Eigen::Matrix4f get_projection_matrix(float eye_fov, float aspect_ratio, float zNear, float zFar)
{
    // TODO: Copy-paste your implementation from the previous assignment.
    zNear *=-1;
    zFar *=-1;
    std::cout<<"zNear is "<<zNear<<std::endl;
    std::cout<<"zFar is "<<zFar<<std::endl;
    Eigen::Matrix4f projection = Eigen::Matrix4f::Identity();
    Eigen::Matrix4f m;
    m<<zNear,0,0,0,
    0,zNear,0,0,
    0,0,zNear+zFar,-zNear*zFar,
    0,0,1,0;
    float halve = eye_fov/2*MY_PI/180;
    float top = tan(halve)*zNear;
    float bottom = -top;
    float right = top*aspect_ratio;
    float left = -right;
    Eigen::Matrix4f n,p;
    n<<2/(right-left),0,0,0,
    0,2/(top-bottom),0,0,
    0,0,2/(zNear-zFar),0,
    0,0,0,1;
    p<<1,0,0,-(right+left)/2,
    0,1,0,-(top+bottom)/2,
    0,0,1,-(zFar+zNear)/2,
    0,0,0,1;
    projection = n*p*m;
    return projection;
}

static bool insideTriangle(float x, float y, const Vector3f* _v)
{   
    // TODO : Implement this function to check if the point (x, y) is inside the triangle represented by _v[0], _v[1], _v[2]
    
    Vector3f point_A = _v[0], point_B = _v[1], point_C = _v[2], point_D = Vector3f(x,y,1);
    Vector3f vector_AB = point_B-point_A, vector_BC = point_C-point_B, vector_CA = point_A-point_C, vector_AD = point_D-point_A, vector_BD = point_D-point_B, vector_CD = point_D-point_C;
    Vector3f AB_X_AD = vector_AB.cross(vector_AD), BC_X_BD = vector_BC.cross(vector_BD), CA_X_CD = vector_CA.cross(vector_CD);
    int a = (AB_X_AD.z())*(BC_X_BD.z()), b = (AB_X_AD.z())*(CA_X_CD.z());
    return (AB_X_AD.z()>0&&BC_X_BD.z()>0&&CA_X_CD.z()>0)||(AB_X_AD.z()<0&&BC_X_BD.z()<0&&CA_X_CD.z()<0);
}

void rst::rasterizer::rasterize_triangle(const Triangle& t) {
    auto v = t.toVector4();
    
    // TODO : Find out the bounding box of current triangle.
    int left = MIN(MIN(v[0].x(),v[1].x()),v[2].x()), right = MAX(MAX(v[0].x(),v[1].x()),v[2].x()), down = MIN(MIN(v[0].y(),v[1].y()),v[2].y()), up = MAX(MAX(v[0].y(),v[1].y()),v[2].y());
    // iterate through the pixel and find if the current pixel is inside the triangle
    const Vector3f points[3] = {Vector3f(t.v[0].x(),t.v[0].y(),1), Vector3f(t.v[1].x(),t.v[1].y(),1), Vector3f(t.v[2].x(),t.v[2].y(),1)};
    Vector3f color = t.getColor();
    for(int i = left;i<right;i++){
        for(int j = down;j<up;j++){
            //background color is black;
            float r = 0,g = 0,b = 0;
            for(float _x_ = i+0.25;_x_<i+1;_x_+=0.5){
                for(float _y_ = j+0.25;_y_<j+1;_y_+=0.5){
                    if(insideTriangle(_x_,_y_,t.v)){
                        r+=0.25f*color.x();
                        g+=0.25f*color.y();
                        b+=0.25f*color.z();
                    }
                }
            }
            auto[alpha, beta, gamma] = computeBarycentric2D(i, j, t.v);
            float w_reciprocal = 1.0/(alpha / v[0].w() + beta / v[1].w() + gamma / v[2].w());
            float z_interpolated = alpha * v[0].z() / v[0].w() + beta * v[1].z() / v[1].w() + gamma * v[2].z() / v[2].w();
            z_interpolated *= w_reciprocal;
            if(insideTriangle(i,j,t.v)&&z_interpolated<depth_buf[get_index(i,j)]){
                this->set_pixel(Vector3f(i,j,z_interpolated),Vector3f(r,g,b));
                depth_buf[get_index(i,j)] = z_interpolated;
            }
        }
    }
}

我觉得应该是这个透视矩阵的问题吧？我看作业1初始时生成的三角形也是倒着的