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#include <mbgl/geometry/line_atlas.hpp>
#include <mbgl/gl/gl.hpp>
#include <mbgl/gl/gl_object_store.hpp>
#include <mbgl/platform/log.hpp>
#include <mbgl/platform/platform.hpp>
#include <mbgl/util/thread_context.hpp>
#include <boost/functional/hash.hpp>
#include <sstream>
#include <cmath>
using namespace mbgl;
LineAtlas::LineAtlas(GLsizei w, GLsizei h)
: width(w),
height(h),
data(std::make_unique<GLbyte[]>(w * h)),
dirty(true) {
}
LineAtlas::~LineAtlas() {
assert(util::ThreadContext::currentlyOn(util::ThreadType::Map));
}
LinePatternPos LineAtlas::getDashPosition(const std::vector<float> &dasharray, bool round, gl::GLObjectStore& glObjectStore) {
assert(util::ThreadContext::currentlyOn(util::ThreadType::Map));
size_t key = round ? std::numeric_limits<size_t>::min() : std::numeric_limits<size_t>::max();
for (const float part : dasharray) {
boost::hash_combine<float>(key, part);
}
// Note: We're not handling hash collisions here.
const auto it = positions.find(key);
if (it == positions.end()) {
auto inserted = positions.emplace(key, addDash(dasharray, round, glObjectStore));
assert(inserted.second);
return inserted.first->second;
} else {
return it->second;
}
}
LinePatternPos LineAtlas::addDash(const std::vector<float> &dasharray, bool round, gl::GLObjectStore& glObjectStore) {
int n = round ? 7 : 0;
int dashheight = 2 * n + 1;
const uint8_t offset = 128;
if (nextRow + dashheight > height) {
Log::Warning(Event::OpenGL, "line atlas bitmap overflow");
return LinePatternPos();
}
float length = 0;
for (const float part : dasharray) {
length += part;
}
float stretch = width / length;
float halfWidth = stretch * 0.5;
// If dasharray has an odd length, both the first and last parts
// are dashes and should be joined seamlessly.
bool oddLength = dasharray.size() % 2 == 1;
for (int y = -n; y <= n; y++) {
int row = nextRow + n + y;
int index = width * row;
float left = 0;
float right = dasharray[0];
unsigned int partIndex = 1;
if (oddLength) {
left -= dasharray.back();
}
for (int x = 0; x < width; x++) {
while (right < x / stretch) {
left = right;
right = right + dasharray[partIndex];
if (oddLength && partIndex == dasharray.size() - 1) {
right += dasharray.front();
}
partIndex++;
}
float distLeft = fabs(x - left * stretch);
float distRight = fabs(x - right * stretch);
float dist = fmin(distLeft, distRight);
bool inside = (partIndex % 2) == 1;
int signedDistance;
if (round) {
float distMiddle = n ? (float)y / n * (halfWidth + 1) : 0;
if (inside) {
float distEdge = halfWidth - fabs(distMiddle);
signedDistance = sqrt(dist * dist + distEdge * distEdge);
} else {
signedDistance = halfWidth - sqrt(dist * dist + distMiddle * distMiddle);
}
} else {
signedDistance = int((inside ? 1 : -1) * dist);
}
data[index + x] = fmax(0, fmin(255, signedDistance + offset));
}
}
LinePatternPos position;
position.y = (0.5 + nextRow + n) / height;
position.height = (2.0 * n) / height;
position.width = length;
nextRow += dashheight;
dirty = true;
bind(glObjectStore);
return position;
};
void LineAtlas::upload(gl::GLObjectStore& glObjectStore) {
if (dirty) {
bind(glObjectStore);
}
}
void LineAtlas::bind(gl::GLObjectStore& glObjectStore) {
assert(util::ThreadContext::currentlyOn(util::ThreadType::Map));
bool first = false;
if (!texture) {
texture.create(glObjectStore);
MBGL_CHECK_ERROR(glBindTexture(GL_TEXTURE_2D, texture.getID()));
MBGL_CHECK_ERROR(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
MBGL_CHECK_ERROR(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
MBGL_CHECK_ERROR(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT));
MBGL_CHECK_ERROR(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
first = true;
} else {
MBGL_CHECK_ERROR(glBindTexture(GL_TEXTURE_2D, texture.getID()));
}
if (dirty) {
if (first) {
MBGL_CHECK_ERROR(glTexImage2D(
GL_TEXTURE_2D, // GLenum target
0, // GLint level
GL_ALPHA, // GLint internalformat
width, // GLsizei width
height, // GLsizei height
0, // GLint border
GL_ALPHA, // GLenum format
GL_UNSIGNED_BYTE, // GLenum type
data.get() // const GLvoid * data
));
} else {
MBGL_CHECK_ERROR(glTexSubImage2D(
GL_TEXTURE_2D, // GLenum target
0, // GLint level
0, // GLint xoffset
0, // GLint yoffset
width, // GLsizei width
height, // GLsizei height
GL_ALPHA, // GLenum format
GL_UNSIGNED_BYTE, // GLenum type
data.get() // const GLvoid *pixels
));
}
dirty = false;
}
};
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