHER_ADJUST 0
 #define PS_ZCLAMP 0
+#define PS_ZFLOOR 0
 #define PS_FEEDBACK_LOOP 0
 #define PS_TEX_IS_FB 0
 #endif
@@ -1400,8 +1401,16 @@ void main()
 		#endif
 	#endif
 
+	#if PS_ZFLOOR
+		float depth_value = floor(gl_FragCoord.z * exp2(32.0f)) * exp2(-32.0f);;
+	#else
+		float depth_value = gl_FragCoord.z;
+	#endif
+	
 	#if PS_ZCLAMP
 		gl_FragDepth = min(gl_FragCoord.z, MaxDepthPS);
+	#elif PS_ZFLOOR
+		gl_FragDepth = depth_value;
 	#endif
 
 #endif // PS_DATE

pcsx2/GS/Renderers/Common/GSDevice.h

@@ -401,6 +401,7 @@ struct alignas(16) GSHWDrawConfig
 
 				// Depth clamp
 				u32 zclamp : 1;
+				u32 zfloor : 1;
 
 				// Hack
 				u32 tcoffsethack : 1;

pcsx2/GS/Renderers/DX11/GSDevice11.cpp

@@ -1760,6 +1760,7 @@ void GSDevice11::SetupPS(const PSSelector& sel, const GSHWDrawConfig::PSConstant
 		sm.AddMacro("PS_DITHER", sel.dither);
 		sm.AddMacro("PS_DITHER_ADJUST", sel.dither_adjust);
 		sm.AddMacro("PS_ZCLAMP", sel.zclamp);
+		sm.AddMacro("PS_ZFLOOR", sel.zfloor);
 		sm.AddMacro("PS_SCANMSK", sel.scanmsk);
 		sm.AddMacro("PS_AUTOMATIC_LOD", sel.automatic_lod);
 		sm.AddMacro("PS_MANUAL_LOD", sel.manual_lod);

pcsx2/GS/Renderers/DX12/GSDevice12.cpp

@@ -2922,6 +2922,7 @@ const ID3DBlob* GSDevice12::GetTFXPixelShader(const GSHWDrawConfig::PSSelector&
 	sm.AddMacro("PS_DITHER", sel.dither);
 	sm.AddMacro("PS_DITHER_ADJUST", sel.dither_adjust);
 	sm.AddMacro("PS_ZCLAMP", sel.zclamp);
+	sm.AddMacro("PS_ZFLOOR", sel.zfloor);
 	sm.AddMacro("PS_SCANMSK", sel.scanmsk);
 	sm.AddMacro("PS_AUTOMATIC_LOD", sel.automatic_lod);
 	sm.AddMacro("PS_MANUAL_LOD", sel.manual_lod);

pcsx2/GS/Renderers/HW/GSRendererHW.cpp

@@ -5138,6 +5138,7 @@ void GSRendererHW::EmulateZbuffer(const GSTextureCache::Target* ds)
 	m_conf.cb_vs.max_depth = GSVector2i(0xFFFFFFFF);
 	//ps_cb.MaxDepth = GSVector4(0.0f, 0.0f, 0.0f, 1.0f);
 	m_conf.ps.zclamp = 0;
+	m_conf.ps.zfloor = !m_cached_ctx.ZBUF.ZMSK;
 
 	if (clamp_z)
 	{

pcsx2/GS/Renderers/Metal/GSDeviceMTL.mm

@@ -1878,6 +1878,7 @@ void GSDeviceMTL::MRESetHWPipelineState(GSHWDrawConfig::VSSelector vssel, GSHWDr
 		setFnConstantI(m_fn_constants, pssel.dither,                GSMTLConstantIndex_PS_DITHER);
 		setFnConstantI(m_fn_constants, pssel.dither_adjust,         GSMTLConstantIndex_PS_DITHER_ADJUST);
 		setFnConstantB(m_fn_constants, pssel.zclamp,                GSMTLConstantIndex_PS_ZCLAMP);
+		setFnConstantB(m_fn_constants, pssel.zfloor,                GSMTLConstantIndex_PS_ZFLOOR);
 		setFnConstantB(m_fn_constants, pssel.tcoffsethack,          GSMTLConstantIndex_PS_TCOFFSETHACK);
 		setFnConstantB(m_fn_constants, pssel.urban_chaos_hle,       GSMTLConstantIndex_PS_URBAN_CHAOS_HLE);
 		setFnConstantB(m_fn_constants, pssel.tales_of_abyss_hle,    GSMTLConstantIndex_PS_TALES_OF_ABYSS_HLE);

pcsx2/GS/Renderers/Metal/GSMTLSharedHeader.h

@@ -208,6 +208,7 @@ enum GSMTLFnConstants
 	GSMTLConstantIndex_PS_DITHER,
 	GSMTLConstantIndex_PS_DITHER_ADJUST,
 	GSMTLConstantIndex_PS_ZCLAMP,
+	GSMTLConstantIndex_PS_ZFLOOR,
 	GSMTLConstantIndex_PS_TCOFFSETHACK,
 	GSMTLConstantIndex_PS_URBAN_CHAOS_HLE,
 	GSMTLConstantIndex_PS_TALES_OF_ABYSS_HLE,

pcsx2/GS/Renderers/Metal/tfx.metal

@@ -61,6 +61,7 @@ constant uint PS_CHANNEL            [[function_constant(GSMTLConstantIndex_PS_CH
 constant uint PS_DITHER             [[function_constant(GSMTLConstantIndex_PS_DITHER)]];
 constant uint PS_DITHER_ADJUST      [[function_constant(GSMTLConstantIndex_PS_DITHER_ADJUST)]];
 constant bool PS_ZCLAMP             [[function_constant(GSMTLConstantIndex_PS_ZCLAMP)]];
+constant bool PS_ZFLOOR             [[function_constant(GSMTLConstantIndex_PS_ZFLOOR)]];
 constant bool PS_TCOFFSETHACK       [[function_constant(GSMTLConstantIndex_PS_TCOFFSETHACK)]];
 constant bool PS_URBAN_CHAOS_HLE    [[function_constant(GSMTLConstantIndex_PS_URBAN_CHAOS_HLE)]];
 constant bool PS_TALES_OF_ABYSS_HLE [[function_constant(GSMTLConstantIndex_PS_TALES_OF_ABYSS_HLE)]];
@@ -102,6 +103,7 @@ constant bool NEEDS_RT = NEEDS_RT_FOR_AFAIL || NEEDS_RT_EARLY || (!PS_PRIM_CHECK
 
 constant bool PS_COLOR0 = !PS_NO_COLOR;
 constant bool PS_COLOR1 = !PS_NO_COLOR1;
+constant bool PS_ZOUTPUT = PS_ZCLAMP || PS_ZFLOOR;
 
 struct MainVSIn
 {
@@ -137,7 +139,7 @@ struct MainPSOut
 {
 	float4 c0 [[color(0), index(0), function_constant(PS_COLOR0)]];
 	float4 c1 [[color(0), index(1), function_constant(PS_COLOR1)]];
-	float depth [[depth(less), function_constant(PS_ZCLAMP)]];
+	float depth [[depth(less), function_constant(PS_ZOUTPUT)]];
 };
 
 // MARK: - Vertex functions
@@ -1209,8 +1211,13 @@ struct PSMain
 		}
 		if (PS_COLOR1)
 			out.c1 = alpha_blend;
+		
+		float depth_value = PS_ZFLOOR ? (floor(in.p.z * exp2(32.0f)) * exp2(-32.0f)) : in.p.z;
+		
 		if (PS_ZCLAMP)
-			out.depth = min(in.p.z, cb.max_depth);
+			out.depth = min(depth_value, cb.max_depth);
+		else if (PS_ZFLOOR)
+			out.depth = depth_value;
 
 		return out;
 	}

pcsx2/GS/Renderers/OpenGL/GSDeviceOGL.cpp

@@ -1389,7 +1389,9 @@ std::string GSDeviceOGL::GetPSSource(const PSSelector& sel)
 		+ fmt::format("#define PS_DITHER {}\n", sel.dither)
 		+ fmt::format("#define PS_DITHER_ADJUST {}\n", sel.dither_adjust)
 		+ fmt::format("#define PS_ZCLAMP {}\n", sel.zclamp)
+		+ fmt::format("#define PS_ZFLOOR {}\n", sel.zfloor)
 		+ fmt::format("#define PS_BLEND_MIX {}\n", sel.blend_mix)
+		+ fmt::format("#define PS_ZCLAMP {}\n", sel.zclamp)
 		+ fmt::format("#define PS_ROUND_INV {}\n", sel.round_inv)
 		+ fmt::format("#define PS_FIXED_ONE_A {}\n", sel.fixed_one_a)
 		+ fmt::format("#define PS_PABE {}\n", sel.pabe)

pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp

@@ -4777,6 +4777,7 @@ VkShaderModule GSDeviceVK::GetTFXFragmentShader(const GSHWDrawConfig::PSSelector
 	AddMacro(ss, "PS_DITHER", sel.dither);
 	AddMacro(ss, "PS_DITHER_ADJUST", sel.dither_adjust);
 	AddMacro(ss, "PS_ZCLAMP", sel.zclamp);
+	AddMacro(ss, "PS_ZFLOOR", sel.zfloor);
 	AddMacro(ss, "PS_PABE", sel.pabe);
 	AddMacro(ss, "PS_SCANMSK", sel.scanmsk);
 	AddMacro(ss, "PS_TEX_IS_FB", sel.tex_is_fb);

pcsx2/ShaderCacheVersion.h

@@ -3,4 +3,4 @@
 
 /// Version number for GS and other shaders. Increment whenever any of the contents of the
 /// shaders change, to invalidate the cache.
-static constexpr u32 SHADER_CACHE_VERSION = 77;
+static constexpr u32 SHADER_CACHE_VERSION = 78;