Drawing Maps with OpenGL
summary
Mapbox releases GPU renderers: mapbox-gl-native (C++ for native) in summer and mapbox-gl-js on the web a month later, using WebGL. Lines are built from triangles (example: six triangles for a stroked segment) with outer quads and alpha interpolation for antialiasing to avoid GL_LINE limits (many devices cap width ~10px). Text uses signed distance fields from Valve instead of FreeType bitmaps with stepped thresholds (0–191 / 192–255) for crisp scaling and halos. Polygons use triangulation instead of slow stencil copies; blurs use offscreen render buffers; a headless Node rendering fallback is experimental.
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chapters (17)
- 0:00Introduction
- 0:22What is OpenGL
- 1:50Primitives
- 2:07Geo Lines
- 2:37Triangles
- 3:58Text
- 4:23FreeType
- 4:33FreeType Overview
- 5:20Scientists and Fields
- 6:04TwoStep Interpolation
- 6:57Text in OpenGL
- 7:32Polygons
- 8:35Vitals
- 9:05Blurs
- 10:54Hardware Compatibility
- 19:00Editor
- 19:26Digital Globe
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