raster_sparse.h

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#pragma once
 
/*
A sparse path through an xy grid. When a value is set != 0, it will get stored
in the sparse grid. The raster will only store the values that are set, and will
not allocate memory for the entire grid. This is useful for large grids where
only a small number of pixels are set.
*/
 
#include "fl/stl/int.h"
#include "fl/math/geometry.h"
#include "fl/stl/unordered_map.h"
#include "fl/stl/span.h"
#include "fl/math/xymap.h"
#include "fl/stl/noexcept.h"
 
#ifndef FASTLED_RASTER_SPARSE_INLINED_COUNT
#define FASTLED_RASTER_SPARSE_INLINED_COUNT 128
#endif
 
namespace fl {
 
class XYMap;
class Gradient;
class Tile2x2_u8;
class Leds;
 
// A raster of u8 values. This is a sparse raster, meaning that it will
// only store the values that are set.
class XYRasterU8Sparse {
  public:
    XYRasterU8Sparse() FL_NOEXCEPT = default;
    XYRasterU8Sparse(int width, int height) {
        setBounds(rect<u16>(0, 0, width, height));
    }
    XYRasterU8Sparse(const XYRasterU8Sparse &) FL_NOEXCEPT = default;
    XYRasterU8Sparse &operator=(XYRasterU8Sparse &&) FL_NOEXCEPT = default;
    XYRasterU8Sparse(XYRasterU8Sparse &&) FL_NOEXCEPT = default;
    XYRasterU8Sparse &operator=(const XYRasterU8Sparse &) FL_NOEXCEPT = default;
 
    XYRasterU8Sparse &reset() {
        mSparseGrid.clear();
        mCache.clear();
        return *this;
    }
 
    XYRasterU8Sparse &clear() { return reset(); }
 
    // Rasterizes point with a value For best visual results, you'll want to
    // rasterize tile2x2 tiles, which are generated for you by the XYPathRenderer
    // to represent sub pixel / neightbor splatting positions along a path.
    // TODO: Bring the math from XYPathRenderer::at_subpixel(float alpha)
    // into a general purpose function.
    void rasterize(const vec2<u16> &pt, u8 value) {
        // Turn it into a Tile2x2_u8 tile and see if we can cache it.
        write(pt, value);
    }
 
    void setSize(u16 width, u16 height) {
        setBounds(rect<u16>(0, 0, width, height));
    }
 
    void setBounds(const rect<u16> &bounds) {
        mAbsoluteBounds = bounds;
        mAbsoluteBoundsSet = true;
    }
 
    using iterator = fl::unordered_map<vec2<u16>, u8>::iterator;
    using const_iterator = fl::unordered_map<vec2<u16>, u8>::const_iterator;
 
    iterator begin() { return mSparseGrid.begin(); }
    const_iterator begin() const { return mSparseGrid.begin(); }
    iterator end() { return mSparseGrid.end(); }
    const_iterator end() const { return mSparseGrid.end(); }
    fl::size size() const { return mSparseGrid.size(); }
    bool empty() const { return mSparseGrid.empty(); }
 
    void rasterize(const span<const Tile2x2_u8> &tiles);
    void rasterize(const Tile2x2_u8 &tile) { rasterize_internal(tile); }
 
    void rasterize_internal(const Tile2x2_u8 &tile,
                            const rect<u16> *optional_bounds = nullptr);
 
    // Renders the subpixel tiles to the raster. Any previous data is
    // cleared. Memory will only be allocated if the size of the raster
    // increased. void rasterize(const span<const Tile2x2_u8> &tiles);
    // u8 &at(u16 x, u16 y) { return mGrid.at(x, y); }
    // const u8 &at(u16 x, u16 y) const { return mGrid.at(x,
    // y); }
 
    pair<bool, u8> at(u16 x, u16 y) const {
        const u8 *val = mSparseGrid.find_value(vec2<u16>(x, y));
        if (val != nullptr) {
            return {true, *val};
        }
        return {false, 0};
    }
 
    rect<u16> bounds() const {
        if (mAbsoluteBoundsSet) {
            return mAbsoluteBounds;
        }
        return bounds_pixels();
    }
 
    rect<u16> bounds_pixels() const {
        u16 min_x = 0;
        bool min_x_set = false;
        u16 min_y = 0;
        bool min_y_set = false;
        u16 max_x = 0;
        bool max_x_set = false;
        u16 max_y = 0;
        bool max_y_set = false;
        for (const auto &it : mSparseGrid) {
            const vec2<u16> &pt = it.first;
            if (!min_x_set || pt.x < min_x) {
                min_x = pt.x;
                min_x_set = true;
            }
            if (!min_y_set || pt.y < min_y) {
                min_y = pt.y;
                min_y_set = true;
            }
            if (!max_x_set || pt.x > max_x) {
                max_x = pt.x;
                max_x_set = true;
            }
            if (!max_y_set || pt.y > max_y) {
                max_y = pt.y;
                max_y_set = true;
            }
        }
        return rect<u16>(min_x, min_y, max_x + 1, max_y + 1);
    }
 
    // Warning! - SLOW.
    u16 width() const { return bounds().width(); }
    u16 height() const { return bounds().height(); }
 
    void draw(const CRGB &color, const XYMap &xymap, fl::span<CRGB> out);
    void draw(const CRGB &color, Leds *leds);
 
    void drawGradient(const Gradient &gradient, const XYMap &xymap, fl::span<CRGB> out);
    void drawGradient(const Gradient &gradient, Leds *leds);
 
    // Inlined, yet customizable drawing access. This will only send you
    // pixels that are within the bounds of the XYMap.
    template <typename XYVisitor>
    void draw(const XYMap &xymap, XYVisitor &visitor) {
        for (const auto &it : mSparseGrid) {
            auto pt = it.first;
            if (!xymap.has(pt.x, pt.y)) {
                continue;
            }
            u32 index = xymap(pt.x, pt.y);
            u8 value = it.second;
            if (value > 0) { // Something wrote here.
                visitor.draw(pt, index, value);
            }
        }
    }
 
    static const int kMaxCacheSize = 8; // Max size for tiny cache.
 
    void write(const vec2<u16> &pt, u8 value) {
        // FL_WARN("write: " << pt.x << "," << pt.y << " value: " <<
        // value); mSparseGrid.insert(pt, value);
 
        u8 **cached = mCache.find_value(pt);
        if (cached) {
            u8 *val = *cached;
            if (*val < value) {
                *val = value;
            }
            return;
        }
        if (mCache.size() <= kMaxCacheSize) {
            // cache it.
            u8 *v = mSparseGrid.find_value(pt);
            if (v == nullptr) {
                // FL_WARN("write: " << pt.x << "," << pt.y << " value: "
                // << value);
                if (mSparseGrid.needs_rehash()) {
                    // mSparseGrid is about to rehash, so we need to clear the
                    // small cache because it shares pointers.
                    mCache.clear();
                }
 
                mSparseGrid.insert(pt, value);
                return;
            }
            mCache.insert(pt, v);
            if (*v < value) {
                *v = value;
            }
            return;
        } else {
            // overflow, clear cache and write directly.
            mCache.clear();
            mSparseGrid.insert(pt, value);
            return;
        }
    }
 
  private:
    using Key = vec2<u16>;
    using Value = u8;
    using HashKey = Hash<Key>;
    using EqualToKey = EqualTo<Key>;
    using FastHashKey = FastHash<Key>;
    using HashMapLarge = fl::unordered_map<Key, Value, HashKey, EqualToKey,
                                     FASTLED_HASHMAP_INLINED_COUNT>;
    HashMapLarge mSparseGrid;
    // Small cache for the last N writes to help performance.
    unordered_map<vec2<u16>, u8 *, FastHashKey, EqualToKey, kMaxCacheSize>
        mCache;
    fl::rect<u16> mAbsoluteBounds;
    bool mAbsoluteBoundsSet = false;
};
 
} // namespace fl
 
namespace fl {
 
// A raster of CRGB values. This is a sparse raster, meaning that it will
// only store the values that are set.
class XYRasterSparse_RGB8 {
  public:
    XYRasterSparse_RGB8() FL_NOEXCEPT = default;
    XYRasterSparse_RGB8(u16 width, u16 height) {
        setBounds(rect<u16>(0, 0, width, height));
    }
    XYRasterSparse_RGB8(const XYRasterSparse_RGB8 &) FL_NOEXCEPT = default;
    XYRasterSparse_RGB8 &operator=(XYRasterSparse_RGB8 &&) FL_NOEXCEPT = default;
    XYRasterSparse_RGB8(XYRasterSparse_RGB8 &&) FL_NOEXCEPT = default;
    XYRasterSparse_RGB8 &operator=(XYRasterSparse_RGB8 &) FL_NOEXCEPT = default;
 
    XYRasterSparse_RGB8 &reset() {
        mSparseGrid.clear();
        mCache.clear();
        return *this;
    }
 
    XYRasterSparse_RGB8 &clear() { return reset(); }
 
    // Rasterizes point with a CRGB color value
    void rasterize(const vec2<u16> &pt, const CRGB &color) {
        write(pt, color);
    }
 
    void setSize(u16 width, u16 height) {
        setBounds(rect<u16>(0, 0, width, height));
    }
 
    void setBounds(const rect<u16> &bounds) {
        mAbsoluteBounds = bounds;
        mAbsoluteBoundsSet = true;
    }
 
    using iterator = fl::unordered_map<vec2<u16>, CRGB>::iterator;
    using const_iterator = fl::unordered_map<vec2<u16>, CRGB>::const_iterator;
 
    iterator begin() { return mSparseGrid.begin(); }
    const_iterator begin() const { return mSparseGrid.begin(); }
    iterator end() { return mSparseGrid.end(); }
    const_iterator end() const { return mSparseGrid.end(); }
    fl::size size() const { return mSparseGrid.size(); }
    bool empty() const { return mSparseGrid.empty(); }
 
    pair<bool, CRGB> at(u16 x, u16 y) const {
        const CRGB *val = mSparseGrid.find_value(vec2<u16>(x, y));
        if (val != nullptr) {
            return {true, *val};
        }
        return {false, CRGB::Black};
    }
 
    rect<u16> bounds() const {
        if (mAbsoluteBoundsSet) {
            return mAbsoluteBounds;
        }
        return bounds_pixels();
    }
 
    rect<u16> bounds_pixels() const {
        u16 min_x = 0;
        bool min_x_set = false;
        u16 min_y = 0;
        bool min_y_set = false;
        u16 max_x = 0;
        bool max_x_set = false;
        u16 max_y = 0;
        bool max_y_set = false;
        for (const auto &it : mSparseGrid) {
            const vec2<u16> &pt = it.first;
            if (!min_x_set || pt.x < min_x) {
                min_x = pt.x;
                min_x_set = true;
            }
            if (!min_y_set || pt.y < min_y) {
                min_y = pt.y;
                min_y_set = true;
            }
            if (!max_x_set || pt.x > max_x) {
                max_x = pt.x;
                max_x_set = true;
            }
            if (!max_y_set || pt.y > max_y) {
                max_y = pt.y;
                max_y_set = true;
            }
        }
        return rect<u16>(min_x, min_y, max_x + 1, max_y + 1);
    }
 
    // Warning! - SLOW.
    u16 width() const { return bounds().width(); }
    u16 height() const { return bounds().height(); }
 
    void draw(const XYMap &xymap, fl::span<CRGB> out);
    void draw(Leds *leds);
 
    // Inlined, yet customizable drawing access. This will only send you
    // pixels that are within the bounds of the XYMap.
    template <typename XYVisitor>
    void draw(const XYMap &xymap, XYVisitor &visitor) {
        for (const auto &it : mSparseGrid) {
            auto pt = it.first;
            if (!xymap.has(pt.x, pt.y)) {
                continue;
            }
            u32 index = xymap(pt.x, pt.y);
            const CRGB &color = it.second;
            // Only draw non-black pixels (since black represents "no data")
            if (color.r != 0 || color.g != 0 || color.b != 0) {
                visitor.draw(pt, index, color);
            }
        }
    }
 
    static const int kMaxCacheSize = 8; // Max size for tiny cache.
 
    void write(const vec2<u16> &pt, const CRGB &color) {
        CRGB **cached = mCache.find_value(pt);
        if (cached) {
            CRGB *val = *cached;
            // For CRGB, we'll replace the existing color (blend could be added later)
            *val = color;
            return;
        }
        if (mCache.size() <= kMaxCacheSize) {
            // cache it.
            CRGB *v = mSparseGrid.find_value(pt);
            if (v == nullptr) {
                if (mSparseGrid.needs_rehash()) {
                    // mSparseGrid is about to rehash, so we need to clear the
                    // small cache because it shares pointers.
                    mCache.clear();
                }
                mSparseGrid.insert(pt, color);
                return;
            }
            mCache.insert(pt, v);
            *v = color;
            return;
        } else {
            // overflow, clear cache and write directly.
            mCache.clear();
            mSparseGrid.insert(pt, color);
            return;
        }
    }
 
  private:
    using Key = vec2<u16>;
    using Value = CRGB;
    using HashKey = Hash<Key>;
    using EqualToKey = EqualTo<Key>;
    using FastHashKey = FastHash<Key>;
    using HashMapLarge = fl::unordered_map<Key, Value, HashKey, EqualToKey,
                                     FASTLED_HASHMAP_INLINED_COUNT>;
    HashMapLarge mSparseGrid;
    // Small cache for the last N writes to help performance.
    unordered_map<vec2<u16>, CRGB *, FastHashKey, EqualToKey, kMaxCacheSize>
        mCache;
    fl::rect<u16> mAbsoluteBounds;
    bool mAbsoluteBoundsSet = false;
};
 
// Backwards compatibility typedef
using XYRasterSparse_CRGB = XYRasterSparse_RGB8;
 
} // namespace fl