光线追踪的原始c++算法

// ----------------------------------------------------------- // scene.cpp // 2004 - Jacco Bikker - jacco@bik5.com - www.bik5.com - <>< // ----------------------------------------------------------- #include "common.h" #include "string.h" #include "scene.h" #include "raytracer.h" #include "stdio.h" #include "memory.h" #include "surface.h" namespace Raytracer { MManager* KdTree::s_MManager = 0; // ----------------------------------------------------------- // Texture class implementation // ----------------------------------------------------------- Texture::Texture( Color* a_Bitmap, int a_Width, int a_Height ) : m_Bitmap( a_Bitmap ), m_Width( a_Width ), m_Height( a_Height ) { } Texture::Texture( char* a_File ) { FILE* f = fopen( a_File, "rb" ); if (f) { // extract width and height from file header unsigned char buffer[20]; fread( buffer, 1, 20, f ); m_Width = *(buffer + 12) + 256 * *(buffer + 13); m_Height = *(buffer + 14) + 256 * *(buffer + 15); fclose( f ); // read pixel data f = fopen( a_File, "rb" ); unsigned char* t = new unsigned char[m_Width * m_Height * 3 + 1024]; fread( t, 1, m_Width * m_Height * 3 + 1024, f ); fclose( f ); // convert RGB 8:8:8 pixel data to realing point RGB m_Bitmap = new Color[m_Width * m_Height]; real rec = 1.0f / 256; for ( int size = m_Width * m_Height, i = 0; i < size; i++ ) m_Bitmap[i] = Color( t[i * 3 + 20] * rec, t[i * 3 + 19] * rec, t[i * 3 + 18] * rec ); delete t; } } Color Texture::GetTexel( real a_U, real a_V ) { // fetch a bilinearly filtered texel real fu = (a_U + 1000.5f) * m_Width; real fv = (a_V + 1000.0f) * m_Width; int u1 = ((int)fu) % m_Width; int v1 = ((int)fv) % m_Height; int u2 = (u1 + 1) % m_Width; int v2 = (v1 + 1) % m_Height; // calculate fractional parts of u and v real fracu = fu - _floor( fu ); real fracv = fv - _floor( fv ); // calculate weight factors real w1 = (1 - fracu) * (1 - fracv); real w2 = fracu * (1 - fracv); real w3 = (1 - fracu) * fracv; real w4 = fracu * fracv; // fetch four texels Color c1 = m_Bitmap[u1 + v1 * m_Width]; Color c2 = m_Bitmap[u2 + v1 * m_Width]; Color c3 = m_Bitmap[u1 + v2 * m_Width]; Color c4 = m_Bitmap[u2 + v2 * m_Width]; // scale and sum the four colors return c1 * w1 + c2 * w2 + c3 * w3 + c4 * w4; } // ----------------------------------------------------------- // Material class implementation // ----------------------------------------------------------- Material::Material() : m_Color( Color( 0.2f, 0.2f, 0.2f ) ), m_Refl( 0 ), m_Diff( 0.2f ), m_Spec( 0.8f ), m_RIndex( 1.5f ), m_DRefl( 0 ), m_Texture( 0 ), m_UScale( 1.0f ), m_VScale( 1.0f ) { } void Material::SetUVScale( real a_UScale, real a_VScale ) { m_UScale = a_UScale; m_VScale = a_VScale; m_RUScale = 1.0f / a_UScale; m_RVScale = 1.0f / a_VScale; } void Material::SetParameters( real a_Refl, real a_Refr, Color& a_Col, real a_Diff, real a_Spec ) { m_Refl = a_Refl; m_Refr = a_Refr; m_Color = a_Col; m_Diff = a_Diff; m_Spec = a_Spec; } // ----------------------------------------------------------- // Primitive methods // ----------------------------------------------------------- Primitive::Primitive( int a_Type, vector3& a_Centre, real a_Radius ) { m_Centre = a_Centre; m_SqRadius = a_Radius * a_Radius; m_Radius = a_Radius; m_RRadius = 1.0f / a_Radius; m_Type = a_Type; m_Material = new Material(); // set vectors for texture mapping m_Vn = vector3( 0, 1, 0 ); m_Ve = vector3( 1, 0, 0 ); m_Vc = m_Vn.Cross( m_Ve ); } Primitive::Primitive( int a_Type, Vertex* a_V1, Vertex* a_V2, Vertex* a_V3 ) { m_Type = a_Type; m_Material = 0; m_Vertex[0] = a_V1; m_Vertex[1] = a_V2; m_Vertex[2] = a_V3; // init precomp vector3 A = m_Vertex[0]->GetPos(); vector3 B = m_Vertex[1]->GetPos(); vector3 C = m_Vertex[2]->GetPos(); vector3 c = B - A; vector3 b = C - A; m_N = b.Cross( c ); int u, v; if (_fabs( m_N.x ) > _fabs( m_N.y)) { if (_fabs( m_N.x ) > _fabs( m_N.z )) k = 0; else k = 2; } else { if (_fabs( m_N.y ) > _fabs( m_N.z )) k = 1; else k = 2; } u = (k + 1) % 3; v = (k + 2) % 3; // precomp real krec = 1.0f / m_N.cell[k]; nu = m_N.cell[u] * krec; nv = m_N.cell[v] * krec; nd = m_N.Dot( A ) * krec; // first line equation real reci = 1.0f / (b.cell[u] * c.cell[v] - b.cell[v] * c.cell[u]); bnu = b.cell[u] * reci; bnv = -b.cell[v] * reci; // second line equation cnu = c.cell[v] * reci; cnv = -c.cell[u] * reci; // finalize normal m_N.Normalize(); m_Vertex[0]->SetNormal( m_N ); m_Vertex[1]->SetNormal( m_N ); m_Vertex[2]->SetNormal( m_N ); } Primitive::~Primitive() { if (m_Type == SPHERE) delete m_Material; } unsigned int modulo[] = { 0, 1, 2, 0, 1 }; int Primitive::Intersect( Ray& a_Ray, real& a_Dist ) { if (m_Type == SPHERE) { vector3 v = a_Ray.GetOrigin() - m_Centre; real b = -DOT( v, a_Ray.GetDirection() ); real det = (b * b) - DOT( v, v ) + m_SqRadius; int retval = MISS; if (det > 0) { det = _sqrt( det ); real i1 = b - det; real i2 = b + det; if (i2 > 0) { if (i1 < 0) { if (i2 < a_Dist) { a_Dist = i2; retval = INPRIM; } } else { if (i1 < a_Dist) { a_Dist = i1; retval = HIT; } } } } return retval; } else { #define ku modulo[k + 1] #define kv modulo[k + 2] vector3 O = a_Ray.GetOrigin(), D = a_Ray.GetDirection(), A = m_Vertex[0]->GetPos(); const real lnd = 1.0f / (D.cell[k] + nu * D.cell[ku] + nv * D.cell[kv]); const real t = (nd - O.cell[k] - nu * O.cell[ku] - nv * O.cell[kv]) * lnd; if (!(a_Dist > t && t > 0)) return MISS; real hu = O.cell[ku] + t * D.cell[ku] - A.cell[ku]; real hv = O.cell[kv] + t * D.cell[kv] - A.cell[kv]; real beta = m_U = hv * bnu + hu * bnv; if (beta < 0) return MISS; real gamma = m_V = hu * cnu + hv * cnv; if (gamma < 0) return MISS; if ((m_U + m_V) > 1) return MISS; a_Dist = t; return (DOT( D, m_N ) > 0)?INPRIM:HIT; } } vector3 Primitive::GetNormal( vector3& a_Pos ) { if (m_Type == SPHERE) { return (a_Pos - m_Centre) * m_RRadius; } else { vector3 N1 = m_Vertex[0]->GetNormal(); vector3 N2 = m_Vertex[1]->GetNormal(); vector3 N3 = m_Vertex[2]->GetNormal(); vector3 N = N1 + m_U * (N2 - N1) + m_V * (N3 - N1); NORMALIZE( N ); return N; } } Color Primitive::GetColor( vector3& a_Pos ) { Color retval; if (!m_Material->GetTexture()) retval = m_Material->GetColor(); else { if (m_Type == SPHERE) { vector3 vp = (a_Pos - m_Centre) * m_RRadius; real phi = _acos( -DOT( vp, m_Vn ) ); real u, v = phi * m_Material->GetVScaleReci() * (1.0f / PI); real theta = (_acos( DOT( m_Ve, vp ) / _sin( phi ))) * (2.0f / PI); if (DOT( m_Vc, vp ) >= 0) u = (1.0f - theta) * m_Material->GetUScaleReci(); else u = theta * m_Material->GetUScaleReci(); retval = m_Material->GetTexture()->GetTexel( u, v ) * m_Material->GetColor(); } else { real U1 = m_Vertex[0]->GetU(), V1 = m_Vertex[0]->GetV(); real U2 = m_Vertex[1]->GetU(), V2 = m_Vertex[1]->GetV(); real U3 = m_Vertex[2]->GetU(), V3 = m_Vertex[2]->GetV(); real u = U1 + m_U * (U2 - U1) + m_V * (U3 - U1); real v = V1 + m_U * (V2 - V1) + m_V * (V3 - V1); retval = m_Material->GetTexture()->GetTexel( u, v ) * m_Material->GetColor(); } } return retval; } #define FINDMINMAX( x0, x1, x2, min, max ) \ min = max = x0; if(x1<min) min=x1; if(x1>max) max=x1; if(x2<min) min=x2; if(x2>max) max=x2; // X-tests #define AXISTEST_X01( a, b, fa, fb ) \ p0 = a * v0.cell[1] - b * v0.cell[2], p2 = a * v2.cell[1] - b * v2.cell[2]; \ if (p0 < p2) { min = p0; max = p2;} else { min = p2; max = p0; } \ rad = fa * a_BoxHalfsize.cell[1] + fb * a