From 339877ea7dd1d4cd2f995a20d30b7d56bab3e65c Mon Sep 17 00:00:00 2001
From: kd-11 <karokidii@gmail.com>
Date: Sun, 7 Jun 2026 17:20:52 +0300
Subject: [PATCH] rsx: Handle mipmap sampling edge case when SNORM emulation is
 active

---
 rpcs3/Emu/RSX/GL/GLDraw.cpp          | 22 +++++++++++++++++++++-
 rpcs3/Emu/RSX/GL/glutils/sampler.cpp |  4 ++--
 rpcs3/Emu/RSX/VK/VKDraw.cpp          |  1 +
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/rpcs3/Emu/RSX/GL/GLDraw.cpp b/rpcs3/Emu/RSX/GL/GLDraw.cpp
index 57a9b08a17..9c09a96d39 100644
--- a/rpcs3/Emu/RSX/GL/GLDraw.cpp
+++ b/rpcs3/Emu/RSX/GL/GLDraw.cpp
@@ -8,6 +8,8 @@
 
 namespace gl
 {
+	extern GLenum tex_min_filter(rsx::texture_minify_filter min_filter);
+
 	inline GLenum comparison_op(rsx::comparison_function op)
 	{
 		return static_cast<GLenum>(op);
@@ -410,8 +412,26 @@ void GLGSRender::load_texture_env()
 
 		if (is_depth_reconstructed || is_snorm)
 		{
+			GLint adjusted_min_filter = GL_NEAREST;
+			if (!is_depth_reconstructed) [[ unlikely ]]
+			{
+				switch (gl::tex_min_filter(tex.min_filter()))
+				{
+				default:
+					break;
+				case GL_LINEAR_MIPMAP_LINEAR:
+				case GL_LINEAR_MIPMAP_NEAREST:
+				case GL_NEAREST_MIPMAP_LINEAR:
+				case GL_NEAREST_MIPMAP_NEAREST:
+					// This is a hack and an unfortunate one at that as there is no feasible workaround.
+					// Doing full trilinear filtering in a shader is just dumb, approximate it instead with NEAREST_NEAREST.
+					adjusted_min_filter = GL_NEAREST_MIPMAP_NEAREST;
+					break;
+				}
+			}
+
 			// Depth format redirected to BGRA8 resample stage. Do not filter to avoid bits leaking.
-			m_fs_sampler_states[i].set_parameteri(GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+			m_fs_sampler_states[i].set_parameteri(GL_TEXTURE_MIN_FILTER, adjusted_min_filter);
 			m_fs_sampler_states[i].set_parameteri(GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 		}
 	}
diff --git a/rpcs3/Emu/RSX/GL/glutils/sampler.cpp b/rpcs3/Emu/RSX/GL/glutils/sampler.cpp
index 4b1b603fc6..005f6fa1d6 100644
--- a/rpcs3/Emu/RSX/GL/glutils/sampler.cpp
+++ b/rpcs3/Emu/RSX/GL/glutils/sampler.cpp
@@ -45,7 +45,7 @@ namespace gl
 		return 1.0f;
 	}
 
-	int tex_min_filter(rsx::texture_minify_filter min_filter)
+	GLenum tex_min_filter(rsx::texture_minify_filter min_filter)
 	{
 		switch (min_filter)
 		{
@@ -60,7 +60,7 @@ namespace gl
 		fmt::throw_exception("Unknown min filter");
 	}
 
-	int tex_mag_filter(rsx::texture_magnify_filter mag_filter)
+	GLenum tex_mag_filter(rsx::texture_magnify_filter mag_filter)
 	{
 		switch (mag_filter)
 		{
diff --git a/rpcs3/Emu/RSX/VK/VKDraw.cpp b/rpcs3/Emu/RSX/VK/VKDraw.cpp
index 8a6789213b..132f832416 100644
--- a/rpcs3/Emu/RSX/VK/VKDraw.cpp
+++ b/rpcs3/Emu/RSX/VK/VKDraw.cpp
@@ -457,6 +457,7 @@ void VKGSRender::load_texture_env()
 		{
 			mag_filter = VK_FILTER_NEAREST;
 			min_filter.filter = VK_FILTER_NEAREST;
+			min_filter.mipmap_mode = VK_SAMPLER_MIPMAP_MODE_NEAREST;
 		}
 
 		if (min_filter.sample_mipmaps && mipmap_count > 1)