void Mesh::CalculateBackfaces(const Maths::Vector4& cameraPos)
{
for ( int i = 0; i < m_numPolys; ++i )
{
Maths::Vector4 a = ( m_transformed[ m_polys[i].Indices[0] ].Position ) - ( m_transformed[ m_polys[i].Indices[1] ].Position );
Maths::Vector4 b = ( m_transformed[ m_polys[i].Indices[2] ].Position ) - ( m_transformed[ m_polys[i].Indices[1] ].Position );
Maths::Vector4 c = b.CrossProduct(a);
Maths::Vector4 d;
m_polys[i].Normal = c;
c.Normalize();
m_polys[i].NormalN = c;
Vector4 p = m_transformed[ m_polys[i].Indices[0] ].Position - cameraPos;
if ( p.DotProduct(c) > 0.0f )
{
m_polys[i].IsCulled = true;
m_transformed[ m_polys[i].Indices[0] ].IsCulled = true;
m_transformed[ m_polys[i].Indices[1] ].IsCulled = true;
m_transformed[ m_polys[i].Indices[2] ].IsCulled = true;
}
else
{
m_polys[i].IsCulled = false;
m_transformed[ m_polys[i].Indices[0] ].IsCulled = false;
m_transformed[ m_polys[i].Indices[1] ].IsCulled = false;
m_transformed[ m_polys[i].Indices[2] ].IsCulled = false;
}
}
}
void OcclusionBuffer::ClipVertices(const Vector4& plane, Vector4* vertices, bool* triangles, unsigned& numTriangles)
{
unsigned num = numTriangles;
for (unsigned i = 0; i < num; ++i)
{
if (triangles[i])
{
unsigned index = i * 3;
float d0 = plane.DotProduct(vertices[index]);
float d1 = plane.DotProduct(vertices[index + 1]);
float d2 = plane.DotProduct(vertices[index + 2]);
// If all vertices behind the plane, reject triangle
if (d0 < 0.0f && d1 < 0.0f && d2 < 0.0f)
{
triangles[i] = false;
continue;
}
// If 2 vertices behind the plane, create a new triangle in-place
else if (d0 < 0.0f && d1 < 0.0f)
{
vertices[index] = ClipEdge(vertices[index], vertices[index + 2], d0, d2);
vertices[index + 1] = ClipEdge(vertices[index + 1], vertices[index + 2], d1, d2);
}
else if (d0 < 0.0f && d2 < 0.0f)
{
vertices[index] = ClipEdge(vertices[index], vertices[index + 1], d0, d1);
vertices[index + 2] = ClipEdge(vertices[index + 2], vertices[index + 1], d2, d1);
}
else if (d1 < 0.0f && d2 < 0.0f)
{
vertices[index + 1] = ClipEdge(vertices[index + 1], vertices[index], d1, d0);
vertices[index + 2] = ClipEdge(vertices[index + 2], vertices[index], d2, d0);
}
// 1 vertex behind the plane: create one new triangle, and modify one in-place
else if (d0 < 0.0f)
{
unsigned newIdx = numTriangles * 3;
triangles[numTriangles] = true;
++numTriangles;
vertices[newIdx] = ClipEdge(vertices[index], vertices[index + 2], d0, d2);
vertices[newIdx + 1] = vertices[index] = ClipEdge(vertices[index], vertices[index + 1], d0, d1);
vertices[newIdx + 2] = vertices[index + 2];
}
else if (d1 < 0.0f)
{
unsigned newIdx = numTriangles * 3;
triangles[numTriangles] = true;
++numTriangles;
vertices[newIdx + 1] = ClipEdge(vertices[index + 1], vertices[index], d1, d0);
vertices[newIdx + 2] = vertices[index + 1] = ClipEdge(vertices[index + 1], vertices[index + 2], d1, d2);
vertices[newIdx] = vertices[index];
}
else if (d2 < 0.0f)
{
unsigned newIdx = numTriangles * 3;
triangles[numTriangles] = true;
++numTriangles;
vertices[newIdx + 2] = ClipEdge(vertices[index + 2], vertices[index + 1], d2, d1);
vertices[newIdx] = vertices[index + 2] = ClipEdge(vertices[index + 2], vertices[index], d2, d0);
vertices[newIdx + 1] = vertices[index + 1];
}
}
}
}
bool Mesh::CullPolygons(const ViewFrustum& frustum, const Maths::Vector4& camPos)
{
int cullCount = 0;
for ( int i = 0; i < m_numPolys; ++i )
{
if ( m_polys[i].IsCulled )
{
cullCount++;
continue;
}
int count = 0;
for ( int vv = 0; vv < 3; ++vv )
{
//Vector4 point = m_transformed[ m_polys[i].Indices[vv] ].Position - camPos;
Vector4 point = m_transformed[ m_polys[i].Indices[vv] ].Position - m_verts[ m_polys[i].Indices[vv] ];
float result = point.DotProduct( frustum.Left.Normal );
if ( result > 0.0f )
{
count++;
m_transformed[ m_polys[i].Indices[vv] ].IsCulled = true;
continue;
}
result = point.DotProduct( frustum.Right.Normal );
if ( result > 0.0f )
{
count++;
m_transformed[ m_polys[i].Indices[vv] ].IsCulled = true;
continue;
}
result = point.DotProduct( frustum.Top.Normal );
if ( result > 0.0f )
{
count++;
m_transformed[ m_polys[i].Indices[vv] ].IsCulled = true;
continue;
}
result = point.DotProduct( frustum.Bottom.Normal );
if ( result > 0.0f )
{
count++;
m_transformed[ m_polys[i].Indices[vv] ].IsCulled = true;
continue;
}
//result = point.DotProduct( frustum.Near.Normal );
//if ( result > 0.0f )
//{
// count++;
// m_transformed[ m_polys[i].Indices[vv] ].IsCulled = true;
// continue;
//}
//result = point.DotProduct( frustum.Far.Normal );
//if ( result > 0.0f )
//{
// count++;
// m_transformed[ m_polys[i].Indices[vv] ].IsCulled = true;
// continue;
//}
}
if ( count == 3 )
{
cullCount++;
m_polys[i].IsCulled = true;
}
}
return ( cullCount == m_numPolys );
}
void Mesh::CalculateLightingPoint( const std::vector<LightPoint>& light, int numLight, const Maths::Vector4& camera)
{
Maths::Vector4 l;
Maths::Vector4 temp, result, n, p;
Maths::Vector4 cof( 1.0f, 1.0f, 10.0f );
BYTE r, g, b;
float distance = 0;
float att = 0;
float a = 0.05f;
float bb = 0.05f;
float c = 0.05f;
float dif, spec;
m_noLight = false;
for ( int i = 0; i < m_numVerts; ++i )
{
if ( !m_transformed[i].IsCulled )
{
result.X = 0; //Red
result.Y = 0; //green
result.Z = 0; //blue
for ( int j = 0; j < numLight; ++j )
{
p = light[j].Position;
l = p - m_transformed[i].Position;
distance = l.Length();
//calculate the attenuation value
att = 1 / (a + ( distance * bb ) + ( distance * distance ) * c );
if ( att < 0 )
att = 0;
temp.X = light[j].Colour.GetR();
temp.Y = light[j].Colour.GetG();
temp.Z = light[j].Colour.GetB();
n = m_transformed[i].Normal;
n.Normalize();
dif = max( 0.0, l.DotProduct( n ) ) * att;
// calculate the speculation
//Vector4 toEye = m_transformed[i].Position - camera;
//Vector4 half = camera + p / 2;
//toEye.Normalize();
//half.Normalize();
//float specPower = 1.0f;
//float spec = pow( max( n.DotProduct( half ), 0.0f ), specPower ) * att;
Vector4 toEye = m_transformed[i].Position - camera;
Vector4 reflect = ( n - l ) * ( 2 * ( n.DotProduct( l ) ) );
toEye.Normalize();
reflect.Normalize();
float specPower = 1.0f;
float spec = pow( max( reflect.DotProduct( toEye ), 0.0f ), specPower ) * att;
temp.X = temp.X * ( (dif + spec) * m_kd_red );
temp.Y = temp.Y * ( (dif + spec) * m_kd_green );
temp.Z = temp.Z * ( (dif + spec) * m_kd_blue );
//temp.X = temp.X * ( dif * m_kd_red ) );
//temp.Y = temp.Y * ( dif * m_kd_green ) );
//temp.Z = temp.Z * ( dif * m_kd_blue ) );
result += temp;
}
//set colour
if ( result.X > 255.0f ) result.X = 255.0f;
if ( result.Y > 255.0f ) result.Y = 255.0f;
if ( result.Z > 255.0f ) result.Z = 255.0f;
if ( result.X < 0.0f ) result.X = 0.0f;
if ( result.Y < 0.0f ) result.Y = 0.0f;
if ( result.Z < 0.0f ) result.Z = 0.0f;
r = (BYTE)result.X;
g = (BYTE)result.Y;
b = (BYTE)result.Z;
m_transformed[i].Colour = Gdiplus::Color::MakeARGB( 255, r, g, b );
}
}
}
void Mesh::CalculateLightingDirectional(const LightDirectional& light, int numLights, const Vector4& camera)
{
Maths::Vector4 total;
Maths::Vector4 temp;
Maths::Vector4 l( light.Position.X, light.Position.Y, light.Position.Z, 1.0f );
Maths::Vector4 n( 0, 0, 0, 0 );
BYTE r, g, b;
float diff, spec = 0;
m_noLight = false;
l.Normalize();
for ( int i = 0; i < m_numVerts; ++i )
{
if ( !m_transformed[i].IsCulled )
{
//reset the colout to black
total.X = 0; //Red
total.Y = 0; //green
total.Z = 0; //blue
for ( int j = 0; j < numLights; ++j )
{
Maths::Vector4 d;
//modulate intensity with coresponding reflectance co-efficient values
temp.X = light.Colour.GetR() * light.Intensity.X;
temp.Y = light.Colour.GetG() * light.Intensity.Y;
temp.Z = light.Colour.GetB() * light.Intensity.Z;
n = m_transformed[i].Normal;
n.Normalize();
//attentuate the rgb values with lambertian attenuation
diff = max(0.0, l.DotProduct( n ));
Vector4 toEye = m_transformed[i].Position - camera;
Vector4 reflect = ( n - l ) * ( 2 * ( n.DotProduct( l ) ) );
toEye.Normalize();
reflect.Normalize();
float specPower = 1.0f;
spec = pow( max( reflect.DotProduct( toEye ), 0.0f ), specPower ) * 0.01f;
if ( diff <= 0.0f )
spec = 0.0f;
temp.X = temp.X * ( (diff + spec) * m_kd_red );
temp.Y = temp.Y * ( (diff + spec) * m_kd_green );
temp.Z = temp.Z * ( (diff + spec) * m_kd_blue );
//temp.X = temp.X * ( diff * m_kd_red + spec ) );
//temp.Y = temp.Y * ( diff * m_kd_green + spec ) );
//temp.Z = temp.Z * ( diff * m_kd_blue + spec ) );
total = total + temp;
}
if ( total.X > 255.0f ) total.X = 255.0f;
if ( total.Y > 255.0f ) total.Y = 255.0f;
if ( total.Z > 255.0f ) total.Z = 255.0f;
if ( total.X < 0.0f ) total.X = 0.0f;
if ( total.Y < 0.0f ) total.Y = 0.0f;
if ( total.Z < 0.0f ) total.Z = 0.0f;
r = (BYTE)total.X;
g = (BYTE)total.Y;
b = (BYTE)total.Z;
m_transformed[i].Colour = Gdiplus::Color::MakeARGB( 255, r, g, b );
}
}
}
// For Shading Purposes
void RT_shade(Ray* ray, int depth) {
if (depth <= MAX_DEPTH){
// Color Coefficients
Vector4* diffuseCoeff = new Vector4();
Vector4* specularCoeff = new Vector4();
double shininess;
// Diffuse and Specular Terms
double diffuseTerm[3] = {0.0, 0.0, 0.0};
double specularTerm[3] = {0.0, 0.0, 0.0};
if (ray->intersectedObject == SPHERE) {
diffuseCoeff->ReInitialize(spheres[ray->intersectID].color_diffuse);
specularCoeff->ReInitialize(spheres[ray->intersectID].color_specular);
shininess = spheres[ray->intersectID].shininess;
}
else if (ray->intersectedObject == TRIANGLE) {
// Interpolate diffuse and specular coefficients
double alpha, beta;
ObtainIntermediateTriangleIntersection(ray->intersectID, ray->intersectPoint, &alpha, &beta);
diffuseCoeff->ReInitialize();
InterpolateTriangleProperty(triangles[ray->intersectID].v[0].color_diffuse,
triangles[ray->intersectID].v[1].color_diffuse,
triangles[ray->intersectID].v[2].color_diffuse,
alpha, beta, diffuseCoeff, false);
specularCoeff->ReInitialize();
InterpolateTriangleProperty(triangles[ray->intersectID].v[0].color_specular,
triangles[ray->intersectID].v[1].color_specular,
triangles[ray->intersectID].v[2].color_specular,
alpha, beta, specularCoeff, false);
// Interpolate shininess
if (alpha > 0) {
double intermediateShininess = beta * triangles[ray->intersectID].v[2].shininess
+ (1 - beta) * triangles[ray->intersectID].v[1].shininess;
shininess = ((alpha - 1) * triangles[ray->intersectID].v[0].shininess
+ intermediateShininess) / alpha;
}
else {
shininess = triangles[ray->intersectID].v[0].shininess;
}
}
// Boundary Checking
assert(diffuseCoeff->HasNonNegativeEntries());
assert(!diffuseCoeff->HasGreaterThanOneEntries());
assert(specularCoeff->HasNonNegativeEntries());
assert(!specularCoeff->HasGreaterThanOneEntries());
assert(shininess >= 0);
// Normal Vector: N
Vector4* N = new Vector4(ray->normal);
N->ConvertToUnitVector();
// Viewer Direction: V = ray->intersectedPoint - ray->source = -ray->dir
Vector4* V = new Vector4(ray->dir);
V->Scale(-1);
V->ConvertToUnitVector();
int dontCheckObject = NONE;
int dontCheckObjectID = NONE;
if (ray->intersectedObject == TRIANGLE) {
dontCheckObject = ray->intersectedObject;
dontCheckObjectID = ray->intersectID;
}
unsigned int i;
for (i = 0; i < num_lights; i++) {
// Shoot a ray in the direction of the light
Vector4* lightPos = new Vector4(lights[i].position);
Ray* checkShadow = new Ray(ray->intersectPoint, lightPos);
bool shadow = false;
double nearestTIntersect = FindNearestTIntersection(checkShadow,dontCheckObject,dontCheckObjectID);
double point2LightDistance = FindDistanceOfIntersectedPointWithLight(ray,i);
if (nearestTIntersect != INFINITY
&& nearestTIntersect< point2LightDistance)
{
shadow = true;
}
// Point to Light Vector: L = light_pos - intersectedPoint
Vector4* L = new Vector4(lights[i].position);
L->Subtraction(ray->intersectPoint);
L->ConvertToUnitVector();
// Reflected Ray: R = 2(N.L)N - L
Vector4* R = new Vector4(ray->normal);
R->Scale(2 * N->DotProduct(L));
R->Subtraction(L);
R->ConvertToUnitVector();
// Dot Product of N and L: NL
double NL = N->DotProduct(L);
if (NL < 0) {
NL = 0;
}
// Dot Product of R and V: RV
double RV = R->DotProduct(V);
if (RV < 0) {
RV = 0;
}
assert(NL <= 1 && RV <= 1);
double attenuationTerm = depth==1?1:1;
if (!shadow) {
unsigned int j;
for (j = 0; j < 3; j++) {
diffuseTerm[j] += attenuationTerm * lights[i].color[j] * diffuseCoeff->vector[j] * NL;
specularTerm[j] += attenuationTerm * lights[i].color[j] * specularCoeff->vector[j] * pow(RV, shininess);
}
}
delete(L);
delete(R);
delete(lightPos);
delete(checkShadow);
}
// Adding diffused light
Vector4* diffusedColor = new Vector4(diffuseTerm);
// //For Debugging Purposes
// if(ray->intersectedObject == SPHERE){
// ray->color->Display();
// diffusedColor->Display();
// cout<<"................................................."<<endl;
// }
ray->color->Addition(diffusedColor);
delete(diffusedColor);
// Adding specular light
Vector4* specularColor = new Vector4(specularTerm);
ray->color->Addition(specularColor);
delete(specularColor);
//R = 2*(NI)N - I ; N = N; I = V = ray->source - ray->IntersectPoint
Vector4* R_ = new Vector4(ray->normal);
Vector4* I = new Vector4(ray->dir);
I->Scale(-1);
R_->Scale(2*N->DotProduct(I));
R_->Subtraction(I);
Vector4* end = new Vector4(ray->intersectPoint);
end->Addition(R_);
Ray* reflectedRay = new Ray(ray->intersectPoint, end);
delete(R_);
delete(I);
delete(end);
assert(dontCheckObject!=SPHERE);
RT_trace(reflectedRay, depth+1, dontCheckObject, dontCheckObjectID);
//For Debugging
// if(ray->intersectedObject==TRIANGLE/* && ray->intersectPoint->vector[1]<-2*screenX/4
// && ray->intersectPoint->vector[1]>-3*screenX/4*/){
// cout<<ray->intersectID;
// cout<<"---->";
// ray->normal->Display();
// cout<<"------>";
// I->Display();
// cout<<I->DotProduct(ray->normal)<<"\t";
// cout<<reflectedRay->dir->DotProduct(ray->normal);
// reflectedRay->dir->Display();
// cout<<": "<<reflectedRay->tIntersect<<"\t";
// reflectedRay->color->Display();
// cout<<endl;
// }
if(reflectedRay->tIntersect!=INFINITY){
reflectedRay->color->Scale(specularCoeff->vector[0], specularCoeff->vector[1], specularCoeff->vector[2]);
ray->color->Addition(reflectedRay->color);
}
delete(reflectedRay);
delete(N);
delete(V);
delete(specularCoeff);
delete(diffuseCoeff);
}
}
double FindNearestTIntersectionWithTriangle(Ray* ray, int* index, int noCheckID = NONE){
assert(noCheckID==NONE || (noCheckID>=0 && noCheckID<num_triangles));
double nearestTIntersect = INFINITY;
*index = NONE;
unsigned int i;
for (i = 0; i < num_triangles; i++) {
if (i==noCheckID){
continue;
}
// Vertices V0, V1 and V2
Vector4* V0 = new Vector4(triangles[i].v[0].position);
Vector4* V1 = new Vector4(triangles[i].v[1].position);
Vector4* V2 = new Vector4(triangles[i].v[2].position);
// Edges: VOV1, V0V2
Vector4* V0V1 = new Vector4(V1);
V0V1->Subtraction(V0);
Vector4* V0V2 = new Vector4(V2);
V0V2->Subtraction(V0);
// Normal: N = V0V1 X V0V2
Vector4* N = new Vector4(V0V1);
N->CrossProductPost(V0V2);
N->ConvertToUnitVector();
// ray and normal should be opposite
if (N->DotProduct(ray->dir)>0){
N->Scale(-1);
}
// N = [A B C]
// AX0 + BY0 + CZ0 + D = 0
double D = -1*N->DotProduct(V0);
if (N->DotProduct(ray->dir) != (double) 0) {
// t = -(N.Ro + D)/ (N.Rd)
double candidateT = -1 * (N->DotProduct(ray->source) + D) / N->DotProduct(ray->dir);
if (candidateT > 0){
// P = Ro + tRd
Vector4* point = new Vector4(ray->dir);
point->Scale(candidateT);
point->Addition(ray->source);
// alpha*V0V1 + beta*V0V2 = V0P
Vector4* V0P = new Vector4(point);
V0P->Subtraction(V0);
double alpha = 0.0;
double beta = 0.0;
//(x01)alpha + (x02)beta = x0p;
//(y01)alpha + (y02)beta = y0p;
//(z01)alpha + (z02)beta = z0p;
double A1 = V0V1->vector[0];
double B1 = V0V2->vector[0];
double C1 = V0P->vector[0];
double A2 = V0V1->vector[1];
double B2 = V0V2->vector[1];
double C2 = V0P->vector[1];
double A3 = V0V1->vector[2];
double B3 = V0V2->vector[2];
double C3 = V0P->vector[2];
SolveLinearEquation(A1, B1, C1, A2, B2, C2, &alpha, &beta);
if (alpha == NONE) {
SolveLinearEquation(A2, B2, C2, A3, B3, C3, &alpha, &beta);
}
if (alpha == NONE) {
SolveLinearEquation(A1, B1, C1, A3, B3, C3, &alpha, &beta);
}
// // For Debugging Purposes
// printf("\nTriangle: %d ==> CandidateT: %f ==> (%f,%f)",i,candidateT,alpha,beta);
if (alpha > 0 && beta > 0 && (alpha + beta) < 1) {
if (nearestTIntersect > candidateT) {
nearestTIntersect = candidateT;
*index = i;
}
}
delete(V0P);
delete(point);
}
}
delete(N);
delete(V0V2);
delete(V0V1);
delete(V2);
delete(V1);
delete(V0);
}
return nearestTIntersect;
}
