private void DrawQuad(TerrainNode node, TerrainQuad quad, List <TileSampler> samplers)
{
if (!quad.IsVisible)
{
return;
}
if (!quad.Drawable)
{
return;
}
if (quad.IsLeaf)
{
MPB.Clear();
for (int i = 0; i < samplers.Count; ++i)
{
// Set the unifroms needed to draw the texture for this sampler
samplers[i].SetTile(MPB, quad.Level, quad.Tx, quad.Ty);
}
// Set the uniforms unique to each quad
node.SetPerQuadUniforms(quad, MPB);
DrawNode(node);
}
else
{
// Draw quads in a order based on distance to camera
var order = new byte[4];
var cameraX = node.LocalCameraPosition.x;
var cameraY = node.LocalCameraPosition.y;
var quadX = quad.Oy + quad.Length / 2.0;
var quadY = quad.Oy + quad.Length / 2.0;
if (cameraY < quadY)
{
if (cameraX < quadX)
{
order[0] = 0;
order[1] = 1;
order[2] = 2;
order[3] = 3;
}
else
{
order[0] = 1;
order[1] = 0;
order[2] = 3;
order[3] = 2;
}
}
else
{
if (cameraX < quadX)
{
order[0] = 2;
order[1] = 0;
order[2] = 3;
order[3] = 1;
}
else
{
order[0] = 3;
order[1] = 1;
order[2] = 2;
order[3] = 0;
}
}
var done = 0;
for (byte i = 0; i < 4; ++i)
{
if (quad.GetChild(order[i]).Visibility == Frustum.VISIBILITY.INVISIBLE)
{
done |= (1 << order[i]);
}
else if (quad.GetChild(order[i]).Drawable)
{
DrawQuad(node, quad.GetChild(order[i]), samplers);
done |= (1 << order[i]);
}
}
if (done < 15)
{
// If the a leaf quad needs to be drawn but its tiles are not ready then this will draw the next parent tile instead that is ready.
// Because of the current set up all tiles always have there tasks run on the frame they are generated so this section of code is never reached.
MPB.Clear();
for (int i = 0; i < samplers.Count; ++i)
{
// Set the unifroms needed to draw the texture for this sampler
samplers[i].SetTile(MPB, quad.Level, quad.Tx, quad.Ty);
}
// Set the uniforms unique to each quad
node.SetPerQuadUniforms(quad, MPB);
DrawNode(node);
}
}
}
