public PostFilter(Shader shader)
{
if (shader is PostShader)
{
this.shader = (PostShader)shader;
}
else
{
throw new Exception("Must be of type PostShader!");
}
}
/// <summary>
/// Applies a <see cref="PostShader"/> to the <see cref="OmegaEngine.Graphics.RenderTarget"/> and outputs the result to the back-buffer
/// </summary>
/// <param name="shader">The <see cref="PostShader"/> to apply</param>
/// <param name="alpha">The level of transparency from 0 (solid) to 255 (invisible)</param>
private void ShaderToBackBuffer(PostShader shader, int alpha)
{
Engine.State.AlphaBlend = alpha;
using (new ProfilerEvent(() => "Apply " + shader))
{
shader.Apply(delegate
{
Engine.Device.BeginScene();
Engine.DrawQuadShader();
Engine.Device.EndScene();
}, _area.Size, shader.OverlayRendering ? null : RenderTarget);
}
}
/// <summary>
/// Updates the <see cref="OmegaEngine.Graphics.RenderTarget"/> using a <see cref="PostShader"/>
/// </summary>
/// <param name="shader">The <see cref="PostShader"/> to apply</param>
protected void ShaderToRenderTarget(PostShader shader)
{
#region Sanity checks
if (shader == null)
{
throw new ArgumentNullException(nameof(shader));
}
#endregion
// Make sure input and output texture aren't the same
var sceneMap = RenderTarget;
if (!shader.OverlayRendering)
{
SwapRenderTarget();
}
// Apply the shader and move data from one texture to the other
using (new ProfilerEvent(() => "Apply " + shader))
shader.Apply(() => RenderTarget.RenderTo(Engine.DrawQuadShader), sceneMap.Size, shader.OverlayRendering ? null : sceneMap);
}
/// <summary>
/// Applies an intermediate shader from <see cref="PostShaders"/> to the output.
/// </summary>
/// <param name="shader">The shader to apply.</param>
/// <param name="sceneOnBackBuffer">
/// Is the scene currently on the backbuffer?<br/>
/// If this is <c>false</c>, it is in <see cref="RenderTarget"/>.
/// </param>
private void ApplyPostShaderIntermediate(PostShader shader, ref bool sceneOnBackBuffer)
{
if (sceneOnBackBuffer && shader.OverlayRendering)
{
// Apply the shader directly on the back-buffer
ShaderToBackBuffer(shader, 0);
}
else
{
// Make sure the scene is inside a texture
if (sceneOnBackBuffer)
{
CopyBackBufferToTexture();
sceneOnBackBuffer = false;
}
// Update the RenderTarget texture to incorporate the PostShader effect
ShaderToRenderTarget(shader);
}
}
/// <summary>
/// Applies the last shader from <see cref="PostShaders"/> to the output.
/// </summary>
/// <param name="shader">The shader to apply.</param>
/// <param name="sceneOnBackBuffer">
/// Is the scene currently on the backbuffer?<br/>
/// If this is <c>false</c>, it is in <see cref="RenderTarget"/>.
/// </param>
private void ApplyPostShaderLast(PostShader shader, ref bool sceneOnBackBuffer)
{
if (FullAlpha == 0)
{ // Opaque
// Scene must be on the back-buffer before using a shader with overlay rendering
if (shader.OverlayRendering && !sceneOnBackBuffer)
{
OutputRenderTarget(0);
}
// Make sure the scene ends up in a texture (out of the back-buffer)
if (!shader.OverlayRendering && sceneOnBackBuffer)
{
CopyBackBufferToTexture();
sceneOnBackBuffer = false;
}
// Apply the shader directly on the back-buffer
ShaderToBackBuffer(shader, 0);
}
else
{ // Transparent
Debug.Assert(!sceneOnBackBuffer, "Scene should never be on back-buffer with alpha-blended output");
if (shader.OverlayRendering)
{
// Update the RenderTarget texture to incorporate the PostShader effect and then output it
ShaderToRenderTarget(shader);
OutputRenderTarget(FullAlpha);
}
else
{
// Apply the shader while outputing to a transparent quad
ShaderToBackBuffer(shader, FullAlpha);
}
}
}
