Add Chromium-only Blender WebEngine parity work

blender-5.2.0/extern/opensubdiv-source/examples/common/ptexMipmapTextureLoader.h

@@ -0,0 +1,139 @@
+//
+//   Copyright 2013 Pixar
+//
+//   Licensed under the terms set forth in the LICENSE.txt file available at
+//   https://opensubdiv.org/license.
+//
+
+#ifndef OPENSUBDIV_EXAMPLES_PTEX_MIPMAP_TEXTURE_LOADER_H
+#define OPENSUBDIV_EXAMPLES_PTEX_MIPMAP_TEXTURE_LOADER_H
+
+#include <Ptexture.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <vector>
+
+
+class PtexMipmapTextureLoader {
+public:
+    PtexMipmapTextureLoader(PtexTexture *ptex,
+                               int maxNumPages,
+                               int maxLevels = -1,
+                               size_t targetMemory = 0,
+                               bool seamlessMipmap = true,
+                               bool padAlpha = false);
+
+    ~PtexMipmapTextureLoader();
+
+    const unsigned char * GetLayoutBuffer() const {
+        return _layoutBuffer;
+    }
+    const unsigned char * GetTexelBuffer() const {
+        return _texelBuffer;
+    }
+    int GetNumFaces() const {
+        return (int)_blocks.size();
+    }
+    int GetNumPages() const {
+        return (int)_pages.size();
+    }
+    int GetPageWidth() const {
+        return _pageWidth;
+    }
+    int GetPageHeight() const {
+        return _pageHeight;
+    }
+    size_t GetMemoryUsage() const {
+        return _memoryUsage;
+    }
+
+/*
+  block : atomic texture unit
+  XXX: face of 128x128 or more (64kb~) texels should be considered separately
+       using ARB_sparse_texture...?
+
+  . : per-face texels for each mipmap level
+  x : guttering pixel
+
+  xxxxxxxxxxxxxx
+  x........xx..x 2x2
+  x........xx..x
+  x........xxxxx
+  x..8x8...xxxxxxx
+  x........xx....x
+  x........xx....x 4x4
+  x........xx....x
+  x........xx....x
+  xxxxxxxxxxxxxxxx
+
+  For each face (w*h), texels with guttering and mipmap is stored into
+  (w+2+w/2+2)*(h+2) area as above.
+
+ */
+
+/*
+  Ptex loader
+
+  Texels buffer : the packed texels
+
+ */
+
+private:
+    struct Block {
+        int index;                 // ptex index
+        int nMipmaps;
+        uint16_t u, v;             // top-left texel offset
+        uint16_t width, height;    // texel dimension (includes mipmap)
+        uint16_t adjSizeDiffs;     // maximum tile size difference around each vertices
+        int8_t   ulog2, vlog2;     // texel dimension log2 (original tile)
+
+        void Generate(PtexMipmapTextureLoader *loader, PtexTexture *ptex,
+                      unsigned char *destination,
+                      int bpp, int width, int maxLevels);
+
+        void SetSize(unsigned char ulog2_, unsigned char vlog2_, bool mipmap);
+
+        int GetNumTexels() const {
+            return width*height;
+        }
+
+        void guttering(PtexMipmapTextureLoader *loader, PtexTexture *ptex,
+                       int level, int width, int height,
+                       unsigned char *pptr, int bpp, int stride);
+
+        static bool sort(const Block *a, const Block *b) {
+            return (a->height > b->height) ||
+                   ((a->height == b->height) && (a->width > b->width));
+        }
+    };
+
+    struct Page;
+    class CornerIterator;
+
+    void generateBuffers();
+    void optimizePacking(int maxNumPages, size_t targetMemory);
+    int  getLevelDiff(int face, int edge);
+    bool getCornerPixel(float *resultPixel, int numchannels,
+                        int face, int edge, int8_t res);
+    void sampleNeighbor(unsigned char *border,
+                        int face, int edge, int length, int bpp);
+    int  resampleBorder(int face, int edgeId, unsigned char *result,
+                        int dstLength, int bpp,
+                        float srcStart = 0.0f, float srcEnd = 1.0f);
+    void addAlphaChannel();
+
+    std::vector<Block> _blocks;
+    std::vector<Page *> _pages;
+
+    PtexTexture *_ptex;
+    int _maxLevels;
+    int _bpp;
+    int _pageWidth, _pageHeight;
+
+    unsigned char *_texelBuffer;
+    unsigned char *_layoutBuffer;
+
+    size_t _memoryUsage;
+};
+
+#endif // OPENSUBDIV_EXAMPLES_PTEX_MIPMAP_TEXTURE_LOADER_H