Use an OpenGL array object to draw the cursor

src/gui/Window.cc

@@ -123,8 +123,12 @@ bool Window::create(std::shared_ptr<Buffer> buffer)
         m_font.get_advance(), 0,
         m_font.get_advance(), m_font.get_line_height(),
         0, m_font.get_line_height()};
+    m_cursor_array = glcxx::Array::create();
+    m_cursor_array->bind();
     m_cursor_buffer = glcxx::Buffer::create(GL_ARRAY_BUFFER, GL_STATIC_DRAW,
             cursor_bounds, sizeof(cursor_bounds));
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 2, GL_INT, GL_FALSE, 0, 0);
 
     m_buffer = buffer;
     m_cursor = m_buffer->piece_table->add_cursor();
@@ -276,15 +280,7 @@ void Window::redraw()
     glClearColor (0.0, 0.0, 0.0, 0.0);
     glClear(GL_COLOR_BUFFER_BIT);
 
-    glBindVertexArray(0);
-    m_shaders.flat->use();
-    m_shaders.flat->set_color(1.0, 0.2, 1.0, 1.0);
-    m_shaders.flat->set_position(0, m_height - m_font.get_line_height());
-    m_cursor_buffer->bind();
-    glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 2, GL_INT, GL_FALSE, 0, 0);
-    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
-
+    draw_cursor();
     m_shaders.text->use();
 
     int advance = m_font.get_advance();
@@ -324,3 +320,12 @@ void Window::redraw()
 
     SDL_GL_SwapWindow(m_window);
 }
+
+void Window::draw_cursor()
+{
+    m_cursor_array->bind();
+    m_shaders.flat->use();
+    m_shaders.flat->set_color(1.0, 0.2, 1.0, 1.0);
+    m_shaders.flat->set_position(0, m_height - m_font.get_line_height());
+    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+}

src/gui/Window.h

@@ -17,6 +17,7 @@ public:
 protected:
     void resize();
     void redraw();
+    void draw_cursor();
     void handle_event(SDL_Event & event);
     void handle_key(uint32_t scancode, uint32_t mod);
     void scroll_down();
@@ -38,6 +39,7 @@ protected:
 
     std::shared_ptr<Buffer> m_buffer;
 
+    std::shared_ptr<glcxx::Array> m_cursor_array;
     std::shared_ptr<glcxx::Buffer> m_cursor_buffer;
 
     std::shared_ptr<PieceTable::Cursor> m_cursor;