Add checks for zero indexes on fill patterns to match fills. (#1638)

Co-authored-by: Bart Louwers <bart@emeel.net>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/mbgl/gfx/drawable_builder.cpp

@@ -167,7 +167,10 @@ void DrawableBuilder::setSegments(const gfx::DrawMode mode,
                                   gfx::IndexVectorBasePtr indexes,
                                   const SegmentBase* segments,
                                   const std::size_t segmentCount) {
-    assert(indexes && indexes->elements());
+    if (!indexes || !indexes->elements()) {
+        assert("Missing segment indexes");
+        return;
+    }
     impl->sharedIndexes = std::move(indexes);
     for (std::size_t i = 0; i < segmentCount; ++i) {
         const auto& seg = segments[i];

src/mbgl/gl/drawable_gl.cpp

@@ -210,10 +210,12 @@ void DrawableGL::upload(gfx::UploadPass& uploadPass) {
 
             if (!glSeg.getVertexArray().isValid()) {
                 auto vertexArray = glContext.createVertexArray();
-                IndexBufferGL& indexBuffer = *static_cast<IndexBufferGL*>(impl->indexes->getBuffer());
+                const auto& indexBuffer = static_cast<IndexBufferGL&>(*impl->indexes->getBuffer());
                 vertexArray.bind(glContext, *indexBuffer.buffer, bindings);
                 assert(vertexArray.isValid());
-                glSeg.setVertexArray(std::move(vertexArray));
+                if (vertexArray.isValid()) {
+                    glSeg.setVertexArray(std::move(vertexArray));
+                }
             }
         };
     }

src/mbgl/renderer/layers/render_fill_layer.cpp

@@ -706,7 +706,7 @@ void RenderFillLayer::update(gfx::ShaderRegistry& shaders,
                 }
             };
 
-            if (patternBuilder) {
+            if (patternBuilder && bucket.sharedTriangles->elements()) {
                 patternBuilder->setShader(fillShader);
                 patternBuilder->setRenderPass(renderPass);
                 if (outlinePatternBuilder) {
@@ -726,7 +726,7 @@ void RenderFillLayer::update(gfx::ShaderRegistry& shaders,
                        "FillPatternTilePropsUBO",
                        getFillPatternTilePropsUBO());
             }
-            if (outlinePatternBuilder) {
+            if (outlinePatternBuilder && bucket.sharedLines->elements()) {
                 outlinePatternBuilder->setShader(outlineShader);
                 outlinePatternBuilder->setRenderPass(renderPass);
                 outlinePatternBuilder->setVertexAttributes(std::move(vertexAttrs));

src/mbgl/renderer/layers/render_raster_layer.cpp

@@ -233,10 +233,15 @@ constexpr auto Image0UniformName = "u_image0";
 constexpr auto Image1UniformName = "u_image1";
 
 void RenderRasterLayer::updateLayerTweaker() {
-    if (layerGroup) {
+    if (layerGroup || imageLayerGroup) {
         tweaker = std::make_shared<RasterLayerTweaker>(getID(), evaluatedProperties);
         tweaker->enableOverdrawInspector(overdrawInspector);
-        layerGroup->setLayerTweaker(tweaker);
+        if (layerGroup) {
+            layerGroup->setLayerTweaker(tweaker);
+        }
+        if (imageLayerGroup) {
+            imageLayerGroup->setLayerTweaker(tweaker);
+        }
     }
 }