diff --git a/src/bin/terrain.rs b/src/bin/terrain.rs
index 34b17a6..775fc82 100644
--- a/src/bin/terrain.rs
+++ b/src/bin/terrain.rs
@@ -23,6 +23,39 @@ use opengl_rust::{
 	timestep::TimeStep,
 };
 
+struct GraphicsContext {
+	window: sdl2::video::Window,
+	gl_ctx: sdl2::video::GLContext,
+	
+	vertex_buffer: gpu_buffers::VertexBuffer,
+	index_buffer: gpu_buffers::IndexBuffer,
+	
+	shader_program: shader::ShaderProgram,
+	attr_pos: u32,
+}
+
+fn draw_graphics (ctx: &GraphicsContext) {
+	let attr_pos = ctx.attr_pos;
+	
+	ctx.window.gl_make_current (&ctx.gl_ctx).unwrap ();
+	glezz::clear_color (0.392f32, 0.710f32, 0.965f32, 1.0f32);
+	glezz::clear (gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT | gl::STENCIL_BUFFER_BIT);
+	
+	ctx.shader_program.use_program ();
+	glezz::enable_vertex_attrib_array (Some (attr_pos));
+	
+	ctx.vertex_buffer.bind ();
+	ctx.index_buffer.bind ();
+	
+	unsafe {
+		gl::VertexAttribPointer (attr_pos, 2, gl::FLOAT, 0, 4 * 2, 0 as *const u8 as *const c_void);
+		
+		gl::DrawRangeElements (gl::TRIANGLES, 0, 6, 6, gl::UNSIGNED_INT, 0 as *const u8 as *const c_void);
+	}
+	
+	ctx.window.gl_swap_window ();
+}
+
 fn main () -> anyhow::Result <()> {
 	let sdl_context = sdl2::init ().map_err (|e| anyhow! ("Can't init SDL: {}", e))?;
 	
@@ -76,7 +109,7 @@ void main (void) {
 	
 	let shader_program = shader::ShaderProgram::new (&vertex_shader, &fragment_shader).map_err (|e| anyhow! ("Can't link shader program: {}", e))?;
 	
-	let attr_pos = shader_program.get_attribute_location (&CString::new ("attr_pos".as_bytes ())?);
+	let attr_pos = shader_program.get_attribute_location (&CString::new ("attr_pos".as_bytes ())?).try_into ()?;
 	
 	let vertex_buffer = gpu_buffers::VertexBuffer::from_slice (&[
 		0.0, 0.0,
@@ -90,6 +123,17 @@ void main (void) {
 		0, 2, 3
 	]);
 	
+	let graphics_ctx = GraphicsContext {
+		window,
+		gl_ctx,
+		
+		vertex_buffer,
+		index_buffer,
+		
+		shader_program,
+		attr_pos,
+	};
+	
 	'running: loop {
 		let frames_to_do = time_step.step ();
 		
@@ -109,23 +153,7 @@ void main (void) {
 			
 		}
 		
-		window.gl_make_current (&gl_ctx).unwrap ();
-		glezz::clear_color (0.392f32, 0.710f32, 0.965f32, 1.0f32);
-		glezz::clear (gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT | gl::STENCIL_BUFFER_BIT);
-		
-		shader_program.use_program ();
-		glezz::enable_vertex_attrib_array (Some (attr_pos.try_into ()?));
-		
-		vertex_buffer.bind ();
-		index_buffer.bind ();
-		
-		unsafe {
-			gl::VertexAttribPointer (attr_pos.try_into ()?, 2, gl::FLOAT, 0, 4 * 2, 0 as *const u8 as *const c_void);
-			
-			gl::DrawRangeElements (gl::TRIANGLES, 0, 6, 6, gl::UNSIGNED_INT, 0 as *const u8 as *const c_void);
-		}
-		
-		window.gl_swap_window ();
+		draw_graphics (&graphics_ctx);
 		graphics_frames += 1;
 		
 		std::thread::sleep (Duration::from_millis (15));