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Create functions for rotation and translation.

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This commit is contained in:
Bill Currie 2012-05-12 08:19:15 +09:00
parent 5b4fdd2a93
commit 4b38048a5c
1 changed files with 24 additions and 9 deletions
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33
libs/video/renderer/glsl/iqm.vert
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@ -16,6 +16,24 @@ varying vec3 normal;
varying vec2 st;
varying vec4 color;
vec3
qmult (vec4 q, vec3 v)
{
float qs = q.w;
vec3 qv = q.xyz;
vec3 t = cross (qv, v);
return (qs * qs) * v + 2.0 * qs * t + dot (qv, v) * qv + cross (qv, t);
}
vec3
dqtrans (vec4 q0, vec4 qe)
{//2.0 * (q0.w * qe.xyz - qe.w * q0.xyz - cross (qe.xyz, q0.xyz));
float qs = q0.w, Ts = qe.w;
vec3 qv = -q0.xyz, Tv = qe.xyz;
return 2.0 * (Ts * qv + qs * Tv + cross (Tv, qv));
}
void
main (void)
{
@ -33,23 +51,20 @@ main (void)
sc = m[3].xyz;
// extract translation from dual quaternion
tr = 2.0 * (q0.w * qe.xyz - qe.w * q0.xyz - cross (qe.xyz, q0.xyz));
tr = dqtrans (q0, qe);
// apply rotation and translation
v = vposition;
v += 2.0 * cross (q0.xyz, cross (q0.xyz, v) + q0.w * v) + tr;
v = qmult (q0, vposition) + tr;
// apply shear
v.z += v.y * sh.z + v.x * sh.y;
v.y += v.x * sh.x;
// apply scale
v *= sc;
// rotate normal (won't bother with shear or scale: not super accurate,
// but probably good enough
n = vnormal;
n += 2.0 * cross (q0.xyz, cross (q0.xyz, n) + q0.w * n);
// but probably good enough)
n = qmult (q0, vnormal);
// rotate tangent (won't bother with shear or scale: not super accurate,
// but probably good enough
t = vtangent.xyz;
t += 2.0 * cross (q0.xyz, cross (q0.xyz, t) + q0.w * t);
// but probably good enough)
t = qmult (q0, vtangent.xyz);
position = v * 8.0;
normal = norm_mat * n;
tangent = norm_mat * t;