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93 lines
3.5 KiB
HLSL
93 lines
3.5 KiB
HLSL
#ifndef PW_GENERALWINDHDRP
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#define PW_GENERALWINDHDRP
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inline void WindCalculations_float ( in float3 i_vertexPos, in float2 i_widthHeight, in float3 i_flex, in float3 i_frequency, out float3 o_vertexPos )
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{
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#ifdef _PW_SF_WIND_ON
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// early out test
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float3 worldOffset = UNITY_MATRIX_M._m03_m13_m23 + _WorldSpaceCameraPos; // grab pos from matrix translation
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// cheeky normalised square dist
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float3 nrmObjDistVector = (worldOffset - _WorldSpaceCameraPos) / _PW_WindGlobalsB.x;
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float nrmSqrdDist = 1 - saturate(dot(nrmObjDistVector,nrmObjDistVector));
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nrmSqrdDist *= nrmSqrdDist;
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o_vertexPos = i_vertexPos; // prime out with pre wind data
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if(nrmSqrdDist > 0.0f)
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{
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// Just for clarity
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float3 windDir = _PW_WindGlobals.xyz;
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float windMain = _PW_WindGlobals.w;
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// curves for mixing flex by wind main
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float3 flex = i_flex * float3(saturate(windMain * 3),saturate(windMain * 2),1-windMain * windMain * 0.5) * windMain * nrmSqrdDist;
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// normalize effects by height scale and reduce effects when object is on its side.
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float3 up = float3(0,1,0);
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float3 zScaleRotVec = mul((float3x3)UNITY_MATRIX_M,up);
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float3 zScaleRotVecNrm = normalize(zScaleRotVec);
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float xDot = max(dot(zScaleRotVec,zScaleRotVecNrm),0.4f); // clamp to 0.4 so really small scales dont become overly flexible
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float upDot = saturate(dot(zScaleRotVecNrm,up));
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i_widthHeight.xy = lerp(i_widthHeight.yy * float2(2,2),i_widthHeight.xy,upDot*upDot) * xDot;
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flex *= xDot;
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i_frequency *= xDot;
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// split translation from scale and rotation for later use
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float3 localWorldPos = mul((float3x3)UNITY_MATRIX_M,i_vertexPos.xyz);
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float3 worldPos = localWorldPos + worldOffset;
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float windTime = -frac(_PW_WindGlobalsB.y * 6.0f) * 6.283185f;
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float3 normLocalWorldPos = localWorldPos / float3(i_widthHeight.x,i_widthHeight.y,i_widthHeight.x);
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float branchdist = dot(normLocalWorldPos.xz , normLocalWorldPos.xz);
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float stemheight = normLocalWorldPos.y;
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// approximate length before flex
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float lengthA = dot(localWorldPos,localWorldPos);
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// Main wind force
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float gust = ((sin(windTime + dot(i_frequency.xxx,worldOffset)) * 0.3 + windMain * 0.5) + (_SinTime.y * 0.4 + windMain) * windMain) * (_SinTime.w * 0.3 + 0.7);
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// trunk flex
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float3 flexTally = 0;
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flexTally.xz = windDir.xz * (stemheight * stemheight * gust * flex.x);
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// scale gust for branch and leaf
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gust = gust * 0.7 + 0.3;
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// branch flex
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#ifndef _PW_SF_BILLBOARD_ON
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flexTally.xyz += windDir.xyz * stemheight * stemheight * (sin(windTime * 2 + dot(worldPos + flexTally * 0.25,float3(1,1,1)) * i_frequency.y) * branchdist * 0.7 + 0.3) * gust * flex.y; // - flextally adds more noise when stem flex's
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#endif
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//normalize flex to maintain tree volume
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float3 vertOffset = localWorldPos + flexTally;
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float flexNorm = saturate(lengthA/dot(vertOffset,vertOffset));
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flexTally = vertOffset * flexNorm;
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// add to tree
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localWorldPos = flexTally;
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// leaf flex
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#ifndef _PW_SF_BILLBOARD_ON
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#ifdef _ALPHATEST_ON
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float leafTime = windTime * 5;
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float3 frequencyOffests = (worldPos + flexTally) * i_frequency.z;
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float3 leafBranchdist = float3(branchdist,branchdist * 0.75f,branchdist);
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float3 leafFlex = (sin(leafTime.xxx + frequencyOffests) * windDir.xyz + windDir.xyz) * leafBranchdist;
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localWorldPos += leafFlex * (stemheight * gust * flex.z) * (flexNorm + 0.5f);
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#endif
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#endif
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o_vertexPos = mul((float3x3)UNITY_MATRIX_I_M,localWorldPos.xyz);
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}
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#else
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o_vertexPos = i_vertexPos;
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#endif
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}
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#endif // PW_GENERALFUNCS
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