Games101 作业1

#include "Triangle.hpp"
#include "rasterizer.hpp"
#include <eigen3/Eigen/Eigen>
#include <iostream>
#include <opencv2/opencv.hpp>

constexpr double MY_PI = 3.1415926;

Eigen::Matrix4f get_view_matrix(Eigen::Vector3f eye_pos)
{
    Eigen::Matrix4f view = Eigen::Matrix4f::Identity();

    Eigen::Matrix4f translate;
    translate << 1, 0, 0, -eye_pos[0], 0, 1, 0, -eye_pos[1], 0, 0, 1,
        -eye_pos[2], 0, 0, 0, 1;

    view = translate * view;

    return view;
}

Eigen::Matrix4f get_model_matrix(float rotation_angle)
{
    Eigen::Matrix4f model = Eigen::Matrix4f::Identity();

    // TODO: Implement this function
    // Create the model matrix for rotating the triangle around the Z axis.
    // Then return it.

    rotation_angle = rotation_angle / 180 * MY_PI;

    Eigen::Matrix4f r;
    r <<    cos(rotation_angle), -sin(rotation_angle), 0.0,0.0, 
            sin(rotation_angle), cos(rotation_angle), 0.0, 0.0,
            0.0,       0.0, 1.0,0.0,
            0.0,       0.0, 1.0,1.0;

    model = r * model;

    return model;
}

Eigen::Matrix4f get_rotation(Vector3f axis, float angle){
    Eigen::Matrix4f I = Eigen::Matrix4f::Identity();
    Eigen::Matrix4f R_n_alpha;
    Vector4f n(axis[0],axis[1],axis[2],0);
    Eigen::Matrix4f cross_prod;
    cross_prod <<   0, -n[2], n[1],
                    n[2], 0, -n[0],
                    -n[1],n[0],0;

    R_n_alpha = cos(angle)*I + (1-cos(angle))*n*n.transpose()+sin(angle)*cross_prod;

    return R_n_alpha;
}

Eigen::Matrix4f get_projection_matrix(float eye_fov, float aspect_ratio,
                                      float zNear, float zFar)
{
    // Students will implement this function

    Eigen::Matrix4f projection = Eigen::Matrix4f::Identity();

    // TODO: Implement this function
    // Create the projection matrix for the given parameters.
    // Then return it.

    float n = zNear;
	float f = zFar;

	float t = tan(eye_fov/2) * abs(n);
    float b = -t;

	float r = aspect_ratio * t;
    float l = -r;

    Eigen::Matrix4f M_ortho_1,M_ortho_2,M_ortho;
	M_ortho_2 << 	2/(r-l), 0.0, 0.0, 0.0,
					0.0, 2/(t-b), 0.0, 0.0,
					0.0, 0.0, 2/(n-f), 0.0,
					0.0, 0.0, 0.0, 		1.0;

	M_ortho_1 << 	1.0, 0.0, 0.0, -(r+l)/2,
					0.0, 1.0, 0.0, -(t+b)/2,
					0.0, 0.0, 1.0, -(n+f)/2,
					0.0, 0.0, 0.0, 1.0;
	M_ortho = M_ortho_2 * M_ortho_1;

	Eigen::Matrix4f M_persp_ortho;
	M_persp_ortho << n, 0.0, 0.0, 0.0,
					0.0, n, 0.0, 0.0,
					0.0, 0.0, n+f, -n*f,
					0.0, 0.0, 1.0, 0.0;
	M_ortho = M_ortho_2 * M_ortho_1;

    projection = M_ortho * M_persp_ortho * projection;

    return projection;
}

int main(int argc, const char** argv)
{
    float angle = 0;
    bool command_line = false;
    std::string filename = "output.png";

    if (argc >= 3) {
        command_line = true;
        angle = std::stof(argv[2]); // -r by default
        if (argc == 4) {
            filename = std::string(argv[3]);
        }
    }

    rst::rasterizer r(700, 700);

    Eigen::Vector3f eye_pos = {0, 0, 5};

    std::vector<Eigen::Vector3f> pos{{2, 0, -2}, {0, 2, -2}, {-2, 0, -2}};

    std::vector<Eigen::Vector3i> ind{{0, 1, 2}};

    auto pos_id = r.load_positions(pos);
    auto ind_id = r.load_indices(ind);

    int key = 0;
    int frame_count = 0;

    if (command_line) {
        r.clear(rst::Buffers::Color | rst::Buffers::Depth);

        r.set_model(get_model_matrix(angle));
        r.set_view(get_view_matrix(eye_pos));
        r.set_projection(get_projection_matrix(45, 1, 0.1, 50));

        r.draw(pos_id, ind_id, rst::Primitive::Triangle);
        cv::Mat image(700, 700, CV_32FC3, r.frame_buffer().data());
        image.convertTo(image, CV_8UC3, 1.0f);

        cv::imwrite(filename, image);

        return 0;
    }

    while (key != 27) {
        r.clear(rst::Buffers::Color | rst::Buffers::Depth);

        r.set_model(get_model_matrix(angle));
        r.set_view(get_view_matrix(eye_pos));
        r.set_projection(get_projection_matrix(45, 1, 0.1, 50));

        r.draw(pos_id, ind_id, rst::Primitive::Triangle);

        cv::Mat image(700, 700, CV_32FC3, r.frame_buffer().data());
        image.convertTo(image, CV_8UC3, 1.0f);
        cv::imshow("image", image);
        key = cv::waitKey(10);

        std::cout << "frame count: " << frame_count++ << '\n';

        if (key == 'a') {
            angle += 10;
        }
        else if (key == 'd') {
            angle -= 10;
        }
    }

    return 0;
}