GAMES101-计算机图形学-作业3
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任务：
- 修改函数rasterize_triangle(const Triangle& t) in rasterizer.cpp: 在此处实现与作业2 类似的插值算法，实现法向量、颜色、纹理颜色的插值。
- 修改函数get_projection_matrix() in main.cpp: 将你自己在之前的实验中实现的投影矩阵填到此处，此时你可以运行./Rasterizer output.png normal来观察法向量实现结果。
- 修改函数phong_fragment_shader() in main.cpp: 实现Blinn-Phong 模型计算Fragment Color.
- 修改函数texture_fragment_shader() in main.cpp: 在实现Blinn-Phong的基础上，将纹理颜色视为公式中的kd，实现Texture Shading FragmentShader.
- 修改函数bump_fragment_shader() in main.cpp: 在实现Blinn-Phong 的基础上，仔细阅读该函数中的注释，实现Bump mapping.
- 修改函数displacement_fragment_shader() in main.cpp: 在实现Bumpmapping 的基础上，实现displacement mapping.
其中从实现texture_fragment_shader()开始会有opencv报错，和读颜色错误有关，解决方法：添加链接描述
1.rasterize_triangle(const Triangle& t) in rasterizer.cpp:
和作业2类似，多了几项需要插值的数
//Screen space rasterization
void rst::rasterizer::rasterize_triangle(const Triangle& t, const std::array<Eigen::Vector3f, 3>& view_pos)
{
auto v = t.toVector4();
//粗略的碰撞盒生成
int min_x = floor(std::min(v[0][0], std::min(v[1][0], v[2][0])));
int min_y = floor(std::min(v[0][1], std::min(v[1][1], v[2][1])));
int max_x = ceil(std::max(v[0][0], std::max(v[1][0], v[2][0])));
int max_y = ceil(std::max(v[0][1], std::max(v[1][1], v[2][1])));
for (int i = min_x; i <= max_x; i++) {
for (int j = min_y; j <= max_y; j++) {
if (insideTriangle(i + 0.5, j + 0.5, t.v)) {
std::tuple<float, float, float> tmpTuple = computeBarycentric2D(float(i + 0.5), float(j + 0.5), t.v);
float alpha = std::get<0>(tmpTuple);
float beta = std::get<1>(tmpTuple);
float gamma = std::get<2>(tmpTuple);
// Z:当前像素深度 zp：zFar-aNear
float Z = 1.0 / (alpha / v[0].w() + beta / v[1].w() + gamma / v[2].w());
float zp = alpha * v[0].z() / v[0].w() + beta * v[1].z() / v[1].w() + gamma * v[2].z() / v[2].w();
zp *= Z;
if (depth_buf[get_index(i, j)] > zp) {
auto interpolated_color = interpolate(alpha, beta, gamma, t.color[0], t.color[1], t.color[2], 1);
auto interpolated_normal = interpolate(alpha, beta, gamma, t.normal[0], t.normal[1], t.normal[2], 1).normalized();
auto interpolated_texcoords = interpolate(alpha, beta, gamma, t.tex_coords[0], t.tex_coords[1], t.tex_coords[2], 1);
auto interpolated_shadingcoords = interpolate(alpha, beta, gamma, view_pos[0], view_pos[1], view_pos[2], 1);
fragment_shader_payload payload(interpolated_color, interpolated_normal.normalized(), interpolated_texcoords, texture ? &*texture : nullptr);
payload.view_pos = interpolated_shadingcoords;
auto pixel_color = fragment_shader(payload);
depth_buf[get_index(i, j)] = zp;
set_pixel(Vector2i(i, j), pixel_color);
}
}
}
}
// TODO: From your HW3, get the triangle rasterization code.
// TODO: Inside your rasterization loop:
// * v[i].w() is the vertex view space depth value z.
// * Z is interpolated view space depth for the current pixel
// * zp is depth between zNear and zFar, used for z-buffer
// float Z = 1.0 / (alpha / v[0].w() + beta / v[1].w() + gamma / v[2].w());
// float zp = alpha * v[0].z() / v[0].w() + beta * v[1].z() / v[1].w() + gamma * v[2].z() / v[2].w();
// zp *= Z;
// TODO: Interpolate the attributes:
// auto interpolated_color
// auto interpolated_normal
// auto interpolated_texcoords
// auto interpolated_shadingcoords
// Use: fragment_shader_payload payload( interpolated_color, interpolated_normal.normalized(), interpolated_texcoords, texture ? &*texture : nullptr);
// Use: payload.view_pos = interpolated_shadingcoords;
// Use: Instead of passing the triangle's color directly to the frame buffer, pass the color to the shaders first to get the final color;
// Use: auto pixel_color = fragment_shader(payload);
}
2.get_projection_matrix() in main.cpp:
直接用之前写的有图片显示颠倒的问题，改了一点
Eigen::Matrix4f get_projection_matrix(float eye_fov, float aspect_ratio, float zNear, float zFar)
{
// TODO: Use the same projection matrix from the previous assignments
Eigen::Matrix4f projection = Eigen::Matrix4f::Identity();
eye_fov = eye_fov / 180 * M_PI;
Eigen::Matrix4f M1;
M1 << zNear, 0, 0, 0,
0, zNear, 0, 0,
0, 0, zNear + zFar, -zNear * zFar,
0, 0, 1, 0;
float t = -zNear * tan(eye_fov / 2);
float b = -t;
float r = t * aspect_ratio;
float l = -r;
Eigen::Matrix4f M2;
M2 << 1, 0, 0, -(r + l) / 2,
0, 1, 0, -(t + b) / 2,
0, 0, 1, -(zNear + zFar) / 2,
0, 0, 0, 1;
Eigen::Matrix4f M3;
M3 << 2 / (r - l), 0, 0, 0,
0, 2 / (t - b), 0, 0,
0, 0, 2 / (zNear - zFar), 0,
0, 0, 0, 1;
projection = M3 * M2 * M1;
return projection;
}
3.phong_fragment_shader() in main.cpp
冯布灵的三项，加起来算就完事。
需要注意的是kd.cwiseProduct(lightInt / r)，老师给的ppt里写的是I/r²，个人李姐是光照强度值直接除r值就是要算的从光源到观测点经过r衰减后的值。
Eigen::Vector3f phong_fragment_shader(const fragment_shader_payload& payload)
{
Eigen::Vector3f ka = Eigen::Vector3f(0.005, 0.005, 0.005);
Eigen::Vector3f kd = payload.color;
Eigen::Vector3f ks = Eigen::Vector3f(0.7937, 0.7937, 0.7937);
auto l1 = light{{20, 20, 20}, {500, 500, 500}};
auto l2 = light{{-20, 20, 0}, {500, 500, 500}};
std::vector<light> lights = {l1, l2};
Eigen::Vector3f amb_light_intensity{10, 10, 10};
Eigen::Vector3f eye_pos{0, 0, 10};
float p = 150;
Eigen::Vector3f color = payload.color;
Eigen::Vector3f point = payload.view_pos;
Eigen::Vector3f normal = payload.normal;
Eigen::Vector3f result_color = {0, 0, 0};
for (auto& light : lights)
{
// TODO: For each light source in the code, calculate what the *ambient*, *diffuse*, and *specular*
// components are. Then, accumulate that result on the *result_color* object.
Vector3f lightPos = light.position;
Vector3f lightInt = light.intensity;
float r = (lightPos - point).dot(lightPos - point);
Vector3f n = normal.normalized(); //n向量
Vector3f l = (lightPos - point).normalized(); //l向量
Vector3f v = (eye_pos - point).normalized(); //v向量
Vector3f h = (v + l).normalized(); //h向量
Vector3f Ld = kd.cwiseProduct(lightInt / r) * __max(0.0f, n.dot(l));
Vector3f Ls = ks.cwiseProduct(lightInt / r) * pow(__max(0.0f, n.dot(h)), p);
result_color += (Ld + Ls);
}
Vector3f La = ka.cwiseProduct(amb_light_intensity); // 环境光 直接乘他妈的
result_color += La;
return result_color * 255.f;
}
4.texture_fragment_shader() in main.cpp:
和上面基本差不多
Eigen::Vector3f texture_fragment_shader(const fragment_shader_payload& payload)
{
Eigen::Vector3f return_color = {0, 0, 0};
if (payload.texture)
{
// TODO: Get the texture value at the texture coordinates of the current fragment
return_color = payload.texture->getColor(payload.tex_coords[0], payload.tex_coords[1]); //颜色值设置为着色器的材质的uv坐标的颜色
}
Eigen::Vector3f texture_color;
texture_color << return_color.x(), return_color.y(), return_color.z();
Eigen::Vector3f ka = Eigen::Vector3f(0.005, 0.005, 0.005);
Eigen::Vector3f kd = texture_color / 255.f;
Eigen::Vector3f ks = Eigen::Vector3f(0.7937, 0.7937, 0.7937);
auto l1 = light{{20, 20, 20}, {500, 500, 500}};
auto l2 = light{{-20, 20, 0}, {500, 500, 500}};
std::vector<light> lights = {l1, l2};
Eigen::Vector3f amb_light_intensity{10, 10, 10};
Eigen::Vector3f eye_pos{0, 0, 10};
float p = 150;
Eigen::Vector3f color = texture_color;
Eigen::Vector3f point = payload.view_pos;
Eigen::Vector3f normal = payload.normal;
Eigen::Vector3f result_color = {0, 0, 0};
for (auto& light : lights)
{
// TODO: For each light source in the code, calculate what the *ambient*, *diffuse*, and *specular*
// components are. Then, accumulate that result on the *result_color* object.
Vector3f lightPos = light.position;
Vector3f lightInt = light.intensity;
float r = (lightPos - point).dot(lightPos - point);
Vector3f n = normal.normalized(); //n向量
Vector3f l = (lightPos - point).normalized(); //l向量
Vector3f v = (eye_pos - point).normalized(); //v向量
Vector3f h = (v + l).normalized(); //h向量
Vector3f Ld = kd.cwiseProduct(lightInt / r) * __max(0.0f, n.dot(l));
Vector3f Ls = ks.cwiseProduct(lightInt / r) * pow(__max(0.0f, n.dot(h)), p);
result_color += (Ld + Ls);
}
Vector3f La = ka.cwiseProduct(amb_light_intensity); // 环境光 直接乘他妈的
result_color += La;
return result_color * 255.f;
}
5.bump_fragment_shader() in main.cpp:
Eigen::Vector3f bump_fragment_shader(const fragment_shader_payload& payload)
{
Eigen::Vector3f ka = Eigen::Vector3f(0.005, 0.005, 0.005);
Eigen::Vector3f kd = payload.color;
Eigen::Vector3f ks = Eigen::Vector3f(0.7937, 0.7937, 0.7937);
auto l1 = light{{20, 20, 20}, {500, 500, 500}};
auto l2 = light{{-20, 20, 0}, {500, 500, 500}};
std::vector<light> lights = {l1, l2};
Eigen::Vector3f amb_light_intensity{10, 10, 10};
Eigen::Vector3f eye_pos{0, 0, 10};
float p = 150;
Eigen::Vector3f color = payload.color;
Eigen::Vector3f point = payload.view_pos;
Eigen::Vector3f normal = payload.normal;
float kh = 0.2, kn = 0.1;
// TODO: Implement bump mapping here
// Let n = normal = (x, y, z)
// Vector t = (x*y/sqrt(x*x+z*z),sqrt(x*x+z*z),z*y/sqrt(x*x+z*z))
// Vector b = n cross product t
// Matrix TBN = [t b n]
// dU = kh * kn * (h(u+1/w,v)-h(u,v))
// dV = kh * kn * (h(u,v+1/h)-h(u,v))
// Vector ln = (-dU, -dV, 1)
// Normal n = normalize(TBN * ln)
float x = normal.x(), y = normal.y(), z = normal.z();
Vector3f t{ x * y / sqrt(x * x + z * z), sqrt(x * x + z * z),z * y / sqrt(x * x + z * z) };
Vector3f b = normal.cross(t);
Matrix3f TBN{
{t.x(),b.x(),normal.x()},
{t.y(),b.y(),normal.y()},
{t.z(),b.z(),normal.z()}
};
float u = payload.tex_coords.x();
float v = payload.tex_coords.y();
float w = payload.texture->width;
float h = payload.texture->height;
float dU = kh * kn * (payload.texture->getColor(u + 1 / w, v).norm() - payload.texture->getColor(u, v).norm());
float dV = kh * kn * (payload.texture->getColor(u, v + 1 / h).norm() - payload.texture->getColor(u, v).norm());
Vector3f ln{ -dU,-dV,1 };
normal = (TBN * ln).normalized();
Eigen::Vector3f result_color = {0, 0, 0};
result_color = normal;
return result_color * 255.f;
}
6.displacement_fragment_shader() in main.cpp
Eigen::Vector3f displacement_fragment_shader(const fragment_shader_payload& payload)
{
Eigen::Vector3f ka = Eigen::Vector3f(0.005, 0.005, 0.005);
Eigen::Vector3f kd = payload.color;
Eigen::Vector3f ks = Eigen::Vector3f(0.7937, 0.7937, 0.7937);
auto l1 = light{{20, 20, 20}, {500, 500, 500}};
auto l2 = light{{-20, 20, 0}, {500, 500, 500}};
std::vector<light> lights = {l1, l2};
Eigen::Vector3f amb_light_intensity{10, 10, 10};
Eigen::Vector3f eye_pos{0, 0, 10};
float p = 150;
Eigen::Vector3f color = payload.color;
Eigen::Vector3f point = payload.view_pos;
Eigen::Vector3f normal = payload.normal;
float kh = 0.2, kn = 0.1;
// TODO: Implement displacement mapping here
// Let n = normal = (x, y, z)
// Vector t = (x*y/sqrt(x*x+z*z),sqrt(x*x+z*z),z*y/sqrt(x*x+z*z))
// Vector b = n cross product t
// Matrix TBN = [t b n]
// dU = kh * kn * (h(u+1/w,v)-h(u,v))
// dV = kh * kn * (h(u,v+1/h)-h(u,v))
// Vector ln = (-dU, -dV, 1)
// Position p = p + kn * n * h(u,v)
// Normal n = normalize(TBN * ln)
float x = normal.x(), y = normal.y(), z = normal.z();
Vector3f t{ x * y / sqrt(x * x + z * z), sqrt(x * x + z * z),z * y / sqrt(x * x + z * z) };
Vector3f b = normal.cross(t);
Matrix3f TBN{
{t.x(),b.x(),normal.x()},
{t.y(),b.y(),normal.y()},
{t.z(),b.z(),normal.z()}
};
float u = payload.tex_coords.x();
float v = payload.tex_coords.y();
float w = payload.texture->width;
float h = payload.texture->height;
float dU = kh * kn * (payload.texture->getColor(u + 1 / w, v).norm() - payload.texture->getColor(u, v).norm());
float dV = kh * kn * (payload.texture->getColor(u, v + 1 / h).norm() - payload.texture->getColor(u, v).norm());
Vector3f ln{ -dU,-dV,1 };
point += (kn * normal * payload.texture->getColor(u, v).norm());
normal = (TBN * ln).normalized();
Eigen::Vector3f result_color = {0, 0, 0};
for (auto& light : lights)
{
// TODO: For each light source in the code, calculate what the *ambient*, *diffuse*, and *specular*
// components are. Then, accumulate that result on the *result_color* object.
Vector3f lightPos = light.position;
Vector3f lightInt = light.intensity;
float r = (lightPos - point).dot(lightPos - point);
Vector3f n = normal.normalized(); //n向量
Vector3f l = (lightPos - point).normalized(); //l向量
Vector3f v = (eye_pos - point).normalized(); //v向量
Vector3f h = (v + l).normalized(); //h向量
Vector3f Ld = kd.cwiseProduct(lightInt / r) * __max(0.0f, n.dot(l));
Vector3f Ls = ks.cwiseProduct(lightInt / r) * pow(__max(0.0f, n.dot(h)), p);
result_color += (Ld + Ls);
}
Vector3f La = ka.cwiseProduct(amb_light_intensity); // 环境光 直接乘他妈的
result_color += La;
return result_color * 255.f;
}
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