From 2d53b7364363b8d32f62905dbdbff01531ebe06d Mon Sep 17 00:00:00 2001
From: Pokechu22 <Pokechu022@gmail.com>
Date: Thu, 12 Jan 2023 12:54:01 -0800
Subject: [PATCH] VertexLoaderTester: Add assertions for
 position/binormal/tangent caches

---
 Source/Core/VideoCommon/VertexLoaderBase.cpp | 80 +++++++++++++++++++-
 1 file changed, 78 insertions(+), 2 deletions(-)

diff --git a/Source/Core/VideoCommon/VertexLoaderBase.cpp b/Source/Core/VideoCommon/VertexLoaderBase.cpp
index e8b38ba345..f04580a074 100644
--- a/Source/Core/VideoCommon/VertexLoaderBase.cpp
+++ b/Source/Core/VideoCommon/VertexLoaderBase.cpp
@@ -13,11 +13,13 @@
 #include <fmt/format.h>
 
 #include "Common/Assert.h"
+#include "Common/BitUtils.h"
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/MsgHandler.h"
 
 #include "VideoCommon/VertexLoader.h"
+#include "VideoCommon/VertexLoaderManager.h"
 #include "VideoCommon/VertexLoader_Color.h"
 #include "VideoCommon/VertexLoader_Normal.h"
 #include "VideoCommon/VertexLoader_Position.h"
@@ -61,8 +63,36 @@ public:
     buffer_a.resize(count * a->m_native_vtx_decl.stride + 4);
     buffer_b.resize(count * b->m_native_vtx_decl.stride + 4);
 
-    int count_a = a->RunVertices(src, buffer_a.data(), count);
-    int count_b = b->RunVertices(src, buffer_b.data(), count);
+    const std::array<u32, 3> old_position_matrix_index_cache =
+        VertexLoaderManager::position_matrix_index_cache;
+    const std::array<std::array<float, 4>, 3> old_position_cache =
+        VertexLoaderManager::position_cache;
+    const std::array<float, 4> old_tangent_cache = VertexLoaderManager::tangent_cache;
+    const std::array<float, 4> old_binormal_cache = VertexLoaderManager::binormal_cache;
+
+    const int count_a = a->RunVertices(src, buffer_a.data(), count);
+
+    const std::array<u32, 3> a_position_matrix_index_cache =
+        VertexLoaderManager::position_matrix_index_cache;
+    const std::array<std::array<float, 4>, 3> a_position_cache =
+        VertexLoaderManager::position_cache;
+    const std::array<float, 4> a_tangent_cache = VertexLoaderManager::tangent_cache;
+    const std::array<float, 4> a_binormal_cache = VertexLoaderManager::binormal_cache;
+
+    // Reset state before running b
+    VertexLoaderManager::position_matrix_index_cache = old_position_matrix_index_cache;
+    VertexLoaderManager::position_cache = old_position_cache;
+    VertexLoaderManager::tangent_cache = old_tangent_cache;
+    VertexLoaderManager::binormal_cache = old_binormal_cache;
+
+    const int count_b = b->RunVertices(src, buffer_b.data(), count);
+
+    const std::array<u32, 3> b_position_matrix_index_cache =
+        VertexLoaderManager::position_matrix_index_cache;
+    const std::array<std::array<float, 4>, 3> b_position_cache =
+        VertexLoaderManager::position_cache;
+    const std::array<float, 4> b_tangent_cache = VertexLoaderManager::tangent_cache;
+    const std::array<float, 4> b_binormal_cache = VertexLoaderManager::binormal_cache;
 
     ASSERT_MSG(VIDEO, count_a == count_b,
                "The two vertex loaders have loaded a different amount of vertices (a: {}, b: {}).",
@@ -75,6 +105,52 @@ public:
                "\nVertex desc:\n{}\n\nVertex attr:\n{}",
                m_VtxDesc, m_VtxAttr);
 
+    ASSERT_MSG(VIDEO, a_position_matrix_index_cache == b_position_matrix_index_cache,
+               "Expected matching position matrix caches after loading (a: {}; b: {})",
+               fmt::join(a_position_matrix_index_cache, ", "),
+               fmt::join(b_position_matrix_index_cache, ", "));
+
+    // Some games (e.g. Donkey Kong Country Returns) have a few draws that contain NaN.
+    // Since NaN != NaN, we need to compare the bits instead.
+    const auto bit_equal = [](float a, float b) {
+      return Common::BitCast<u32>(a) == Common::BitCast<u32>(b);
+    };
+
+    // The last element is allowed to be garbage for SIMD overwrites.
+    // For XY, the last 2 are garbage.
+    const bool positions_match = [&] {
+      const size_t max_component = m_VtxAttr.g0.PosElements == CoordComponentCount::XYZ ? 3 : 2;
+      for (size_t vertex = 0; vertex < 3; vertex++)
+      {
+        if (!std::equal(a_position_cache[vertex].begin(),
+                        a_position_cache[vertex].begin() + max_component,
+                        b_position_cache[vertex].begin(), bit_equal))
+        {
+          return false;
+        }
+      }
+      return true;
+    }();
+
+    ASSERT_MSG(VIDEO, positions_match,
+               "Expected matching position caches after loading (a: {} / {} / {}; b: {} / {} / {})",
+               fmt::join(a_position_cache[0], ", "), fmt::join(a_position_cache[1], ", "),
+               fmt::join(a_position_cache[2], ", "), fmt::join(b_position_cache[0], ", "),
+               fmt::join(b_position_cache[1], ", "), fmt::join(b_position_cache[2], ", "));
+
+    // The last element is allowed to be garbage for SIMD overwrites
+    ASSERT_MSG(VIDEO,
+               std::equal(a_tangent_cache.begin(), a_tangent_cache.begin() + 3,
+                          b_tangent_cache.begin(), b_tangent_cache.begin() + 3, bit_equal),
+               "Expected matching tangent caches after loading (a: {}; b: {})",
+               fmt::join(a_tangent_cache, ", "), fmt::join(b_tangent_cache, ", "));
+
+    ASSERT_MSG(VIDEO,
+               std::equal(a_binormal_cache.begin(), a_binormal_cache.begin() + 3,
+                          b_binormal_cache.begin(), b_binormal_cache.begin() + 3, bit_equal),
+               "Expected matching binormal caches after loading (a: {}; b: {})",
+               fmt::join(a_binormal_cache, ", "), fmt::join(b_binormal_cache, ", "));
+
     memcpy(dst, buffer_a.data(), count_a * m_native_vtx_decl.stride);
     m_numLoadedVertices += count;
     return count_a;