mirror of https://github.com/minetest/minetest.git
Merge 2fdf26a1ba into b23042839b
This commit is contained in:
DS
GitHub
commit
8402855ae5
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@ -17,11 +17,13 @@ with this program; if not, write to the Free Software Foundation, Inc.,
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*/
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#include "imagefilters.h"
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#include "debug.h"
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#include "util/numeric.h"
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#include <cmath>
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#include <cassert>
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#include <vector>
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#include <algorithm>
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#include <array>
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// Simple 2D bitmap class with just the functionality needed here
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class Bitmap {
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@ -132,6 +134,7 @@ static void imageCleanTransparentWithInlining(video::IImage *src, u32 threshold)
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// Add RGB values weighted by alpha IF the pixel is opaque, otherwise
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// use full weight since we want to propagate colors.
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// FIXME: But why are we weighting them more than opaque pixels?
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video::SColor d = get_pixel(sx, sy);
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u32 a = d.getAlpha() <= threshold ? 255 : d.getAlpha();
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ss += a;
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@ -161,6 +164,364 @@ static void imageCleanTransparentWithInlining(video::IImage *src, u32 threshold)
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}
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}
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static void imageCleanTransparentNew(video::IImage *src, u32 threshold)
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{
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// with threshold = 127, the average of the whole texture is far too dominant
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threshold = 0; //TODO
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using ImgLvl = std::pair<u32 *, core::dimension2d<u32>>;
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sanity_check(src->getColorFormat() == video::ECF_A8R8G8B8);
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// Early return if no alpha < threshold
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{
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const core::dimension2d<u32> dim = src->getDimension();
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u32 *const data = reinterpret_cast<u32 *>(src->getData());
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bool has_transparent = false;
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for (u32 idx = 0; idx < dim.Width * dim.Height; ++idx) {
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if (video::SColor(data[idx]).getAlpha() <= threshold) {
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has_transparent = true;
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break;
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}
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}
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if (!has_transparent)
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return;
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}
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// Step 0: Allocate images
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// levels[i+1] is 2 times smaller than levels[i], rounded up
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std::vector<std::unique_ptr<u32[]>> level_ups;
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std::vector<ImgLvl> levels;
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{
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core::dimension2d<u32> dim = src->getDimension();
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levels.emplace_back(reinterpret_cast<u32 *>(src->getData()), dim);
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while (dim.Width > 1 || dim.Height > 1) {
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dim.Width = (dim.Width + 1) / 2;
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dim.Height = (dim.Height + 1) / 2;
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auto data = std::unique_ptr<u32[]>(new u32[dim.Width * dim.Height]);
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levels.emplace_back(data.get(), dim);
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level_ups.push_back(std::move(data));
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}
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}
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if (levels.size() <= 1) {
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// just one pixel. can't do anything
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return;
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}
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// Step 1: Scale down
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auto mix4cols = [](std::array<video::SColor, 4> colors) -> video::SColor {
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u32 sr = 0, sg = 0, sb = 0, sa = 0;
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auto add_color = [&](video::SColor c) {
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u32 alph = c.getAlpha();
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sr += alph * c.getRed();
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sg += alph * c.getGreen();
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sb += alph * c.getBlue();
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sa += alph;
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};
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for (auto c : colors)
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add_color(c);
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if (sa == 0)
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return 0;
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//~ if (sa == 255 * 4) { // common case
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//~ sr = 0, sg = 0, sb = 0;
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//~ for (auto c : colors) {
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//~ sr += c.getRed();
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//~ sg += c.getGreen();
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//~ sb += c.getBlue();
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//~ }
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//~ sr /= 4;
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//~ sg /= 4;
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//~ sb /= 4;
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//~ return video::SColor(255, sr, sg, sb);
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//~ }
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//~ u64 d = (1 << 16) / sa;
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//~ sr = (sr * d) >> 16;
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//~ sg = (sg * d) >> 16;
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//~ sb = (sb * d) >> 16;
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//~ sa = ((sa + 1) * d) >> 16;
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sr /= sa;
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sg /= sa;
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sb /= sa;
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sa = (sa + 1) / 4; // +1 for better rounding // TODO: maybe always round up, to make sure colors are preserved? (+3)
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return video::SColor(sa, sr, sg, sb);
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};
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for (size_t lvl = 0; lvl + 1 < levels.size(); ++lvl) {
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u32 *const data_large = levels[lvl].first;
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u32 *const data_small = levels[lvl+1].first;
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const core::dimension2d<u32> dim_large = levels[lvl].second;
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const core::dimension2d<u32> dim_small = levels[lvl+1].second;
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// round dim_large down. odd rows and columns are handled separately
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u32 idx_small = 0;
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u32 idx_large = 0; // index of upper left pixel in large image
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u32 y_small;
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for (y_small = 0; y_small < dim_large.Height / 2; ++y_small) {
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u32 x_small;
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for (x_small = 0; x_small < dim_large.Width / 2; ++x_small) {
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assert(idx_small == y_small * dim_small.Width + x_small);
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assert(idx_large == y_small * 2 * dim_large.Width + x_small * 2);
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data_small[idx_small] = mix4cols({
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data_large[idx_large],
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data_large[idx_large + 1],
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data_large[idx_large + dim_large.Width],
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data_large[idx_large + dim_large.Width + 1],
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}).color;
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idx_small += 1;
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idx_large += 2;
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}
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// odd column
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if (x_small != dim_small.Width) {
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assert(idx_small == y_small * dim_small.Width + x_small);
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assert(idx_large == y_small * 2 * dim_large.Width + x_small * 2);
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data_small[idx_small] = mix4cols({
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data_large[idx_large],
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0,
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data_large[idx_large + dim_large.Width],
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0,
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}).color;
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idx_small += 1;
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idx_large += 1;
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}
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idx_large += dim_large.Width;
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}
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// odd row
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if (y_small != dim_small.Height) {
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u32 x_small;
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for (x_small = 0; x_small < dim_large.Width / 2; ++x_small) {
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assert(idx_small == y_small * dim_small.Width + x_small);
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assert(idx_large == y_small * 2 * dim_large.Width + x_small * 2);
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data_small[idx_small] = mix4cols({
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data_large[idx_large],
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data_large[idx_large + 1],
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0,
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0,
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}).color;
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idx_small += 1;
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idx_large += 2;
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}
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// odd column (corner pixel)
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if (x_small != dim_small.Width) {
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assert(idx_small == y_small * dim_small.Width + x_small);
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assert(idx_large == y_small * 2 * dim_large.Width + x_small * 2);
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//~ data_small[idx_small] = data_large[idx_large];
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data_small[idx_small] = mix4cols({
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data_large[idx_large],
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0,
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0,
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0,
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}).color;
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idx_small += 1;
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idx_large += 1;
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}
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}
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}
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// Step 2: Propagate back
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// If a pixel's alpha is < threshold, we sample the smaller level with bilinear
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// interpolation.
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for (int lvl = levels.size() - 2; lvl >= 0; --lvl) {
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u32 *const data_large = levels[lvl].first;
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u32 *const data_small = levels[lvl+1].first;
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const core::dimension2d<u32> dim_large = levels[lvl].second;
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const core::dimension2d<u32> dim_small = levels[lvl+1].second;
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bool even_width = !(dim_large.Width & 1);
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bool even_height = !(dim_large.Height & 1);
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// c0 is near, c1 middle-far
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auto bilinear_filter_2 = [](video::SColor c0, video::SColor c1) -> video::SColor {
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u8 r = std::min<u32>(255, (c0.getRed() * 3 + c1.getRed() + 1) / 4);
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u8 g = std::min<u32>(255, (c0.getGreen() * 3 + c1.getGreen() + 1) / 4);
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u8 b = std::min<u32>(255, (c0.getBlue() * 3 + c1.getBlue() + 1) / 4);
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u8 a = std::min<u32>(255, (c0.getAlpha() * 3 + c1.getAlpha() + 1) / 4);
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return video::SColor(a, r, g, b);
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//~ return c0;
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};
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// c0 is near, c1 and c2 middle-far, c3 far
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// we sample in the quarter of c0:
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// +----+----+
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// | | |
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// | c0 | c1 |
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// | x| |
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// +----+----+
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// | | |
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// | c2 | c3 |
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// | | |
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// +----+----+
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auto bilinear_filter_4 = [](video::SColor c0, video::SColor c1,
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video::SColor c2, video::SColor c3) -> video::SColor {
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//~ return c0 * 0.75 * 0.75 + (c1 + c2) * 0.25 * 0.75 + c3 * 0.25 * 0.25;
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u8 r = std::min<u32>(255, (c0.getRed() * 3 * 3 + (c1.getRed() + c2.getRed()) * 1 * 3 + c3.getRed() * 1 * 1 + 7) / 16);
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u8 g = std::min<u32>(255, (c0.getGreen() * 3 * 3 + (c1.getGreen() + c2.getGreen()) * 1 * 3 + c3.getGreen() * 1 * 1 + 7) / 16);
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u8 b = std::min<u32>(255, (c0.getBlue() * 3 * 3 + (c1.getBlue() + c2.getBlue()) * 1 * 3 + c3.getBlue() * 1 * 1 + 7) / 16);
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u8 a = std::min<u32>(255, (c0.getAlpha() * 3 * 3 + (c1.getAlpha() + c2.getAlpha()) * 1 * 3 + c3.getAlpha() * 1 * 1 + 7) / 16);
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return video::SColor(a, r, g, b);
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//~ return c0;
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};
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// Corners
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auto handle_pixel_from_1 = [&](u32 idx_large, u32 idx_small) {
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u8 alpha = video::SColor(data_large[idx_large]).getAlpha();
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if (alpha <= threshold) {
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video::SColor col = data_small[idx_small];
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col.setAlpha(alpha);
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data_large[idx_large] = col.color;
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}
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};
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handle_pixel_from_1(0, 0); // (0,0)
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if (even_width)
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handle_pixel_from_1(dim_large.Width - 1, dim_small.Width - 1); // (b,0)
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if (even_height)
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handle_pixel_from_1(dim_large.Width * (dim_large.Height - 1),
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dim_small.Width * (dim_small.Height - 1)); // (0,b)
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if (even_height && even_width)
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handle_pixel_from_1(dim_large.Width * dim_large.Height - 1,
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dim_small.Width * dim_small.Height - 1); // (b,b)
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// Borders (without corners)
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auto handle_pixel_from_2 = [&](u32 idx_large, u32 idx_small_0, u32 idx_small_1) {
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u8 alpha = video::SColor(data_large[idx_large]).getAlpha();
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if (alpha <= threshold) {
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video::SColor col = bilinear_filter_2(data_small[idx_small_0],
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data_small[idx_small_1]);
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col.setAlpha(alpha);
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data_large[idx_large] = col.color;
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}
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};
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// top row
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{
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u32 idx_large = 1; // (1,0)
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u32 idx_small = 0; // (0,0)
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for (u32 x_small = 0; x_small + 1 < dim_small.Width; ++x_small) {
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// left pixel
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handle_pixel_from_2(idx_large, idx_small, idx_small + 1);
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idx_large += 1;
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// right pixel
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handle_pixel_from_2(idx_large, idx_small + 1, idx_small);
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idx_large += 1;
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idx_small += 1;
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}
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}
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// bottom row
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if (even_height) {
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u32 idx_large = dim_large.Width * (dim_large.Height - 1) + 1; // (1,b)
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u32 idx_small = dim_small.Width * (dim_small.Height - 1); // (0,b)
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for (u32 x_small = 0; x_small + 1 < dim_small.Width; ++x_small) {
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// left pixel
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handle_pixel_from_2(idx_large, idx_small, idx_small + 1);
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idx_large += 1;
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// right pixel
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handle_pixel_from_2(idx_large, idx_small + 1, idx_small);
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idx_large += 1;
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idx_small += 1;
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}
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}
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// left column
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{
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u32 idx_large = dim_large.Width; // (0,1)
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u32 idx_small = 0; // (0,0)
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for (u32 y_small = 0; y_small + 1 < dim_small.Height; ++y_small) {
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// left pixel
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handle_pixel_from_2(idx_large, idx_small, idx_small + dim_small.Width);
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idx_large += dim_large.Width;
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// right pixel
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handle_pixel_from_2(idx_large, idx_small + dim_small.Width, idx_small);
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idx_large += dim_large.Width;
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idx_small += dim_small.Width;
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}
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}
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// right column
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if (even_width) {
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u32 idx_large = dim_large.Width * 2 - 1; // (b,1)
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u32 idx_small = dim_small.Width - 1; // (b,0)
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for (u32 y_small = 0; y_small + 1 < dim_small.Height; ++y_small) {
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// left pixel
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handle_pixel_from_2(idx_large, idx_small, idx_small + dim_small.Width);
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idx_large += dim_large.Width;
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// right pixel
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handle_pixel_from_2(idx_large, idx_small + dim_small.Width, idx_small);
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idx_large += dim_large.Width;
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idx_small += dim_small.Width;
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}
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}
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// Inner pixels
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auto handle_pixel_from_4 = [&](u32 idx_large, u32 idx_small_0, u32 idx_small_1,
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u32 idx_small_2, u32 idx_small_3) {
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u8 alpha = video::SColor(data_large[idx_large]).getAlpha();
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if (alpha <= threshold) {
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video::SColor col = bilinear_filter_4(data_small[idx_small_0],
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data_small[idx_small_1], data_small[idx_small_2],
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data_small[idx_small_3]);
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col.setAlpha(alpha);
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data_large[idx_large] = col.color;
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}
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};
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{
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//~ u32 idx_large = dim_large.Width + 1; // (1,1)
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u32 idx_small = 0; // (0,0)
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for (u32 y_small = 0; y_small + 1 < dim_small.Height; ++y_small) {
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u32 idx_large = (y_small * 2 + 1) * dim_large.Width + 1; // (1,y)
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for (u32 x_small = 0; x_small + 1 < dim_small.Width; ++x_small) {
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assert(idx_small == y_small * dim_small.Width + x_small);
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// left up
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handle_pixel_from_4(idx_large,
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idx_small,
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idx_small + 1,
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idx_small + dim_small.Width,
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idx_small + dim_small.Width + 1
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);
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// right up
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handle_pixel_from_4(idx_large + 1,
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idx_small + 1,
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idx_small,
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idx_small + dim_small.Width + 1,
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idx_small + dim_small.Width
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);
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// left down
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handle_pixel_from_4(idx_large + dim_large.Width,
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idx_small + dim_small.Width,
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idx_small + dim_small.Width + 1,
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idx_small,
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idx_small + 1
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);
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// right down
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handle_pixel_from_4(idx_large + dim_large.Width + 1,
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idx_small + dim_small.Width + 1,
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idx_small + dim_small.Width,
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idx_small + 1,
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idx_small
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);
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idx_small += 1;
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idx_large += 2;
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}
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idx_large += dim_large.Width;
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idx_small += 1;
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}
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}
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}
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}
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/* Fill in RGB values for transparent pixels, to correct for odd colors
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* appearing at borders when blending. This is because many PNG optimizers
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* like to discard RGB values of transparent pixels, but when blending then
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@ -171,11 +532,13 @@ static void imageCleanTransparentWithInlining(video::IImage *src, u32 threshold)
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* Parameter "threshold" is the alpha level below which pixels are considered
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* transparent. Should be 127 when the texture is used with ALPHA_CHANNEL_REF,
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* 0 when alpha blending is used.
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* FIXME: Why threshold? PNG optimizers only do their stuff if alpha = 0.
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*/
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void imageCleanTransparent(video::IImage *src, u32 threshold)
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{
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if (src->getColorFormat() == video::ECF_A8R8G8B8)
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imageCleanTransparentWithInlining<true>(src, threshold);
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//~ imageCleanTransparentWithInlining<true>(src, threshold);
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imageCleanTransparentNew(src, threshold);
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else
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imageCleanTransparentWithInlining<false>(src, threshold);
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}
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