Add ktx

ktx/external/lodepng/examples/example_encode.cpp

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+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+#include "lodepng.h"
+#include <iostream>
+
+/*
+3 ways to encode a PNG from RGBA pixel data to a file (and 2 in-memory ways).
+NOTE: these samples overwrite the file or test.png without warning!
+*/
+
+//g++ lodepng.cpp examples/example_encode.cpp -I./ -ansi -pedantic -Wall -Wextra -O3
+
+//Example 1
+//Encode from raw pixels to disk with a single function call
+//The image argument has width * height RGBA pixels or width * height * 4 bytes
+void encodeOneStep(const char* filename, std::vector<unsigned char>& image, unsigned width, unsigned height) {
+  //Encode the image
+  unsigned error = lodepng::encode(filename, image, width, height);
+
+  //if there's an error, display it
+  if(error) std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;
+}
+
+//Example 2
+//Encode from raw pixels to an in-memory PNG file first, then write it to disk
+//The image argument has width * height RGBA pixels or width * height * 4 bytes
+void encodeTwoSteps(const char* filename, std::vector<unsigned char>& image, unsigned width, unsigned height) {
+  std::vector<unsigned char> png;
+
+  unsigned error = lodepng::encode(png, image, width, height);
+  if(!error) lodepng::save_file(png, filename);
+
+  //if there's an error, display it
+  if(error) std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;
+}
+
+//Example 3
+//Save a PNG file to disk using a State, normally needed for more advanced usage.
+//The image argument has width * height RGBA pixels or width * height * 4 bytes
+void encodeWithState(const char* filename, std::vector<unsigned char>& image, unsigned width, unsigned height) {
+  std::vector<unsigned char> png;
+  lodepng::State state; //optionally customize this one
+
+  unsigned error = lodepng::encode(png, image, width, height, state);
+  if(!error) lodepng::save_file(png, filename);
+
+  //if there's an error, display it
+  if(error) std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;
+}
+
+//saves image to filename given as argument. Warning, this overwrites the file without warning!
+int main(int argc, char *argv[]) {
+  //NOTE: this sample will overwrite the file or test.png without warning!
+  const char* filename = argc > 1 ? argv[1] : "test.png";
+
+  //generate some image
+  unsigned width = 512, height = 512;
+  std::vector<unsigned char> image;
+  image.resize(width * height * 4);
+  for(unsigned y = 0; y < height; y++)
+  for(unsigned x = 0; x < width; x++) {
+    image[4 * width * y + 4 * x + 0] = 255 * !(x & y);
+    image[4 * width * y + 4 * x + 1] = x ^ y;
+    image[4 * width * y + 4 * x + 2] = x | y;
+    image[4 * width * y + 4 * x + 3] = 255;
+  }
+
+  encodeOneStep(filename, image, width, height);
+}