The imgp file loader

imgp.cpp

#include<iostream>
#include <fstream>
#include <map>
#include<vector>

#include <stb_image.h>
#include <stb_image_write.h>

#define IMGP_SIZE 1024 * 1024

unsigned char buffer[IMGP_SIZE];
unsigned char result[IMGP_SIZE];


unsigned char* imgpParse() {
	int width = *(int*)(buffer);
	int height = *(int*)(buffer + 4);
	auto indexPtr = (unsigned char *)buffer + 8;
	int* colorDataPtr = (int*)(buffer + 8);
	auto cnt = width * height;
	std::map<unsigned char, unsigned short> colorMap;
	unsigned int colorCnt = *(unsigned char*)(buffer + 8 + width * height + 10);
	int* colorPtr = (int*)(buffer + 8 + width * height + 10 + 2);
	for (unsigned int i = 0; i < colorCnt; i++)
	{
		unsigned short rgba5551 = 0;
		int color = *(int*)(colorPtr + i);
		int alpha = color >> 23;
		rgba5551 = alpha;
		rgba5551 = alpha | ( 2 * (color & 0x1F | (32 * ((color >> 6) & 0x1F | (32 * (color >> 11))))));
		colorMap.insert({ i, rgba5551 });
	}
	unsigned short* resultPtr = (unsigned short *)result;
	for (int i = 0; i < cnt; i++)
	{
		resultPtr[i] = colorMap.at(*(indexPtr + i));
	}
	std::cout << std::endl;
	std::cout << width << "  " << colorMap.size() << std::endl;
	return result;
}

unsigned char* imgpLoad(char *path) {
	std::ifstream is(path, std::ifstream::in | std::ifstream::binary);
	if (is) {
		// get length of file:
		is.seekg(0, is.end);
		int length = is.tellg();
		is.seekg(0, is.beg);


		std::cout << "Reading " << length << " characters... ";
		// read data as a block:
		is.read((char *)buffer, length);

		if (is)
			std::cout << "all characters read successfully.";
		else
			std::cout << "error: only " << is.gcount() << " could be read";
		is.close();

	}
	return imgpParse();
}

void saveImage(char* filepath, GLFWwindow* w) {
	int size = 30;
	int width, height;
	glfwGetFramebufferSize(w, &width, &height);
	GLsizei nrChannels = 4;
	GLsizei bufferSize = nrChannels * size * size;
	std::vector<char> buffer(bufferSize);
	glPixelStorei(GL_PACK_ALIGNMENT, 1);
	glReadBuffer(GL_BACK);
	auto res = glGetError();
	std::cout << res << std::endl;
	glReadPixels(0, 0, size, size, GL_RGBA, GL_UNSIGNED_BYTE, buffer.data());
	res = glGetError();
	std::cout << res << std::endl;
	stbi_write_png(filepath, size, size, nrChannels, buffer.data(), size * nrChannels);
}