GS: Pass through primitive ID in geometry shaders in DX12 and VK

Fixes primid destination alpha on sprites

bin/resources/shaders/dx11/tfx.fx

@@ -13,6 +13,7 @@
 #ifndef GS_IIP
 #define GS_IIP 0
 #define GS_PRIM 3
+#define GS_FORWARD_PRIMID 0
 #endif
 
 #ifndef PS_FST
@@ -102,7 +103,7 @@ struct PS_INPUT
 #else
 	nointerpolation float4 c : COLOR0;
 #endif
-#if PS_DATE >= 1 && PS_DATE <= 3
+#if (PS_DATE >= 1 && PS_DATE <= 3) || GS_FORWARD_PRIMID
 	uint primid : SV_PrimitiveID;
 #endif
 };
@@ -1026,13 +1027,40 @@ VS_OUTPUT vs_main(VS_INPUT input)
 // Geometry Shader
 //////////////////////////////////////////////////////////////////////
 
+#if GS_FORWARD_PRIMID
+#define PRIMID_IN , uint primid : SV_PrimitiveID
+#define VS2PS(x) vs2ps_impl(x, primid)
+PS_INPUT vs2ps_impl(VS_OUTPUT vs, uint primid)
+{
+	PS_INPUT o;
+	o.p = vs.p;
+	o.t = vs.t;
+	o.ti = vs.ti;
+	o.c = vs.c;
+	o.primid = primid;
+	return o;
+}
+#else
+#define PRIMID_IN
+#define VS2PS(x) vs2ps_impl(x)
+PS_INPUT vs2ps_impl(VS_OUTPUT vs)
+{
+	PS_INPUT o;
+	o.p = vs.p;
+	o.t = vs.t;
+	o.ti = vs.ti;
+	o.c = vs.c;
+	return o;
+}
+#endif
+
 #if GS_PRIM == 0
 
 [maxvertexcount(6)]
-void gs_main(point VS_OUTPUT input[1], inout TriangleStream<VS_OUTPUT> stream)
+void gs_main(point VS_OUTPUT input[1], inout TriangleStream<PS_INPUT> stream PRIMID_IN)
 {
 	// Transform a point to a NxN sprite
-	VS_OUTPUT Point = input[0];
+	PS_INPUT Point = VS2PS(input[0]);
 
 	// Get new position
 	float4 lt_p = input[0].p;
@@ -1066,11 +1094,11 @@ void gs_main(point VS_OUTPUT input[1], inout TriangleStream<VS_OUTPUT> stream)
 #elif GS_PRIM == 1
 
 [maxvertexcount(6)]
-void gs_main(line VS_OUTPUT input[2], inout TriangleStream<VS_OUTPUT> stream)
+void gs_main(line VS_OUTPUT input[2], inout TriangleStream<PS_INPUT> stream PRIMID_IN)
 {
 	// Transform a line to a thick line-sprite
-	VS_OUTPUT left = input[0];
+	PS_INPUT left = VS2PS(input[0]);
-	VS_OUTPUT right = input[1];
+	PS_INPUT right = VS2PS(input[1]);
 	float2 lt_p = input[0].p.xy;
 	float2 rt_p = input[1].p.xy;
 
@@ -1114,10 +1142,10 @@ void gs_main(line VS_OUTPUT input[2], inout TriangleStream<VS_OUTPUT> stream)
 #elif GS_PRIM == 3
 
 [maxvertexcount(4)]
-void gs_main(line VS_OUTPUT input[2], inout TriangleStream<VS_OUTPUT> stream)
+void gs_main(line VS_OUTPUT input[2], inout TriangleStream<PS_INPUT> stream PRIMID_IN)
 {
-	VS_OUTPUT lt = input[0];
+	PS_INPUT lt = VS2PS(input[0]);
-	VS_OUTPUT rb = input[1];
+	PS_INPUT rb = VS2PS(input[1]);
 
 	// flat depth
 	lt.p.z = rb.p.z;
@@ -1128,13 +1156,13 @@ void gs_main(line VS_OUTPUT input[2], inout TriangleStream<VS_OUTPUT> stream)
 	lt.c = rb.c;
 
 	// Swap texture and position coordinate
-	VS_OUTPUT lb = rb;
+	PS_INPUT lb = rb;
 	lb.p.x = lt.p.x;
 	lb.t.x = lt.t.x;
 	lb.ti.x = lt.ti.x;
 	lb.ti.z = lt.ti.z;
 
-	VS_OUTPUT rt = rb;
+	PS_INPUT rt = rb;
 	rt.p.y = lt.p.y;
 	rt.t.y = lt.t.y;
 	rt.ti.y = lt.ti.y;

bin/resources/shaders/vulkan/tfx.glsl

@@ -113,6 +113,9 @@ layout(location = 0) out GSOutput
 
 void WriteVertex(vec4 pos, vec4 t, vec4 ti, vec4 c)
 {
+#if GS_FORWARD_PRIMID
+	gl_PrimitiveID = gl_PrimitiveIDIn;
+#endif
 	gl_Position = pos;
 	gsOut.t = t;
 	gsOut.ti = ti;

pcsx2/GS/Renderers/Common/GSDevice.h

@@ -263,6 +263,7 @@ struct alignas(16) GSHWDrawConfig
 				GSTopology topology : 2;
 				bool expand : 1;
 				bool iip : 1;
+				bool forward_primid : 1;
 			};
 			u8 key;
 		};

pcsx2/GS/Renderers/DX11/GSTextureFX11.cpp

@@ -137,6 +137,7 @@ void GSDevice11::SetupGS(GSSelector sel)
 			sm.AddMacro("GS_IIP", sel.iip);
 			sm.AddMacro("GS_PRIM", static_cast<int>(sel.topology));
 			sm.AddMacro("GS_EXPAND", sel.expand);
+			sm.AddMacro("GS_FORWARD_PRIMID", sel.forward_primid);
 
 			gs = m_shader_cache.GetGeometryShader(m_dev.get(), m_tfx_source, sm.GetPtr(), "gs_main");
 

pcsx2/GS/Renderers/DX12/GSDevice12.cpp

@@ -1506,6 +1506,7 @@ const ID3DBlob* GSDevice12::GetTFXGeometryShader(GSHWDrawConfig::GSSelector sel)
 	sm.AddMacro("GS_IIP", sel.iip);
 	sm.AddMacro("GS_PRIM", static_cast<int>(sel.topology));
 	sm.AddMacro("GS_EXPAND", sel.expand);
+	sm.AddMacro("GS_FORWARD_PRIMID", sel.forward_primid);
 
 	ComPtr<ID3DBlob> gs(m_shader_cache.GetGeometryShader(m_tfx_source, sm.GetPtr(), "gs_main"));
 	it = m_tfx_geometry_shaders.emplace(sel.key, std::move(gs)).first;

pcsx2/GS/Renderers/HW/GSRendererHW.cpp

@@ -3589,11 +3589,13 @@ void GSRendererHW::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sourc
 		m_conf.depth.date = 1;
 		m_conf.depth.date_one = 1;
 	}
+	else if (DATE_PRIMID)
+	{
+		m_conf.ps.date = 1 + m_context->TEST.DATM;
+		m_conf.gs.forward_primid = 1;
+	}
 	else if (DATE)
 	{
-		if (DATE_PRIMID)
-			m_conf.ps.date = 1 + m_context->TEST.DATM;
-		else
 		m_conf.depth.date = 1;
 	}
 

pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp

@@ -1933,6 +1933,7 @@ VkShaderModule GSDeviceVK::GetTFXGeometryShader(GSHWDrawConfig::GSSelector sel)
 	AddMacro(ss, "GS_IIP", sel.iip);
 	AddMacro(ss, "GS_PRIM", static_cast<int>(sel.topology));
 	AddMacro(ss, "GS_EXPAND", sel.expand);
+	AddMacro(ss, "GS_FORWARD_PRIMID", sel.forward_primid);
 	ss << m_tfx_source;
 
 	VkShaderModule mod = g_vulkan_shader_cache->GetGeometryShader(ss.str());