texture_cache: Implement rendering to 3D textures

This allows rendering to 3D textures with more than one slice.
Applications are allowed to render to more than one slice of a texture
using gl_Layer from a VTG shader.

This also requires reworking how 3D texture collisions are handled, for
now, this commit allows rendering to slices but not to miplevels. When a
render target attempts to write to a mipmap, we fallback to the previous
implementation (copying or flushing as needed).

- Fixes color correction 3D textures on UE4 games (rainbow effects).
- Allows Xenoblade games to render to 3D textures directly.

4 files changed, 76 insertions, 80 deletions

diff --git a/src/video_core/texture_cache/surface_base.cpp b/src/video_core/texture_cache/surface_base.cpp
index 715f39d0d..94d3a6ae5 100644
--- a/src/video_core/texture_cache/surface_base.cpp
+++ b/src/video_core/texture_cache/surface_base.cpp
@@ -248,12 +248,11 @@ void SurfaceBaseImpl::FlushBuffer(Tegra::MemoryManager& memory_manager,
 
     // Use an extra temporal buffer
     auto& tmp_buffer = staging_cache.GetBuffer(1);
-    // Special case for 3D Texture Segments
-    const bool must_read_current_data =
-        params.block_depth > 0 && params.target == VideoCore::Surface::SurfaceTarget::Texture2D;
     tmp_buffer.resize(guest_memory_size);
     host_ptr = tmp_buffer.data();
-    if (must_read_current_data) {
+
+    if (params.target == SurfaceTarget::Texture3D) {
+        // Special case for 3D texture segments
         memory_manager.ReadBlockUnsafe(gpu_addr, host_ptr, guest_memory_size);
     }
 
diff --git a/src/video_core/texture_cache/surface_base.h b/src/video_core/texture_cache/surface_base.h
index 79e10ffbb..173f2edba 100644
--- a/src/video_core/texture_cache/surface_base.h
+++ b/src/video_core/texture_cache/surface_base.h
@@ -217,8 +217,8 @@ public:
     }
 
     bool IsProtected() const {
-        // Only 3D Slices are to be protected
-        return is_target && params.block_depth > 0;
+        // Only 3D slices are to be protected
+        return is_target && params.target == SurfaceTarget::Texture3D;
     }
 
     bool IsRenderTarget() const {
@@ -250,6 +250,11 @@ public:
         return GetView(ViewParams(overview_params.target, 0, num_layers, 0, params.num_levels));
     }
 
+    TView Emplace3DView(u32 slice, u32 depth, u32 base_level, u32 num_levels) {
+        return GetView(ViewParams(VideoCore::Surface::SurfaceTarget::Texture3D, slice, depth,
+                                  base_level, num_levels));
+    }
+
     std::optional<TView> EmplaceIrregularView(const SurfaceParams& view_params,
                                               const GPUVAddr view_addr,
                                               const std::size_t candidate_size, const u32 mipmap,
@@ -272,8 +277,8 @@ public:
     std::optional<TView> EmplaceView(const SurfaceParams& view_params, const GPUVAddr view_addr,
                                      const std::size_t candidate_size) {
         if (params.target == SurfaceTarget::Texture3D ||
-            (params.num_levels == 1 && !params.is_layered) ||
-            view_params.target == SurfaceTarget::Texture3D) {
+            view_params.target == SurfaceTarget::Texture3D ||
+            (params.num_levels == 1 && !params.is_layered)) {
             return {};
         }
         const auto layer_mipmap{GetLayerMipmap(view_addr)};
diff --git a/src/video_core/texture_cache/surface_params.cpp b/src/video_core/texture_cache/surface_params.cpp
index 884fabffe..642eeb850 100644
--- a/src/video_core/texture_cache/surface_params.cpp
+++ b/src/video_core/texture_cache/surface_params.cpp
@@ -215,10 +215,19 @@ SurfaceParams SurfaceParams::CreateForFramebuffer(Core::System& system, std::siz
     params.num_levels = 1;
     params.emulated_levels = 1;
 
-    const bool is_layered = config.layers > 1 && params.block_depth == 0;
-    params.is_layered = is_layered;
-    params.depth = is_layered ? config.layers.Value() : 1;
-    params.target = is_layered ? SurfaceTarget::Texture2DArray : SurfaceTarget::Texture2D;
+    if (config.memory_layout.is_3d != 0) {
+        params.depth = config.layers.Value();
+        params.is_layered = false;
+        params.target = SurfaceTarget::Texture3D;
+    } else if (config.layers > 1) {
+        params.depth = config.layers.Value();
+        params.is_layered = true;
+        params.target = SurfaceTarget::Texture2DArray;
+    } else {
+        params.depth = 1;
+        params.is_layered = false;
+        params.target = SurfaceTarget::Texture2D;
+    }
     return params;
 }
 
diff --git a/src/video_core/texture_cache/texture_cache.h b/src/video_core/texture_cache/texture_cache.h
index 6f63217a2..4ee0d76b9 100644
--- a/src/video_core/texture_cache/texture_cache.h
+++ b/src/video_core/texture_cache/texture_cache.h
@@ -508,12 +508,12 @@ private:
             return RecycleStrategy::Flush;
         }
         // 3D Textures decision
-        if (params.block_depth > 1 || params.target == SurfaceTarget::Texture3D) {
+        if (params.target == SurfaceTarget::Texture3D) {
             return RecycleStrategy::Flush;
         }
         for (const auto& s : overlaps) {
             const auto& s_params = s->GetSurfaceParams();
-            if (s_params.block_depth > 1 || s_params.target == SurfaceTarget::Texture3D) {
+            if (s_params.target == SurfaceTarget::Texture3D) {
                 return RecycleStrategy::Flush;
             }
         }
@@ -726,76 +726,60 @@ private:
      * @param params    The parameters on the new surface.
      * @param gpu_addr  The starting address of the new surface.
      * @param cpu_addr  The starting address of the new surface on physical memory.
-     * @param preserve_contents Indicates that the new surface should be loaded from memory or
-     *                          left blank.
      */
     std::optional<std::pair<TSurface, TView>> Manage3DSurfaces(VectorSurface& overlaps,
                                                                const SurfaceParams& params,
-                                                               const GPUVAddr gpu_addr,
-                                                               const VAddr cpu_addr,
-                                                               bool preserve_contents) {
-        if (params.target == SurfaceTarget::Texture3D) {
-            bool failed = false;
-            if (params.num_levels > 1) {
-                // We can't handle mipmaps in 3D textures yet, better fallback to LLE approach
-                return std::nullopt;
-            }
-            TSurface new_surface = GetUncachedSurface(gpu_addr, params);
-            bool modified = false;
-            for (auto& surface : overlaps) {
-                const SurfaceParams& src_params = surface->GetSurfaceParams();
-                if (src_params.target != SurfaceTarget::Texture2D) {
-                    failed = true;
-                    break;
-                }
-                if (src_params.height != params.height) {
-                    failed = true;
-                    break;
-                }
-                if (src_params.block_depth != params.block_depth ||
-                    src_params.block_height != params.block_height) {
-                    failed = true;
-                    break;
+                                                               GPUVAddr gpu_addr, VAddr cpu_addr) {
+        if (params.num_levels > 1) {
+            // We can't handle mipmaps in 3D textures yet, better fallback to LLE approach
+            return std::nullopt;
+        }
+
+        if (overlaps.size() == 1) {
+            const auto& surface = overlaps[0];
+            const SurfaceParams& overlap_params = surface->GetSurfaceParams();
+            // Don't attempt to render to textures with more than one level for now
+            // The texture has to be to the right or the sample address if we want to render to it
+            if (overlap_params.num_levels == 1 && cpu_addr >= surface->GetCpuAddr()) {
+                const u32 offset = static_cast<u32>(cpu_addr - surface->GetCpuAddr());
+                const u32 slice = std::get<2>(params.GetBlockOffsetXYZ(offset));
+                if (slice < overlap_params.depth) {
+                    auto view = surface->Emplace3DView(slice, params.depth, 0, 1);
+                    return std::make_pair(std::move(surface), std::move(view));
                 }
-                const u32 offset = static_cast<u32>(surface->GetCpuAddr() - cpu_addr);
-                const auto offsets = params.GetBlockOffsetXYZ(offset);
-                const auto z = std::get<2>(offsets);
-                modified |= surface->IsModified();
-                const CopyParams copy_params(0, 0, 0, 0, 0, z, 0, 0, params.width, params.height,
-                                             1);
-                ImageCopy(surface, new_surface, copy_params);
             }
-            if (failed) {
+        }
+
+        if (params.depth == 1) {
+            return std::nullopt;
+        }
+
+        TSurface new_surface = GetUncachedSurface(gpu_addr, params);
+        bool modified = false;
+        for (auto& surface : overlaps) {
+            const SurfaceParams& src_params = surface->GetSurfaceParams();
+            if (src_params.height != params.height ||
+                src_params.block_depth != params.block_depth ||
+                src_params.block_height != params.block_height) {
                 return std::nullopt;
             }
-            for (const auto& surface : overlaps) {
-                Unregister(surface);
-            }
-            new_surface->MarkAsModified(modified, Tick());
-            Register(new_surface);
-            auto view = new_surface->GetMainView();
-            return {{std::move(new_surface), view}};
-        } else {
-            for (const auto& surface : overlaps) {
-                if (!surface->MatchTarget(params.target)) {
-                    if (overlaps.size() == 1 && surface->GetCpuAddr() == cpu_addr) {
-                        if (Settings::IsGPULevelExtreme()) {
-                            return std::nullopt;
-                        }
-                        Unregister(surface);
-                        return InitializeSurface(gpu_addr, params, preserve_contents);
-                    }
-                    return std::nullopt;
-                }
-                if (surface->GetCpuAddr() != cpu_addr) {
-                    continue;
-                }
-                if (surface->MatchesStructure(params) == MatchStructureResult::FullMatch) {
-                    return {{surface, surface->GetMainView()}};
-                }
-            }
-            return InitializeSurface(gpu_addr, params, preserve_contents);
+            modified |= surface->IsModified();
+
+            const u32 offset = static_cast<u32>(surface->GetCpuAddr() - cpu_addr);
+            const u32 slice = std::get<2>(params.GetBlockOffsetXYZ(offset));
+            const u32 width = params.width;
+            const u32 height = params.height;
+            const CopyParams copy_params(0, 0, 0, 0, 0, slice, 0, 0, width, height, 1);
+            ImageCopy(surface, new_surface, copy_params);
         }
+        for (const auto& surface : overlaps) {
+            Unregister(surface);
+        }
+        new_surface->MarkAsModified(modified, Tick());
+        Register(new_surface);
+
+        auto view = new_surface->GetMainView();
+        return std::make_pair(std::move(new_surface), std::move(view));
     }
 
     /**
@@ -873,10 +857,9 @@ private:
             }
         }
 
-        // Check if it's a 3D texture
-        if (params.block_depth > 0) {
-            auto surface =
-                Manage3DSurfaces(overlaps, params, gpu_addr, cpu_addr, preserve_contents);
+        // Manage 3D textures
+        if (params.target == SurfaceTarget::Texture3D) {
+            auto surface = Manage3DSurfaces(overlaps, params, gpu_addr, cpu_addr);
             if (surface) {
                 return *surface;
             }