Texture Loader: added option to detect and clip uniform images

DiligentGraphics · Oct 10, 2024 · d5069a7 · d5069a7
1 parent c546d12
commit d5069a7
Show file tree

Hide file tree

Showing 4 changed files with 72 additions and 3 deletions.
diff --git a/TextureLoader/interface/Image.h b/TextureLoader/interface/Image.h
@@ -164,6 +164,9 @@ struct Image : public ObjectBase<IObject>
 
     static IMAGE_FILE_FORMAT GetFileFormat(const Uint8* pData, size_t Size, const char* FilePath = nullptr);
 
+    /// Returns true if the image is uniform, i.e. all pixels have the same value
+    bool IsUniform() const;
+
 private:
     template <typename AllocatorType, typename ObjectType>
     friend class MakeNewRCObj;

diff --git a/TextureLoader/interface/TextureLoader.h b/TextureLoader/interface/TextureLoader.h
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2023 Diligent Graphics LLC
+ *  Copyright 2019-2024 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -136,6 +136,13 @@ struct TextureLoadInfo
     ///             - Two-channel source image is replicated to RG channels, B channel is set to 0.
     TextureComponentMapping Swizzle DEFAULT_INITIALIZER(TextureComponentMapping::Identity());
 
+    /// When non-zero, specifies the dimension that uniform images should be clipped to.
+    ///
+    /// \remarks    When this parameter is non-zero, the loader will check if all pixels
+    ///             in the image have the same value. If this is the case, the image will
+    ///             be clipped to the specified dimension.
+    Uint32 UniformImageClipDim DEFAULT_INITIALIZER(0);
+
 #if DILIGENT_CPP_INTERFACE
     explicit TextureLoadInfo(const Char*         _Name,
                              USAGE               _Usage             = TextureLoadInfo{}.Usage,

diff --git a/TextureLoader/src/Image.cpp b/TextureLoader/src/Image.cpp
@@ -589,6 +589,59 @@ IMAGE_FILE_FORMAT Image::GetFileFormat(const Uint8* pData, size_t Size, const ch
     return IMAGE_FILE_FORMAT_UNKNOWN;
 }
 
+template <typename T>
+bool IsImageUniform(const void* pData, Uint32 Width, Uint32 Height, Uint32 NumComponents, Uint32 RowStride)
+{
+    if (Width == 0 || Height == 0 || NumComponents == 0)
+        return false;
+
+    const T* pFirstPixel = static_cast<const T*>(pData);
+    for (Uint32 Pass = 0; Pass < 2; ++Pass)
+    {
+        // On the first pass, sparsely sample the image to quickly detect non-uniform images
+        const Uint32 Step = (Pass == 0) ? 32 : 1;
+        for (Uint32 y = 0; y < Height; y += Step)
+        {
+            const T* pRow = reinterpret_cast<const T*>(static_cast<const Uint8*>(pData) + y * RowStride);
+            for (Uint32 x = 0; x < Width; x += Step)
+            {
+                for (Uint32 c = 0; c < NumComponents; ++c)
+                {
+                    if (pRow[x * NumComponents + c] != pFirstPixel[c])
+                        return false;
+                }
+            }
+        }
+    }
+
+    return true;
+}
+
+bool Image::IsUniform() const
+{
+    if (!m_pData)
+        return false;
+
+    Uint32 ComponentSize = GetValueSize(m_Desc.ComponentType);
+    switch (ComponentSize)
+    {
+        case 1:
+            return IsImageUniform<Uint8>(m_pData->GetConstDataPtr(), m_Desc.Width, m_Desc.Height, m_Desc.NumComponents, m_Desc.RowStride);
+
+        case 2:
+            return IsImageUniform<Uint16>(m_pData->GetConstDataPtr(), m_Desc.Width, m_Desc.Height, m_Desc.NumComponents, m_Desc.RowStride);
+
+        case 4:
+            return IsImageUniform<Uint32>(m_pData->GetConstDataPtr(), m_Desc.Width, m_Desc.Height, m_Desc.NumComponents, m_Desc.RowStride);
+
+        case 8:
+            return IsImageUniform<Uint64>(m_pData->GetConstDataPtr(), m_Desc.Width, m_Desc.Height, m_Desc.NumComponents, m_Desc.RowStride);
+
+        default:
+            UNEXPECTED("Unexpected component size (", ComponentSize, ")");
+            return false;
+    }
+}
 
 IMAGE_FILE_FORMAT CreateImageFromFile(const Char* FilePath,
                                       Image**     ppImage,

diff --git a/TextureLoader/src/TextureLoaderImpl.cpp b/TextureLoader/src/TextureLoaderImpl.cpp
@@ -199,8 +199,12 @@ void TextureLoaderImpl::LoadFromImage(Image* pImage, const TextureLoadInfo& TexL
 {
     VERIFY_EXPR(pImage != nullptr);
 
-    const ImageDesc& ImgDesc  = pImage->GetDesc();
-    const Uint32     CompSize = GetValueSize(ImgDesc.ComponentType);
+    ImageDesc ImgDesc = pImage->GetDesc();
+    if (TexLoadInfo.UniformImageClipDim != 0 && pImage->IsUniform())
+    {
+        ImgDesc.Width  = std::min(ImgDesc.Width, TexLoadInfo.UniformImageClipDim);
+        ImgDesc.Height = std::min(ImgDesc.Height, TexLoadInfo.UniformImageClipDim);
+    }
 
     m_TexDesc.Type      = RESOURCE_DIM_TEX_2D;
     m_TexDesc.Width     = ImgDesc.Width;
@@ -209,6 +213,8 @@ void TextureLoaderImpl::LoadFromImage(Image* pImage, const TextureLoadInfo& TexL
     if (TexLoadInfo.MipLevels > 0)
         m_TexDesc.MipLevels = std::min(m_TexDesc.MipLevels, TexLoadInfo.MipLevels);
 
+    const Uint32 CompSize = GetValueSize(ImgDesc.ComponentType);
+
     if (m_TexDesc.Format == TEX_FORMAT_UNKNOWN)
     {
         Uint32 NumComponents = ImgDesc.NumComponents;