add text buffer code

1 files changed, 33 insertions, 0 deletions

diff --git a/src/geometry/text_buffer.cpp b/src/geometry/text_buffer.cpp
new file mode 100644
index 0000000000..92580cdc32
--- /dev/null
+++ b/src/geometry/text_buffer.cpp
@@ -0,0 +1,33 @@
+#include <llmr/geometry/text_buffer.hpp>
+#include <llmr/platform/gl.hpp>
+#include <llmr/util/math.hpp>
+
+#include <cmath>
+
+using namespace llmr;
+
+const double TextVertexBuffer::angleFactor = 128 / M_PI;
+
+
+size_t TextVertexBuffer::add(const GlyphPosition& pos) {
+    size_t idx = index();
+    void *data = addElement();
+
+    int16_t *shorts = static_cast<int16_t *>(data);
+    shorts[0] = pos.x;
+    shorts[1] = pos.y;
+    shorts[2] = round(pos.ox * 64); // use 1/64 pixels for placement
+    shorts[3] = round(pos.oy * 64);
+
+    uint8_t *ubytes = static_cast<uint8_t *>(data);
+    ubytes[8] = pos.tx / 4;
+    ubytes[9] = pos.ty / 4;
+    ubytes[10] = pos.labelminzoom * 10;
+    ubytes[11] = pos.minzoom * 10; // 1/10 zoom levels: z16 == 160.
+    ubytes[12] = fmin(pos.maxzoom, 25) * 10; // 1/10 zoom levels: z16 == 160.
+    ubytes[13] = (int16_t)round(pos.angle * angleFactor) % 256;
+    ubytes[14] = util::max((int16_t)round(pos.rangefrom * angleFactor), (int16_t)0) % 256;
+    ubytes[15] = util::min((int16_t)round(pos.rangeto * angleFactor), (int16_t)255) % 256;
+
+    return idx;
+}