- 遍歷所有光線查找最近的交點與現場...
店:迭代兩個步驟完成第一次背光線追蹤光線的位置,表面法線和材料特性struct
如果發現相交而不是最後一個「遞歸」層添加反射/折射光線到最後列出。
也是他們的索引存儲到處理射線struct
現在你應該光線抱着你需要重建顏色全部交叉信息。爲了做到這一點:對於每個匹配的實際遞歸層的光線的
- 遍歷所有遞歸水平向後
計算射線顏色
所以使用光照方程你要。如果光線包含兒童根據材料特性(反射和折射係數...)
現在的第一縷應該包含您要輸出的顏色的顏色添加到結果。
制服使用:
tm_eye
視攝像機矩陣
aspect
視圖YS/XS長寬比
n0
空的空間折射率(未使用還)
focal_length
相機焦距的
fac_siz
分辨率場景廣場紋理
fac_num
實際上花車的數量SED的場景貼圖
fac_txr
紋理單元的場景貼圖
前瞻:
片段着色器包含我的調試輸出,所以你還需要紋理如果使用看QA :
TODO:
添加基質的對象,相機等
附加材料性能(光澤,反射/折射係數)
Snell定律現在的新光線的方向是錯誤的。 ..
可以是單獨的R,G,B至3倍開始的光線,並在端
假SSS表面散射結合基於光線長度
更好地貫徹落實燈(現在他們是在一個代碼常量)
實現更多的原語(現在只有三角形支持)
[EDIT1]代碼調試和升級
我刪除舊的源代碼以適應30KB的限制。如果你需要它,然後從編輯歷史中挖掘它。有一段時間,更高級的調試,這和這裏的結果:
這個版本得到了解決了一些幾何,準確,域名的問題和錯誤。我得到了實現兩者的反射和折射如圖所示在這個調試平局測試線:
在調試視圖只有立方體是透明的,最後一絲不打什麼被忽略。所以,你可以看到光線分裂...由於全反射角度,光線在立方體內部結束。爲了速度的原因,我禁用了物體內部的所有反射。
用於交叉點檢測的32位floats
與距離有點嘈雜,因此您可以使用64位doubles
來代替,但在這種情況下速度會明顯下降。另一種選擇是重寫方程以使用在這種情況下更精確的相對座標。
這裏float
着色器源:
頂點:
//------------------------------------------------------------------
#version 420 core
//------------------------------------------------------------------
uniform float aspect;
uniform float focal_length;
uniform mat4x4 tm_eye;
layout(location=0) in vec2 pos;
out smooth vec2 txt_pos; // frag position on screen <-1,+1> for debug prints
out smooth vec3 ray_pos; // ray start position
out smooth vec3 ray_dir; // ray start direction
//------------------------------------------------------------------
void main(void)
{
vec4 p;
txt_pos=pos;
// perspective projection
p=tm_eye*vec4(pos.x/aspect,pos.y,0.0,1.0);
ray_pos=p.xyz;
p-=tm_eye*vec4(0.0,0.0,-focal_length,1.0);
ray_dir=normalize(p.xyz);
gl_Position=vec4(pos,0.0,1.0);
}
//------------------------------------------------------------------
片段:
//------------------------------------------------------------------
#version 420 core
//------------------------------------------------------------------
// Ray tracer ver: 1.000
//------------------------------------------------------------------
in smooth vec3 ray_pos; // ray start position
in smooth vec3 ray_dir; // ray start direction
uniform float n0; // refractive index of camera origin
uniform int fac_siz; // square texture x,y resolution size
uniform int fac_num; // number of valid floats in texture
uniform sampler2D fac_txr; // scene mesh data texture
out layout(location=0) vec4 frag_col;
//---------------------------------------------------------------------------
//#define _debug_print
#define _reflect
#define _refract
//---------------------------------------------------------------------------
#ifdef _debug_print
in vec2 txt_pos; // frag screen position <-1,+1>
uniform sampler2D txr_font; // ASCII 32x8 characters font texture unit
uniform float txt_fxs,txt_fys; // font/screen resolution ratio
const int _txtsiz=64; // text buffer size
int txt[_txtsiz],txtsiz; // text buffer and its actual size
vec4 txt_col=vec4(0.0,0.0,0.0,1.0); // color interface for txt_print()
bool _txt_col=false; // is txt_col active?
void txt_decimal(vec2 v); // print vec3 into txt
void txt_decimal(vec3 v); // print vec3 into txt
void txt_decimal(vec4 v); // print vec3 into txt
void txt_decimal(float x); // print float x into txt
void txt_decimal(int x); // print int x into txt
void txt_print(float x0,float y0); // print txt at x0,y0 [chars]
#endif
//---------------------------------------------------------------------------
void main(void)
{
const vec3 light_dir=normalize(vec3(0.1,0.1,1.0));
const float light_iamb=0.1; // dot offset
const float light_idir=0.5; // directional light amplitude
const vec3 back_col=vec3(0.2,0.2,0.2); // background color
const float _zero=1e-6; // to avoid intrsection with start point of ray
const int _fac_triangles=0; // r,g,b, refl,refr,n, type, triangle count, { x0,y0,z0,x1,y1,z1,x2,y2,z2 }
const int _fac_spheres =1; // r,g,b, refl,refr,n, type, sphere count, { x,y,z,r }
// ray scene intersection
struct _ray
{
vec3 pos,dir,nor;
vec3 col;
float refl,refr;// reflection,refraction intensity coeficients
float n0,n1,l; // refaction index (start,end) , ray length
int lvl,i0,i1; // recursion level, reflect, refract
};
const int _lvls=5;
const int _rays=(1<<_lvls)-1;
_ray ray[_rays]; int rays;
vec3 v0,v1,v2,pos;
vec3 c,col;
float refr,refl;
float tt,t,n1,a;
int i0,ii,num,id;
// fac texture access
vec2 st; int i,j; float ds=1.0/float(fac_siz-1);
#define fac_get texture(fac_txr,st).r; st.s+=ds; i++; j++; if (j==fac_siz) { j=0; st.s=0.0; st.t+=ds; }
// enque start ray
ray[0].pos=ray_pos;
ray[0].dir=normalize(ray_dir);
ray[0].nor=vec3(0.0,0.0,0.0);
ray[0].refl=0.0;
ray[0].refr=0.0;
ray[0].n0=n0;
ray[0].n1=1.0;
ray[0].l =0.0;
ray[0].lvl=0;
ray[0].i0=-1;
ray[0].i1=-1;
rays=1;
// debug print area
#ifdef _debug_print
bool _dbg=false;
float dbg_x0=45.0;
float dbg_y0= 1.0;
float dbg_xs=12.0;
float dbg_ys=_rays+1.0;
dbg_xs=40.0;
dbg_ys=10;
float x=0.5*(1.0+txt_pos.x)/txt_fxs; x-=dbg_x0;
float y=0.5*(1.0-txt_pos.y)/txt_fys; y-=dbg_y0;
// inside bbox?
if ((x>=0.0)&&(x<=dbg_xs)
&&(y>=0.0)&&(y<=dbg_ys))
{
// prints on
_dbg=true;
// preset debug ray
ray[0].pos=vec3(0.0,0.0,0.0)*2.5;
ray[0].dir=vec3(0.0,0.0,1.0);
}
#endif
// loop all enqued rays
for (i0=0;i0<rays;i0++)
{
// loop through all objects
// find closest forward intersection between them and ray[i0]
// strore it to ray[i0].(nor,col)
// strore it to pos,n1
t=tt=-1.0; ii=1; ray[i0].l=0.0;
ray[i0].col=back_col;
pos=ray[i0].pos; n1=n0;
for (st=vec2(0.0,0.0),i=j=0;i<fac_num;)
{
c.r=fac_get; // RGBA
c.g=fac_get;
c.b=fac_get;
refl=fac_get;
refr=fac_get;
n1=fac_get; // refraction index
a=fac_get; id=int(a); // object type
a=fac_get; num=int(a); // face count
if (id==_fac_triangles)
for (;num>0;num--)
{
v0.x=fac_get; v0.y=fac_get; v0.z=fac_get;
v1.x=fac_get; v1.y=fac_get; v1.z=fac_get;
v2.x=fac_get; v2.y=fac_get; v2.z=fac_get;
vec3 e1,e2,n,p,q,r;
float t,u,v,det,idet;
//compute ray triangle intersection
e1=v1-v0;
e2=v2-v0;
// Calculate planes normal vector
p=cross(ray[i0].dir,e2);
det=dot(e1,p);
// Ray is parallel to plane
if (abs(det)<1e-8) continue;
idet=1.0/det;
r=ray[i0].pos-v0;
u=dot(r,p)*idet;
if ((u<0.0)||(u>1.0)) continue;
q=cross(r,e1);
v=dot(ray[i0].dir,q)*idet;
if ((v<0.0)||(u+v>1.0)) continue;
t=dot(e2,q)*idet;
if ((t>_zero)&&((t<=tt)||(ii!=0)))
{
ii=0; tt=t;
// store color,n ...
ray[i0].col=c;
ray[i0].refl=refl;
ray[i0].refr=refr;
// barycentric interpolate position
t=1.0-u-v;
pos=(v0*t)+(v1*u)+(v2*v);
// compute normal (store as dir for now)
e1=v1-v0;
e2=v2-v1;
ray[i0].nor=cross(e1,e2);
}
}
if (id==_fac_spheres)
for (;num>0;num--)
{
float r;
v0.x=fac_get; v0.y=fac_get; v0.z=fac_get; r=fac_get;
// compute l0 length of ray(p0,dp) to intersection with sphere(v0,r)
// where rr= r^-2
float aa,bb,cc,dd,l0,l1,rr;
vec3 p0,dp;
p0=ray[i0].pos-v0; // set sphere center to (0,0,0)
dp=ray[i0].dir;
rr = 1.0/(r*r);
aa=2.0*rr*dot(dp,dp);
bb=2.0*rr*dot(p0,dp);
cc= rr*dot(p0,p0)-1.0;
dd=((bb*bb)-(2.0*aa*cc));
if (dd<0.0) continue;
dd=sqrt(dd);
l0=(-bb+dd)/aa;
l1=(-bb-dd)/aa;
if (l0<0.0) l0=l1;
if (l1<0.0) l1=l0;
t=min(l0,l1); if (t<=_zero) t=max(l0,l1);
if ((t>_zero)&&((t<=tt)||(ii!=0)))
{
ii=0; tt=t;
// store color,n ...
ray[i0].col=c;
ray[i0].refl=refl;
ray[i0].refr=refr;
// position,normal
pos=ray[i0].pos+(ray[i0].dir*t);
ray[i0].nor=pos-v0;
}
}
}
ray[i0].l=tt;
ray[i0].nor=normalize(ray[i0].nor);
// split ray from pos and ray[i0].nor
if ((ii==0)&&(ray[i0].lvl<_lvls-1))
{
t=dot(ray[i0].dir,ray[i0].nor);
// reflect
#ifdef _reflect
if ((ray[i0].refl>_zero)&&(t<_zero)) // do not reflect inside objects
{
ray[i0].i0=rays;
ray[rays]=ray[i0];
ray[rays].lvl++;
ray[rays].i0=-1;
ray[rays].i1=-1;
ray[rays].pos=pos;
ray[rays].dir=ray[rays].dir-(2.0*t*ray[rays].nor);
ray[rays].n0=ray[i0].n0;
ray[rays].n1=ray[i0].n0;
rays++;
}
#endif
// refract
#ifdef _refract
if (ray[i0].refr>_zero)
{
ray[i0].i1=rays;
ray[rays]=ray[i0];
ray[rays].lvl++;
ray[rays].i0=-1;
ray[rays].i1=-1;
ray[rays].pos=pos;
t=dot(ray[i0].dir,ray[i0].nor);
if (t>0.0) // exit object
{
ray[rays].n0=ray[i0].n0;
ray[rays].n1=n0;
v0=-ray[i0].nor; t=-t;
}
else{ // enter object
ray[rays].n0=n1;
ray[rays].n1=ray[i0].n0;
ray[i0 ].n1=n1;
v0=ray[i0].nor;
}
n1=ray[i0].n0/ray[i0].n1;
tt=1.0-(n1*n1*(1.0-t*t));
if (tt>=0.0)
{
ray[rays].dir=(ray[i0].dir*n1)-(v0*((n1*t)+sqrt(tt)));
rays++;
}
}
#endif
}
else if (i0>0) // ignore last ray if nothing hit
{
ray[i0]=ray[rays-1];
rays--; i0--;
}
}
// back track ray intersections and compute output color col
// lvl is sorted ascending so backtrack from end
for (i0=rays-1;i0>=0;i0--)
{
// directional + ambient light
t=abs(dot(ray[i0].nor,light_dir)*light_idir)+light_iamb;
t*=1.0-ray[i0].refl-ray[i0].refr;
ray[i0].col.rgb*=t;
// reflect
ii=ray[i0].i0;
if (ii>=0) ray[i0].col.rgb+=ray[ii].col.rgb*ray[i0].refl;
// refract
ii=ray[i0].i1;
if (ii>=0) ray[i0].col.rgb+=ray[ii].col.rgb*ray[i0].refr;
}
col=ray[0].col;
// debug prints
#ifdef _debug_print
/*
if (_dbg)
{
txtsiz=0;
txt_decimal(_lvls);
txt[txtsiz]=' '; txtsiz++;
txt_decimal(rays);
txt[txtsiz]=' '; txtsiz++;
txt_decimal(_rays);
txt_print(dbg_x0,dbg_y0);
for (ii=0;ii<rays;ii++)
{
txtsiz=0;
txt_decimal(ray[ii].lvl);
txt_print(dbg_x0,dbg_y0+ii+1);
}
for (ii=0,st=vec2(0.0,0.0),i=j=0;i<fac_num;ii++)
{
c.r=fac_get; // RGBA
txtsiz=0;
txt_decimal(c.r);
txt_print(dbg_x0,dbg_y0+ii+1);
}
if (_txt_col) col=txt_col.rgb;
}
*/
if (_dbg)
{
float x=dbg_x0,y=dbg_y0;
vec3 a=vec3(1.0,2.0,3.0);
vec3 b=vec3(5.0,6.0,7.0);
txtsiz=0; txt_decimal(dot(a,b)); txt_print(x,y); y++;
txtsiz=0; txt_decimal(cross(a,b)); txt_print(x,y); y++;
if (_txt_col) col=txt_col.rgb;
}
#endif
frag_col=vec4(col,1.0);
}
//---------------------------------------------------------------------------
#ifdef _debug_print
//---------------------------------------------------------------------------
void txt_decimal(vec2 v) // print vec2 into txt
{
txt[txtsiz]='('; txtsiz++;
txt_decimal(v.x); txt[txtsiz]=','; txtsiz++;
txt_decimal(v.y); txt[txtsiz]=')'; txtsiz++;
txt[txtsiz]=0; // string terminator
}
//---------------------------------------------------------------------------
void txt_decimal(vec3 v) // print vec3 into txt
{
txt[txtsiz]='('; txtsiz++;
txt_decimal(v.x); txt[txtsiz]=','; txtsiz++;
txt_decimal(v.y); txt[txtsiz]=','; txtsiz++;
txt_decimal(v.z); txt[txtsiz]=')'; txtsiz++;
txt[txtsiz]=0; // string terminator
}
//---------------------------------------------------------------------------
void txt_decimal(vec4 v) // print vec4 into txt
{
txt[txtsiz]='('; txtsiz++;
txt_decimal(v.x); txt[txtsiz]=','; txtsiz++;
txt_decimal(v.y); txt[txtsiz]=','; txtsiz++;
txt_decimal(v.z); txt[txtsiz]=','; txtsiz++;
txt_decimal(v.w); txt[txtsiz]=')'; txtsiz++;
txt[txtsiz]=0; // string terminator
}
//---------------------------------------------------------------------------
void txt_decimal(float x) // print float x into txt
{
int i,j,c; // l is size of string
float y,a;
const float base=10;
// handle sign
if (x<0.0) { txt[txtsiz]='-'; txtsiz++; x=-x; }
else { txt[txtsiz]='+'; txtsiz++; }
// divide to int(x).fract(y) parts of number
y=x; x=floor(x); y-=x;
// handle integer part
i=txtsiz; // start of integer part
for (;txtsiz<_txtsiz;)
{
a=x;
x=floor(x/base);
a-=base*x;
txt[txtsiz]=int(a)+'0'; txtsiz++;
if (x<=0.0) break;
}
j=txtsiz-1; // end of integer part
for (;i<j;i++,j--) // reverse integer digits
{
c=txt[i]; txt[i]=txt[j]; txt[j]=c;
}
// handle fractional part
for (txt[txtsiz]='.',txtsiz++;txtsiz<_txtsiz;)
{
y*=base;
a=floor(y);
y-=a;
txt[txtsiz]=int(a)+'0'; txtsiz++;
if (y<=0.0) break;
}
txt[txtsiz]=0; // string terminator
}
//---------------------------------------------------------------------------
void txt_decimal(int x) // print int x into txt
{
int a,i,j,c; // l is size of string
const int base=10;
// handle sign
if (x<0.0) { txt[txtsiz]='-'; txtsiz++; x=-x; }
else { txt[txtsiz]='+'; txtsiz++; }
// handle integer part
i=txtsiz; // start of integer part
for (;txtsiz<_txtsiz;)
{
a=x;
x/=base;
a-=base*x;
txt[txtsiz]=int(a)+'0'; txtsiz++;
if (x<=0) break;
}
j=txtsiz-1; // end of integer part
for (;i<j;i++,j--) // reverse integer digits
{
c=txt[i]; txt[i]=txt[j]; txt[j]=c;
}
txt[txtsiz]=0; // string terminator
}
//---------------------------------------------------------------------------
void txt_print(float x0,float y0) // print txt at x0,y0 [chars]
{
int i;
float x,y;
// fragment position [chars] relative to x0,y0
x=0.5*(1.0+txt_pos.x)/txt_fxs; x-=x0;
y=0.5*(1.0-txt_pos.y)/txt_fys; y-=y0;
// inside bbox?
if ((x<0.0)||(x>float(txtsiz))||(y<0.0)||(y>1.0)) return;
// get font texture position for target ASCII
i=int(x); // char index in txt
x-=float(i);
i=txt[i];
x+=float(int(i&31));
y+=float(int(i>>5));
x/=32.0; y/=8.0; // offset in char texture
txt_col=texture(txr_font,vec2(x,y));
_txt_col=true;
}
//---------------------------------------------------------------------------
#endif
//---------------------------------------------------------------------------
的代碼還沒有優化我想有正常工作的物理第一。仍然沒有實施Fresnells,但使用refl,refr
材料系數。你
也可以忽略調試打印的東西(它們被#define
封裝)。
我建立一個小型的類幾何紋理,所以我可以輕鬆設置場景中的對象。這是一幕是如何發起的預覽:
ray.beg();
// r g b rfl rfr n
ray.add_material(1.0,1.0,1.0,0.3,0.0,_n_glass); ray.add_box (0.0, 0.0, 6.0,9.0,9.0,0.1);
ray.add_material(1.0,1.0,1.0,0.1,0.8,_n_glass); ray.add_sphere(0.0, 0.0, 0.5,0.5);
ray.add_material(1.0,0.1,0.1,0.3,0.0,_n_glass); ray.add_sphere(+2.0, 0.0, 2.0,0.5);
ray.add_material(0.1,1.0,0.1,0.3,0.0,_n_glass); ray.add_box (-2.0, 0.0, 2.0,0.5,0.5,0.5);
ray.add_material(0.1,0.1,1.0,0.3,0.0,_n_glass);
ray.add_tetrahedron
(
0.0, 0.0, 3.0,
-1.0,-1.0, 4.0,
+1.0,-1.0, 4.0,
0.0,+1.0, 4.0
);
ray.end();
非常重要,這樣計算法線面臨淘汰的對象,因爲這是用於檢測內部/外部對象口岸。
我想你正在使用蒙特卡洛技術 - 然後隨機選擇反射或折射。 – Plow
我想你可以嘗試迭代。創建一個光線列表進行處理,並添加到列表中...對於像7條光線這樣的有限遞歸層,您可以將其硬編碼爲靜態數組。另一種選擇是使用幾何着色器,並在那裏發射新的光線,但我不知道這是否可行,因爲我不知道如何傳遞數據的架構。 – Spektre
我使用更新的代碼添加了** [edit1] **。所以概念的證明是有效的。然而,使用32位浮點的第4級遞歸較慢,但仍比CPU光線追蹤器快一個數量級。 – Spektre