private void GetCurrentCompatibilityBinding(out CompatibilitySetter compatibilityBinding)
{
lock (Lock) {
if (CurrentCompatibilityBinding == null)
{
IsDirty = true;
CreateCompatibilityBinding(out CurrentCompatibilityBinding);
}
compatibilityBinding = CurrentCompatibilityBinding;
}
}
// We use LCG to create a single throwaway delegate that is responsible for filling
// all the relevant effect parameters with the value(s) of each field of the struct.
private void CreateCompatibilityBinding(out CompatibilitySetter result)
{
var t = typeof(T);
var tp = typeof(EffectParameter);
var uniformParameter = Effect.Parameters[Name];
if (uniformParameter == null)
{
throw new Exception("Shader has no uniform named '" + Name + "'");
}
if (uniformParameter.ParameterClass != EffectParameterClass.Struct)
{
throw new Exception("Shader uniform is not a struct");
}
var pValue = Expression.Parameter(t.MakeByRefType(), "value");
var body = new List <Expression>();
foreach (var p in uniformParameter.StructureMembers)
{
var field = t.GetField(p.Name, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
if (field == null)
{
throw new Exception(string.Format("No field named '{0}' found when binding type {1}", p.Name, t.Name));
}
var setMethod = tp.GetMethod("SetValue", new[] { field.FieldType });
if (setMethod == null)
{
throw new Exception(string.Format("No setter for effect parameter type {0}", field.FieldType.Name));
}
var vParameter = Expression.Constant(p, tp);
var fieldValue = Expression.Field(pValue, field);
body.Add(Expression.Call(vParameter, setMethod, fieldValue));
}
var bodyBlock = Expression.Block(body);
var expr = Expression.Lambda <CompatibilitySetter>(bodyBlock, pValue);
result = expr.Compile();
}
