Torque3D/Templates/Full/game/shaders/common/terrain/terrain.hlsl
2016-03-20 21:50:21 +10:00

55 lines
2.2 KiB
HLSL

//-----------------------------------------------------------------------------
// Copyright (c) 2012 GarageGames, LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//-----------------------------------------------------------------------------
float calcBlend( float texId, float2 layerCoord, float layerSize, float4 layerSample )
{
// This is here to disable the blend if none of
// the neighbors equal the current id.
//
// We depend on the input layer samples being
// rounded to the correct integer ids.
//
float4 diff = saturate( abs( layerSample - texId ) );
float noBlend = any( 1 - diff );
// Check if any of the layer samples
// match the current texture id.
float4 factors = 0;
[unroll]
for(int i = 0; i < 4; i++)
if(layerSample[i] == texId)
factors[i] = 1;
// This is a custom bilinear filter.
float2 uv = layerCoord * layerSize;
float2 xy = floor( uv );
float2 ratio = uv - xy;
float2 opposite = 1 - ratio;
// NOTE: This will optimize down to two lerp operations.
float blend = ( factors.b * opposite.x + factors.g * ratio.x ) * opposite.y +
( factors.r * opposite.x + factors.a * ratio.x ) * ratio.y;
return noBlend * blend;
}