Code up an initial version of the iqm vertex shader.

Probably more bugs than an old kitchen cupboard :P

libs/video/renderer/glsl/iqm.vert

@@ -0,0 +1,55 @@
+uniform mat4 bonemats[80];
+attribute vec4 vcolor;
+attribute vec4 vweights;
+attribute vec4 vbones;
+attribute vec2 texcoord;
+attribute vec4 vtangent;
+attribute vec3 vnormal;
+attribute vec3 position;
+
+varying vec3 bitangent;
+varying vec3 tangent;
+varying vec3 normal;
+varying vec2 st;
+varying vec4 color;
+
+void
+main (void)
+{
+	mat4        m;
+	vec4        q0, qe;
+	vec3        sh, sc, tr, v, n, t;
+
+	m  = bonemats[int (vbones.x)] * vweights.x;
+	m += bonemats[int (vbones.y)] * vweights.y;
+	m += bonemats[int (vbones.z)] * vweights.z;
+	m += bonemats[int (vbones.w)] * vweights.w;
+	q0 = m[0].yzwx;
+	qe = m[1].yzwx;
+	sh = m[2].xyz;
+	sc = m[3].xyz;
+
+	tr = 2.0 * (q0.w * qe.xyz - qe.w * q0.xyz - cross (qe.xyz, q0.xyz));
+	v = position;
+	// apply rotation and translation
+	v += 2.0 * cross (q0.xyz, cross (q0.xyz, v) + q0.w * v) + 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);
+	// 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);
+	gl_Position = mvp_mat * vec4 (v, 1.0);
+	normal = mat3 (mvp_mat[0].xyz, mvp_mat[1].xyz, mvp_mat[3].xyz) * n;
+	tangent = mat3 (mvp_mat[0].xyz, mvp_mat[1].xyz, mvp_mat[3].xyz) * t;
+	bitangent = cross (normal, tangent) * vtangent.w;
+	color = vcolor;
+	st = texcoord;
+}