win32加载图片获得像素值

　　在写光栅渲染器时，需要加载图片获得像素以便进行纹理插值，试了几种方法发现下面这种比价简单，效率也可以接受

　　Texture2D是我自己定义的类，其中m_pixelBuffer是一个动态二维数组，每个元素为ZCFLOAT3（自定义类型用来保存颜色rgb值）。

#include "LoadBitmap.h"
#include <windows.h>
#include <gdiplus.h>

#include <iostream>
#include <fstream>
#include <sstream>

#pragma comment(lib, "gdiplus.lib")
using namespace std;
using namespace Gdiplus;

Texture2D MathUtil::LoadBitmapToColorArray(wstring filePath)
{
    GdiplusStartupInput gdiplusstartupinput;
    ULONG_PTR gdiplustoken;
    GdiplusStartup(&gdiplustoken, &gdiplusstartupinput, nullptr);

    Bitmap* bmp = new Bitmap(filePath.c_str());
    if (!bmp)
    {
        MessageBox(nullptr, "error", "picture path is null!", MB_OK);
        delete bmp;
        GdiplusShutdown(gdiplustoken);
        return Texture2D(0,0);
    }
    else
    {
        UINT height = bmp->GetHeight();
        UINT width = bmp->GetWidth();
        //Texture2D
        Texture2D texture(width, height);

        Color color;

        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
            {
                bmp->GetPixel(x, y, &color);

                texture.m_pixelBuffer[x][y] = ZCFLOAT3(
                    color.GetRed() / 255.f,
                    color.GetGreen() / 255.f,
                    color.GetBlue() / 255.f
                );
            }

        delete bmp;
        GdiplusShutdown(gdiplustoken);
        return texture;
    }
    
}