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#include <mbgl/geometry/glyph_atlas.hpp>
#include <mbgl/map/vector_tile.hpp>
#include <mbgl/platform/gl.hpp>
#include <mbgl/platform/platform.hpp>
#include <cassert>
#include <algorithm>
using namespace mbgl;
GlyphAtlas::GlyphAtlas(uint16_t width, uint16_t height)
: width(width),
height(height),
bin(width, height),
data(new char[width *height]),
dirty(true) {
}
GlyphAtlas::~GlyphAtlas() {
delete[] data;
}
Rect<uint16_t> GlyphAtlas::addGlyph(uint64_t tile_id, const std::string& face_name,
const SDFGlyph& glyph) {
std::lock_guard<std::mutex> lock(mtx);
// Use constant value for now.
const uint8_t buffer = 3;
std::map<uint32_t, GlyphValue>& face = index[face_name];
std::map<uint32_t, GlyphValue>::iterator it = face.find(glyph.id);
// The glyph is already in this texture.
if (it != face.end()) {
GlyphValue& value = it->second;
value.ids.insert(tile_id);
return value.rect;
}
// The glyph bitmap has zero width.
if (!glyph.bitmap.size()) {
return Rect<uint16_t>{ 0, 0, 0, 0 };
}
uint16_t buffered_width = glyph.metrics.width + buffer * 2;
uint16_t buffered_height = glyph.metrics.height + buffer * 2;
// Add a 1px border around every image.
uint16_t pack_width = buffered_width;
uint16_t pack_height = buffered_height;
// Increase to next number divisible by 4, but at least 1.
// This is so we can scale down the texture coordinates and pack them
// into 2 bytes rather than 4 bytes.
pack_width += (4 - pack_width % 4);
pack_height += (4 - pack_height % 4);
Rect<uint16_t> rect = bin.allocate(pack_width, pack_height);
if (rect.w == 0) {
fprintf(stderr, "glyph bitmap overflow");
return rect;
}
assert(rect.x + rect.w <= width);
assert(rect.y + rect.h <= height);
face.emplace(glyph.id, GlyphValue { rect, tile_id });
// Copy the bitmap
char *target = data;
const char *source = glyph.bitmap.data();
for (uint32_t y = 0; y < buffered_height; y++) {
uint32_t y1 = width * (rect.y + y) + rect.x;
uint32_t y2 = buffered_width * y;
for (uint32_t x = 0; x < buffered_width; x++) {
target[y1 + x] = source[y2 + x];
}
}
dirty = true;
return rect;
}
void GlyphAtlas::removeGlyphs(uint64_t tile_id) {
std::lock_guard<std::mutex> lock(mtx);
for (auto& faces : index) {
std::map<uint32_t, GlyphValue>& face = faces.second;
for (auto it = face.begin(); it != face.end(); /* we advance in the body */) {
GlyphValue& value = it->second;
value.ids.erase(tile_id);
if (!value.ids.size()) {
const Rect<uint16_t>& rect = value.rect;
// Clear out the bitmap.
char *target = data;
for (uint32_t y = 0; y < rect.h; y++) {
uint32_t y1 = width * (rect.y + y) + rect.x;
for (uint32_t x = 0; x < rect.w; x++) {
target[y1 + x] = 0;
}
}
dirty = true;
bin.release(rect);
// Make sure to post-increment the iterator: This will return the
// current iterator, but will go to the next position before we
// erase the element from the map. That way, the iterator stays
// valid.
face.erase(it++);
} else {
++it;
}
}
}
}
void GlyphAtlas::bind() {
if (!texture) {
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
} else {
glBindTexture(GL_TEXTURE_2D, texture);
}
if (dirty) {
std::lock_guard<std::mutex> lock(mtx);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, data);
dirty = false;
#if defined(DEBUG)
// platform::show_debug_image("Glyph Atlas", data, width, height);
#endif
}
};
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