[core] Reuse fill-extrusion textures between frames (#8896)

2 files changed, 30 insertions, 25 deletions

diff --git a/src/mbgl/util/offscreen_texture.cpp b/src/mbgl/util/offscreen_texture.cpp
index e719ac566e..fe24774b7c 100644
--- a/src/mbgl/util/offscreen_texture.cpp
+++ b/src/mbgl/util/offscreen_texture.cpp
@@ -6,16 +6,28 @@
 
 namespace mbgl {
 
+OffscreenTexture::OffscreenTexture(OffscreenTexture&&) = default;
+OffscreenTexture& OffscreenTexture::operator=(OffscreenTexture&&) = default;
+
 class OffscreenTexture::Impl {
 public:
-    Impl(gl::Context& context_, const Size size_) : context(context_), size(std::move(size_)) {
+    Impl(gl::Context& context_, const Size size_, OffscreenTextureAttachment type_)
+        : context(context_), size(std::move(size_)), type(type_) {
         assert(!size.isEmpty());
     }
 
     void bind() {
         if (!framebuffer) {
             texture = context.createTexture(size, gl::TextureFormat::RGBA);
-            framebuffer = context.createFramebuffer(*texture);
+
+            if (type == OffscreenTextureAttachment::Depth) {
+                gl::Renderbuffer<gl::RenderbufferType::DepthComponent> depth =
+                    context.createRenderbuffer<gl::RenderbufferType::DepthComponent>(size);
+                framebuffer = context.createFramebuffer(*texture, depth);
+
+            } else {
+                framebuffer = context.createFramebuffer(*texture);
+            }
         } else {
             context.bindFramebuffer = framebuffer->framebuffer;
         }
@@ -37,29 +49,18 @@ public:
         return size;
     }
 
-    void bindRenderbuffers(gl::TextureUnit unit) {
-        if (!framebuffer) {
-            texture = context.createTexture(size, gl::TextureFormat::RGBA, unit);
-            gl::Renderbuffer<gl::RenderbufferType::DepthComponent> depthTarget = context.createRenderbuffer<gl::RenderbufferType::DepthComponent>(size);
-            framebuffer = context.createFramebuffer(*texture, depthTarget);
-
-        } else {
-            context.bindFramebuffer = framebuffer->framebuffer;
-        }
-
-        context.activeTexture = unit;
-        context.viewport = { 0, 0, size };
-    }
-
 private:
     gl::Context& context;
     const Size size;
+    OffscreenTextureAttachment type;
     optional<gl::Framebuffer> framebuffer;
     optional<gl::Texture> texture;
 };
 
-OffscreenTexture::OffscreenTexture(gl::Context& context, const Size size)
-    : impl(std::make_unique<Impl>(context, std::move(size))) {
+OffscreenTexture::OffscreenTexture(gl::Context& context,
+                                   const Size size,
+                                   OffscreenTextureAttachment type)
+    : impl(std::make_unique<Impl>(context, std::move(size), type)) {
     assert(!size.isEmpty());
 }
 
@@ -81,8 +82,4 @@ const Size& OffscreenTexture::getSize() const {
     return impl->getSize();
 }
 
-void OffscreenTexture::bindRenderbuffers(gl::TextureUnit unit) {
-    impl->bindRenderbuffers(unit);
-}
-
 } // namespace mbgl
diff --git a/src/mbgl/util/offscreen_texture.hpp b/src/mbgl/util/offscreen_texture.hpp
index 4e9e936114..ae96286340 100644
--- a/src/mbgl/util/offscreen_texture.hpp
+++ b/src/mbgl/util/offscreen_texture.hpp
@@ -10,13 +10,21 @@ class Context;
 class Texture;
 } // namespace gl
 
+enum class OffscreenTextureAttachment {
+    None,
+    Depth,
+};
+
 class OffscreenTexture : public View {
 public:
-    OffscreenTexture(gl::Context&, Size size = { 256, 256 });
+    OffscreenTexture(gl::Context&,
+                     Size size = { 256, 256 },
+                     OffscreenTextureAttachment type = OffscreenTextureAttachment::None);
     ~OffscreenTexture();
+    OffscreenTexture(OffscreenTexture&&);
+    OffscreenTexture& operator=(OffscreenTexture&&);
 
     void bind() override;
-    void bindRenderbuffers(gl::TextureUnit unit = 0);
 
     PremultipliedImage readStillImage();
 
@@ -26,7 +34,7 @@ public:
 
 private:
     class Impl;
-    const std::unique_ptr<Impl> impl;
+    std::unique_ptr<Impl> impl;
 };
 
 } // namespace mbgl