Update code for loading normal map from image

Signed-off-by: Ian Chen <[email protected]>

ogre2/src/Ogre2Material.cc

@@ -31,6 +31,8 @@
 #include <OgreMaterialManager.h>
 #include <OgrePixelFormatGpuUtils.h>
 #include <OgreTechnique.h>
+#include <OgreTextureBox.h>
+#include <OgreTextureFilters.h>
 #include <OgreTextureGpuManager.h>
 #include <Vao/OgreVaoManager.h>
 #ifdef _MSC_VER
@@ -130,6 +132,13 @@ class gz::rendering::Ogre2MaterialPrivate
         return "invalid";
     }
   }
+
+  /// \brief Helper function to convert normal maps to two-component normalized
+  /// signed 8-bit format, and generate mip maps
+  /// \param[in/out] _texture Normal map texture
+  /// \param[in/out] _image Normal map image data to be uploaded to the texture
+  public: void PrepareAndUploadNormalMap(Ogre::TextureGpu *_texture,
+      Ogre::Image2 &_image);
 };
 
 using namespace gz;
@@ -1215,6 +1224,8 @@ void Ogre2Material::SetTextureMapDataImpl(const std::string& _name,
       root->getRenderSystem()->getTextureGpuManager();
 
   // create the gpu texture
+  Ogre::uint32 filters = Ogre::TextureFilter::TypeGenerateDefaultMipmaps;
+  filters |= this->ogreDatablock->suggestFiltersForType(_type);
   Ogre::uint32 textureFlags = 0;
   textureFlags |= Ogre::TextureFlags::AutomaticBatching;
   Ogre::TextureGpu *texture = textureMgr->createOrRetrieveTexture(
@@ -1223,7 +1234,7 @@ void Ogre2Material::SetTextureMapDataImpl(const std::string& _name,
       textureFlags | Ogre::TextureFlags::ManualTexture,
       Ogre::TextureTypes::Type2D,
       Ogre::ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME,
-      0u);
+      filters);
 
   // Has to be loaded
   if (texture->getWidth() == 0)
@@ -1236,13 +1247,20 @@ void Ogre2Material::SetTextureMapDataImpl(const std::string& _name,
     texture->setTextureType(Ogre::TextureTypes::Type2D);
     texture->setNumMipmaps(1u);
     texture->setResolution(_img->Width(), _img->Height());
-    texture->scheduleTransitionTo(Ogre::GpuResidency::Resident);
-    texture->waitForData();
 
-    // upload raw color image data to gpu texture
     Ogre::Image2 img;
     img.loadDynamicImage(&data[0], false, texture);
-    img.uploadTo(texture, 0, 0);
+    if (_type == Ogre::PBSM_NORMAL)
+    {
+      this->dataPtr->PrepareAndUploadNormalMap(texture, img);
+    }
+    else
+    {
+      // upload raw color image data to gpu texture
+      texture->scheduleTransitionTo(Ogre::GpuResidency::Resident);
+      texture->waitForData();
+      img.uploadTo(texture, 0, 0);
+    }
   }
 
   // Now assign it to the material
@@ -1558,3 +1576,102 @@ ShaderParamsPtr Ogre2Material::FragmentShaderParams()
 {
   return this->dataPtr->fragmentShaderParams;
 }
+
+//////////////////////////////////////////////////
+void Ogre2MaterialPrivate::PrepareAndUploadNormalMap(Ogre::TextureGpu *_texture,
+    Ogre::Image2 &_image)
+{
+  // The code below is adapted from ogre-next v2-3. It replicates the steps that
+  // ogre does when it loads a normal map from file.
+  // Here we adapte the code to load a normal map texture from an image in
+  // memory
+  // \todo(iche033) See if there is a way to reuse these functions
+  // from ogre-next without copying the code here.
+
+  // Step 1: convert to two component signed 8 bit format:
+  // Ogre::PFG_RG8_SNORM format
+  // see PrepareForNormalMapping::_executeStreaming function in
+  // OgreMain/src/OgreTextureFilters.cpp
+  const Ogre::uint8 numMipmaps = _image.getNumMipmaps();
+  const Ogre::PixelFormatGpu dstFormat = Ogre::PFG_RG8_SNORM;
+  const Ogre::uint32 rowAlignment = 4u;
+  const size_t dstSizeBytes = Ogre::PixelFormatGpuUtils::calculateSizeBytes(
+      _image.getWidth(),
+      _image.getHeight(),
+      _image.getDepth(),
+      _image.getNumSlices(),
+      dstFormat, numMipmaps,
+      rowAlignment );
+  void *imgData = OGRE_MALLOC_SIMD( dstSizeBytes, Ogre::MEMCATEGORY_RESOURCE);
+  for (Ogre::uint8 mip = 0; mip<numMipmaps; ++mip)
+  {
+    Ogre::TextureBox srcBox = _image.getData( mip );
+    const Ogre::uint32 width = srcBox.width;
+    const Ogre::uint32 height = srcBox.height;
+
+    Ogre::TextureBox dstBox = srcBox;
+    dstBox.bytesPerPixel =
+        Ogre::PixelFormatGpuUtils::getBytesPerPixel(dstFormat);
+    dstBox.bytesPerRow =
+        Ogre::PixelFormatGpuUtils::getSizeBytes(
+        width, 1u, 1u, 1u, dstFormat, 4u);
+    dstBox.bytesPerImage =
+        Ogre::PixelFormatGpuUtils::getSizeBytes(width, height, 1u, 1u,
+        dstFormat, 4u);
+    dstBox.data = Ogre::PixelFormatGpuUtils::advancePointerToMip(
+        imgData, width, height, srcBox.depth, srcBox.numSlices, mip, dstFormat);
+
+    Ogre::PixelFormatGpuUtils::convertForNormalMapping(
+        srcBox, _image.getPixelFormat(),
+        dstBox, dstFormat);
+  }
+  _image.loadDynamicImage(imgData, _image.getWidth(), _image.getHeight(),
+      _image.getDepthOrSlices(), _image.getTextureType(), dstFormat, false,
+      numMipmaps);
+  _texture->setPixelFormat(dstFormat);
+
+  // _image.save(_name + ".png", 0, 1);
+   // std::cerr << "tex format " << texture->getWidth() << " " << texture->getHeight() << ": " << texture->getPixelFormat() << " mip "
+     //      << static_cast<int>(texture->getNumMipmaps()) << std::endl;
+   //std::cerr << "image format " << _image.getWidth() << " " << _image.getHeight() << ": " << _image.getPixelFormat() << std::endl;
+   //std::cerr << " Ogre::PFG_RG8_SNORM " << Ogre::PFG_RG8_SNORM << std::endl;
+
+  // Step 2: Set mip map count
+  // see GenerateHwMipmaps::_executeStreaming function in
+  // OgreMain/src/OgreTextureFilters.cpp
+  Ogre::uint8 maxMipmaps = Ogre::PixelFormatGpuUtils::getMaxMipmapCount(
+      _texture->getWidth(),
+      _texture->getHeight(),
+      _texture->getDepth() );
+  _texture->setNumMipmaps(maxMipmaps);
+
+  _texture->scheduleTransitionTo(Ogre::GpuResidency::Resident);
+  _texture->waitForData();
+  _image.uploadTo(_texture, 0, 0);
+
+  // Step 3: Generate and copy mip maps
+  // see GenerateHwMipmaps::_executeSerial function in
+  // OgreMain/src/OgreTextureFilters.cpp
+  Ogre::TextureGpuManager *textureManager = _texture->getTextureManager();
+  Ogre::TextureGpu *tempTexture = textureManager->createTexture(
+      "___tempMipmapTexture",
+      Ogre::GpuPageOutStrategy::Discard,
+      Ogre::TextureFlags::RenderToTexture |
+      Ogre::TextureFlags::AllowAutomipmaps |
+      Ogre::TextureFlags::DiscardableContent,
+      _texture->getTextureType());
+  tempTexture->copyParametersFrom(_texture);
+  tempTexture->unsafeScheduleTransitionTo(Ogre::GpuResidency::Resident);
+  Ogre::TextureBox box = _texture->getEmptyBox(0);
+  _texture->copyTo(tempTexture, box, 0, box, 0);
+  tempTexture->_autogenerateMipmaps();
+
+  Ogre::uint8 mipmaps = _texture->getNumMipmaps();
+  for (size_t i = 1u; i < mipmaps; ++i)
+  {
+    box = _texture->getEmptyBox( i );
+    tempTexture->copyTo(_texture, box, i, box, i);
+  }
+  textureManager->destroyTexture(tempTexture);
+  tempTexture = 0;
+}