From 8d006da57b729f712c7cce0be339b5ff1b8f395e Mon Sep 17 00:00:00 2001
From: Dank074 <torresefrain10@gmail.com>
Date: Thu, 29 Jul 2021 16:40:55 -0500
Subject: [PATCH] added pngencoder

---
 src/core/communication/codec/BinaryWriter.ts |  19 ++-
 src/nitro/utils/PNGEncoder.ts                | 135 +++++++++++++++++++
 2 files changed, 151 insertions(+), 3 deletions(-)
 create mode 100644 src/nitro/utils/PNGEncoder.ts

diff --git a/src/core/communication/codec/BinaryWriter.ts b/src/core/communication/codec/BinaryWriter.ts
index 8eae1ef7..3ae18385 100644
--- a/src/core/communication/codec/BinaryWriter.ts
+++ b/src/core/communication/codec/BinaryWriter.ts
@@ -1,10 +1,12 @@
 export class BinaryWriter
 {
     private _buffer: Uint8Array;
+    private _position: number;
 
     constructor()
     {
         this._buffer = new Uint8Array();
+        this._position = 0;
     }
 
     public writeByte(byte: number): BinaryWriter
@@ -74,12 +76,13 @@ export class BinaryWriter
     {
         if(!array) return;
 
-        const mergedArray = new Uint8Array(this._buffer.length + array.length);
+        const mergedArray = new Uint8Array( ((this.position + array.length) > this._buffer.length) ?  (this.position + array.length) : this._buffer.length);
 
         mergedArray.set(this._buffer);
-        mergedArray.set(array, this._buffer.length);
+        mergedArray.set(array, this.position);
 
         this._buffer = mergedArray;
+        this.position += array.length;
     }
 
     public getBuffer(): ArrayBuffer
@@ -87,8 +90,18 @@ export class BinaryWriter
         return this._buffer.buffer;
     }
 
+    public get position(): number
+    {
+        return this._position;
+    }
+
+    public set position(pos: number)
+    {
+        this._position = pos;
+    }
+
     public toString(encoding?: string): string
     {
         return new TextDecoder(encoding).decode(this._buffer);
     }
-}
\ No newline at end of file
+}
diff --git a/src/nitro/utils/PNGEncoder.ts b/src/nitro/utils/PNGEncoder.ts
new file mode 100644
index 00000000..ef7777ed
--- /dev/null
+++ b/src/nitro/utils/PNGEncoder.ts
@@ -0,0 +1,135 @@
+import { RenderTexture } from '@pixi/core';
+import { BinaryWriter } from '../../core/communication/codec/BinaryWriter';
+import { TextureUtils } from '../../room';
+
+export class PNGEncoder
+{
+    private static crcTable: number[];
+    private static crcTableComputed: boolean = false;
+
+    public static encode(texture: RenderTexture): ArrayBuffer
+    {
+        if(!texture) return null;
+
+        const canvas = TextureUtils.generateCanvas(texture);
+
+        if(!canvas) return null;
+
+        const width     = canvas.width;
+        const height    = canvas.height;
+        const context   = canvas.getContext('2d');
+        const imageData = context.getImageData(0, 0, width, height);
+
+        const writer1 = new BinaryWriter();
+        writer1.writeInt(2303741511);
+        writer1.writeInt(218765834);
+
+        const writer2 = new BinaryWriter();
+        writer2.writeInt(width);
+        writer2.writeInt(height);
+        writer2.writeInt(134610944);
+        writer2.writeByte(0);
+
+        PNGEncoder.writeChunk(writer1, 1229472850, writer2);
+
+        const writer3 = new BinaryWriter();
+
+        let _local_5 = 0;
+
+        while(_local_5 < texture.height)
+        {
+            writer3.writeByte(0);
+
+            let _local_7 = 0;
+
+            while(_local_7 < texture.width)
+            {
+                const _local_6 = PNGEncoder.getPixel(imageData, _local_7, _local_5);
+
+                writer3.writeInt((((_local_6 & 0xFFFFFF) << 8) | 0xFF));
+
+                _local_7++;
+            }
+
+            _local_5++;
+        }
+
+        PNGEncoder.writeChunk(writer1, 1229209940, writer3);
+        PNGEncoder.writeChunk(writer1, 1229278788, null);
+    }
+
+    private static getPixel(imageData: ImageData, x: number, y: number): number
+    {
+        const r = imageData.data[ ((y*(imageData.width*4)) + (x*4)) + 0 ];
+        const g = imageData.data[ ((y*(imageData.width*4)) + (x*4)) + 1 ];
+        const b = imageData.data[ ((y*(imageData.width*4)) + (x*4)) + 2 ];
+        const a = imageData.data[ ((y*(imageData.width*4)) + (x*4)) + 3 ];
+
+        return (r << 16 | g << 8 | b | a << 24);
+    }
+
+    private static writeChunk(writer1: BinaryWriter, _arg_2: number, writer2: BinaryWriter):void
+    {
+        if(!PNGEncoder.crcTableComputed)
+        {
+            PNGEncoder.crcTableComputed = true;
+            PNGEncoder.crcTable = [];
+
+            let _local_9 = 0;
+
+            while(_local_9 < 0x0100)
+            {
+                let _local_8 = _local_9;
+                let _local_10 = 0;
+
+                while(_local_10 < 8)
+                {
+                    if((_local_8 & 0x01))
+                    {
+                        _local_8 = (3988292384 ^ (_local_8 >>> 1));
+                    }
+                    else
+                    {
+                        _local_8 = (_local_8 >>> 1);
+                    }
+
+                    _local_10++;
+                }
+
+                PNGEncoder.crcTable[_local_9] = _local_8;
+                _local_9++;
+            }
+        }
+
+        let _local_4 = 0;
+
+        if(writer2 !== null) _local_4 = writer2.getBuffer().byteLength;
+
+        writer1.writeInt(_local_4);
+
+        const _local_5: number = writer1.position;
+
+        writer1.writeInt(_arg_2);
+
+        if(writer2 !== null) writer1.writeBytes(writer2.getBuffer());
+
+        const _local_6: number = writer1.position;
+
+        writer1.position = _local_5;
+
+        let _local_8 = 0xFFFFFFFF;
+
+        let _local_7 = 0;
+
+        while(_local_7 < (_local_6 - _local_5))
+        {
+            _local_8 = (PNGEncoder.crcTable[((_local_8 ^ writer1.getBuffer()[--writer1.position]) & 0xFF)] ^ (_local_8 >>> 8));
+            _local_7++;
+        }
+
+        _local_8 = (_local_8 ^ 0xFFFFFFFF);
+
+        writer1.position = _local_6;
+        writer1.writeInt(_local_8);
+    }
+}