/// <summary>
/// Merge this state with another one.
/// </summary>
/// <param name="state">
/// A <see cref="IGraphicsState"/> having the same <see cref="StateIdentifier"/> of this state.
/// </param>
public override void Merge(IGraphicsState state)
{
if (state == null)
{
throw new ArgumentNullException("state");
}
DepthTestState otherState = state as DepthTestState;
if (otherState == null)
{
throw new ArgumentException("not a DepthTestState", "state");
}
_Function = otherState._Function;
}
/// <summary>
/// Indicates whether the current object is equal to another object of the same type.
/// </summary>
/// <param name="other">
/// A <see cref="GraphicsState"/> to compare to this GraphicsState.
/// </param>
/// <returns>
/// It returns true if the current object is equal to <paramref name="other"/>.
/// </returns>
/// <remarks>
/// <para>
/// This method test only whether <paramref name="other"/> type equals to this type.
/// </para>
/// </remarks>
/// <exception cref="ArgumentNullException">
/// This exception is thrown if the parameter <paramref name="other"/> is null.
/// </exception>
public override bool Equals(IGraphicsState other)
{
if (base.Equals(other) == false)
{
return(false);
}
Debug.Assert(other is DepthTestState);
DepthTestState otherState = (DepthTestState)other;
if (otherState.Function != Function)
{
return(false);
}
return(true);
}
/// <summary>
/// Apply this depth test render state.
/// </summary>
/// <param name="ctx">
/// A <see cref="GraphicsContext"/> which has defined the shader program <paramref name="program"/>.
/// </param>
/// <param name="program">
/// The <see cref="ShaderProgram"/> which has the state set.
/// </param>
public override void ApplyState(GraphicsContext ctx, ShaderProgram program)
{
if (ctx == null)
{
throw new ArgumentNullException("ctx");
}
DepthTestState currentState = (DepthTestState)ctx.GetCurrentState(StateIndex);
if (currentState != null)
{
ApplyStateCore(ctx, program, currentState);
}
else
{
ApplyStateCore(ctx, program);
}
ctx.SetCurrentState(this);
}
private void ApplyStateCore(GraphicsContext ctx, ShaderProgram program, DepthTestState currentState)
{
if (_Enabled)
{
// Enable depth test
if (currentState.Enabled == false)
{
Gl.Enable(EnableCap.DepthTest);
}
// Specify depth function
if (currentState.Function != Function)
{
Gl.DepthFunc(Function);
}
}
else
{
// Disable depth test
if (currentState != null && currentState.Enabled == true)
{
Gl.Disable(EnableCap.DepthTest);
}
}
}
