Add ktx

ktx/external/lodepng/examples/example_decode.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 decode a PNG from a file to RGBA pixel data (and 2 in-memory ways).
+*/
+
+//g++ lodepng.cpp example_decode.cpp -ansi -pedantic -Wall -Wextra -O3
+
+
+//Example 1
+//Decode from disk to raw pixels with a single function call
+void decodeOneStep(const char* filename) {
+  std::vector<unsigned char> image; //the raw pixels
+  unsigned width, height;
+
+  //decode
+  unsigned error = lodepng::decode(image, width, height, filename);
+
+  //if there's an error, display it
+  if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+
+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
+}
+
+//Example 2
+//Load PNG file from disk to memory first, then decode to raw pixels in memory.
+void decodeTwoSteps(const char* filename) {
+  std::vector<unsigned char> png;
+  std::vector<unsigned char> image; //the raw pixels
+  unsigned width, height;
+
+  //load and decode
+  unsigned error = lodepng::load_file(png, filename);
+  if(!error) error = lodepng::decode(image, width, height, png);
+
+  //if there's an error, display it
+  if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+
+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
+}
+
+//Example 3
+//Load PNG file from disk using a State, normally needed for more advanced usage.
+void decodeWithState(const char* filename) {
+  std::vector<unsigned char> png;
+  std::vector<unsigned char> image; //the raw pixels
+  unsigned width, height;
+  lodepng::State state; //optionally customize this one
+
+  unsigned error = lodepng::load_file(png, filename); //load the image file with given filename
+  if(!error) error = lodepng::decode(image, width, height, state, png);
+
+  //if there's an error, display it
+  if(error) std::cout << "decoder error " << error << ": "<< lodepng_error_text(error) << std::endl;
+
+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...
+  //State state contains extra information about the PNG such as text chunks, ...
+}
+
+int main(int argc, char *argv[]) {
+  const char* filename = argc > 1 ? argv[1] : "test.png";
+
+  decodeOneStep(filename);
+}
+