31 lines
1009 B
GLSL
31 lines
1009 B
GLSL
// Geometric Skinning with Approximate Dual Quaternion Blending, Kavan
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// Based on https://github.com/tcoppex/aer-engine/blob/master/demos/aura/data/shaders/Skinning.glsl
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uniform vec4 skinBones[skinMaxBones * 3];
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void getSkinningDualQuat(const ivec4 bone, vec4 weight, out vec4 A, inout vec4 B, out vec4 S) {
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// Retrieve the real and dual part of the dual-quaternions
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ivec4 bonei = bone * 3;
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mat4 matA = mat4(
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skinBones[bonei.x],
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skinBones[bonei.y],
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skinBones[bonei.z],
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skinBones[bonei.w]);
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mat4 matB = mat4(
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skinBones[bonei.x + 1],
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skinBones[bonei.y + 1],
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skinBones[bonei.z + 1],
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skinBones[bonei.w + 1]);
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//Apply scaling first
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S = skinBones[bonei.x + 2];
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// Handles antipodality by sticking joints in the same neighbourhood
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// weight.xyz *= sign(matA[3] * mat3x4(matA)).xyz;
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weight.xyz *= sign(matA[3] * matA).xyz;
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// Apply weights
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A = matA * weight; // Real part
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B = matB * weight; // Dual part
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// Normalize
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float invNormA = 1.0 / length(A);
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A *= invNormA;
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B *= invNormA;
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}
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