1 files changed, 87 insertions, 0 deletions
diff --git a/src/mbgl/gl/offscreen_texture.cpp b/src/mbgl/gl/offscreen_texture.cpp
new file mode 100644
index 0000000000..96d8b7e4c4
--- /dev/null
+++ b/src/mbgl/gl/offscreen_texture.cpp
@@ -0,0 +1,87 @@
+#include <mbgl/gl/offscreen_texture.hpp>
+#include <mbgl/gl/renderable_resource.hpp>
+#include <mbgl/gl/context.hpp>
+#include <mbgl/gl/framebuffer.hpp>
+
+namespace mbgl {
+namespace gl {
+
+class OffscreenTextureResource final : public gl::RenderableResource {
+public:
+    OffscreenTextureResource(gl::Context& context_,
+                             const Size size_,
+                             const gfx::TextureChannelDataType type_)
+        : context(context_), size(size_), type(type_) {
+        assert(!size.isEmpty());
+    }
+
+    OffscreenTextureResource(gl::Context& context_,
+                             const Size size_,
+                             gfx::Renderbuffer<gfx::RenderbufferPixelType::Depth>& depth_,
+                             const gfx::TextureChannelDataType type_)
+        : context(context_), size(size_), depth(&depth_), type(type_) {
+        assert(!size.isEmpty());
+    }
+
+    void bind() override {
+        if (!framebuffer) {
+            texture = context.createTexture(size, gfx::TexturePixelType::RGBA, type);
+            if (depth) {
+                framebuffer = context.createFramebuffer(*texture, *depth);
+            } else {
+                framebuffer = context.createFramebuffer(*texture);
+            }
+        } else {
+            context.bindFramebuffer = framebuffer->framebuffer;
+        }
+
+        context.activeTextureUnit = 0;
+        context.scissorTest = false;
+        context.viewport = { 0, 0, size };
+    }
+
+    PremultipliedImage readStillImage() {
+        assert(framebuffer);
+        context.bindFramebuffer = framebuffer->framebuffer;
+        return context.readFramebuffer<PremultipliedImage>(size);
+    }
+
+    gfx::Texture& getTexture() {
+        assert(texture);
+        return *texture;
+    }
+
+private:
+    gl::Context& context;
+    const Size size;
+    optional<gfx::Texture> texture;
+    gfx::Renderbuffer<gfx::RenderbufferPixelType::Depth>* depth = nullptr;
+    const gfx::TextureChannelDataType type;
+    optional<gl::Framebuffer> framebuffer;
+};
+
+OffscreenTexture::OffscreenTexture(gl::Context& context,
+                                   const Size size_,
+                                   const gfx::TextureChannelDataType type)
+    : gfx::OffscreenTexture(size, std::make_unique<OffscreenTextureResource>(context, size_, type)) {
+}
+
+OffscreenTexture::OffscreenTexture(
+    gl::Context& context,
+    const Size size_,
+    gfx::Renderbuffer<gfx::RenderbufferPixelType::Depth>& renderbuffer,
+    const gfx::TextureChannelDataType type)
+    : gfx::OffscreenTexture(
+          size, std::make_unique<OffscreenTextureResource>(context, size_, renderbuffer, type)) {
+}
+
+PremultipliedImage OffscreenTexture::readStillImage() {
+    return getResource<OffscreenTextureResource>().readStillImage();
+}
+
+gfx::Texture& OffscreenTexture::getTexture() {
+    return getResource<OffscreenTextureResource>().getTexture();
+}
+
+} // namespace gl
+} // namespace mbgl