#include "ImageLoader.h"

#include "picoPNG.h"

#include "IOManager.h"

#include "BengineErrors.h"

namespace Bengine {

GLTexture ImageLoader::loadPNG(std::string filePath) {

//Create a GLTexture and initialize all its fields to 0

GLTexture texture = {};

//This is the input data to decodePNG, which we load from a file

std::vector<unsigned char> in;

//This is the output data from decodePNG, which is the pixel data for our texture

std::vector<unsigned char> out;

unsigned long width, height;

//Read in the image file contents into a buffer

if (IOManager::readFileToBuffer(filePath, in) == false) {

fatalError("Failed to load PNG file to buffer!");

}

//Decode the .png format into an array of pixels

int errorCode = decodePNG(out, width, height, &(in[0]), in.size());

if (errorCode != 0) {

fatalError("decodePNG failed with error: " + std::to_string(errorCode));

}

//Generate the openGL texture object

glGenTextures(1, &(texture.id));

//Bind the texture object

glBindTexture(GL_TEXTURE_2D, texture.id);

//Upload the pixels to the texture

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, &(out[0]));

//Set some texture parameters

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);

//Generate the mipmaps

glGenerateMipmap(GL_TEXTURE_2D);

//Unbind the texture

glBindTexture(GL_TEXTURE_2D, 0);

texture.width = width;

texture.height = height;

//Return a copy of the texture data

return texture;

}

}