Merge pull request #10477 from Pokechu22/light-dir-double-normalize

Sanitize and use increased precision when normalizing light directions

Source/Core/VideoCommon/VertexShaderManager.cpp

@@ -172,14 +172,22 @@ void VertexShaderManager::SetConstants(const std::vector<std::string>& textures)
       dstlight.pos[1] = light.dpos[1];
       dstlight.pos[2] = light.dpos[2];
 
+      // TODO: Hardware testing is needed to confirm that this normalization is correct
+      auto sanitize = [](float f) {
+        if (std::isnan(f))
+          return 0.0f;
+        else if (std::isinf(f))
+          return f > 0.0f ? 1.0f : -1.0f;
+        else
+          return f;
+      };
       double norm = double(light.ddir[0]) * double(light.ddir[0]) +
                     double(light.ddir[1]) * double(light.ddir[1]) +
                     double(light.ddir[2]) * double(light.ddir[2]);
       norm = 1.0 / sqrt(norm);
-      float norm_float = static_cast<float>(norm);
-      dstlight.dir[0] = light.ddir[0] * norm_float;
-      dstlight.dir[1] = light.ddir[1] * norm_float;
-      dstlight.dir[2] = light.ddir[2] * norm_float;
+      dstlight.dir[0] = sanitize(static_cast<float>(light.ddir[0] * norm));
+      dstlight.dir[1] = sanitize(static_cast<float>(light.ddir[1] * norm));
+      dstlight.dir[2] = sanitize(static_cast<float>(light.ddir[2] * norm));
     }
     dirty = true;