[D3D12] Add epsilon to texture coordinates to resolve tie in nearest-neighbor filtering

src/xenia/gpu/dxbc_shader_translator.cc

@@ -8234,12 +8234,24 @@ void DxbcShaderTranslator::ProcessTextureFetchInstruction(
     // It's probably applicable to tfetchCube too, we're going to assume it's
     // used for them the same way as for stacked textures.
     // http://web.archive.org/web/20090511231340/http://msdn.microsoft.com:80/en-us/library/bb313959.aspx
+    // Adding 1/1024 - quarter of one fixed-point unit of subpixel precision
+    // (not to touch rounding when the GPU is converting to fixed-point) - to
+    // resolve the ambiguity when the texture coordinate is directly between two
+    // pixels, which hurts nearest-neighbor sampling (fixes the XBLA logo being
+    // blocky in Banjo-Kazooie and the outlines around things and overall
+    // blockiness in Halo 3).
     float offset_x = instr.attributes.offset_x;
+    if (instr.opcode != FetchOpcode::kGetTextureWeights) {
+      offset_x += 1.0f / 1024.0f;
+    }
     float offset_y = 0.0f, offset_z = 0.0f;
     if (instr.dimension == TextureDimension::k2D ||
         instr.dimension == TextureDimension::k3D ||
         instr.dimension == TextureDimension::kCube) {
       offset_y = instr.attributes.offset_y;
+      if (instr.opcode != FetchOpcode::kGetTextureWeights) {
+        offset_y += 1.0f / 1024.0f;
+      }
       // Don't care about the Z offset for cubemaps when getting weights because
       // zero Z will be returned anyway (the face index doesn't participate in
       // bilinear filtering).
@@ -8247,6 +8259,9 @@ void DxbcShaderTranslator::ProcessTextureFetchInstruction(
           (instr.dimension == TextureDimension::kCube &&
            instr.opcode != FetchOpcode::kGetTextureWeights)) {
         offset_z = instr.attributes.offset_z;
+        if (instr.opcode != FetchOpcode::kGetTextureWeights) {
+          offset_z += 1.0f / 1024.0f;
+        }
       }
     }
 
@@ -8262,6 +8277,9 @@ void DxbcShaderTranslator::ProcessTextureFetchInstruction(
     // unlikely to be used on purpose.
     // http://web.archive.org/web/20090514012026/http://msdn.microsoft.com:80/en-us/library/bb313957.aspx
     uint32_t size_and_is_3d_temp = UINT32_MAX;
+    // With 1/1024 this will always be true anyway, but let's keep the shorter
+    // path without the offset in case some day this hack won't be used anymore
+    // somehow.
     bool has_offset = offset_x != 0.0f || offset_y != 0.0f || offset_z != 0.0f;
     if (instr.opcode == FetchOpcode::kGetTextureWeights || has_offset ||
         instr.attributes.unnormalized_coordinates ||