diff --git a/Outputs/OpenGL/ScanTarget.cpp b/Outputs/OpenGL/ScanTarget.cpp
index f9b119fe2..7a77da148 100644
--- a/Outputs/OpenGL/ScanTarget.cpp
+++ b/Outputs/OpenGL/ScanTarget.cpp
@@ -100,12 +100,21 @@ Outputs::Display::ScanTarget::Scan *ScanTarget::begin_scan() {
 	write_pointers_.scan_buffer = next_write_pointer;
 
 	// Fill in extra OpenGL-specific details.
-//	result->data_y = write_pointers_.write_area;
-	result->composite_y = 0;
+	result->composite_y = 0;	// TODO.
 
+	vended_scan_ = result;
 	return static_cast<Outputs::Display::ScanTarget::Scan *>(result);
 }
 
+void ScanTarget::end_scan() {
+	if(vended_scan_) {
+		vended_scan_->data_y = TextureAddressGetY(vended_write_area_pointer_);
+		vended_scan_->end_points[0].data_offset += TextureAddressGetX(vended_write_area_pointer_);
+		vended_scan_->end_points[1].data_offset += TextureAddressGetX(vended_write_area_pointer_);
+    }
+    vended_scan_ = nullptr;
+}
+
 uint8_t *ScanTarget::begin_data(size_t required_length, size_t required_alignment) {
 	if(allocation_has_failed_) return nullptr;
 
@@ -138,7 +147,7 @@ uint8_t *ScanTarget::begin_data(size_t required_length, size_t required_alignmen
 	}
 
 	// Everything checks out, return the pointer.
-	write_pointers_.write_area = TextureAddress(aligned_start_x, output_y);
+	vended_write_area_pointer_ = write_pointers_.write_area = TextureAddress(aligned_start_x, output_y);
 	return &write_area_texture_[size_t(write_pointers_.write_area) * data_type_size_];
 
 	// Note state at exit:
diff --git a/Outputs/OpenGL/ScanTarget.hpp b/Outputs/OpenGL/ScanTarget.hpp
index 149762c59..58bf5ed0e 100644
--- a/Outputs/OpenGL/ScanTarget.hpp
+++ b/Outputs/OpenGL/ScanTarget.hpp
@@ -30,6 +30,7 @@ class ScanTarget: public Outputs::Display::ScanTarget {
 		// Outputs::Display::ScanTarget overrides.
 		void set_modals(Modals) override;
 		Scan *begin_scan() override;
+		void end_scan() override;
 		uint8_t *begin_data(size_t required_length, size_t required_alignment) override;
 		void end_data(size_t actual_length) override;
 		void submit() override;
@@ -74,6 +75,10 @@ class ScanTarget: public Outputs::Display::ScanTarget {
 		GLuint write_area_texture_name_ = 0;
 		bool texture_exists_ = false;
 
+		// Ephemeral information for the begin/end functions.
+		Scan *vended_scan_ = nullptr;
+		int vended_write_area_pointer_ = 0;
+
 		// Track allocation failures.
 		bool allocation_has_failed_ = false;