[core] Use gl::Program to resolve some rough edges in the GL binding types

* Extract `ignore` util to separate header.
* `Segment` now tracks offset and length of indices, rather than primitives. This is more natural.
* Introduce `VertexVector` and `IndexVector` types. These types carry information about the intended draw mode (`Triangles`, `LineStrip`, etc.), and ensure that elements are always appended in a group size appropriate for that draw mode, for both indexed and unindexed rendering.
* `Program`, rather than `Drawable`, is now the unifying object for draw calls. `Program` is the best place to type check the draw call, because it is typed to carry information about the intended primitive, vertex type, attributes, and uniforms.
* Use the debug shaders for debug tile rendering, like gl-js.
* Fix the draw mode for background. It was drawing triangle strips with a triangles array. Surprised this didn’t cause issues. Now it’s type checked.

1 files changed, 7 insertions, 8 deletions

diff --git a/src/mbgl/renderer/painter_line.cpp b/src/mbgl/renderer/painter_line.cpp
index 7f9556fd3f..a495edc428 100644
--- a/src/mbgl/renderer/painter_line.cpp
+++ b/src/mbgl/renderer/painter_line.cpp
@@ -24,18 +24,17 @@ void Painter::renderLine(PaintParameters& parameters,
     const auto& properties = layer.impl->paint;
 
     auto draw = [&] (auto& program, auto&& uniformValues) {
-        context.draw({
+        program.draw(
+            context,
+            gl::Triangles(),
             depthModeForSublayer(0, gl::DepthMode::ReadOnly),
             stencilModeForClipping(tile.clip),
             colorModeForRenderPass(),
-            program,
             std::move(uniformValues),
-            gl::Segmented<gl::Triangles>(
-                *bucket.vertexBuffer,
-                *bucket.indexBuffer,
-                bucket.segments
-            )
-        });
+            *bucket.vertexBuffer,
+            *bucket.indexBuffer,
+            bucket.segments
+        );
     };
 
     if (!properties.lineDasharray.value.from.empty()) {