private SpriteVertex[] QuadFromSprite(Sprite sprite)
{
SpriteVertex[] verts = new SpriteVertex[4];
Rectangle src = sprite.Source;
Rectangle dest = sprite.Destination;
var width = sprite.Texture.Description.Width;
var height = sprite.Texture.Description.Height;
verts[0].Position = PointToNdc(dest.Left, dest.Bottom, 0f);
verts[1].Position = PointToNdc(dest.Left, dest.Top, 0f);
verts[2].Position = PointToNdc(dest.Right, dest.Top, 0f);
verts[3].Position = PointToNdc(dest.Right, dest.Bottom, 0f);
verts[0].TexCoord = new Vector2((float)src.Left / width, (float)src.Bottom / height);
verts[1].TexCoord = new Vector2((float)src.Left / width, (float)src.Top / height);
verts[2].TexCoord = new Vector2((float)src.Right / width, (float)src.Top / height);
verts[3].TexCoord = new Vector2((float)src.Right / width, (float)src.Bottom / height);
for(int i = 0; i < verts.Length; i++) {
verts[i].Color = sprite.Color;
}
var tx = 0.5f * (verts[0].Position.X + verts[3].Position.X);
var ty = 0.5f * (verts[0].Position.Y + verts[1].Position.Y);
var origin = new Vector2(tx, ty);
var translate = new Vector2(0f, 0f);
var transform = Matrix.AffineTransformation2D(1f, 0f, translate);
for(int i = 0; i < verts.Length; ++i) {
Vector3 position = verts[i].Position;
position = Vector3.TransformCoordinate(position, transform);
verts[i].Position = position;
}
return verts;
}
public void DrawSprite(Sprite sprite)
{
if (!_SpriteCacheByResource.ContainsKey(sprite.Texture))
_SpriteCacheByResource[sprite.Texture] = new List<Sprite>();
_SpriteCacheByResource[sprite.Texture].Add(sprite);
}