//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="CollisionTexture.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using StgSharp.Internal;
using StgSharp.Geometries;
using StgSharp.Graphics;
using StgSharp.Graphics.OpenGL;

using StgSharp.Math;
using StgSharp.MVVM;

using System;
using System.Buffers;
using System.Collections.Generic;
using System.Linq;
using System.Resources;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Stg
{
    public interface IOneDimensionalCollisionTexture2D
    {

        public void Init( Radius angleStride, string name );

    }

    public sealed class OneDimensionalCollisionTexture2D_GL : glRender, IOneDimensionalCollisionTexture2D
    {

        private float[] textureOutput;
        private ElementBuffer ebo;
        private FrameBuffer fbo;
        private RenderBuffer rbo;

        private ShaderProgram generatingShader;

        private TextureGL t;

        private VertexArray vao;
        private VertexBuffer vbo;

        public OneDimensionalCollisionTexture2D_GL() { }

        public override bool IsContextSharable => false;

        public void GenerateCollisionTexture(
            IEnumerable<IInstancingBuffer> bufferEnumeration )
        {
            fbo.Bind( 0 );
            GL.ClearColor( 0, 0, 0, 1 );
            GL.Clear( MaskBufferBit.DEPTH | MaskBufferBit.COLOR );
            generatingShader.Use();
            vao.Bind( 0 );

            foreach( IInstancingBuffer item in bufferEnumeration ) {
                IGeometry g = item.TypicalShape;

                if( !( g is PlainGeometry ) ) {
                    throw new InvalidOperationException(
                        "The current particle buffer contains non-planar geometry," );
                }

                ebo.Bind( 0 );
                ebo.SetValue<int>( 0, g.VertexIndices, BufferUsage.StreamDraw );

                vbo.WriteVectorData<Vec4>(
                    0, item.CoordAndRotationSpan, BufferUsage.StreamDraw );
                vao.SetVertexAttribute(
                    1, 3, TypeCode.Single, false, 4 * sizeof( float ), 0 );
                vao.SetVertexAttribute(
                    2, 1, TypeCode.Single, false, 4 * sizeof( float ),
                    3 * sizeof( float ) );

                vbo.WriteScalerData<float>(
                    2, item.ScalingSpan, BufferUsage.StreamDraw );
                vao.SetVertexAttribute(
                    3, 1, TypeCode.Single, false, sizeof( float ), 0 );

                vbo.WriteVectorData( 1, g.VertexStream,
                                     BufferUsage.StreamDraw );
                vao.SetVertexAttribute(
                    0, 3, TypeCode.Single, false, 4 * sizeof( float ), 0 );

                GL.DrawElementsInstanced(
                    GeometryType.TRIANGLES,
                    ( ( uint )g.VertexIndices.Length ) / 3, TypeCode.UInt32,
                    IntPtr.Zero, ( uint )item.ScalingSpan.Length );
            }

            t.Bind2D( 0 );
            GL.GetTextureImage(
                Texture2DTarget.Texture2D, 0, ImageChannel.SingleColor,
                PixelChannelLayout.Float, textureOutput );
            VertexArray.BindNull();
        }

        public void Init( Radius angleStride, string name )
        {
            primeArgs = new ViewPort(
                1, (int)(( new Radius( Scaler.Pi ) ) / angleStride), name,
                IntPtr.Zero );

            PlatformSpecifiedInitialize();
            CustomizeInit();
        }

        #pragma warning disable CS8618

        protected override void CustomizeDeinit()
        {
            throw new NotImplementedException();
        }

        protected override void CustomizeInit()
        {
            generatingShader = CreateShaderProgram();

            Shader vertexShader = CreateShaderSegment( ShaderType.Vertex, 1 );
            Shader fragmentShader = CreateShaderSegment(
                ShaderType.Fragment, 1 );

            vertexShader.Compile( 0, InternalIO.CollisionTextureVertexShader );
            fragmentShader.Compile(
                0, InternalIO.CollisionTextureFragmentShader );
            vertexShader.AttachTo( 0, generatingShader );
            fragmentShader.AttachTo( 0, generatingShader );

            generatingShader.Link();
            generatingShader.Use();

            vbo = CreateVertexBuffer( 3 );
            vao = CreateVertexArray( 1 );
            ebo = CreateElementBuffer( 1 );


            fbo = CreateFrameBuffer( 1 );
            rbo = CreateRenderBuffer( 1 );
            GL.SetRenderBufferStorage(
                RenderBufferInternalFormat.Depth24_Stencil8, this.Size );


            t = CreateTexture( 1 );
            t.Bind2D( 0 );
            GL.TextureImage2d<byte>(
                Texture2DTarget.Texture2D, 0, ImageChannel.WithAlphaChannel,
                ( uint )Width, ( uint )Height, ImageChannel.WithAlphaChannel,
                PixelChannelLayout.Byte, Array.Empty<byte>() );

            t.Set2dWrapProperty( 0, TextureWrap.Repeat, TextureWrap.Repeat );
            t.Set2dFilterProperty(
                0, TextureFilter.Nearest, TextureFilter.Nearest );

            GL.FrameBufferTexture2d(
                FrameBufferTarget.All, glAttachment.Color( 0 ),
                Texture2DTarget.Texture2D, t[ 0 ], 0 );

            GL.CombineFrameBufferRenderBuffer(
                FrameBufferAttachment.Color, rbo[ 0 ] );

            textureOutput = new float[this.Width];
        }

    }
}