From e29cd4cc9311ec8c7f4eafe962f4ebef75ed7eba Mon Sep 17 00:00:00 2001
From: kd-11 <karokidii@gmail.com>
Date: Sun, 22 Feb 2026 20:57:16 +0300
Subject: [PATCH] gl: Implement SNORM and SRGB format overrides

---
 rpcs3/Emu/RSX/GL/GLDraw.cpp    | 47 +++++++++++++++++++++++++++++-----
 rpcs3/Emu/RSX/GL/GLTexture.cpp | 38 +++++++++++++++++++++++++++
 rpcs3/Emu/RSX/GL/GLTexture.h   |  2 ++
 3 files changed, 81 insertions(+), 6 deletions(-)

diff --git a/rpcs3/Emu/RSX/GL/GLDraw.cpp b/rpcs3/Emu/RSX/GL/GLDraw.cpp
index b167ab24c2..c564adfa20 100644
--- a/rpcs3/Emu/RSX/GL/GLDraw.cpp
+++ b/rpcs3/Emu/RSX/GL/GLDraw.cpp
@@ -334,17 +334,52 @@ void GLGSRender::load_texture_env()
 			continue;
 		}
 
+		if (!is_sampler_dirty)
+		{
+			if (sampler_state->format_class != previous_format_class)
+			{
+				// Host details changed but RSX is not aware
+				m_graphics_state |= rsx::fragment_program_state_dirty;
+			}
+
+			if (m_fs_sampler_states[i])
+			{
+				// Nothing to change, use cached sampler
+				continue;
+			}
+		}
+
 		sampler_state->format_ex = tex.format_ex();
 
-		if (is_sampler_dirty)
+		if (sampler_state->format_ex.texel_remap_control &&
+			sampler_state->image_handle &&
+			sampler_state->upload_context == rsx::texture_upload_context::shader_read) [[ unlikely ]]
 		{
-			m_fs_sampler_states[i].apply(tex, fs_sampler_state[i].get());
-		}
-		else if (sampler_state->format_class != previous_format_class)
-		{
-			m_graphics_state |= rsx::fragment_program_state_dirty;
+			// Check if we need to override the view format
+			const auto gl_format = sampler_state->image_handle->view_format();
+			GLenum format_override = gl_format;
+			rsx::flags32_t flags_to_erase = 0u;
+
+			if (sampler_state->format_ex.hw_SNORM_possible())
+			{
+				format_override = gl::get_compatible_snorm_format(gl_format);
+				flags_to_erase = rsx::texture_control_bits::SEXT_MASK;
+			}
+			else if (sampler_state->format_ex.hw_SRGB_possible())
+			{
+				format_override = gl::get_compatible_srgb_format(gl_format);
+				flags_to_erase = rsx::texture_control_bits::GAMMA_CTRL_MASK;
+			}
+
+			if (format_override != GL_NONE && format_override != gl_format)
+			{
+				sampler_state->image_handle = sampler_state->image_handle->as(format_override);
+				sampler_state->format_ex.texel_remap_control &= (~flags_to_erase);
+			}
 		}
 
+		m_fs_sampler_states[i].apply(tex, fs_sampler_state[i].get());
+
 		const auto texture_format = sampler_state->format_ex.format();
 		// Depth format redirected to BGRA8 resample stage. Do not filter to avoid bits leaking.
 		// If accurate graphics are desired, force a bitcast to COLOR as a workaround.
diff --git a/rpcs3/Emu/RSX/GL/GLTexture.cpp b/rpcs3/Emu/RSX/GL/GLTexture.cpp
index 9a439177f4..181e5058c8 100644
--- a/rpcs3/Emu/RSX/GL/GLTexture.cpp
+++ b/rpcs3/Emu/RSX/GL/GLTexture.cpp
@@ -266,6 +266,44 @@ namespace gl
 		fmt::throw_exception("Unknown format 0x%x", texture_format);
 	}
 
+	GLenum get_compatible_snorm_format(GLenum base_format)
+	{
+		switch (base_format)
+		{
+		case GL_R8:
+			return GL_R8_SNORM;
+		case GL_RG8:
+			return GL_RG8_SNORM;
+		case GL_RGBA8:
+			return GL_RGBA8_SNORM;
+		case GL_R16:
+			return GL_R16_SNORM;
+		case GL_RG16:
+			return GL_RG16_SNORM;
+		case GL_RGBA16:
+			return GL_RGBA16_SNORM;
+		default:
+			return GL_NONE;
+		}
+	}
+
+	GLenum get_compatible_srgb_format(GLenum base_format)
+	{
+		switch (base_format)
+		{
+		case GL_RGBA8:
+			return GL_SRGB8_ALPHA8_EXT;
+		case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+			return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
+		case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+			return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
+		case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+			return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
+		default:
+			return GL_NONE;
+		}
+	}
+
 	cs_shuffle_base* get_trivial_transform_job(const pixel_buffer_layout& pack_info)
 	{
 		if (!pack_info.swap_bytes)
diff --git a/rpcs3/Emu/RSX/GL/GLTexture.h b/rpcs3/Emu/RSX/GL/GLTexture.h
index dc6d90098a..10c26dc536 100644
--- a/rpcs3/Emu/RSX/GL/GLTexture.h
+++ b/rpcs3/Emu/RSX/GL/GLTexture.h
@@ -62,6 +62,8 @@ namespace gl
 	std::tuple<GLenum, GLenum> get_format_type(u32 texture_format);
 	pixel_buffer_layout get_format_type(texture::internal_format format);
 	std::array<GLenum, 4> get_swizzle_remap(u32 texture_format);
+	GLenum get_compatible_snorm_format(GLenum base_format);
+	GLenum get_compatible_srgb_format(GLenum base_format);
 
 	viewable_image* create_texture(u32 gcm_format, u16 width, u16 height, u16 depth, u16 mipmaps, rsx::texture_dimension_extended type);