GS: Offset interlace when upscaling

bin/resources/shaders/dx11/interlace.fx

@@ -6,7 +6,6 @@ SamplerState Sampler;
 cbuffer cb0
 {
 	float2 ZrH;
-	float hH;
 };
 
 struct PS_INPUT
@@ -17,14 +16,16 @@ struct PS_INPUT
 
 float4 ps_main0(PS_INPUT input) : SV_Target0
 {
-	clip(frac(input.t.y * hH) - 0.5);
+	if ((int(input.p.y) & 1) == 0)
+		discard;
 
 	return Texture.Sample(Sampler, input.t);
 }
 
 float4 ps_main1(PS_INPUT input) : SV_Target0
 {
-	clip(0.5 - frac(input.t.y * hH));
+	if ((int(input.p.y) & 1) != 0)
+		discard;
 
 	return Texture.Sample(Sampler, input.t);
 }

bin/resources/shaders/opengl/interlace.glsl

@@ -7,14 +7,13 @@ in vec2 PSin_t;
 in vec4 PSin_c;
 
 uniform vec2 ZrH;
-uniform float hH;
 
 layout(location = 0) out vec4 SV_Target0;
 
 // TODO ensure that clip (discard) is < 0 and not <= 0 ???
 void ps_main0()
 {
-    if (fract(PSin_t.y * hH) - 0.5 < 0.0)
+    if ((int(gl_FragCoord.y) & 1) == 0)
         discard;
     // I'm not sure it impact us but be safe to lookup texture before conditional if
     // see: http://www.opengl.org/wiki/GLSL_Sampler#Non-uniform_flow_control
@@ -25,7 +24,7 @@ void ps_main0()
 
 void ps_main1()
 {
-    if (0.5 - fract(PSin_t.y * hH) < 0.0)
+    if ((int(gl_FragCoord.y) & 1) != 0)
         discard;
     // I'm not sure it impact us but be safe to lookup texture before conditional if
     // see: http://www.opengl.org/wiki/GLSL_Sampler#Non-uniform_flow_control

bin/resources/shaders/vulkan/interlace.glsl

@@ -21,7 +21,6 @@ layout(location = 0) out vec4 o_col0;
 layout(push_constant) uniform cb0
 {
 	vec2 ZrH;
-	float hH;
 };
 
 layout(set = 0, binding = 0) uniform sampler2D samp0;
@@ -30,7 +29,7 @@ layout(set = 0, binding = 0) uniform sampler2D samp0;
 void ps_main0()
 {
 	o_col0 = texture(samp0, v_tex);
-	if (fract(v_tex.y * hH) - 0.5 < 0.0)
+	if ((int(gl_FragCoord.y) & 1) == 0)
 		discard;
 }
 #endif
@@ -39,7 +38,7 @@ void ps_main0()
 void ps_main1()
 {
 	o_col0 = texture(samp0, v_tex);
-	if (0.5 - fract(v_tex.y * hH) < 0.0)
+	if ((int(gl_FragCoord.y) & 1) != 0)
 		discard;
 }
 #endif

pcsx2/GS/Renderers/Common/GSDevice.cpp

@@ -358,8 +358,9 @@ void GSDevice::Interlace(const GSVector2i& ds, int field, int mode, float yoffse
 	if (mode == 0 || mode == 2) // weave or blend
 	{
 		// weave first
+		const int offset = static_cast<int>(yoffset) * (1 - field);
 
-		DoInterlace(m_merge, m_weavebob, field, false, 0);
+		DoInterlace(m_merge, m_weavebob, field, false, offset);
 
 		if (mode == 2)
 		{

pcsx2/GS/Renderers/Common/GSDevice.h

@@ -85,8 +85,7 @@ class InterlaceConstantBuffer
 {
 public:
 	GSVector2 ZrH;
-	float hH;
+	float _pad[2];
-	float _pad[1];
 
 	InterlaceConstantBuffer() { memset(this, 0, sizeof(*this)); }
 };

pcsx2/GS/Renderers/Common/GSRenderer.cpp

@@ -315,6 +315,9 @@ bool GSRenderer::Merge(int field)
 
 		g_gs_device->Merge(tex, src_gs_read, dst, fs, m_regs->PMODE, m_regs->EXTBUF, c);
 
+		// Offset is not compatible with scanmsk, as scanmsk renders every other line, but at x7 the interlace offset will be 7 lines
+		const int offset = m_scanmask_used ? 0 : (int)(tex[1] ? tex[1]->GetScale().y : tex[0]->GetScale().y);
+
 		if (m_regs->SMODE2.INT && GSConfig.InterlaceMode != GSInterlaceMode::Off)
 		{
 			const bool scanmask = m_scanmask_used && scanmask_frame && GSConfig.InterlaceMode == GSInterlaceMode::Automatic;
@@ -323,12 +326,12 @@ bool GSRenderer::Merge(int field)
 			{
 				constexpr int field2 = 1;
 				constexpr int mode = 2;
-				g_gs_device->Interlace(ds, field ^ field2, mode, tex[1] ? tex[1]->GetScale().y : tex[0]->GetScale().y);
+
+				g_gs_device->Interlace(ds, field ^ field2, mode, offset);
 			}
 			else
 			{
 				const int field2 = scanmask ? 0 : 1 - ((static_cast<int>(GSConfig.InterlaceMode) - 1) & 1);
-				const int offset = tex[1] ? tex[1]->GetScale().y : tex[0]->GetScale().y;
 				const int mode = scanmask ? 2 : ((static_cast<int>(GSConfig.InterlaceMode) - 1) >> 1);
 
 				g_gs_device->Interlace(ds, field ^ field2, mode, offset);

pcsx2/GS/Renderers/DX11/GSDevice11.cpp

@@ -725,7 +725,6 @@ void GSDevice11::DoInterlace(GSTexture* sTex, GSTexture* dTex, int shader, bool
 	InterlaceConstantBuffer cb;
 
 	cb.ZrH = GSVector2(0, 1.0f / s.y);
-	cb.hH = s.y / 2;
 
 	m_ctx->UpdateSubresource(m_interlace.cb.get(), 0, nullptr, &cb, 0, 0);
 

pcsx2/GS/Renderers/DX12/GSDevice12.cpp

@@ -720,7 +720,6 @@ void GSDevice12::DoInterlace(GSTexture* sTex, GSTexture* dTex, int shader, bool
 
 	InterlaceConstantBuffer cb;
 	cb.ZrH = GSVector2(0, 1.0f / s.y);
-	cb.hH = s.y / 2;
 
 	GL_PUSH("DoInterlace %dx%d Shader:%d Linear:%d", size.x, size.y, shader, linear);
 

pcsx2/GS/Renderers/OpenGL/GSDeviceOGL.cpp

@@ -436,7 +436,6 @@ bool GSDeviceOGL::Create(HostDisplay* display)
 				return false;
 			m_interlace.ps[i].SetFormattedName("Merge pipe %zu", i);
 			m_interlace.ps[i].RegisterUniform("ZrH");
-			m_interlace.ps[i].RegisterUniform("hH");
 		}
 	}
 
@@ -1382,7 +1381,6 @@ void GSDeviceOGL::DoInterlace(GSTexture* sTex, GSTexture* dTex, int shader, bool
 
 	m_interlace.ps[shader].Bind();
 	m_interlace.ps[shader].Uniform2f(0, 0, 1.0f / s.y);
-	m_interlace.ps[shader].Uniform1f(1, s.y / 2);
 
 	StretchRect(sTex, sRect, dTex, dRect, m_interlace.ps[shader], linear);
 }

pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp

@@ -834,7 +834,6 @@ void GSDeviceVK::DoInterlace(GSTexture* sTex, GSTexture* dTex, int shader, bool
 
 	InterlaceConstantBuffer cb;
 	cb.ZrH = GSVector2(0, 1.0f / s.y);
-	cb.hH = s.y / 2;
 
 	GL_PUSH("DoInterlace %dx%d Shader:%d Linear:%d", size.x, size.y, shader, linear);