From 780240e6979b198e7bd10feaad5399b8b4b63762 Mon Sep 17 00:00:00 2001 From: Wollnashorn Date: Wed, 5 Apr 2023 01:29:46 +0200 Subject: [PATCH] shader_recompiler: Add subpixel offset for correct rounding at `ImageGather` On AMD a subpixel offset of 1/512 of the texel size is applied to the texture coordinates at a ImageGather call to ensure the rounding at the texel centers is done the same way as in Maxwell or other Nvidia architectures. See https://www.reedbeta.com/blog/texture-gathers-and-coordinate-precision/ for more details why this might be necessary. This should fix shadow artifacts at object edges in Zelda: Breath of the Wild (#9957, #6956). --- .../backend/glsl/emit_glsl_image.cpp | 29 ++++++++++++++ .../backend/spirv/emit_spirv_image.cpp | 39 +++++++++++++++++++ src/shader_recompiler/profile.h | 4 ++ src/video_core/renderer_opengl/gl_device.cpp | 1 + src/video_core/renderer_opengl/gl_device.h | 5 +++ .../renderer_opengl/gl_shader_cache.cpp | 1 + .../renderer_vulkan/vk_pipeline_cache.cpp | 1 + .../vulkan_common/vulkan_device.cpp | 1 + src/video_core/vulkan_common/vulkan_device.h | 5 +++ 9 files changed, 86 insertions(+) diff --git a/src/shader_recompiler/backend/glsl/emit_glsl_image.cpp b/src/shader_recompiler/backend/glsl/emit_glsl_image.cpp index f335c8af0..418505475 100644 --- a/src/shader_recompiler/backend/glsl/emit_glsl_image.cpp +++ b/src/shader_recompiler/backend/glsl/emit_glsl_image.cpp @@ -143,6 +143,21 @@ IR::Inst* PrepareSparse(IR::Inst& inst) { } return sparse_inst; } + +std::string ImageGatherSubpixelOffset(const IR::TextureInstInfo& info, std::string_view texture, + std::string_view coords) { + switch (info.type) { + case TextureType::Color2D: + case TextureType::Color2DRect: + return fmt::format("{}+vec2(0.001953125)/vec2(textureSize({}, 0))", coords, texture); + case TextureType::ColorArray2D: + case TextureType::ColorCube: + return fmt::format("vec3({0}.xy+vec2(0.001953125)/vec2(textureSize({1}, 0)),{0}.z)", coords, + texture); + default: + return std::string{coords}; + } +} } // Anonymous namespace void EmitImageSampleImplicitLod(EmitContext& ctx, IR::Inst& inst, const IR::Value& index, @@ -340,6 +355,13 @@ void EmitImageGather(EmitContext& ctx, IR::Inst& inst, const IR::Value& index, LOG_WARNING(Shader_GLSL, "Device does not support sparse texture queries. STUBBING"); ctx.AddU1("{}=true;", *sparse_inst); } + std::string coords_with_subpixel_offset; + if (ctx.profile.need_gather_subpixel_offset) { + // Apply a subpixel offset of 1/512 the texel size of the texture to ensure same rounding on + // AMD hardware as on Maxwell or other Nvidia architectures. + coords_with_subpixel_offset = ImageGatherSubpixelOffset(info, texture, coords); + coords = coords_with_subpixel_offset; + } if (!sparse_inst || !supports_sparse) { if (offset.IsEmpty()) { ctx.Add("{}=textureGather({},{},int({}));", texel, texture, coords, @@ -387,6 +409,13 @@ void EmitImageGatherDref(EmitContext& ctx, IR::Inst& inst, const IR::Value& inde LOG_WARNING(Shader_GLSL, "Device does not support sparse texture queries. STUBBING"); ctx.AddU1("{}=true;", *sparse_inst); } + std::string coords_with_subpixel_offset; + if (ctx.profile.need_gather_subpixel_offset) { + // Apply a subpixel offset of 1/512 the texel size of the texture to ensure same rounding on + // AMD hardware as on Maxwell or other Nvidia architectures. + coords_with_subpixel_offset = ImageGatherSubpixelOffset(info, texture, coords); + coords = coords_with_subpixel_offset; + } if (!sparse_inst || !supports_sparse) { if (offset.IsEmpty()) { ctx.Add("{}=textureGather({},{},{});", texel, texture, coords, dref); diff --git a/src/shader_recompiler/backend/spirv/emit_spirv_image.cpp b/src/shader_recompiler/backend/spirv/emit_spirv_image.cpp index 02073c420..968901d42 100644 --- a/src/shader_recompiler/backend/spirv/emit_spirv_image.cpp +++ b/src/shader_recompiler/backend/spirv/emit_spirv_image.cpp @@ -261,6 +261,39 @@ Id BitTest(EmitContext& ctx, Id mask, Id bit) { const Id bit_value{ctx.OpBitwiseAnd(ctx.U32[1], shifted, ctx.Const(1u))}; return ctx.OpINotEqual(ctx.U1, bit_value, ctx.u32_zero_value); } + +Id ImageGatherSubpixelOffset(EmitContext& ctx, const IR::TextureInstInfo& info, Id texture, + Id coords) { + // Apply a subpixel offset of 1/512 the texel size of the texture to ensure same rounding on + // AMD hardware as on Maxwell or other Nvidia architectures. + const auto calculate_offset{[&](size_t dim) -> std::array { + const Id nudge{ctx.Const(0x1p-9f)}; + const Id image_size{ctx.OpImageQuerySizeLod(ctx.U32[dim], texture, ctx.u32_zero_value)}; + const Id offset_x{ctx.OpFDiv( + ctx.F32[1], nudge, + ctx.OpConvertUToF(ctx.F32[1], ctx.OpCompositeExtract(ctx.U32[1], image_size, 0)))}; + const Id offset_y{ctx.OpFDiv( + ctx.F32[1], nudge, + ctx.OpConvertUToF(ctx.F32[1], ctx.OpCompositeExtract(ctx.U32[1], image_size, 1)))}; + return {ctx.OpFAdd(ctx.F32[1], ctx.OpCompositeExtract(ctx.F32[1], coords, 0), offset_x), + ctx.OpFAdd(ctx.F32[1], ctx.OpCompositeExtract(ctx.F32[1], coords, 1), offset_y)}; + }}; + switch (info.type) { + case TextureType::Color2D: + case TextureType::Color2DRect: { + const auto offset{calculate_offset(2)}; + return ctx.OpCompositeConstruct(ctx.F32[2], offset[0], offset[1]); + } + case TextureType::ColorArray2D: + case TextureType::ColorCube: { + const auto offset{calculate_offset(3)}; + return ctx.OpCompositeConstruct(ctx.F32[3], offset[0], offset[1], + ctx.OpCompositeExtract(ctx.F32[1], coords, 2)); + } + default: + return coords; + } +} } // Anonymous namespace Id EmitBindlessImageSampleImplicitLod(EmitContext&) { @@ -423,6 +456,9 @@ Id EmitImageGather(EmitContext& ctx, IR::Inst* inst, const IR::Value& index, Id const IR::Value& offset, const IR::Value& offset2) { const auto info{inst->Flags()}; const ImageOperands operands(ctx, offset, offset2); + if (ctx.profile.need_gather_subpixel_offset) { + coords = ImageGatherSubpixelOffset(ctx, info, TextureImage(ctx, info, index), coords); + } return Emit(&EmitContext::OpImageSparseGather, &EmitContext::OpImageGather, ctx, inst, ctx.F32[4], Texture(ctx, info, index), coords, ctx.Const(info.gather_component), operands.MaskOptional(), operands.Span()); @@ -432,6 +468,9 @@ Id EmitImageGatherDref(EmitContext& ctx, IR::Inst* inst, const IR::Value& index, const IR::Value& offset, const IR::Value& offset2, Id dref) { const auto info{inst->Flags()}; const ImageOperands operands(ctx, offset, offset2); + if (ctx.profile.need_gather_subpixel_offset) { + coords = ImageGatherSubpixelOffset(ctx, info, TextureImage(ctx, info, index), coords); + } return Emit(&EmitContext::OpImageSparseDrefGather, &EmitContext::OpImageDrefGather, ctx, inst, ctx.F32[4], Texture(ctx, info, index), coords, dref, operands.MaskOptional(), operands.Span()); diff --git a/src/shader_recompiler/profile.h b/src/shader_recompiler/profile.h index 253e0d0bd..31390e869 100644 --- a/src/shader_recompiler/profile.h +++ b/src/shader_recompiler/profile.h @@ -52,6 +52,10 @@ struct Profile { bool need_declared_frag_colors{}; /// Prevents fast math optimizations that may cause inaccuracies bool need_fastmath_off{}; + /// Some GPU vendors use a lower fixed point format of 16.8 when calculating pixel coordinates + /// in the ImageGather instruction than the Maxwell architecture does. Applying an offset does + /// fix this mismatching rounding behaviour. + bool need_gather_subpixel_offset{}; /// OpFClamp is broken and OpFMax + OpFMin should be used instead bool has_broken_spirv_clamp{}; diff --git a/src/video_core/renderer_opengl/gl_device.cpp b/src/video_core/renderer_opengl/gl_device.cpp index 22ed16ebf..d36a0a7a1 100644 --- a/src/video_core/renderer_opengl/gl_device.cpp +++ b/src/video_core/renderer_opengl/gl_device.cpp @@ -169,6 +169,7 @@ Device::Device(Core::Frontend::EmuWindow& emu_window) { has_draw_texture = GLAD_GL_NV_draw_texture; warp_size_potentially_larger_than_guest = !is_nvidia && !is_intel; need_fastmath_off = is_nvidia; + need_gather_subpixel_offset = is_amd; can_report_memory = GLAD_GL_NVX_gpu_memory_info; // At the moment of writing this, only Nvidia's driver optimizes BufferSubData on exclusive diff --git a/src/video_core/renderer_opengl/gl_device.h b/src/video_core/renderer_opengl/gl_device.h index 3ff8cad83..e8104c4de 100644 --- a/src/video_core/renderer_opengl/gl_device.h +++ b/src/video_core/renderer_opengl/gl_device.h @@ -160,6 +160,10 @@ public: return need_fastmath_off; } + bool NeedsGatherSubpixelOffset() const { + return need_gather_subpixel_offset; + } + bool HasCbufFtouBug() const { return has_cbuf_ftou_bug; } @@ -225,6 +229,7 @@ private: bool has_draw_texture{}; bool warp_size_potentially_larger_than_guest{}; bool need_fastmath_off{}; + bool need_gather_subpixel_offset{}; bool has_cbuf_ftou_bug{}; bool has_bool_ref_bug{}; bool can_report_memory{}; diff --git a/src/video_core/renderer_opengl/gl_shader_cache.cpp b/src/video_core/renderer_opengl/gl_shader_cache.cpp index 479bb8ba3..b40aa6f5e 100644 --- a/src/video_core/renderer_opengl/gl_shader_cache.cpp +++ b/src/video_core/renderer_opengl/gl_shader_cache.cpp @@ -218,6 +218,7 @@ ShaderCache::ShaderCache(RasterizerOpenGL& rasterizer_, Core::Frontend::EmuWindo .lower_left_origin_mode = true, .need_declared_frag_colors = true, .need_fastmath_off = device.NeedsFastmathOff(), + .need_gather_subpixel_offset = device.NeedsGatherSubpixelOffset(), .has_broken_spirv_clamp = true, .has_broken_unsigned_image_offsets = true, diff --git a/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp b/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp index 0684cceed..f51257267 100644 --- a/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp +++ b/src/video_core/renderer_vulkan/vk_pipeline_cache.cpp @@ -329,6 +329,7 @@ PipelineCache::PipelineCache(RasterizerVulkan& rasterizer_, const Device& device .lower_left_origin_mode = false, .need_declared_frag_colors = false, + .need_gather_subpixel_offset = device.NeedsGatherSubpixelOffset(), .has_broken_spirv_clamp = driver_id == VK_DRIVER_ID_INTEL_PROPRIETARY_WINDOWS, .has_broken_spirv_position_input = driver_id == VK_DRIVER_ID_QUALCOMM_PROPRIETARY, diff --git a/src/video_core/vulkan_common/vulkan_device.cpp b/src/video_core/vulkan_common/vulkan_device.cpp index 6f288b3f8..0939b62c9 100644 --- a/src/video_core/vulkan_common/vulkan_device.cpp +++ b/src/video_core/vulkan_common/vulkan_device.cpp @@ -431,6 +431,7 @@ Device::Device(VkInstance instance_, vk::PhysicalDevice physical_, VkSurfaceKHR "AMD GCN4 and earlier have broken VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT"); has_broken_cube_compatibility = true; } + need_gather_subpixel_offset = true; } if (extensions.sampler_filter_minmax && is_amd) { // Disable ext_sampler_filter_minmax on AMD GCN4 and lower as it is broken. diff --git a/src/video_core/vulkan_common/vulkan_device.h b/src/video_core/vulkan_common/vulkan_device.h index 41b5da18a..50e95bcca 100644 --- a/src/video_core/vulkan_common/vulkan_device.h +++ b/src/video_core/vulkan_common/vulkan_device.h @@ -554,6 +554,10 @@ public: return features.robustness2.nullDescriptor; } + bool NeedsGatherSubpixelOffset() const { + return need_gather_subpixel_offset; + } + u32 GetMaxVertexInputAttributes() const { return properties.properties.limits.maxVertexInputAttributes; } @@ -664,6 +668,7 @@ private: bool must_emulate_bgr565{}; ///< Emulates BGR565 by swizzling RGB565 format. bool dynamic_state3_blending{}; ///< Has all blending features of dynamic_state3. bool dynamic_state3_enables{}; ///< Has all enables features of dynamic_state3. + bool need_gather_subpixel_offset{}; ///< Needs offset at ImageGather for correct rounding. u64 device_access_memory{}; ///< Total size of device local memory in bytes. u32 sets_per_pool{}; ///< Sets per Description Pool