something something triangles

src/c3nav/mapdata/render/engines/base.py

@@ -53,6 +53,10 @@ class RenderEngine(ABC):
         # render the image to png.
         pass
 
+    @staticmethod
+    def hex_to_rgb(hexcolor):
+        return tuple(int(hexcolor[i:i + 2], 16)/255 for i in range(1, 6, 2))
+
     def clip_altitudes(self, new_geometry, new_altitude=None):
         # register new geometry with an altitude
         # a geometry with no altitude will reset the altitude information of its area as if nothing was ever there

src/c3nav/mapdata/render/engines/opengl.py

@@ -1,10 +1,15 @@
 import io
+from collections import deque
+from typing import Union
 
 import ModernGL
 import numpy as np
 from PIL import Image
+from shapely.geometry import MultiPolygon, Polygon
+from trimesh.creation import triangulate_polygon
 
 from c3nav.mapdata.render.engines.base import RenderEngine
+from c3nav.mapdata.utils.geometry import assert_multipolygon
 
 
 class OpenGLEngine(RenderEngine):
@@ -15,8 +20,7 @@ class OpenGLEngine(RenderEngine):
         self.ctx = ModernGL.create_standalone_context()
 
         self.color_rbo = self.ctx.renderbuffer((self.width, self.height))
-        self.depth_rbo = self.ctx.depth_renderbuffer((self.width, self.height))
-        self.fbo = self.ctx.framebuffer([self.color_rbo], self.depth_rbo)
+        self.fbo = self.ctx.framebuffer([self.color_rbo])
         self.fbo.use()
 
         self.ctx.clear(*(i/255 for i in self.background_rgb))
@@ -42,12 +46,36 @@ class OpenGLEngine(RenderEngine):
             '''),
         ])
 
+        scale_x = self.scale / self.width * 2
+        scale_y = self.scale / self.height * 2
+
+        self.np_scale = np.array((scale_x, -scale_y))
+        self.np_offset = np.array((-self.minx * scale_x - 1, self.maxy * scale_y - 1))
+
+    def _create_geometry(self, geometry: Union[Polygon, MultiPolygon], append=None):
+        triangles = deque()
+
+        for i, polygon in enumerate(assert_multipolygon(geometry)):
+            vertices, faces = triangulate_polygon(polygon)
+            triangles.append(vertices[faces.flatten()])
+
+        vertices = np.vstack(triangles).astype(np.float32)
+        vertices = vertices * self.np_scale + self.np_offset
+        if append is not None:
+            append = np.array(append, dtype=np.float32).flatten()
+            vertices = np.hstack((
+                vertices,
+                append.reshape(1, append.size).repeat(vertices.shape[0], 0)
+            ))
+        return vertices.flatten()
+
     def _add_geometry(self, geometry, fill=None, stroke=None, altitude=None, height=None, shape_cache_key=None):
-        pass
+        if fill is not None:
+            self.vertices.append(self._create_geometry(geometry, self.hex_to_rgb(fill.color)))
 
     def get_png(self) -> bytes:
         if self.vertices:
-            vbo = self.ctx.buffer(np.hstack(self.vertices).tobytes())
+            vbo = self.ctx.buffer(np.hstack(self.vertices).astype(np.float32).tobytes())
 
             # We control the 'in_vert' and `in_color' variables
             vao = self.ctx.simple_vertex_array(self.prog, vbo, ['in_vert', 'in_color'])

src/requirements/opengl.txt

@@ -0,0 +1 @@
+ModernGL>=4.2,<4.3

src/requirements/production.txt

@@ -5,6 +5,7 @@ csscompressor
 djangorestframework>=3.6,<3.7
 django-filter>=1.0,<1.1
 shapely>=1.5,<1.6
+trimesh>=2.20,<2.21
 rtree>=0.8,<0.9
 celery>=4.0,<4.1
 requests>=2.17,<2.18