实验要求
>Ray trace and correctly draw a sphere object in the scene
>Ray trace and correctly draw a cube object in the scene
>Ray trace and correctly draw a model object in the scene
>Correctly perform Phong shading by supporting ambient, diffuse, and specular lighting in your renderer. Interpolate the normals of the vertices of the polygons to determine the normals at each pixel to be used for shading.
>Display shadows by not illuminating surfaces by lights from which they are occluded.
>Correctly perform recursive reflection (up to 3 iterations) by creating a shiny surface and bounce rays off of it.
>Read in material properties of an object in the scene, including the image files and texture coordinates, and add textures to your raytraced triangle objects and model objects. Use barycentric coordinates to calculate the material properties and texture coordinates at each pixel. Texture mapping for model object is not required.
实验步骤：
1. Xcode 配置好glfw glew
2.不知所措 先找几个reference
https://github.com/zihexue/opengl_RayTracing/tree/master/raytracing
https://blog.csdn.net/khflash/article/details/79186423
https://blog.csdn.net/hmbxsy/article/details/80509876
3.大概要做的事情：建模型：sphere,cube,model；摄像头 ；光源 ；阴影 ；材质