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| |
| #ifndef TESSELLATION_NPATCH_GLSLLIB |
| #define TESSELLATION_NPATCH_GLSLLIB |
| |
| struct NPatchTessPatch |
| { |
| float b210; |
| float b120; |
| float b021; |
| float b012; |
| float b102; |
| float b201; |
| float b111; |
| float n110; |
| float n011; |
| float n101; |
| float t110; |
| float t011; |
| float t101; |
| }; |
| |
| #if TESSELLATION_CONTROL_SHADER |
| layout (vertices = 3) out; |
| |
| layout(location=15) out NPatchTessPatch tcTessPatch[]; |
| |
| // global setup in main |
| vec3 ctWorldPos[3]; |
| vec3 ctNorm[3]; |
| vec3 ctTangent[3]; |
| |
| uniform vec3 cameraPosition; |
| uniform vec2 distanceRange; |
| uniform float disableCulling; |
| |
| float isBackFace() |
| { |
| vec3 faceNormal = normalize( cross( ctWorldPos[2] - ctWorldPos[0], ctWorldPos[1] - ctWorldPos[0] ) ); |
| |
| vec3 ncd = normalize( ctWorldPos[0] - cameraPosition ); |
| |
| return sign( 0.2 + dot(faceNormal, ncd) ); // 0.2 is a conservative offset to account for curved surfaces |
| } |
| |
| float adaptiveCameraFactor( in float minTess, in float maxTess ) |
| { |
| float distanceValue0 = distance( cameraPosition, ctWorldPos[0] ); |
| float distanceValue1 = distance( cameraPosition, ctWorldPos[1] ); |
| float distanceValue2 = distance( cameraPosition, ctWorldPos[2] ); |
| |
| float range = distanceRange[1] - distanceRange[0]; |
| |
| vec3 edgeDistance; |
| edgeDistance[0] = ((distanceValue1 + distanceValue2) / 2.0) / range; |
| edgeDistance[1] = ((distanceValue2 + distanceValue0) / 2.0) / range; |
| edgeDistance[2] = ((distanceValue0 + distanceValue1) / 2.0) / range; |
| |
| edgeDistance = clamp( edgeDistance, vec3(0.0), vec3(1.0) ); |
| |
| //float af = mix( minTess, maxTess, 1.0 - edgeDistance[gl_InvocationID] ); |
| float af = 1.0 - edgeDistance[gl_InvocationID]; |
| af = clamp( af*af*maxTess , minTess, maxTess ); |
| |
| return af; |
| } |
| |
| float adaptiveFeatureFactor( in float minTess, in float maxTess ) |
| { |
| vec3 adaptValue; |
| adaptValue[0] = clamp( dot(ctNorm[1], ctNorm[2]), -1.0, 1.0 ); |
| adaptValue[1] = clamp( dot(ctNorm[2], ctNorm[0]), -1.0, 1.0 ); |
| adaptValue[2] = clamp( dot(ctNorm[0], ctNorm[1]), -1.0, 1.0 ); |
| |
| //float af = min( adaptValue[0], min(adaptValue[1], adaptValue[2]) ); |
| // map [-1, +1] range to [0, 1] range |
| float af = (adaptValue[gl_InvocationID] + 1.0) / 2.0; |
| |
| af = mix( minTess, maxTess, 1.0 - af ); |
| |
| return af; |
| } |
| |
| float getwij(int i, int j) |
| { |
| return dot(gl_in[j].gl_Position.xyz - gl_in[i].gl_Position.xyz, ctNorm[i]); |
| } |
| |
| float getvij(int i, int j) |
| { |
| vec3 pji = gl_in[j].gl_Position.xyz - gl_in[i].gl_Position.xyz; |
| vec3 nij = ctNorm[i] + ctNorm[j]; |
| |
| return 2.0*dot(pji, nij)/dot(pji, pji); |
| } |
| |
| void tessShader ( in float tessEdge, in float tessInner ) |
| { |
| // setup control points |
| // notations and formulas see http://alex.vlachos.com/graphics/CurvedPNTriangles.pdf |
| // note we compute separate x,y,z component for each invocation |
| float b300 = gl_in[0].gl_Position[gl_InvocationID]; |
| float b030 = gl_in[1].gl_Position[gl_InvocationID]; |
| float b003 = gl_in[2].gl_Position[gl_InvocationID]; |
| float n200 = ctNorm[0][gl_InvocationID]; |
| float n020 = ctNorm[1][gl_InvocationID]; |
| float n002 = ctNorm[2][gl_InvocationID]; |
| float t200 = ctTangent[0][gl_InvocationID]; |
| float t020 = ctTangent[1][gl_InvocationID]; |
| float t002 = ctTangent[2][gl_InvocationID]; |
| |
| // compute tangent control points |
| tcTessPatch[gl_InvocationID].b210 = (2.0*b300 + b030 - getwij(0,1)*n200)/3.0; |
| tcTessPatch[gl_InvocationID].b120 = (2.0*b030 + b300 - getwij(1,0)*n020)/3.0; |
| tcTessPatch[gl_InvocationID].b021 = (2.0*b030 + b003 - getwij(1,2)*n020)/3.0; |
| tcTessPatch[gl_InvocationID].b012 = (2.0*b003 + b030 - getwij(2,1)*n002)/3.0; |
| tcTessPatch[gl_InvocationID].b102 = (2.0*b003 + b300 - getwij(2,0)*n002)/3.0; |
| tcTessPatch[gl_InvocationID].b201 = (2.0*b300 + b003 - getwij(0,2)*n200)/3.0; |
| // compute center control point |
| float E = ( tcTessPatch[gl_InvocationID].b210 |
| + tcTessPatch[gl_InvocationID].b120 |
| + tcTessPatch[gl_InvocationID].b021 |
| + tcTessPatch[gl_InvocationID].b012 |
| + tcTessPatch[gl_InvocationID].b102 |
| + tcTessPatch[gl_InvocationID].b201 ) / 6.0; |
| |
| float V = ( b300 + b030 + b003 ) / 3.0; |
| tcTessPatch[gl_InvocationID].b111 = E + (E-V)*0.5; |
| |
| // compute normals |
| tcTessPatch[gl_InvocationID].n110 = n200 + n020 - getvij(0,1) * (b030 - b300); |
| tcTessPatch[gl_InvocationID].n011 = n020 + n002 - getvij(1,2) * (b003 - b030); |
| tcTessPatch[gl_InvocationID].n101 = n002 + n200 - getvij(2,0) * (b300 - b003); |
| // compute tangents |
| tcTessPatch[gl_InvocationID].t110 = t200 + t020 - getvij(0,1) * (b030 - b300); |
| tcTessPatch[gl_InvocationID].t011 = t020 + t002 - getvij(1,2) * (b003 - b030); |
| tcTessPatch[gl_InvocationID].t101 = t002 + t200 - getvij(2,0) * (b300 - b003); |
| |
| // compute backface |
| float bf = isBackFace(); |
| bf = max(disableCulling, bf); |
| |
| // adapative tessellation factor regarding features |
| float af = adaptiveFeatureFactor( tessInner, tessEdge ); |
| |
| //float cf = adaptiveCameraFactor( tessInner, tessEdge ); |
| |
| // Calculate the tessellation levels |
| gl_TessLevelInner[0] = af * bf; |
| gl_TessLevelOuter[gl_InvocationID] = af * bf; |
| } |
| |
| #endif |
| |
| #if TESSELLATION_EVALUATION_SHADER |
| layout (triangles, fractional_odd_spacing, ccw) in; |
| |
| layout(location=15) in NPatchTessPatch tcTessPatch[]; |
| |
| // global setup in main |
| vec3 ctNorm[3]; |
| vec3 teNorm; |
| vec3 ctTangent[3]; |
| vec3 teTangent; |
| vec3 teBinormal; |
| |
| bool doLinear(int i, int j) |
| { |
| /* |
| vec3 edgeji = gl_in[j].gl_Position.xyz - gl_in[i].gl_Position.xyz; |
| |
| float di = sign( dot( ctNorm[i], edgeji ) ); |
| float dj = sign( dot( ctNorm[j], -edgeji ) ); |
| |
| if ( di != dj ) |
| return false; |
| else |
| return true;*/ |
| |
| // Always do linear normal interpolation for now |
| // Seems to produce always good results unless we would produce |
| // a s-shaped triangle. |
| return true; |
| } |
| |
| vec4 tessShader ( ) |
| { |
| // pre compute square tesselation coord |
| vec3 tessSquared = gl_TessCoord * gl_TessCoord; |
| vec3 tessCubed = tessSquared * gl_TessCoord; |
| |
| // combine control points |
| vec3 b210 = vec3(tcTessPatch[0].b210, tcTessPatch[1].b210, tcTessPatch[2].b210); |
| vec3 b120 = vec3(tcTessPatch[0].b120, tcTessPatch[1].b120, tcTessPatch[2].b120); |
| vec3 b021 = vec3(tcTessPatch[0].b021, tcTessPatch[1].b021, tcTessPatch[2].b021); |
| vec3 b012 = vec3(tcTessPatch[0].b012, tcTessPatch[1].b012, tcTessPatch[2].b012); |
| vec3 b102 = vec3(tcTessPatch[0].b102, tcTessPatch[1].b102, tcTessPatch[2].b102); |
| vec3 b201 = vec3(tcTessPatch[0].b201, tcTessPatch[1].b201, tcTessPatch[2].b201); |
| vec3 b111 = vec3(tcTessPatch[0].b111, tcTessPatch[1].b111, tcTessPatch[2].b111); |
| |
| // combine control normals |
| vec3 n110 = vec3(tcTessPatch[0].n110, tcTessPatch[1].n110, tcTessPatch[2].n110); |
| vec3 n011 = vec3(tcTessPatch[0].n011, tcTessPatch[1].n011, tcTessPatch[2].n011); |
| vec3 n101 = vec3(tcTessPatch[0].n101, tcTessPatch[1].n101, tcTessPatch[2].n101); |
| |
| // combine control tangents |
| vec3 t110 = vec3(tcTessPatch[0].t110, tcTessPatch[1].t110, tcTessPatch[2].t110); |
| vec3 t011 = vec3(tcTessPatch[0].t011, tcTessPatch[1].t011, tcTessPatch[2].t011); |
| vec3 t101 = vec3(tcTessPatch[0].t101, tcTessPatch[1].t101, tcTessPatch[2].t101); |
| |
| // NPatch normal |
| if ( doLinear( 0, 1 ) == true ) |
| { |
| // linear normal |
| teNorm = ctNorm[0] * gl_TessCoord[2] |
| + ctNorm[1] * gl_TessCoord[0] |
| + ctNorm[2] * gl_TessCoord[1]; |
| // NPatch tangent |
| teTangent = ctTangent[0] * gl_TessCoord[2] |
| + ctTangent[1] * gl_TessCoord[0] |
| + ctTangent[2] * gl_TessCoord[1]; |
| } |
| else |
| { |
| // quadratic normal |
| teNorm = ctNorm[0] * tessSquared[2] |
| + ctNorm[1] * tessSquared[0] |
| + ctNorm[2] * tessSquared[1] |
| + n110*gl_TessCoord[2] * gl_TessCoord[0] |
| + n011*gl_TessCoord[0] * gl_TessCoord[1] |
| + n101*gl_TessCoord[2] * gl_TessCoord[1]; |
| |
| // NPatch tangent |
| teTangent = ctTangent[0] * tessSquared[2] |
| + ctTangent[1] * tessSquared[0] |
| + ctTangent[2] * tessSquared[1] |
| + t110*gl_TessCoord[2] * gl_TessCoord[0] |
| + t011*gl_TessCoord[0] * gl_TessCoord[1] |
| + t101*gl_TessCoord[2] * gl_TessCoord[1]; |
| } |
| |
| // NPatch binormal |
| teBinormal = cross( teNorm, teTangent ); |
| |
| // npatch interpolated position |
| vec3 finalPos = gl_in[0].gl_Position.xyz * tessCubed[2] |
| + gl_in[1].gl_Position.xyz * tessCubed[0] |
| + gl_in[2].gl_Position.xyz * tessCubed[1] |
| + b210 * 3.0 * tessSquared[2] * gl_TessCoord[0] |
| + b120 * 3.0 * tessSquared[0] * gl_TessCoord[2] |
| + b201 * 3.0 * tessSquared[2] * gl_TessCoord[1] |
| + b021 * 3.0 * tessSquared[0] * gl_TessCoord[1] |
| + b102 * 3.0 * tessSquared[1] * gl_TessCoord[2] |
| + b012 * 3.0 * tessSquared[1] * gl_TessCoord[0] |
| + b111 * 6.0 * gl_TessCoord[0] * gl_TessCoord[1] * gl_TessCoord[2]; |
| |
| return vec4( finalPos, 1.0 ); |
| } |
| #endif |
| |
| #endif |
| |