BPMemory: Refactor/consolidate TexUnit Addressing

Currently the logic for addressing the individual TexUnits is splattered all
across dolphin's codebase, this commit attempts to consolidate it all into a
single place and formalise it using our new TexUnitAddress struct.

3 files changed, 18 insertions, 28 deletions

diff --git a/Source/Core/VideoBackends/Software/DebugUtil.cpp b/Source/Core/VideoBackends/Software/DebugUtil.cpp
index 397442f8e8..c580461172 100644
--- a/Source/Core/VideoBackends/Software/DebugUtil.cpp
+++ b/Source/Core/VideoBackends/Software/DebugUtil.cpp
@@ -52,13 +52,8 @@ void Shutdown()
 
 static void SaveTexture(const std::string& filename, u32 texmap, s32 mip)
 {
-  FourTexUnits& texUnit = bpmem.tex[(texmap >> 2) & 1];
-  u8 subTexmap = texmap & 3;
-
-  TexImage0& ti0 = texUnit.texImage0[subTexmap];
-
-  u32 width = ti0.width + 1;
-  u32 height = ti0.height + 1;
+  u32 width = bpmem.tex.GetUnit(texmap).texImage0.width + 1;
+  u32 height = bpmem.tex.GetUnit(texmap).texImage0.height + 1;
 
   auto data = std::make_unique<u8[]>(width * height * 4);
 
@@ -80,10 +75,7 @@ void GetTextureRGBA(u8* dst, u32 texmap, s32 mip, u32 width, u32 height)
 
 static s32 GetMaxTextureLod(u32 texmap)
 {
-  FourTexUnits& texUnit = bpmem.tex[(texmap >> 2) & 1];
-  u8 subTexmap = texmap & 3;
-
-  u8 maxLod = texUnit.texMode1[subTexmap].max_lod;
+  u8 maxLod = bpmem.tex.GetUnit(texmap).texMode1.max_lod;
   u8 mip = maxLod >> 4;
   u8 fract = maxLod & 0xf;
 
diff --git a/Source/Core/VideoBackends/Software/Rasterizer.cpp b/Source/Core/VideoBackends/Software/Rasterizer.cpp
index de9925d596..df04ab5a31 100644
--- a/Source/Core/VideoBackends/Software/Rasterizer.cpp
+++ b/Source/Core/VideoBackends/Software/Rasterizer.cpp
@@ -163,13 +163,12 @@ static void InitSlope(Slope* slope, float f1, float f2, float f3, float DX31, fl
 
 static inline void CalculateLOD(s32* lodp, bool* linear, u32 texmap, u32 texcoord)
 {
-  const FourTexUnits& texUnit = bpmem.tex[(texmap >> 2) & 1];
-  const u8 subTexmap = texmap & 3;
+  auto texUnit = bpmem.tex.GetUnit(texmap);
 
   // LOD calculation requires data from the texture mode for bias, etc.
   // it does not seem to use the actual texture size
-  const TexMode0& tm0 = texUnit.texMode0[subTexmap];
-  const TexMode1& tm1 = texUnit.texMode1[subTexmap];
+  const TexMode0& tm0 = texUnit.texMode0;
+  const TexMode1& tm1 = texUnit.texMode1;
 
   float sDelta, tDelta;
   if (tm0.diag_lod == LODType::Diagonal)
diff --git a/Source/Core/VideoBackends/Software/TextureSampler.cpp b/Source/Core/VideoBackends/Software/TextureSampler.cpp
index f54002bdb5..064e9df41c 100644
--- a/Source/Core/VideoBackends/Software/TextureSampler.cpp
+++ b/Source/Core/VideoBackends/Software/TextureSampler.cpp
@@ -74,8 +74,8 @@ void Sample(s32 s, s32 t, s32 lod, bool linear, u8 texmap, u8* sample)
   bool mipLinear = false;
 
 #if (ALLOW_MIPMAP)
-  const FourTexUnits& texUnit = bpmem.tex[(texmap >> 2) & 1];
-  const TexMode0& tm0 = texUnit.texMode0[texmap & 3];
+  auto texUnit = bpmem.tex.GetUnit(texmap);
+  const TexMode0& tm0 = texUnit.texMode0;
 
   const s32 lodFract = lod & 0xf;
 
@@ -115,26 +115,25 @@ void Sample(s32 s, s32 t, s32 lod, bool linear, u8 texmap, u8* sample)
 
 void SampleMip(s32 s, s32 t, s32 mip, bool linear, u8 texmap, u8* sample)
 {
-  const FourTexUnits& texUnit = bpmem.tex[(texmap >> 2) & 1];
-  const u8 subTexmap = texmap & 3;
+  auto texUnit = bpmem.tex.GetUnit(texmap);
 
-  const TexMode0& tm0 = texUnit.texMode0[subTexmap];
-  const TexImage0& ti0 = texUnit.texImage0[subTexmap];
-  const TexTLUT& texTlut = texUnit.texTlut[subTexmap];
+  const TexMode0& tm0 = texUnit.texMode0;
+  const TexImage0& ti0 = texUnit.texImage0;
+  const TexTLUT& texTlut = texUnit.texTlut;
   const TextureFormat texfmt = ti0.format;
   const TLUTFormat tlutfmt = texTlut.tlut_format;
 
   const u8* imageSrc;
   const u8* imageSrcOdd = nullptr;
-  if (texUnit.texImage1[subTexmap].cache_manually_managed)
+  if (texUnit.texImage1.cache_manually_managed)
   {
-    imageSrc = &texMem[texUnit.texImage1[subTexmap].tmem_even * TMEM_LINE_SIZE];
+    imageSrc = &texMem[texUnit.texImage1.tmem_even * TMEM_LINE_SIZE];
     if (texfmt == TextureFormat::RGBA8)
-      imageSrcOdd = &texMem[texUnit.texImage2[subTexmap].tmem_odd * TMEM_LINE_SIZE];
+      imageSrcOdd = &texMem[texUnit.texImage2.tmem_odd * TMEM_LINE_SIZE];
   }
   else
   {
-    const u32 imageBase = texUnit.texImage3[subTexmap].image_base << 5;
+    const u32 imageBase = texUnit.texImage3.image_base << 5;
     imageSrc = Memory::GetPointer(imageBase);
   }
 
@@ -198,7 +197,7 @@ void SampleMip(s32 s, s32 t, s32 mip, bool linear, u8 texmap, u8* sample)
     WrapCoord(&imageSPlus1, tm0.wrap_s, image_width_minus_1 + 1);
     WrapCoord(&imageTPlus1, tm0.wrap_t, image_height_minus_1 + 1);
 
-    if (!(texfmt == TextureFormat::RGBA8 && texUnit.texImage1[subTexmap].cache_manually_managed))
+    if (!(texfmt == TextureFormat::RGBA8 && texUnit.texImage1.cache_manually_managed))
     {
       TexDecoder_DecodeTexel(sampledTex, imageSrc, imageS, imageT, image_width_minus_1, texfmt,
                              tlut, tlutfmt);
@@ -250,7 +249,7 @@ void SampleMip(s32 s, s32 t, s32 mip, bool linear, u8 texmap, u8* sample)
     WrapCoord(&imageS, tm0.wrap_s, image_width_minus_1 + 1);
     WrapCoord(&imageT, tm0.wrap_t, image_height_minus_1 + 1);
 
-    if (!(texfmt == TextureFormat::RGBA8 && texUnit.texImage1[subTexmap].cache_manually_managed))
+    if (!(texfmt == TextureFormat::RGBA8 && texUnit.texImage1.cache_manually_managed))
       TexDecoder_DecodeTexel(sample, imageSrc, imageS, imageT, image_width_minus_1, texfmt, tlut,
                              tlutfmt);
     else