GS/HW: Adjust point sampler behavior.

VK/GL: Get rid of it completely as it doesn't seem needed anymore.
DX: Only enable it with combination with GPU Palette Conversion enabled as that's when the issue occurs.

bin/resources/shaders/opengl/tfx_fs.glsl

@@ -132,15 +132,6 @@ vec4 sample_c(vec2 uv)
 	return texelFetch(TextureSampler, ivec2(uv), 0);
 #else
 
-#if PS_POINT_SAMPLER
-	// Weird issue with ATI/AMD cards,
-	// it looks like they add 127/128 of a texel to sampling coordinates
-	// occasionally causing point sampling to erroneously round up.
-	// I'm manually adjusting coordinates to the centre of texels here,
-	// though the centre is just paranoia, the top left corner works fine.
-	// As of 2018 this issue is still present.
-	uv = (trunc(uv * WH.zw) + vec2(0.5, 0.5)) / WH.zw;
-#endif
 #if !PS_ADJS && !PS_ADJT
 	uv *= STScale;
 #else

bin/resources/shaders/vulkan/tfx.glsl

@@ -372,15 +372,7 @@ vec4 sample_c(vec2 uv)
 #elif PS_REGION_RECT
 	return texelFetch(Texture, ivec2(uv), 0);
 #else
-#if PS_POINT_SAMPLER
-		// Weird issue with ATI/AMD cards,
-		// it looks like they add 127/128 of a texel to sampling coordinates
-		// occasionally causing point sampling to erroneously round up.
-		// I'm manually adjusting coordinates to the centre of texels here,
-		// though the centre is just paranoia, the top left corner works fine.
-		// As of 2018 this issue is still present.
-		uv = (trunc(uv * WH.zw) + vec2(0.5, 0.5)) / WH.zw;
-#endif
+
 #if !PS_ADJS && !PS_ADJT
 	uv *= STScale;
 #else

pcsx2/GS/Renderers/HW/GSRendererHW.cpp

@@ -5010,7 +5010,7 @@ __ri void GSRendererHW::EmulateTextureSampler(const GSTextureCache::Target* rt,
 	m_conf.ps.tcc = m_cached_ctx.TEX0.TCC;
 
 	m_conf.ps.ltf = bilinear && shader_emulated_sampler;
-	m_conf.ps.point_sampler = g_gs_device->Features().broken_point_sampler && !target_region && (!bilinear || shader_emulated_sampler);
+	m_conf.ps.point_sampler = g_gs_device->Features().broken_point_sampler && GSConfig.GPUPaletteConversion && !target_region && (!bilinear || shader_emulated_sampler);
 
 	const int tw = static_cast<int>(1 << m_cached_ctx.TEX0.TW);
 	const int th = static_cast<int>(1 << m_cached_ctx.TEX0.TH);

pcsx2/GS/Renderers/OpenGL/GSDeviceOGL.cpp

@@ -606,7 +606,7 @@ bool GSDeviceOGL::CreateTextureFX()
 
 bool GSDeviceOGL::CheckFeatures(bool& buggy_pbo)
 {
-	bool vendor_id_amd = false;
+	//bool vendor_id_amd = false;
 	bool vendor_id_nvidia = false;
 	//bool vendor_id_intel = false;
 
@@ -615,7 +615,7 @@ bool GSDeviceOGL::CheckFeatures(bool& buggy_pbo)
 		std::strstr(vendor, "ATI"))
 	{
 		Console.WriteLn(Color_StrongRed, "OGL: AMD GPU detected.");
-		vendor_id_amd = true;
+		//vendor_id_amd = true;
 	}
 	else if (std::strstr(vendor, "NVIDIA Corporation"))
 	{
@@ -712,7 +712,7 @@ bool GSDeviceOGL::CheckFeatures(bool& buggy_pbo)
 		Console.Warning("Not using PBOs for texture downloads, this may reduce performance.");
 
 	// optional features based on context
-	m_features.broken_point_sampler = vendor_id_amd;
+	m_features.broken_point_sampler = false;
 	m_features.primitive_id = true;
 
 	m_features.framebuffer_fetch = GLAD_GL_EXT_shader_framebuffer_fetch;
@@ -1377,7 +1377,6 @@ std::string GSDeviceOGL::GetPSSource(const PSSelector& sel)
 		+ fmt::format("#define PS_COLCLIP {}\n", sel.colclip)
 		+ fmt::format("#define PS_DATE {}\n", sel.date)
 		+ fmt::format("#define PS_TCOFFSETHACK {}\n", sel.tcoffsethack)
-		+ fmt::format("#define PS_POINT_SAMPLER {}\n", sel.point_sampler)
 		+ fmt::format("#define PS_REGION_RECT {}\n", sel.region_rect)
 		+ fmt::format("#define PS_BLEND_A {}\n", sel.blend_a)
 		+ fmt::format("#define PS_BLEND_B {}\n", sel.blend_b)

pcsx2/GS/Renderers/Vulkan/GSDeviceVK.cpp

@@ -2575,7 +2575,7 @@ bool GSDeviceVK::CheckFeatures()
 	m_features.framebuffer_fetch =
 		m_optional_extensions.vk_ext_rasterization_order_attachment_access && !GSConfig.DisableFramebufferFetch;
 	m_features.texture_barrier = GSConfig.OverrideTextureBarriers != 0;
-	m_features.broken_point_sampler = isAMD;
+	m_features.broken_point_sampler = false;
 
 	// geometryShader is needed because gl_PrimitiveID is part of the Geometry SPIR-V Execution Model.
 	m_features.primitive_id = m_device_features.geometryShader;
@@ -4722,7 +4722,6 @@ VkShaderModule GSDeviceVK::GetTFXFragmentShader(const GSHWDrawConfig::PSSelector
 	AddMacro(ss, "PS_COLCLIP", sel.colclip);
 	AddMacro(ss, "PS_DATE", sel.date);
 	AddMacro(ss, "PS_TCOFFSETHACK", sel.tcoffsethack);
-	AddMacro(ss, "PS_POINT_SAMPLER", sel.point_sampler);
 	AddMacro(ss, "PS_REGION_RECT", sel.region_rect);
 	AddMacro(ss, "PS_BLEND_A", sel.blend_a);
 	AddMacro(ss, "PS_BLEND_B", sel.blend_b);

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 = 52;
+static constexpr u32 SHADER_CACHE_VERSION = 53;