Var* GBufferConditionerGLSL::_conditionOutput( Var *unconditionedOutput, MultiLine *meta )
{
Var *retVar = new Var;
retVar->setType("vec4");
retVar->setName("_gbConditionedOutput");
LangElement *outputDecl = new DecOp( retVar );
switch(mNormalStorageType)
{
case CartesianXYZ:
meta->addStatement( new GenOp( " // g-buffer conditioner: vec4(normal.xyz, depth)\r\n" ) );
meta->addStatement( new GenOp( " @ = vec4(@, @.a);\r\n", outputDecl,
_posnegEncode(new GenOp("@.xyz", unconditionedOutput)), unconditionedOutput ) );
break;
case CartesianXY:
meta->addStatement( new GenOp( " // g-buffer conditioner: vec4(normal.xy, depth Hi + z-sign, depth Lo)\r\n" ) );
meta->addStatement( new GenOp( " @ = vec4(@, @.a);", outputDecl,
_posnegEncode(new GenOp("vec3(@.xy, sign(@.z))", unconditionedOutput, unconditionedOutput)), unconditionedOutput ) );
break;
case Spherical:
meta->addStatement( new GenOp( " // g-buffer conditioner: vec4(normal.theta, normal.phi, depth Hi, depth Lo)\r\n" ) );
meta->addStatement( new GenOp( " @ = vec4(@, 0.0, @.a);\r\n", outputDecl,
_posnegEncode(new GenOp("vec2(atan2(@.y, @.x) / 3.14159265358979323846f, @.z)", unconditionedOutput, unconditionedOutput, unconditionedOutput ) ),
unconditionedOutput ) );
break;
}
// Encode depth into two channels
if(mNormalStorageType != CartesianXYZ)
{
const U64 maxValPerChannel = 1 << mBitsPerChannel;
const U64 extraVal = (maxValPerChannel * maxValPerChannel - 1) - (maxValPerChannel - 1) * 2;
meta->addStatement( new GenOp( " \r\n // Encode depth into hi/lo\r\n" ) );
meta->addStatement( new GenOp( avar( " vec3 _tempDepth = fract(@.a * vec3(1.0, %llu.0, %llu.0));\r\n", maxValPerChannel - 1, extraVal ),
unconditionedOutput ) );
meta->addStatement( new GenOp( avar( " @.zw = _tempDepth.xy - _tempDepth.yz * vec2(1.0/%llu.0, 1.0/%llu.0);\r\n\r\n", maxValPerChannel - 1, maxValPerChannel - 1 ),
retVar ) );
}
AssertFatal( retVar != NULL, avar( "Cannot condition output to buffer format: %s", GFXStringTextureFormat[getBufferFormat()] ) );
return retVar;
}
Var* GBufferConditionerGLSL::_conditionOutput( Var *unconditionedOutput, MultiLine *meta )
{
Var *retVar = new Var;
retVar->setType("float4");
retVar->setName("_gbConditionedOutput");
LangElement *outputDecl = new DecOp( retVar );
switch(mNormalStorageType)
{
case CartesianXYZ:
meta->addStatement( new GenOp( " // g-buffer conditioner: float4(normal.xyz, depth)\r\n" ) );
meta->addStatement( new GenOp( " @ = float4(@, @.a);\r\n", outputDecl,
_posnegEncode(new GenOp("@.xyz", unconditionedOutput)), unconditionedOutput ) );
break;
case CartesianXY:
meta->addStatement( new GenOp( " // g-buffer conditioner: float4(normal.xy, depth Hi + z-sign, depth Lo)\r\n" ) );
meta->addStatement( new GenOp( " @ = float4(@, @.a);", outputDecl,
_posnegEncode(new GenOp("float3(@.xy, sign(@.z))", unconditionedOutput, unconditionedOutput)), unconditionedOutput ) );
break;
case Spherical:
meta->addStatement( new GenOp( " // g-buffer conditioner: float4(normal.theta, normal.phi, depth Hi, depth Lo)\r\n" ) );
meta->addStatement( new GenOp( " @ = float4(@, 0.0, @.a);\r\n", outputDecl,
_posnegEncode(new GenOp("float2(atan2(@.y, @.x) / 3.14159265358979323846f, @.z)", unconditionedOutput, unconditionedOutput, unconditionedOutput ) ),
unconditionedOutput ) );
// HACK: This fixes the noise present when using a floating point
// gbuffer on Geforce cards and the "flat areas unlit" issues.
//
// We need work around atan2() above to fix this issue correctly
// without the extra overhead of this test.
//
meta->addStatement( new GenOp( " if ( abs( dot( @.xyz, float3( 0.0, 0.0, 1.0 ) ) ) > 0.999f ) @ = float4( 0, 1 * sign( @.z ), 0, @.a );\r\n",
unconditionedOutput, retVar, unconditionedOutput, unconditionedOutput ) );
break;
case LambertAzimuthal:
//http://en.wikipedia.org/wiki/Lambert_azimuthal_equal-area_projection
//
// Note we're casting to half to use partial precision
// sqrt which is much faster on older Geforces while
// still being acceptable for normals.
//
meta->addStatement( new GenOp( " // g-buffer conditioner: float4(normal.X, normal.Y, depth Hi, depth Lo)\r\n" ) );
meta->addStatement( new GenOp( " @ = float4(@, 0.0, @.a);\r\n", outputDecl,
_posnegEncode(new GenOp("sqrt(half(2.0/(1.0 - @.y))) * half2(@.xz)", unconditionedOutput, unconditionedOutput)),
unconditionedOutput ) );
break;
}
// Encode depth into two channels
if(mNormalStorageType != CartesianXYZ)
{
const U64 maxValPerChannel = 1 << mBitsPerChannel;
meta->addStatement( new GenOp( " \r\n // Encode depth into hi/lo\r\n" ) );
meta->addStatement( new GenOp( avar( " float2 _tempDepth = frac(@.a * float2(1.0, %llu.0));\r\n", maxValPerChannel - 1 ),
unconditionedOutput ) );
meta->addStatement( new GenOp( avar( " @.zw = _tempDepth.xy - _tempDepth.yy * float2(1.0/%llu.0, 0.0);\r\n\r\n", maxValPerChannel - 1 ),
retVar ) );
}
AssertFatal( retVar != NULL, avar( "Cannot condition output to buffer format: %s", GFXStringTextureFormat[getBufferFormat()] ) );
return retVar;
}
