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#pragma once
#include <mbgl/algorithm/generate_clip_ids.hpp>
#include <mbgl/math/log2.hpp>
#include <mbgl/platform/log.hpp>
namespace mbgl {
namespace algorithm {
template <typename Renderables>
void ClipIDGenerator::update(Renderables& renderables) {
std::size_t size = 0;
const auto end = renderables.end();
for (auto it = renderables.begin(); it != end; it++) {
auto& tileID = it->first;
auto& renderable = it->second;
if (!renderable.used) {
continue;
}
renderable.clip = {};
Leaf leaf{ renderable.clip };
// Try to add all remaining ids as children. We sorted the tile list
// by z earlier, so all preceding items cannot be children of the current
// tile. We also compute the lower bound of the next wrap, because items of the next wrap
// can never be children of the current wrap.
auto child_it = std::next(it);
const auto children_end = std::lower_bound(
child_it, end, UnwrappedTileID{ static_cast<int16_t>(tileID.wrap + 1), { 0, 0, 0 } },
[](auto& a, auto& b) { return a.first < b; });
for (; child_it != children_end; ++child_it) {
auto& childTileID = child_it->first;
if (childTileID.isChildOf(tileID)) {
leaf.add(childTileID.canonical);
}
}
// Find a leaf with matching children.
for (auto its = pool.equal_range(tileID); its.first != its.second; ++its.first) {
auto& existing = its.first->second;
if (existing == leaf) {
leaf.clip = existing.clip;
break;
}
}
if (leaf.clip.reference.none()) {
// We haven't found an existing clip ID
size++;
}
pool.emplace(tileID, std::move(leaf));
}
if (size > 0) {
const uint32_t bit_count = util::ceil_log2(size + 1);
const std::bitset<8> mask = uint64_t(((1ul << bit_count) - 1) << bit_offset);
// We are starting our count with 1 since we need at least 1 bit set to distinguish between
// areas without any tiles whatsoever and the current area.
uint8_t count = 1;
for (auto& pair : renderables) {
auto& renderable = pair.second;
if (!renderable.used) {
continue;
}
renderable.clip.mask |= mask;
// Assign only to clip IDs that have no value yet.
if (renderable.clip.reference.none()) {
renderable.clip.reference = uint32_t(count++) << bit_offset;
}
}
bit_offset += bit_count;
}
if (bit_offset > 8) {
Log::Error(Event::OpenGL, "stencil mask overflow");
}
}
} // namespace algorithm
} // namespace mbgl
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