Implement some missing lua functions, PNG format creation (requires zlib)

1 files changed, 262 insertions, 1 deletions

diff --git a/src/Format.cpp b/src/Format.cpp
index 71a0e9e..ef0050d 100644
--- a/src/Format.cpp
+++ b/src/Format.cpp
@@ -1,7 +1,10 @@
 
-#include <time.h>
+#include <ctime>
 #include <string>
+#include <stdexcept>
+#include <zlib.h>
 #include "Format.h"
+#include "graphics/Graphics.h"
 
 std::string format::UnixtimeToDate(time_t unixtime, std::string dateFormat)
 {
@@ -33,3 +36,261 @@ std::string format::UnixtimeToDateMini(time_t unixtime)
 		return UnixtimeToDate(unixtime, "%H:%M:%S");
 	}
 }
+
+struct PNGChunk
+{
+	int Length;
+	char Name[4];
+	char * Data;
+
+	//char[4] CRC();
+
+	PNGChunk(int length, std::string name)
+	{
+		if(name.length()!=4)
+			throw std::runtime_error("Invalid chunk name");
+		std::copy(name.begin(), name.begin()+4, Name);
+		Length = length;
+		if(length)
+		{
+			Data = new char[length];
+			std::fill(Data, Data+length, 0);
+		}
+		else
+		{
+			Data = NULL;
+		}
+	}
+	unsigned long CRC()
+	{
+		if(!Data)
+		{
+			return format::CalculateCRC((unsigned char*)Name, 4);
+		}
+		else
+		{
+			unsigned char * temp = new unsigned char[4+Length];
+			std::copy(Name, Name+4, temp);
+			std::copy(Data, Data+Length, temp+4);
+			unsigned long tempRet = format::CalculateCRC(temp, 4+Length);
+			delete[] temp;
+			return tempRet;
+		}
+	}
+	~PNGChunk()
+	{
+		if(Data)
+			delete[] Data;
+	}
+};
+
+std::vector<char> format::VideoBufferToPNG(const VideoBuffer & vidBuf)
+{
+	std::vector<PNGChunk*> chunks;
+
+	//Begin IHDR (Image header) chunk (Image size and depth)
+	PNGChunk IHDRChunk = PNGChunk(13, "IHDR");
+
+	//Image Width
+	IHDRChunk.Data[0] = (vidBuf.Width>>24)&0xFF;
+	IHDRChunk.Data[1] = (vidBuf.Width>>16)&0xFF;
+	IHDRChunk.Data[2] = (vidBuf.Width>>8)&0xFF;
+	IHDRChunk.Data[3] = (vidBuf.Width)&0xFF;
+
+	//Image Height
+	IHDRChunk.Data[4] = (vidBuf.Height>>24)&0xFF;
+	IHDRChunk.Data[5] = (vidBuf.Height>>16)&0xFF;
+	IHDRChunk.Data[6] = (vidBuf.Height>>8)&0xFF;
+	IHDRChunk.Data[7] = (vidBuf.Height)&0xFF;
+
+	//Bit depth
+	IHDRChunk.Data[8] = 8; //8bits per channel or 24bpp
+
+	//Colour type
+	IHDRChunk.Data[9] = 2; //RGB triple
+
+	//Everything else is default
+	chunks.push_back(&IHDRChunk);
+
+	//Begin image data, format is 8bit RGB (24bit pixel)
+	int dataPos = 0;
+	unsigned char * uncompressedData = new unsigned char[(vidBuf.Width*vidBuf.Height*3)+vidBuf.Height];
+
+	//Byte ordering and filtering
+	unsigned char * previousRow = new unsigned char[vidBuf.Width*3];
+	std::fill(previousRow, previousRow+(vidBuf.Width*3), 0);
+	unsigned char * currentRow = new unsigned char[vidBuf.Width*3];
+	for(int y = 0; y < vidBuf.Height; y++)
+	{
+		int rowPos = 0;
+		for(int x = 0; x < vidBuf.Width; x++)
+		{
+			currentRow[rowPos++] = PIXR(vidBuf.Buffer[(y*vidBuf.Width)+x]);
+			currentRow[rowPos++] = PIXG(vidBuf.Buffer[(y*vidBuf.Width)+x]);
+			currentRow[rowPos++] = PIXB(vidBuf.Buffer[(y*vidBuf.Width)+x]);
+		}
+
+		uncompressedData[dataPos++] = 2; //Up Sub(x) filter 
+		for(int b = 0; b < rowPos; b++)
+		{
+			int filteredByte = (currentRow[b]-previousRow[b])&0xFF;
+			uncompressedData[dataPos++] = filteredByte;
+		}
+
+		unsigned char * tempRow = previousRow;
+		previousRow = currentRow;
+		currentRow = tempRow;
+	}
+	delete[] currentRow;
+	delete[] previousRow;
+
+	//Compression
+	int compressedBufferSize = (vidBuf.Width*vidBuf.Height*3)*2;
+	unsigned char * compressedData = new unsigned char[compressedBufferSize];
+
+	int result;
+    z_stream zipStream; 
+    zipStream.zalloc = Z_NULL;
+    zipStream.zfree = Z_NULL;
+    zipStream.opaque = Z_NULL;
+
+    result = deflateInit2(&zipStream,
+            9,              // level
+            Z_DEFLATED,     // method
+            10,             // windowBits
+            1,              // memLevel
+            Z_DEFAULT_STRATEGY // strategy
+    );
+
+    if (result != Z_OK) exit(result);
+
+    zipStream.next_in = uncompressedData;
+    zipStream.avail_in = dataPos;
+
+    zipStream.next_out = compressedData;
+    zipStream.avail_out = compressedBufferSize;
+
+
+    result = deflate(&zipStream, Z_FINISH);
+    if (result != Z_STREAM_END) exit(result);
+
+    int compressedSize = compressedBufferSize-zipStream.avail_out;
+	PNGChunk IDATChunk = PNGChunk(compressedSize, "IDAT");
+	std::copy(compressedData, compressedData+compressedSize, IDATChunk.Data);
+	chunks.push_back(&IDATChunk);
+
+	deflateEnd(&zipStream);
+
+	delete[] compressedData;
+	delete[] uncompressedData;
+
+	PNGChunk IENDChunk = PNGChunk(0, "IEND");
+	chunks.push_back(&IENDChunk);
+
+	//Write chunks to output buffer
+	int finalDataSize = 8;
+	for(std::vector<PNGChunk*>::iterator iter = chunks.begin(), end = chunks.end(); iter != end; ++iter)
+	{
+		PNGChunk * cChunk = *iter;
+		finalDataSize += 4 + 4 + 4;
+		finalDataSize += cChunk->Length;
+	}
+	unsigned char * finalData = new unsigned char[finalDataSize];
+	int finalDataPos = 0;
+
+	//PNG File header
+	finalData[finalDataPos++] = 0x89;
+	finalData[finalDataPos++] = 0x50;
+	finalData[finalDataPos++] = 0x4E;
+	finalData[finalDataPos++] = 0x47;
+	finalData[finalDataPos++] = 0x0D;
+	finalData[finalDataPos++] = 0x0A;
+	finalData[finalDataPos++] = 0x1A;
+	finalData[finalDataPos++] = 0x0A;
+
+	for(std::vector<PNGChunk*>::iterator iter = chunks.begin(), end = chunks.end(); iter != end; ++iter)
+	{
+		PNGChunk * cChunk = *iter;
+
+		//Chunk length
+		finalData[finalDataPos++] = (cChunk->Length>>24)&0xFF;
+		finalData[finalDataPos++] = (cChunk->Length>>16)&0xFF;
+		finalData[finalDataPos++] = (cChunk->Length>>8)&0xFF;
+		finalData[finalDataPos++] = (cChunk->Length)&0xFF;
+
+		//Chunk name
+		std::copy(cChunk->Name, cChunk->Name+4, finalData+finalDataPos);
+		finalDataPos += 4;
+
+		//Chunk data
+		if(cChunk->Data)
+		{
+			std::copy(cChunk->Data, cChunk->Data+cChunk->Length, finalData+finalDataPos);
+			finalDataPos += cChunk->Length;
+		}
+
+		//Chunk CRC
+		unsigned long tempCRC = cChunk->CRC();
+		finalData[finalDataPos++] = (tempCRC>>24)&0xFF;
+		finalData[finalDataPos++] = (tempCRC>>16)&0xFF;
+		finalData[finalDataPos++] = (tempCRC>>8)&0xFF;
+		finalData[finalDataPos++] = (tempCRC)&0xFF;
+	}
+
+	std::vector<char> outputData(finalData, finalData+finalDataPos);
+
+	delete[] finalData;
+
+	return outputData;
+}
+
+//CRC functions, copypasta from W3 PNG spec.
+
+/* Table of CRCs of all 8-bit messages. */
+unsigned long crc_table[256];
+
+/* Flag: has the table been computed? Initially false. */
+int crc_table_computed = 0;
+
+/* Make the table for a fast CRC. */
+void make_crc_table(void)
+{
+ unsigned long c;
+ int n, k;
+
+ for (n = 0; n < 256; n++) {
+   c = (unsigned long) n;
+   for (k = 0; k < 8; k++) {
+     if (c & 1)
+       c = 0xedb88320L ^ (c >> 1);
+     else
+       c = c >> 1;
+   }
+   crc_table[n] = c;
+ }
+ crc_table_computed = 1;
+}
+
+/* Update a running CRC with the bytes buf[0..len-1]--the CRC
+  should be initialized to all 1's, and the transmitted value
+  is the 1's complement of the final running CRC (see the
+  crc() routine below)). */
+
+unsigned long update_crc(unsigned long crc, unsigned char *buf, int len)
+{
+	unsigned long c = crc;
+	int n;
+
+	if (!crc_table_computed)
+		make_crc_table();
+	for (n = 0; n < len; n++)
+	{
+		c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
+	}
+	return c;
+}
+
+unsigned long format::CalculateCRC(unsigned char * data, int len)
+{
+	return update_crc(0xffffffffL, data, len) ^ 0xffffffffL;
+}
\ No newline at end of file