[core] Don't use glClear optimization for layers that aren't the bottommost

Fixes #3292

3 files changed, 17 insertions, 6 deletions

diff --git a/package.json b/package.json
index 7ebe666fa0..a96d5fb3ff 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,7 @@
   ],
   "devDependencies": {
     "aws-sdk": "^2.2.21",
-    "mapbox-gl-test-suite": "mapbox/mapbox-gl-test-suite#78bde0077848b4af0efd490d124bde3ea9f56ec9",
+    "mapbox-gl-test-suite": "mapbox/mapbox-gl-test-suite#48d397ea31e551324f85f0eb2088a5017023cab5",
     "node-gyp": "^3.2.1",
     "request": "^2.67.0",
     "tape": "^4.2.2"
diff --git a/src/mbgl/renderer/painter.cpp b/src/mbgl/renderer/painter.cpp
index f9d3270792..3ecfe8c34f 100644
--- a/src/mbgl/renderer/painter.cpp
+++ b/src/mbgl/renderer/painter.cpp
@@ -255,8 +255,8 @@ void Painter::renderPass(RenderPass pass_,
 }
 
 void Painter::renderBackground(const BackgroundLayer& layer) {
-    // Note: This function is only called for textured background. Otherwise, the background color
-    // is created with glClear.
+    // Note that for bottommost layers without a pattern, the background color is drawn with
+    // glClear rather than this method.
     const BackgroundPaintProperties& properties = layer.paint;
 
     if (!properties.pattern.value.to.empty()) {
@@ -316,13 +316,24 @@ void Painter::renderBackground(const BackgroundLayer& layer) {
         backgroundBuffer.bind();
         patternShader->bind(0);
         spriteAtlas->bind(true);
+    } else {
+        Color color = properties.color;
+        color[0] *= properties.opacity;
+        color[1] *= properties.opacity;
+        color[2] *= properties.opacity;
+        color[3] *= properties.opacity;
+
+        config.program = plainShader->program;
+        plainShader->u_matrix = identityMatrix;
+        plainShader->u_color = color;
+        backgroundArray.bind(*plainShader, backgroundBuffer, BUFFER_OFFSET(0));
     }
 
     config.stencilTest = GL_FALSE;
     config.depthFunc.reset();
     config.depthTest = GL_TRUE;
     config.depthMask = GL_FALSE;
-    config.depthRange = { 1.0f, 1.0f };
+    setDepthSublayer(0);
 
     MBGL_CHECK_ERROR(glDrawArrays(GL_TRIANGLE_STRIP, 0, 4));
 }
diff --git a/src/mbgl/style/style.cpp b/src/mbgl/style/style.cpp
index a328b890d8..d82689f220 100644
--- a/src/mbgl/style/style.cpp
+++ b/src/mbgl/style/style.cpp
@@ -236,7 +236,7 @@ RenderData Style::getRenderData() const {
             continue;
 
         if (const BackgroundLayer* background = layer->as<BackgroundLayer>()) {
-            if (background->paint.pattern.value.from.empty()) {
+            if (layer.get() == layers[0].get() && background->paint.pattern.value.from.empty()) {
                 // This is a solid background. We can use glClear().
                 result.backgroundColor = background->paint.color;
                 result.backgroundColor[0] *= background->paint.opacity;
@@ -244,7 +244,7 @@ RenderData Style::getRenderData() const {
                 result.backgroundColor[2] *= background->paint.opacity;
                 result.backgroundColor[3] *= background->paint.opacity;
             } else {
-                // This is a textured background. We need to render it with a quad.
+                // This is a textured background, or not the bottommost layer. We need to render it with a quad.
                 result.order.emplace_back(*layer);
             }
             continue;