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EvalDir

vec3 EvalDirectionalLight(vec2 uv) {
  vec3 lightDirWS = normalize(uLightDir);
  vec3 normalWS = normalize(GetGBufferNormalWorld(uv));
  float ndotl = max(0.0,dot(lightDirWS,normalWS));
  float visibility = GetGBufferuShadow(uv);
  Le = uLightRadiance * visibility * ndotl;
  return Le;
}

EvalDiffuse

vec3 EvalDiffuse(vec3 wi, vec3 wo, vec2 uv) {
  vec3 normal = normalize(GetGBufferNormalWorld(uv));
  vec3 diff = GetGBufferDiffuse(uv);
  float cosTheta = dot(normalize(wi),normal);
  vec3 L = diff * INV_PI * cosTheta;
  return L;
}

main：

vec3 worldPos = vPosWorld.xyz;
vec2 uv0 = GetScreenCoordinate(worldPos);
vec3 wi = normalize(uLightDir);
vec3 wo = normalize(uCameraPos - worldPos);
float scale = 5.0;
vec3 dirL = EvalDirectionalLight(uv0);
L+=dirL*EvalDiffuse(wi,wo,uv0)*scale;

RayMarch

bool RayMarch(vec3 ori, vec3 dir, out vec3 hitPos) {
  vec2 ori_uv = GetScreenCoordinate(ori);
  vec2 dir_uv = GetScreenCoordinate(dir);
  float step_size = 2.0/float(total_step)/length(dir_uv);
  
  const int first_step=1;
  for(int i = first_step;i<=total_step;++i)
  { 
    vec3 pos = ori+dir*step_size*float(i);
    vec2 pos_uv = GetScreenCoordinate(pos);
    if(GetGBufferDepth(pos_uv)+EPS<GetDepth(pos))
    {
      hitPos = pos;
      return true;
    }
  }
 // hitPos = vec3(normalize(dir_uv),0.0);
  return false;
}

镜面反射查询

  //test mirro:
  vec3 test_dir = vec3(0.0);
  test_dir=reflect(-wo,normal);
  vec3 test_hit;
  if(RayMarch(worldPos,test_dir,test_hit))
  {
    indir = GetGBufferDiffuse(GetScreenCoordinate(test_hit));    
  }

间接光着色（spp=1）

  //indir shading:
  for(int i=0;i<SAMPLE_NUM;++i)
  {
    float pdf=0.0;
    vec3 dir=SampleHemisphereUniform(s,pdf);
    //vec3 dir=SampleHemisphereCos(s,pdf);
    dir = dirToWorld(normal,dir);
    vec3 hitPos=vec3(0.0);
    vec3 direct = normalize(vec3(1.0,0.0,0.0));
    direct = normalize(dir);
    if(RayMarch(worldPos,direct,hitPos))
    {
      vec2 uv1=GetScreenCoordinate(hitPos);
      if(length(res)>0.0) 
        indir += res;//avoid neg   
    }
  }

其他图片结果

cube2

直接光

间接光spp=100

直接光+间接光spp=100

cave

直接光

间接光spp=100

【说明：为了显示明显，仅显示间接光时将间接光强度进行了增大】

直接光+间接光spp=100

主函数 main

vec3 dirToWorld(vec3 normal,vec3 localDir)
{
  vec3 b1=vec3(0.0);
  vec3 b2=vec3(0.0);
  LocalBasis(normal,b1,b2);
  mat3 tbn = mat3(b1,b2,normal);
  return tbn*localDir;
}

void main() {
  float s = InitRand(gl_FragCoord.xy);
  vec3 L = vec3(0.0);
  vec3 worldPos = vPosWorld.xyz;
  vec2 uv0 = GetScreenCoordinate(worldPos);
  vec3 dirL = EvalDirectionalLight(uv0);
  //L = GetGBufferDiffuse(uv0);
  vec3 wi = normalize(uLightDir);
  vec3 wo = normalize(uCameraPos - worldPos);
  float scale = 5.0;
  L+=dirL*EvalDiffuse(wi,wo,uv0)*scale;
  //L = dirL/scale;
  vec3 normal = GetGBufferNormalWorld(uv0);
  //raymarch:
  vec3 indir=vec3(0.0);

  //test mirro:
  // vec3 test_dir = vec3(0.0);
  // test_dir=reflect(-wo,normal);
  // vec3 test_hit;
  // if(RayMarch(worldPos,test_dir,test_hit))
  // {
  //   indir = GetGBufferDiffuse(GetScreenCoordinate(test_hit));    
  // }


  //indir shading:
  for(int i=0;i<SAMPLE_NUM;++i)
  {
    float pdf=0.0;
    vec3 dir=SampleHemisphereUniform(s,pdf);
    //vec3 dir=SampleHemisphereCos(s,pdf);
    dir = dirToWorld(normal,dir);
    vec3 brdf0 = EvalDiffuse(wi,wo,uv0)/pdf;
    vec3 hitPos=vec3(0.0);
    vec3 direct = normalize(vec3(1.0,0.0,0.0));
    direct = normalize(dir);
    if(RayMarch(worldPos,direct,hitPos))
    {
      vec2 uv1=GetScreenCoordinate(hitPos);
      vec3 res = brdf0*EvalDiffuse(-wi,vec3(0.0),uv1)
                 *EvalDirectionalLight(uv1);      
      //vec3 res = EvalDiffuse(-direct,vec3(0.0),uv1);
      if(length(res)>0.0) 
        indir += res;//avoid neg   
    }
  }
  indir/=float(SAMPLE_NUM);
  //L= indir*10.0;
  L+=indir;
  vec3 color = pow(clamp(L, vec3(0.0), vec3(1.0)), vec3(1.0 / 2.2));
  //color=vec3(0.6);
  gl_FragColor = vec4(vec3(color.rgb), 1.0);
}