1 files changed, 33 insertions, 0 deletions
diff --git a/src/mbgl/geometry/text_buffer.cpp b/src/mbgl/geometry/text_buffer.cpp
new file mode 100644
index 0000000000..295ff02efa
--- /dev/null
+++ b/src/mbgl/geometry/text_buffer.cpp
@@ -0,0 +1,33 @@
+#include <mbgl/geometry/text_buffer.hpp>
+#include <mbgl/platform/gl.hpp>
+#include <mbgl/util/math.hpp>
+
+#include <cmath>
+
+using namespace mbgl;
+
+const double TextVertexBuffer::angleFactor = 128.0 / M_PI;
+
+size_t TextVertexBuffer::add(int16_t x, int16_t y, float ox, float oy, uint16_t tx, uint16_t ty, float angle, float minzoom, std::array<float, 2> range, float maxzoom, float labelminzoom) {
+    size_t idx = index();
+    void *data = addElement();
+
+    int16_t *shorts = static_cast<int16_t *>(data);
+    shorts[0] = x;
+    shorts[1] = y;
+    shorts[2] = std::round(ox * 64); // use 1/64 pixels for placement
+    shorts[3] = std::round(oy * 64);
+
+    uint8_t *ubytes = static_cast<uint8_t *>(data);
+    ubytes[8] = labelminzoom * 10;
+    ubytes[9] = minzoom * 10; // 1/10 zoom levels: z16 == 160.
+    ubytes[10] = fmin(maxzoom, 25) * 10; // 1/10 zoom levels: z16 == 160.
+    ubytes[11] = (int16_t)round(angle * angleFactor) % 256;
+    ubytes[12] = util::max((int16_t)std::round(range[0] * angleFactor), (int16_t)0) % 256;
+    ubytes[13] = util::min((int16_t)std::round(range[1] * angleFactor), (int16_t)255) % 256;
+
+    ubytes[14] = tx / 4;
+    ubytes[15] = ty / 4;
+
+    return idx;
+}