stb_image代替其他库

stb 下载
stb 是一个非常好用的lib， 本身只需要头文件就行，MIT协议，可以商用

用它做OPENGL 3d engine的读取库是很合适。如png图像，RGBA，四通道图像读取，并且修改像素，如制作一个地图，使用修改像素的方法直接标识地点

#include <stdio.h>
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
 int main(int argc, char** argv)
 {
     int w, h, n;
     unsigned char *data = stbi_load("1.png", &w, &h, &n, 0);
      cout<<"w is :"<<w <<" h is :"<< h<<" channel is :"<< n <<endl;
     //rgba,write 10 red pixel at line 11
     for (int dx = 0; dx < 10; ++dx)
     {
         data[n * w * 10 + dx * n + 0] = 255;
         data[n * w * 10 + dx * n + 1] = 0;
         data[n * w * 10 + dx * n + 2] = 0;
         data[n * w * 10 + dx * n + 3] = 255;
     }
     //write image
     stbi_write_png("write.png", w, h, n, data, w * n);
     stbi_image_free(data);
     return 0;
 }

可以直接存也可以直接从内存中把图像给opengl贴图就行

void load_mem()
{
	FILE* inFile = fopen("test.png", "rb");
	fseek(inFile, 0, SEEK_END);
	unsigned int bufSize = ftell(inFile);
	fseek(inFile, 0, SEEK_SET);
	unsigned char* buf = new unsigned char[bufSize];
	fread(buf, bufSize, 1, inFile);
	fclose(inFile);
	int w = 128;
	int h = 128;
	int n = 4;
	unsigned char *rgba = stbi_load_from_memory(buf, bufSize, &w, &h, &n, 0);
	stbi_write_png("memory.png", w, h, n, rgba, w * n);
	stbi_image_free(rgba);
	delete[] buf;
}

我们要保存一个图片也可以从内存中直接读取后保存，假定我们熟悉使用opencv也是非常方便，不过，在程序中显然不能为了一个png等图片引入opencv，要看功能而定。