#region Copyright & License Information
/*
 * Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
 * This file is part of OpenRA, which is free software. It is made
 * available to you under the terms of the GNU General Public License
 * as published by the Free Software Foundation. For more information,
 * see COPYING.
 */
#endregion

using System;
using System.Drawing;
using OpenRA.FileFormats;
using OpenRA.FileFormats.Graphics;
using OpenRA.Traits;

namespace OpenRA.Graphics
{
	class TerrainRenderer
	{
		IVertexBuffer<Vertex> vertexBuffer;

		World world;
		Map map;

		public TerrainRenderer(World world, WorldRenderer wr)
		{
			this.world = world;
			this.map = world.Map;

			var terrainPalette = wr.Palette("terrain").Index;
			var vertices = new Vertex[4 * map.Bounds.Height * map.Bounds.Width];
			int nv = 0;

			for (var j = map.Bounds.Top; j < map.Bounds.Bottom; j++)
				for (var i = map.Bounds.Left; i < map.Bounds.Right; i++)
				{
					var tile = wr.Theater.TileSprite(map.MapTiles.Value[i, j]);
					Util.FastCreateQuad(vertices, Game.CellSize * new float2(i, j), tile, terrainPalette, nv, tile.size);
					nv += 4;
				}

			vertexBuffer = Game.Renderer.Device.CreateVertexBuffer(vertices.Length);
			vertexBuffer.SetData(vertices, nv);
		}

		public void Draw(WorldRenderer wr, Viewport viewport)
		{
			int verticesPerRow = 4*map.Bounds.Width;

			int visibleRows = (int)(Game.Renderer.Resolution.Height * 1f / Game.CellSize / viewport.Zoom + 2);

			int firstRow = (int)(viewport.Location.Y * 1f / Game.CellSize - map.Bounds.Top);
			int lastRow = firstRow + visibleRows;

			if (lastRow < 0 || firstRow > map.Bounds.Height)
				return;

			if (world.VisibleBounds.HasValue)
			{
				var r = world.VisibleBounds.Value;
				if (firstRow < r.Top - map.Bounds.Top)
					firstRow = r.Top - map.Bounds.Top;

				if (firstRow > r.Bottom - map.Bounds.Top)
					firstRow = r.Bottom - map.Bounds.Top;
			}

			// Sanity checking
			if (firstRow < 0)
				firstRow = 0;

			if (lastRow > map.Bounds.Height)
				lastRow = map.Bounds.Height;

			if (lastRow < firstRow)
				lastRow = firstRow;

			Game.Renderer.WorldSpriteRenderer.DrawVertexBuffer(
				vertexBuffer, verticesPerRow * firstRow, verticesPerRow * (lastRow - firstRow),
				PrimitiveType.QuadList, wr.Theater.Sheet);

			foreach (var r in world.WorldActor.TraitsImplementing<IRenderOverlay>())
				r.Render(wr);
		}
	}
}