fix framebuffer drawing on ios

include/llmr/map/transform_state.hpp

@@ -19,6 +19,7 @@ public:
     box cornersToBox(uint32_t z) const;
 
     // Dimensions
+    bool hasSize() const;
     uint16_t getWidth() const;
     uint16_t getHeight() const;
     uint16_t getFramebufferWidth() const;

include/llmr/renderer/painter.hpp

@@ -103,6 +103,7 @@ public:
     void bindFramebuffer();
     void pushFramebuffer();
     GLuint popFramebuffer();
+    void discardFramebuffers();
     void drawComposite(GLuint texture, const CompositeProperties &properties);
 
     bool needsAnimation() const;

src/map/map.cpp

@@ -134,15 +134,17 @@ void Map::render(uv_async_t *async) {
 
     map->prepare();
 
-    if (map->is_rendered.test_and_set() == false) {
-        if (map->is_clean.test_and_set() == false) {
-            map->render();
-            map->is_swapped.clear();
-            map->view.swap();
-        } else {
-            // We set the rendered flag in the test above, so we have to reset it
-            // now that we're not actually rendering because the map is clean.
-            map->is_rendered.clear();
+    if (map->state.hasSize()) {
+        if (map->is_rendered.test_and_set() == false) {
+            if (map->is_clean.test_and_set() == false) {
+                map->render();
+                map->is_swapped.clear();
+                map->view.swap();
+            } else {
+                // We set the rendered flag in the test above, so we have to reset it
+                // now that we're not actually rendering because the map is clean.
+                map->is_rendered.clear();
+            }
         }
     }
 }
@@ -556,8 +558,6 @@ void Map::renderLayers(const std::vector<LayerDescription>& layers) {
     if (debug::renderTree) {
         std::cout << std::string(--indent * 4, ' ') << "}" << std::endl;
     }
-
-    glFlush();
 }
 
 template <typename Styles>

src/map/transform_state.cpp

@@ -59,6 +59,10 @@ box TransformState::cornersToBox(uint32_t z) const {
 
 #pragma mark - Dimensions
 
+bool TransformState::hasSize() const {
+    return width && height;
+}
+
 uint16_t TransformState::getWidth() const {
     return width;
 }

src/renderer/painter_composite.cpp

@@ -11,7 +11,7 @@ void Painter::drawComposite(GLuint texture, const CompositeProperties &propertie
     // Normally, we're using premultiplied alpha, but the resulting image we've
     // just drawn is non-premultiplied. That means when blending, we have to make
     // sure that we account for that.
-    glBlendFunc(GL_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
     useProgram(compositeShader->program);
     compositeShader->setMatrix(nativeMatrix);

src/renderer/painter_framebuffers.cpp

@@ -7,7 +7,11 @@ using namespace llmr;
 
 
 void Painter::clearFramebuffers() {
+#ifdef TARGET_OS_IPHONE
+    glBindFramebuffer(GL_FRAMEBUFFER, 1);
+#else
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
+#endif
 
     // Delete any framebuffers that we might have allocated
     glDeleteTextures((int)fbos_color.size(), fbos.data());
@@ -24,10 +28,18 @@ void Painter::clearFramebuffers() {
 
 void Painter::bindFramebuffer() {
     if (fbo_level < 0) {
+#ifdef TARGET_OS_IPHONE
+        glBindFramebuffer(GL_FRAMEBUFFER, 1);
+#else
         glBindFramebuffer(GL_FRAMEBUFFER, 0);
-    } else if (fbos.size() > (size_t)fbo_level) {
+#endif
+    } else if (fbos.size() > (size_t) fbo_level) {
         GLuint fbo = fbos[fbo_level];
         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+#if GL_EXT_discard_framebuffer
+        const GLenum discards[] = { GL_COLOR_ATTACHMENT0, GL_DEPTH_ATTACHMENT, GL_STENCIL_ATTACHMENT };
+        glDiscardFramebufferEXT(GL_FRAMEBUFFER, 3, discards);
+#endif
     } else {
         // TODO: Convert this to textures so we can composite them and use them in blend operations