// Points p1, p2, & p3 specified in counter clock-wise order
void calcNormal(float v[3][3], float out[3])
{
float v1[3],v2[3];
static const int x = 0;
static const int y = 1;
static const int z = 2;
// Calculate two vectors from the three points
v1[x] = v[0][x] - v[1][x];
v1[y] = v[0][y] - v[1][y];
v1[z] = v[0][z] - v[1][z];
v2[x] = v[1][x] - v[2][x];
v2[y] = v[1][y] - v[2][y];
v2[z] = v[1][z] - v[2][z];
// Take the cross product of the two vectors to get
// the normal vector which will be stored in out
out[x] = v1[y]*v2[z] - v1[z]*v2[y];
out[y] = v1[z]*v2[x] - v1[x]*v2[z];
out[z] = v1[x]*v2[y] - v1[y]*v2[x];
// Normalize the vector (shorten length to one)
ReduceToUnit(out);
}
void TriObject::applyNormals()
{
if (numfaces == 0) return;
delete[]nx;
delete[]ny;
delete[]nz;
nx = new float[numfaces / 3];
ny = new float[numfaces / 3];
nz = new float[numfaces / 3];
if (nx == NULL || ny == NULL || nz == NULL)
{
delete[]nx;
delete[]ny;
delete[]nz;
normalapplied = FALSE;
return;
}
float normal[3];
for (int i = 0; i < numfaces / 3; i++)
{
CalcNormal(3 * i, normal);
ReduceToUnit(normal);
nx[i] = normal[0];
ny[i] = normal[1];
nz[i] = normal[2];
}
normalapplied = TRUE;
}
void calcNormal(float v[3][3], float out[3]) /* Calculates Normal For A Quad Using 3 Points */
{
float v1[3],v2[3]; /* Vector 1 (x,y,z) & Vector 2 (x,y,z) */
static const int x = 0; /* Define X Coord */
static const int y = 1; /* Define Y Coord */
static const int z = 2; /* Define Z Coord */
/* Finds The Vector Between 2 Points By Subtracting
* The x,y,z Coordinates From One Point To Another.
* Calculate The Vector From Point 1 To Point 0
*/
v1[x] = v[0][x] - v[1][x]; /* Vector 1.x=Vertex[0].x-Vertex[1].x */
v1[y] = v[0][y] - v[1][y]; /* Vector 1.y=Vertex[0].y-Vertex[1].y */
v1[z] = v[0][z] - v[1][z]; /* Vector 1.z=Vertex[0].y-Vertex[1].z */
/* Calculate The Vector From Point 2 To Point 1 */
v2[x] = v[1][x] - v[2][x]; /* Vector 2.x=Vertex[0].x-Vertex[1].x */
v2[y] = v[1][y] - v[2][y]; /* Vector 2.y=Vertex[0].y-Vertex[1].y */
v2[z] = v[1][z] - v[2][z]; /* Vector 2.z=Vertex[0].z-Vertex[1].z */
/* Compute The Cross Product To Give Us A Surface Normal */
out[x] = v1[y]*v2[z] - v1[z]*v2[y]; /* Cross Product For Y - Z */
out[y] = v1[z]*v2[x] - v1[x]*v2[z]; /* Cross Product For X - Z */
out[z] = v1[x]*v2[y] - v1[y]*v2[x]; /* Cross Product For X - Y */
ReduceToUnit(out); /* Normalize The Vectors */
}
void calcNormal(float v[3][3], float out[3]) // Calculates Normal For A Quad Using 3 Points
{
float v1[3],v2[3]; // Vector 1 (x,y,z) & Vector 2 (x,y,z)
static const int x = 0; // Define X Coord
static const int y = 1; // Define Y Coord
static const int z = 2; // Define Z Coord
// Finds The Vector Between 2 Points By Subtracting
// The x,y,z Coordinates From One Point To Another.
// Calculate The Vector From Point 1 To Point 0
v1[x] = v[0][x] - v[1][x]; // Vector 1.x=Vertex[0].x-Vertex[1].x
v1[y] = v[0][y] - v[1][y]; // Vector 1.y=Vertex[0].y-Vertex[1].y
v1[z] = v[0][z] - v[1][z]; // Vector 1.z=Vertex[0].y-Vertex[1].z
// Calculate The Vector From Point 2 To Point 1
v2[x] = v[1][x] - v[2][x]; // Vector 2.x=Vertex[0].x-Vertex[1].x
v2[y] = v[1][y] - v[2][y]; // Vector 2.y=Vertex[0].y-Vertex[1].y
v2[z] = v[1][z] - v[2][z]; // Vector 2.z=Vertex[0].z-Vertex[1].z
// Compute The Cross Product To Give Us A Surface Normal
out[x] = v1[y]*v2[z] - v1[z]*v2[y]; // Cross Product For Y - Z
out[y] = v1[z]*v2[x] - v1[x]*v2[z]; // Cross Product For X - Z
out[z] = v1[x]*v2[y] - v1[y]*v2[x]; // Cross Product For X - Y
ReduceToUnit(out); // Normalize The Vectors
}
void calcNormal(float v[3][3], float out[3])
{
float v1[3],v2[3];
static const int x = 0;
static const int y = 1;
static const int z = 2;
v1[x] = v[0][x] - v[1][x];
v1[y] = v[0][y] - v[1][y];
v1[z] = v[0][z] - v[1][z];
v2[x] = v[1][x] - v[2][x];
v2[y] = v[1][y] - v[2][y];
v2[z] = v[1][z] - v[2][z];
out[x] = v1[y]*v2[z] - v1[z]*v2[y];
out[y] = v1[z]*v2[x] - v1[x]*v2[z];
out[z] = v1[x]*v2[y] - v1[y]*v2[x];
ReduceToUnit(out);
}
//From OpenGL superbible
void CalcNormal(float const *v1,float const *v2,float const *v3,float * out)
{
float vt1[3],vt2[3];
static const int x=0;
static const int y=1;
static const int z=2;
//calculate 2 vectors from 3 points
vt1[x]=v1[x]-v2[x];
vt1[y]=v1[y]-v2[y];
vt1[z]=v1[z]-v2[z];
vt2[x]=v2[x]-v3[x];
vt2[y]=v2[y]-v3[y];
vt2[z]=v2[z]-v3[z];
//Take the cross product
out[x]=vt1[y]*vt2[z]-vt1[z]*vt2[y];
out[y]=vt1[z]*vt2[x]-vt1[x]*vt2[z];
out[z]=vt1[x]*vt2[y]-vt1[y]*vt2[x];
ReduceToUnit(out);
}
