///////////////////////////////////////////////////////////////////////////////////////////////////
// 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);
}
void SetUpFrame(GLFrame &frame,const M3DVector3f origin, const M3DVector3f forward, const M3DVector3f up) {
frame.SetOrigin(origin);
frame.SetForwardVector(forward);
M3DVector3f side,oUp;
m3dCrossProduct3(side,forward,up);
m3dCrossProduct3(oUp,side,forward);
frame.SetUpVector(oUp);
frame.Normalize();
}
void SetUpFrame(GLFrame &cameraFrame,const M3DVector3f origin,
const M3DVector3f forward,
const M3DVector3f cameraUpDirection) {
cameraFrame.SetOrigin(origin);
cameraFrame.SetForwardVector(forward);
M3DVector3f side,oUp;
m3dCrossProduct3(side,forward,cameraUpDirection);
m3dCrossProduct3(oUp,side,forward);
cameraFrame.SetUpVector(oUp);
cameraFrame.Normalize();
};
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 Camerak::strafeRight(){
M3DVector3f temp,fwd,up,right;
Vec3 thisMove;
cam.GetOrigin(temp);
lastPos.fromM3D(temp);
cam.GetForwardVector(fwd);
cam.GetUpVector(up);
m3dCrossProduct3(right,fwd,up);
thisMove.fromM3D(right);
thisMove*= movement_rate;
move+=thisMove;
}
// Ditto above, but for doubles
void m3dFindNormal(M3DVector3d result, const M3DVector3d point1, const M3DVector3d point2,
const M3DVector3d point3)
{
M3DVector3d v1,v2; // Temporary vectors
// Calculate two vectors from the three points. Assumes counter clockwise
// winding!
v1[0] = point1[0] - point2[0];
v1[1] = point1[1] - point2[1];
v1[2] = point1[2] - point2[2];
v2[0] = point2[0] - point3[0];
v2[1] = point2[1] - point3[1];
v2[2] = point2[2] - point3[2];
// Take the cross product of the two vectors to get
// the normal vector.
m3dCrossProduct3(result, v1, v2);
}
// Ditto above, but for doubles
void m3dGetPlaneEquation(M3DVector4d planeEq, const M3DVector3d p1, const M3DVector3d p2, const M3DVector3d p3)
{
// Get two vectors... do the cross product
M3DVector3d v1, v2;
// V1 = p3 - p1
v1[0] = p3[0] - p1[0];
v1[1] = p3[1] - p1[1];
v1[2] = p3[2] - p1[2];
// V2 = P2 - p1
v2[0] = p2[0] - p1[0];
v2[1] = p2[1] - p1[1];
v2[2] = p2[2] - p1[2];
// Unit normal to plane - Not sure which is the best way here
m3dCrossProduct3(planeEq, v1, v2);
m3dNormalizeVector3(planeEq);
// Back substitute to get D
planeEq[3] = -(planeEq[0] * p3[0] + planeEq[1] * p3[1] + planeEq[2] * p3[2]);
}
void MouseMoveEvent(int x, int y)
{
if (isStartTrackBall)
{
GLfloat theta;
M3DVector3f p1, p2, n;
int width = glutGet(GLUT_WINDOW_WIDTH);
int height = glutGet(GLUT_WINDOW_HEIGHT);
MousePtToSphereVec(p1, mMouseX, mMouseY, width, height);
MousePtToSphereVec(p2, x, y, width, height);
mMouseX = x;
mMouseY = y;
m3dNormalizeVector3(p1);
m3dNormalizeVector3(p2);
theta = acos(m3dDotProduct3(p1, p2)) ;
//theta = m3dGetAngleBetweenVectors3(p1, p2);
m3dCrossProduct3(n, p1, p2);
m3dNormalizeVector3(n);
M3DMatrix44f tempRotation;
m3dLoadIdentity44(tempRotation);
GLfloat dis = m3dGetDistance3(p1, p2);
if (dis != 0.0f)
{
m3dRotationMatrix44(tempRotation, theta, m3dGetVectorX(n), m3dGetVectorY(n), m3dGetVectorZ(n));
}
m3dMatrixMultiply44(mRotation, tempRotation, mRotation);
glutPostRedisplay();
}
}
