using System.Runtime.InteropServices;

namespace UnityEngine.Rendering.PostProcessing
{
    internal class SGSR2Upscaler_2PassFS: SGSR2Upscaler
    {
        protected override string VariantName => "SGSR2 2-Pass Fragment";

        private Material _material;

        public override void CreateContext(PostProcessRenderContext context, Upscaling config)
        {
            base.CreateContext(context, config);

            _material = new Material(context.resources.shaders.sgsr2Upscaler.twoPassFragment);
        }

        public override void DestroyContext()
        {
            RuntimeUtilities.Destroy(_material);
            
            base.DestroyContext();
        }

        protected override void DoRender(CommandBuffer cmd, PostProcessRenderContext context, Upscaling config)
        {
            uint frameIndex = _frameCount % 2;

            cmd.SetGlobalTexture("InputColor", context.source);
            cmd.SetGlobalTexture("MotionDepthClipAlphaBuffer", _motionDepthClipAlpha);
            cmd.SetGlobalTexture("PrevOutput", _upscaleHistory[frameIndex ^ 1]);
            cmd.SetGlobalConstantBuffer(_paramsBuffer, "cbSGSR2", 0, Marshal.SizeOf<SGSR2.Params>());
            
            cmd.Blit(BuiltinRenderTextureType.None, _motionDepthClipAlpha, _material, 0);
            cmd.Blit(BuiltinRenderTextureType.None, _upscaleHistory[frameIndex], _material, 1);
            cmd.Blit(_upscaleHistory[frameIndex], context.destination);
        }
    }
}