///////////////////////////////////////////////////////////////////////////////////////////////////
// Calculate the tangent basis for a triangle on the surface of a model
// This vector is needed for most normal mapping shaders
void m3dCalculateTangentBasis(M3DVector3f vTangent, const M3DVector3f vTriangle[3], const M3DVector2f vTexCoords[3], const M3DVector3f N)
{
M3DVector3f dv2v1, dv3v1;
float dc2c1t, dc2c1b, dc3c1t, dc3c1b;
float M;
m3dSubtractVectors3(dv2v1, vTriangle[1], vTriangle[0]);
m3dSubtractVectors3(dv3v1, vTriangle[2], vTriangle[0]);
dc2c1t = vTexCoords[1][0] - vTexCoords[0][0];
dc2c1b = vTexCoords[1][1] - vTexCoords[0][1];
dc3c1t = vTexCoords[2][0] - vTexCoords[0][0];
dc3c1b = vTexCoords[2][1] - vTexCoords[0][1];
M = (dc2c1t * dc3c1b) - (dc3c1t * dc2c1b);
M = 1.0f / M;
m3dScaleVector3(dv2v1, dc3c1b);
m3dScaleVector3(dv3v1, dc2c1b);
m3dSubtractVectors3(vTangent, dv2v1, dv3v1);
m3dScaleVector3(vTangent, M); // This potentially changes the direction of the vector
m3dNormalizeVector3(vTangent);
M3DVector3f B;
m3dCrossProduct3(B, N, vTangent);
m3dCrossProduct3(vTangent, B, N);
m3dNormalizeVector3(vTangent);
}
//verlet x = vt + 1/2*at^2
void nextPosition(int currentPtc) {
M3DVector3f temp;
//get last shift: + vt
m3dSubtractVectors3(temp, ClothLnk[currentPtc].position, ClothLnk[currentPtc].pre_position);
m3dAddVectors3(ClothLnk[currentPtc].next_position, ClothLnk[currentPtc].position, temp);
//if (currentPtc==55)
// printf(" [%d].shift {%.1f, %.1f, %.1f} \n", currentPtc, shift[0], shift[1], shift[2]);
//get accumulation: + 1/2*at^2
m3dCopyVector3(temp, ClothLnk[currentPtc].force);
m3dScaleVector3(temp, (GLfloat)TimeStep*TimeStep*AccumulateStiff/ClothLnk[currentPtc].Mass/2);
m3dAddVectors3(ClothLnk[currentPtc].next_position, ClothLnk[currentPtc].next_position, temp);
//collide
//if (adjustPositionByCollision(ClothLnk[currentPtc].next_position) ) {
// m3dCopyVector3(ClothLnk[currentPtc].next_position, ClothLnk[currentPtc].position);
//}
adjustPositionByCollision(ClothLnk[currentPtc].position, ClothLnk[currentPtc].next_position);
M3DVector3f shift;
m3dSubtractVectors3(shift, ClothLnk[currentPtc].next_position, ClothLnk[currentPtc].position);
GLfloat length = (GLfloat)m3dGetVectorLength(shift);
if (length >= shiftRange ) {
m3dScaleVector3(shift, 1.0f/length);
m3dAddVectors3(ClothLnk[currentPtc].next_position, ClothLnk[currentPtc].position, shift);
}
}
void normal(float result[], const float A[], const float B[], const float C[]) {
float C_min_B[3], A_min_B[3];
m3dSubtractVectors3(C_min_B, C, B);
m3dSubtractVectors3(A_min_B, A, B);
m3dCrossProduct3(result, C_min_B, A_min_B);
m3dNormalizeVector3(result);
}
//----------------------------------------------------
void TriangleFace(M3DVector3f a, M3DVector3f b, M3DVector3f c) {
M3DVector3f normal, bMa, cMa;
m3dSubtractVectors3(bMa, b, a);
m3dSubtractVectors3(cMa, c, a);
m3dCrossProduct3(normal, bMa, cMa);
m3dNormalizeVector3(normal);
glVertexAttrib3fv(GLT_ATTRIBUTE_NORMAL, normal);
glVertex3fv(a);
glVertex3fv(b);
glVertex3fv(c);
}
void LookAt(GLFrame &frame, const M3DVector3f eye,
const M3DVector3f at,
const M3DVector3f up) {
M3DVector3f forward;
m3dSubtractVectors3(forward, at, eye);
SetUpFrame(frame, eye, forward, up);
}
void LookAt(GLFrame &cameraFrame, const M3DVector3f cameraPosition,
const M3DVector3f targetPosition,
const M3DVector3f cameraUpDirection) {
M3DVector3f forward;
m3dSubtractVectors3(forward, targetPosition, cameraPosition);
SetUpFrame(cameraFrame, cameraPosition, forward, cameraUpDirection);
}
// ditto above... but with floats
float m3dClosestPointOnRay(M3DVector3f vPointOnRay, const M3DVector3f vRayOrigin, const M3DVector3f vUnitRayDir,
const M3DVector3f vPointInSpace)
{
M3DVector3f v;
m3dSubtractVectors3(v, vPointInSpace, vRayOrigin);
float t = m3dDotProduct3(vUnitRayDir, v);
// This is the point on the ray
vPointOnRay[0] = vRayOrigin[0] + (t * vUnitRayDir[0]);
vPointOnRay[1] = vRayOrigin[1] + (t * vUnitRayDir[1]);
vPointOnRay[2] = vRayOrigin[2] + (t * vUnitRayDir[2]);
return m3dGetDistanceSquared3(vPointOnRay, vPointInSpace);
}
void sewClothModel() {
M3DVector3f temp, displacement;
for (int i = 0; i < PTCAMT; i ++) {
m3dLoadVector3(displacement, 0.0f, 0.0f, 0.0f);
clearForce(i);
getInternalForce(i);
//sew together
getTensionForce(i, ClothCenter, 0.01f);
m3dScaleVector3(ClothLnk[i].force, TensionCoefficient);
nextPosition(i);
m3dSubtractVectors3(temp, ClothLnk[i].next_position, ClothLnk[i].position);
m3dAddVectors3(displacement, displacement, temp);
}
m3dScaleVector3(displacement, (GLfloat)800000/PTCAMT);
//printf(" total displace: %.1f %.1f %.1f\n", displacement[0], displacement[1], displacement[2]);
m3dAddVectors3(ClothCenter, ClothCenter, displacement);
//m3dLoadVector3(TotalDisplacement, 0.0f, 0.0f, 0.0f);
refreshPosition();
}
void look_at(GLFrame & frame, const M3DVector3f eye, const M3DVector3f at, const M3DVector3f up) {
M3DVector3f forward;
m3dSubtractVectors3(forward, at, eye);
set_up_frame(frame, eye, forward, up);
}
