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Graphics/hw5/RTX.frag

236 lines
9.5 KiB

#define _DEBUG_BREAK {gl_FragColor=vec4(1,0,0,1); return;}
#define REFRACTION (c2 >= 0.? (eta*W + (eta*c1 - sqrt(c2))*N) : ((W + c1*N)/sqrt(1.-c1*c1)))
vec3 foregroundColor = vec3(.0841, .5329, .9604);
vec3 groundColor = vec3(.2, .3, .5);
vec4 groundSpecular = vec4(.71, .71, .71, 10.);
uniform float uTime;// TIME, IN SECONDS
uniform vec3 Ambient[ns], Diffuse[ns];
uniform vec4 Specular[ns];
uniform float ks[ns], kr[ns], kf[ns];
uniform vec4 Sph[ns];
uniform sampler2D uSampler[ns];
uniform vec3 V0;
uniform int sel;
const float kf_air = 1.000293;
varying vec3 trPos;
const float pi=3.14159265359;
const float _2pi=2.*pi;
/***********PLEASE DO INCREASE n_ref(RT DEPTH) FOR BETTER RESULTS************/
/*---->*/const int n_ref=7; //2^n-1 because each hit now spawn at most 2 rays.
/**BUT BE CAUTIOUS IF YOU DON'T HAVE A DECENT GRAPHICS CARD (below GTX 950M)**/
const int max_stack = (n_ref+1)/4;
vec3 scolor = vec3(0,0,0);
struct Ray{
vec3 V;
vec3 W;
float kf, cumulativeK;
} stack1[max_stack], stack2[max_stack];
bool modulo2(int n){
return n-2*(n/2) == 1;
}
vec2 getTextCoord(vec3 tex_sph, float R){
float tex_x=atan(tex_sph.z,tex_sph.x)/_2pi + 0.5;//*Correct aspect ratio of texture 2:1 -> 2pir:2r
tex_x=fract(tex_x+uTime/20.);
return vec2(tex_x,-asin(tex_sph.y/R)/pi + 0.5);
}
void main(){
vec3 LDir=vec3(.5,.5,.5);
vec3 LCol=vec3(1.,1.,1.);
float currKf = kf_air;
vec3 color=vec3(.2, .3, .5);
vec3 V = V0;
vec3 W=(trPos-V);
bool rtxoff = false, showtexture = true, selected = false;
float currentK = 1.;
int curr_ptr = 0, curr_top = 0, next_top = 0;
bool final = false, stackswap = false, stop = false;
for(int j=0;j<n_ref;j++)
{
for(int curr = 0; curr < max_stack; ++curr){
if(curr == curr_ptr){
bool skip = false;
if(j > 0){
Ray currR;
if(stackswap)
currR = stack1[curr];
else
currR = stack2[curr];
currKf = currR.kf;
currentK = currR.cumulativeK;
if(currKf <= 0.001 || currentK <= 0.001)
skip = true;
V = currR.V;
W = currR.W;
}
else
W = normalize(W);
if(!skip){
float tMin=10000.;
int iMin = -1;
for(int i=0;i<cns;i++){
vec3 Vp=V-Sph[i].xyz;
float B=dot(W,Vp);
float C=dot(Vp,Vp)-Sph[i].w*Sph[i].w;
float D=B*B-C;
if(D>0.){
float t=-B-sqrt(D);
if(t >= 0.01 && t < tMin){
tMin = t; // This is an optimization, we don't have to do lighting/tex
iMin = i; // for objects that are occuluded, which is expensive!
}
else if (t >= -0.01 && t <0.01){
t = -(t + 2.*B);
if(t > 0.01 && t < tMin){
tMin = t;
iMin = i;
}
}
}
}
if(iMin >= 0){
if(j == 0 && iMin == sel)
selected = true;
float t = tMin;
vec3 S=V+t*W;
for(int i = 0; i < cns; ++ i)
if(i == iMin)
{
vec3 texture_color;
if(showtexture)
{
vec3 tex_sph = (S-Sph[i].xyz);
texture_color=texture2D(uSampler[i],getTextCoord(tex_sph, Sph[i].w)).xyz;
}
else texture_color = foregroundColor;
vec3 N=normalize(S-Sph[i].xyz);
vec3 realLDir=normalize(LDir-S);
float c1 =dot(N, W);
float eta, nextkf;
if(c1<0.){
color=(Ambient[i]+Diffuse[i]*max(0.,dot(N,realLDir))*LCol)*texture_color;
if(rtxoff || final) //if it's the last hit
{
color += Specular[i].xyz*pow(max(0.,
dot(-2.*c1*N-realLDir,realLDir)),Specular[i].w);
scolor += color * currentK;
break;
}
else{
c1 = -c1;
eta = currKf/kf[i];
nextkf = kf[i];
}
}
else{
N = -N;
eta = currKf/kf_air;
nextkf = kf_air;
color = Ambient[i];
}
float c2 = (1.-eta*eta*(1.-c1*c1));
float nextks = currentK * ks[i], nextkr = currentK * kr[i];
bool refl = nextks > 0.01, refr = nextkr > 0.01;
if(refl || refr)
for(int k = 0; k < max_stack; ++k)
if(k == next_top){
if(stackswap){
if(refl)
{
stack2[k] = Ray(S, 2. * c1 * N + W, currKf, nextks); //reflection
currentK -= nextks;
next_top ++;
}
if(refr)
{
if(refl)
stack2[k+1] = Ray(S, REFRACTION, nextkf, nextkr); //refraction
else
stack2[k] = Ray(S, REFRACTION, nextkf, nextkr); //refraction
currentK -= nextkr;
next_top ++;
}
}else{
if(refl)
{ //remember, c1 = -NW now
stack1[k] = Ray(S, 2. * c1 * N + W, currKf, nextks); //reflection
currentK -= nextks;
next_top ++;
}
if(refr)
{
if(refl)
stack1[k+1] = Ray(S, REFRACTION, nextkf, nextkr); //refraction
else
stack1[k] = Ray(S, REFRACTION, nextkf, nextkr); //refraction
currentK -= nextkr;
next_top ++;
}
}
break;
}
scolor += color * currentK;
break;
}
}
else {
float t = -(.2+V.y)/W.y;
float sx = V.x + t* W.x, sz = V.z + t * W.z;
if(t >= 0. && abs(sx) < 1.5 && abs(sz) < 3.)
{
vec3 S = vec3(sx, -.2, sz);
vec3 realLDir=normalize(LDir - S);
color=(0.5+0.5*max(0.,realLDir.y)*LCol)*texture2D(uSampler[4],vec2((sx+1.4)/3., (sz+1.5)/4.)).xyz;
if(rtxoff || final&&abs(sx)<1.5 && abs(sz+.6)<3.)
{
color += groundSpecular.xyz* //specular for ground.
pow(max(0., dot(vec3(-realLDir.x, realLDir.y,-realLDir.z),-W)),groundSpecular.w);
scolor += currentK * color;
}
else
{
for(int k = 0; k < max_stack; ++k)
if(k == next_top){
if(stackswap)
stack2[k] = Ray(S, vec3(W.x, -W.y, W.z), kf_air, currentK * 0.15); //reflection
else
stack1[k] = Ray(S, vec3(W.x, -W.y, W.z), kf_air, currentK * 0.15); //reflection
next_top ++;
break;
}
scolor += (currentK*.85)*color;
}
}
else{
if(j > 0)
scolor += currentK * (pow(max(0.,dot(W, normalize(LDir - V))), 10.) * vec3(3.,3.,3.) + foregroundColor*0.1);
else scolor = foregroundColor*0.6;
}
}
}
if(++curr_ptr >= curr_top){
if(next_top <= 0)
stop = true;
if(next_top * 2 > max_stack)
final = true;
curr_top = next_top;
next_top = 0;
curr_ptr = 0;
stackswap = !stackswap;
}
break;
}
}
if(stop)
break;
}
if(selected)
scolor.x += 0.5;
gl_FragColor=vec4(sqrt(scolor),1.);
}