Vector4 Shading(const Vector3 &pos, const Vector3 &normal, const Material &mat, const Light &light)
{
// 光线方向，由物体指向光源
Vector3 L = light.position - pos;
// 光源距离
float dist = L.Magnitude();
L.SetNormalize();
// 光强，按点光源计算
float I = 1.0f / (light.attenuation0 + light.attenuation1 * dist + light.attenuation2 * dist * dist);
// 环境光
Vector4 amb_color = light.ambient * mat.ambient * I;
amb_color = clamp(amb_color, 0.0f, 1.0f);
Vector3 N = normal;
N.SetNormalize();
// 顶点法线
float light_angle = DotProduct(L, N);
light_angle = max_t(light_angle, 0.0f);
// 漫反射
Vector4 diff_color = light.diffuse * mat.diffuse * light_angle * I;
diff_color = clamp(diff_color, 0.0f, 1.0f);
// 观察方向（相机空间）
Vector3 V = -pos;
V.SetNormalize();
// 半角向量
Vector3 H = L + V;
H.SetNormalize();
// 镜面反射
float view_angle = DotProduct(H, N);
view_angle = max_t(view_angle, 0.0f);
Vector4 spec_color = light.specular * mat.specular * powf(view_angle, mat.specular.w) * I;
spec_color = clamp(spec_color, 0.0f, 1.0f);
Vector4 ret = amb_color + diff_color + spec_color;
return ret;
}
void Renderer::Lighting(void)
{
if (shading_mode_ == kFrame || shading_mode_ == kNoLightingEffect)
{
return;
}
else if (shading_mode_ == kFlat)
{
assert(light_);
if (!light_)
return;
for (int i = 2; i < rend_primitive_.size; i += 3)
{
// 假设为三角形
if ((i + 1) % 3 != 0)
continue;
Vector3 p0 = rend_primitive_.vertexs[i - 2].position.GetVector3();
Vector3 p1 = rend_primitive_.vertexs[i - 1].position.GetVector3();
Vector3 p2 = rend_primitive_.vertexs[i].position.GetVector3();
Vector3 pos = (p0 + p1 + p2) * (1.0f / 3.0f);
Vector3 e0 = p1 - p0;
Vector3 e1 = p2 - p1;
Vector3 normal = CrossProduct(e0, e1);
normal.SetNormalize();
Vector4 color = Shading(pos, normal, *mat_, *light_);
rend_primitive_.vertexs[i - 2].color = color;
rend_primitive_.vertexs[i - 1].color = color;
rend_primitive_.vertexs[i].color = color;
}
}
else if (shading_mode_ == kGouraud)
{
assert(light_);
if (!light_)
return;
for (int i = 0; i < rend_primitive_.size; ++i)
{
// 顶点位置
const Vector3 pos = rend_primitive_.vertexs[i].position.GetVector3();
const Vector3 &normal = rend_primitive_.vertexs[i].normal;
Vector4 color = Shading(pos, normal, *mat_, *light_);
rend_primitive_.vertexs[i].color = color;
}
}
else if (shading_mode_ == kPhong)
{
for (int i = 0; i < rend_primitive_.size; ++i)
{
// 记录物体原来的位置
rend_primitive_.vertexs[i].global_pos = rend_primitive_.vertexs[i].position.GetVector3();
}
return;
}
}
/* v0
/\
/ \
/ \
/ \
/ \
v2 ------------ v1
*/
void Renderer::DiffTriangleUp(const RendVertex &v0, const RendVertex &v1, const RendVertex &v2)
{
float dy = v1.position.y - v0.position.y;
float dx_left = (v2.position.x - v0.position.x) / dy;
float dx_right = (v1.position.x - v0.position.x) / dy;
float done_over_z_left = (1.0f / v2.position.w - 1.0f / v0.position.w) / dy;
float done_over_z_right = (1.0f / v1.position.w - 1.0f / v0.position.w) / dy;
Vector4 dc_left = (v2.color - v0.color) / dy;
Vector4 dc_right = (v1.color - v0.color) / dy;
// 透视差值uv
Vector2 uv_over_z_top = v0.uv / v0.position.w;
Vector2 uv_over_z_left = v2.uv / v2.position.w;
Vector2 uv_over_z_right = v1.uv / v1.position.w;
Vector2 duv_over_z_left = (uv_over_z_left - uv_over_z_top) / dy;
Vector2 duv_over_z_right = (uv_over_z_right - uv_over_z_top) / dy;
// 仿射映射差值uv
Vector2 duv_left = (v2.uv - v0.uv) / dy;
Vector2 duv_right = (v1.uv - v0.uv) / dy;
// 对法线差值
Vector3 dnormal_left = (v2.normal - v0.normal) / dy;
Vector3 dnormal_right = (v1.normal - v0.normal) / dy;
// 对物体原来位置做差值
Vector3 dpos_left = (v2.global_pos - v0.global_pos) / dy;
Vector3 dpos_right = (v1.global_pos - v0.global_pos) / dy;
float x_begin = v0.position.x;
float x_end = v0.position.x;
float one_over_z_begin = 1.0f / v0.position.w;
float one_over_z_end = 1.0f / v0.position.w;
Vector4 color_begin = v0.color;
Vector4 color_end = v0.color;
Vector2 uv_over_z_begin = uv_over_z_top;
Vector2 uv_over_z_end = uv_over_z_top;
Vector2 uv_begin = v0.uv;
Vector2 uv_end = v0.uv;
Vector3 normal_begin = v0.normal;
Vector3 normal_end = v0.normal;
Vector3 pos_begin = v0.global_pos;
Vector3 pos_end = v0.global_pos;
int y = (int)v0.position.y;
if (y < 0)
{
float d = -v0.position.y;
x_begin += dx_left * d;
x_end += dx_right * d;
one_over_z_begin += done_over_z_left * d;
one_over_z_end += done_over_z_right * d;
color_begin += dc_left * d;
color_end += dc_right * d;
uv_over_z_begin += duv_over_z_left * d;
uv_over_z_end += duv_over_z_right * d;
uv_begin += duv_left * d;
uv_end += duv_right * d;
normal_begin += dnormal_left * d;
normal_end += dnormal_right * d;
pos_begin += dpos_left * d;
pos_end += dpos_right * d;
y = 0;
}
int bumpmap_width = 0;
int bumpmap_height = 0;
float s1 = v1.uv.u - v0.uv.u;
float s2 = v2.uv.u - v0.uv.u;
float t1 = v1.uv.v - v0.uv.v;
float t2 = v2.uv.v - v0.uv.v;
float div = s1 * t2 - s2 * t1;
Vector3 Q1 = v1.position.GetVector3() - v0.position.GetVector3();
Vector3 Q2 = v2.position.GetVector3() - v0.position.GetVector3();
Vector3 B = (s2 * Q1 - s1 * Q2) / div;
B.SetNormalize();
Vector3 T = (t2 * Q1 - t1 * Q2) / div;
T.SetNormalize();
if (bumpmap_ && shading_mode_ == kPhong)
{
bumpmap_width = bumpmap_->get_width();
bumpmap_height = bumpmap_->get_height();
}
// floor v1.position.y
for (; y < min_t((int)v1.position.y, height_); ++y)
{
int x = (int)x_begin;
float done_over_z = (one_over_z_begin - one_over_z_end) / (x_begin - x_end);
float one_over_z = one_over_z_begin;
Vector4 dc = (color_begin - color_end) / (x_begin - x_end);
Vector4 c = color_begin;
Vector2 duv_over_z = (uv_over_z_begin - uv_over_z_end) / (x_begin - x_end);
Vector2 uv_over_z = uv_over_z_begin;
Vector2 duv = (uv_begin - uv_end) / (x_begin - x_end);
Vector2 uv = uv_begin;
Vector3 dnormal = (normal_begin - normal_end) / (x_begin - x_end);
Vector3 normal = normal_begin;
Vector3 dpos = (pos_begin - pos_end) / (x_begin - x_end);
Vector3 pos = pos_begin;
if (x_begin < 0)
{
one_over_z += done_over_z * (-x_begin);
c += dc * (-x_begin);
uv_over_z += duv_over_z * (-x_begin);
uv += duv * (-x_begin);
normal += dnormal * (-x_begin);
pos += dpos * (-x_begin);
x = 0;
}
// floor x_end
for (; x < min_t((int)(x_end), width_); ++x,
one_over_z += done_over_z,
c += dc,
uv += duv,
uv_over_z += duv_over_z,
normal += dnormal,
pos += dpos)
{
// 1/z buffer
float prev_one_over_z = get_one_over_z_buffer(x, y);
if (one_over_z < prev_one_over_z)
continue;
set_one_over_z_buffer(x, y, one_over_z);
if (shading_mode_ == kPhong)
{
if (bumpmap_)
{
int x = uv.x * (bumpmap_width - 3) + 1;
int y = uv.y * (bumpmap_height - 3) + 1;
// uint8 off_x = bumpmap_->GetDumpData(x + 1, y) - bumpmap_->GetDumpData(x - 1, y);
// uint8 off_y = bumpmap_->GetDumpData(x, y + 1) - bumpmap_->GetDumpData(y, y - 1);
// normal += (off_x / 255.0f) * B + (off_y / 255.0f) * T;
}
// Phong着色时，c每次重新计算
c = Shading(pos, normal, *mat_, *light_);
}
Vector4 cvtex(1.0f, 1.0f, 1.0f, 1.0f);
if (texture_)
{
Vector2 uv_ = uv;
if (diff_perspective)
{
uv_ = uv_over_z / one_over_z;
}
uv_.u = clamp(uv_.u, 0.0f, 1.0f);
uv_.v = clamp(uv_.v, 0.0f, 1.0f);
cvtex = texture_->GetDataUV(uv_.u, uv_.v);
}
uint32 cl = vector4_to_ARGB32(clamp(c * cvtex, 0.0f, 1.0f));
set_pixel(x, y, cl);
}
x_begin += dx_left;
x_end += dx_right;
one_over_z_begin += done_over_z_left;
one_over_z_end += done_over_z_right;
color_begin += dc_left;
color_end += dc_right;
uv_over_z_begin += duv_over_z_left;
uv_over_z_end += duv_over_z_right;
uv_begin += duv_left;
uv_end += duv_right;
normal_begin += dnormal_left;
normal_end += dnormal_right;
pos_begin += dpos_left;
pos_end += dpos_right;
}
}
// rend_primitive 相机空间
void Renderer::ModelViewTransform(const Matrix44 &model_view)
{
Matrix33 normal_trans = model_view.GetMatrix33();
normal_trans.SetInverse();
normal_trans.SetTranspose();
// 转换灯光位置
if (light_)
{
Vector4 pl;
pl.SetVector3(light_->position);
pl.w = 1.0f;
pl = pl * model_view;
light_pos_ = pl.GetVector3();
}
#if 0
for (int i = 0; i < rend_primitive_.size; ++i)
{
if (((i + 1) % 3) == 0)
{
Vector3 p0 = rend_primitive_.vertexs[i - 2].position.GetVector3();
Vector3 p1 = rend_primitive_.vertexs[i - 1].position.GetVector3();
Vector3 p2 = rend_primitive_.vertexs[i].position.GetVector3();
Vector3 e0 = p0 - p1;
Vector3 e1 = p1 - p2;
Vector3 n = rend_primitive_.vertexs[i-1].normal;
float dot = DotProduct(e0, n);
// Logger::GtLogInfo("before:0\t%f", dot);
assert(equalf(dot, 0, 0.001));
dot = DotProduct(e1, n);
// Logger::GtLogInfo("before:1\t%f", dot);
assert(equalf(dot, 0, 0.001));
}
}
#endif
for (int i = 0; i < rend_primitive_.size; ++i)
{
Vector4 &position = rend_primitive_.vertexs[i].position;
position = position * model_view;
Vector3 &normal = rend_primitive_.vertexs[i].normal;
normal = normal * normal_trans;
normal.SetNormalize();
}
#if 0
for (int i = 0; i < rend_primitive_.size; ++i)
{
if (((i + 1) % 3) == 0)
{
Vector4 p0 = rend_primitive_.vertexs[i - 2].position;
Vector4 p1 = rend_primitive_.vertexs[i - 1].position;
Vector4 p2 = rend_primitive_.vertexs[i].position;
Vector3 e0 = (p0 - p1).GetVector3();
Vector3 e1 = (p1 - p2).GetVector3();
Vector3 N = CrossProduct(e0, e1);
N.SetNormalize();
float dot = DotProduct(N, e0);
Logger::GtLogInfo("dot e0 \t%f", dot);
dot = DotProduct(N, e1);
Logger::GtLogInfo("dot e1 \t%f", dot);
Vector3 n0 = rend_primitive_.vertexs[i - 2].normal;
Vector3 n1 = rend_primitive_.vertexs[i - 1].normal;
Vector3 n2 = rend_primitive_.vertexs[i].normal;
Vector3 zero = CrossProduct(N, n1);
zero.Display();
dot = DotProduct(e0, n0);
Logger::GtLogInfo("after:0\t%f", dot);
dot = DotProduct(e1, n0);
Logger::GtLogInfo("after:1\t%f", dot);
}
}
#endif
}