Render background with plain shader

5 files changed, 38 insertions, 17 deletions

diff --git a/include/mbgl/renderer/painter.hpp b/include/mbgl/renderer/painter.hpp
index fcbafc52d5..e2d56b1514 100644
--- a/include/mbgl/renderer/painter.hpp
+++ b/include/mbgl/renderer/painter.hpp
@@ -86,6 +86,8 @@ public:
     void renderLine(LineBucket& bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix);
     void renderSymbol(SymbolBucket& bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix);
     void renderRaster(RasterBucket& bucket, std::shared_ptr<StyleLayer> layer_desc, const Tile::ID& id, const mat4 &matrix);
+    void renderBackground(std::shared_ptr<StyleLayer> layer_desc);
+
     std::array<float, 3> spinWeights(float spin_value);
 
     void preparePrerender(RasterBucket &bucket);
@@ -142,6 +144,12 @@ public:
         return flipMatrix;
     }();
 
+    const mat4 identityMatrix = []{
+        mat4 identity;
+        matrix::identity(identity);
+        return identity;
+    }();
+
 private:
     Map& map;
 
@@ -170,6 +178,13 @@ public:
     std::unique_ptr<DotShader> dotShader;
     std::unique_ptr<GaussianShader> gaussianShader;
 
+    StaticVertexBuffer backgroundBuffer = {
+        { -1, -1 }, { 1, -1 },
+        { -1,  1 }, { 1,  1 }
+    };
+
+    VertexArrayObject backgroundArray;
+
     // Set up the stencil quad we're using to generate the stencil mask.
     StaticVertexBuffer tileStencilBuffer = {
         // top left triangle
diff --git a/include/mbgl/style/style.hpp b/include/mbgl/style/style.hpp
index 6acb5d0cb8..c09de6ebba 100644
--- a/include/mbgl/style/style.hpp
+++ b/include/mbgl/style/style.hpp
@@ -20,7 +20,6 @@ namespace mbgl {
 class Sprite;
 class StyleLayer;
 class StyleLayerGroup;
-struct BackgroundProperties;
 
 class Style {
 public:
@@ -47,8 +46,6 @@ public:
 
     bool hasTransitions() const;
 
-    const BackgroundProperties &getBackgroundProperties() const;
-
     const std::string &getSpriteURL() const;
 
 public:
diff --git a/src/map/map.cpp b/src/map/map.cpp
index 86f7f9812a..ed4cdd005c 100644
--- a/src/map/map.cpp
+++ b/src/map/map.cpp
@@ -625,7 +625,15 @@ void Map::renderLayers(std::shared_ptr<StyleLayerGroup> group) {
 
 void Map::renderLayer(std::shared_ptr<StyleLayer> layer_desc, RenderPass pass, const Tile::ID* id, const mat4* matrix) {
     if (layer_desc->type == StyleLayerType::Background) {
-        // This layer defines the background color.
+        // This layer defines a background color/image.
+        if (pass == RenderPass::Translucent) return;
+
+        if (debug::renderTree) {
+            std::cout << std::string(indent * 4, ' ') << "- " << layer_desc->id << " ("
+                      << layer_desc->type << ")" << std::endl;
+        }
+
+        painter.renderBackground(layer_desc);
     } else {
         // This is a singular layer.
         if (!layer_desc->bucket) {
diff --git a/src/renderer/painter.cpp b/src/renderer/painter.cpp
index 240aff6887..f29d60f8d3 100644
--- a/src/renderer/painter.cpp
+++ b/src/renderer/painter.cpp
@@ -143,8 +143,7 @@ void Painter::clear() {
     glStencilMask(0xFF);
     depthMask(true);
 
-    const BackgroundProperties &properties = map.getStyle()->getBackgroundProperties();
-    glClearColor(properties.color[0], properties.color[1], properties.color[2], properties.color[3]);
+    glClearColor(0, 0, 0, 0);
     glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 }
 
@@ -184,6 +183,19 @@ void Painter::renderTileLayer(const Tile& tile, std::shared_ptr<StyleLayer> laye
     }
 }
 
+void Painter::renderBackground(std::shared_ptr<StyleLayer> layer_desc) {
+    const BackgroundProperties& properties = layer_desc->getProperties<BackgroundProperties>();
+
+    useProgram(plainShader->program);
+    plainShader->setMatrix(identityMatrix);
+    plainShader->setColor(properties.color);
+    backgroundArray.bind(*plainShader, backgroundBuffer, BUFFER_OFFSET(0));
+
+    glDisable(GL_STENCIL_TEST);
+    depthRange(strata + strata_epsilon, 1.0f);
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    glEnable(GL_STENCIL_TEST);
+}
 
 const mat4 &Painter::translatedMatrix(const mat4& matrix, const std::array<float, 2> &translation, const Tile::ID &id, TranslateAnchorType anchor) {
     if (translation[0] == 0 && translation[1] == 0) {
diff --git a/src/style/style.cpp b/src/style/style.cpp
index ee930751ea..6f0a0e3b28 100644
--- a/src/style/style.cpp
+++ b/src/style/style.cpp
@@ -103,15 +103,4 @@ void Style::loadJSON(const uint8_t *const data) {
     updateClasses();
 }
 
-const BackgroundProperties &Style::getBackgroundProperties() const {
-    if (layers && layers->layers.size()) {
-        const auto first = layers->layers.front();
-        if (first && first->type == StyleLayerType::Background) {
-            return first->getProperties<BackgroundProperties>();
-        }
-    }
-
-    return defaultStyleProperties<BackgroundProperties>();
-}
-
 }