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update Spheremap Transform algorithm

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This commit is contained in:
hyzboy 2020-01-02 21:40:48 +08:00
parent e7e70491b1
commit 1cfb30faea
1 changed files with 19 additions and 11 deletions
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30
SpheremapNormal.cpp
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@ -6,7 +6,7 @@
Normal to GBufffer:
G=normalize(N.xy)*sqrt(N.z*0.5+0.5)
G=normalize(N.xy)*sqrt(-N.z*0.5+0.5)
GBuffer to Normal:
@ -19,7 +19,7 @@ namespace hgl
void normal_compress(uint8 *x,uint8 *y,const uint8 *rgb,const uint count)
{
Vector3f in;
Vector2f in_xy;
float f;
Vector2f out;
for(uint i=0;i<count;i++)
@ -28,8 +28,11 @@ namespace hgl
in.y=float(*rgb)/255.0f;++rgb;
in.z=float(*rgb)/255.0f;++rgb;
in_xy=in.xy().Normalized();
out=in_xy*sqrt(in.z*0.5+0.5);
//Spheremap Transform,PSNR 48.071 dB,15 GPU cycles
f=sqrt(8*in.z+8);
out=in.xy()/f+Vector2f(0.5);
out=out.Clamp01();
*x=out.x*255;++x;
*y=out.y*255;++y;
@ -39,20 +42,25 @@ namespace hgl
void normal_decompress(uint8 *rgb,const uint8 *x,const uint8 *y,const uint count)
{
Vector2f in;
Vector2f in_normal;
Vector2f fenc;
Vector3f out;
float s;
float f,g;
for(uint i=0;i<count;i++)
{
in.x=(*x)/255.0f;++x;
in.y=(*y)/255.0f;++y;
//Spheremap Transform,PSNR 48.071 dB,15 GPU cycles
fenc=in*4.0f-Vector2f(2.0f);
f=dot(fenc,fenc);
g=sqrt(1.0-f/4.0f);
out.z=length(in)*2.0-1;
in_normal=in.Normalized();
s=sqrt(1-out.z*out.z);
out.x=in_normal.x*s;
out.y=in_normal.y*s;
out.x=fenc.x*g;
out.y=fenc.y*g;
out.z=1-f/2.0f;
out=out.Clamp01();
*rgb=out.x*255;++rgb;
*rgb=out.y*255;++rgb;