[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, 12 insertions, 15 deletions

diff --git a/src/mbgl/renderer/painter_symbol.cpp b/src/mbgl/renderer/painter_symbol.cpp
index 2f94544486..d2dee5d99d 100644
--- a/src/mbgl/renderer/painter_symbol.cpp
+++ b/src/mbgl/renderer/painter_symbol.cpp
@@ -46,7 +46,9 @@ void Painter::renderSymbol(PaintParameters& parameters,
         const bool drawAcrossEdges = (frame.mapMode == MapMode::Continuous) && (true || !(layout.textAllowOverlap || layout.iconAllowOverlap ||
               layout.textIgnorePlacement || layout.iconIgnorePlacement));
 
-        context.draw({
+        program.draw(
+            context,
+            gl::Triangles(),
             values_.pitchAlignment == AlignmentType::Map
                 ? depthModeForSublayer(0, gl::DepthMode::ReadOnly)
                 : gl::DepthMode::disabled(),
@@ -54,14 +56,11 @@ void Painter::renderSymbol(PaintParameters& parameters,
                 ? gl::StencilMode::disabled()
                 : stencilModeForClipping(tile.clip),
             colorModeForRenderPass(),
-            program,
             std::move(uniformValues),
-            gl::Segmented<gl::Triangles>(
-                *buffers.vertexBuffer,
-                *buffers.indexBuffer,
-                buffers.segments
-            )
-        });
+            *buffers.vertexBuffer,
+            *buffers.indexBuffer,
+            buffers.segments
+        );
     };
 
     if (bucket.hasIconData()) {
@@ -119,22 +118,20 @@ void Painter::renderSymbol(PaintParameters& parameters,
     }
 
     if (bucket.hasCollisionBoxData()) {
-        context.draw({
+        programs->collisionBox.draw(
+            context,
+            gl::Lines { 1.0f },
             gl::DepthMode::disabled(),
             gl::StencilMode::disabled(),
             colorModeForRenderPass(),
-            programs->collisionBox,
             CollisionBoxProgram::UniformValues {
                 uniforms::u_matrix::Value{ tile.matrix },
                 uniforms::u_scale::Value{ std::pow(2.0f, float(state.getZoom() - tile.tile.id.overscaledZ)) },
                 uniforms::u_zoom::Value{ float(state.getZoom() * 10) },
                 uniforms::u_maxzoom::Value{ float((tile.id.canonical.z + 1) * 10) },
             },
-            gl::Unindexed<gl::Lines>(
-                *bucket.collisionBox.vertexBuffer,
-                1.0f
-            )
-        });
+            *bucket.collisionBox.vertexBuffer
+        );
     }
 }