作业1的视角问题

[hyt589]

我能够正确的画出三角形并且可以旋转，但是视角似乎不对，三角形起初只在窗口左下角显示出了一半，我看代码感觉应该是在中间啊

我的代码如下:

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.
    float rad = radian(rotation_angle);
    model(0,0) = std::cos(rad);
    model(0,1) = -std::sin(rad);
    model(1,0) = std::sin(rad);
    model(1,1) = std::cos(rad);

    return model;
}

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 = std::abs(n) * std::tan(.5f * radian(eye_fov));
    float b = -t;
    float r = aspect_ratio * t;
    float l = -r;
    

    Eigen::Matrix4f perspective_to_orthogonal = Eigen::Matrix4f::Identity();
    perspective_to_orthogonal(0,0) = n;
    perspective_to_orthogonal(1,1) = n;
    perspective_to_orthogonal(2,2) = n + f;
    perspective_to_orthogonal(2,3) = -f * n;
    perspective_to_orthogonal(3,2) = 1;
    perspective_to_orthogonal(3,3) = 0;

    Eigen::Matrix4f move_to_center = Eigen::Matrix4f::Identity();
    move_to_center(0,3) = -(r-l)/2.f;
    move_to_center(1,3) = -(t-b)/2.f;
    move_to_center(2,3) = -(n-f)/2.f;

    Eigen::Matrix4f scale_to_canonical = Eigen::Matrix4f::Identity();
    scale_to_canonical(0,0) = 2.f/(r-l);
    scale_to_canonical(1,1) = 2.f/(t-b);
    scale_to_canonical(2,2) = 2.f/(n-f);

    Eigen::Matrix4f orthogonal_projection = scale_to_canonical * move_to_center;

    projection = orthogonal_projection * perspective_to_orthogonal;

    return projection;
}

• This topic was modified 3 years, 9 months ago by hyt589.

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[youthdou]

move_to_center不需要

[zero]

move_to_center的参数不正确，应该是

move_to_center(0,3) = -(r+l)/2.f;
 move_to_center(1,3) = -(t+b)/2.f;
 move_to_center(2,3) = -(n+f)/2.f;

• This reply was modified 3 years, 7 months ago by zero.
• This reply was modified 3 years, 7 months ago by zero.

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