void renProjectTriangle(S_Renderer *pRenderer, S_Model *pModel, int i)
{
S_Coords aa, bb, cc; /* souradnice vrcholu po transformaci */
S_Coords naa, nbb, ncc; /* normaly ve vrcholech po transformaci */
S_Coords nn; /* normala trojuhelniku po transformaci */
int u1, v1, u2, v2, u3, v3; /* souradnice vrcholu po projekci do roviny obrazovky */
S_Triangle * triangle;
IZG_ASSERT(pRenderer && pModel && i >= 0 && i < trivecSize(pModel->triangles));
/* z modelu si vytahneme trojuhelnik */
triangle = trivecGetPtr(pModel->triangles, i);
/* transformace vrcholu matici model */
trTransformVertex(&aa, cvecGetPtr(pModel->vertices, triangle->v[0]));
trTransformVertex(&bb, cvecGetPtr(pModel->vertices, triangle->v[1]));
trTransformVertex(&cc, cvecGetPtr(pModel->vertices, triangle->v[2]));
/* promitneme vrcholy trojuhelniku na obrazovku */
trProjectVertex(&u1, &v1, &aa);
trProjectVertex(&u2, &v2, &bb);
trProjectVertex(&u3, &v3, &cc);
/* pro osvetlovaci model transformujeme take normaly ve vrcholech */
trTransformVector(&naa, cvecGetPtr(pModel->normals, triangle->v[0]));
trTransformVector(&nbb, cvecGetPtr(pModel->normals, triangle->v[1]));
trTransformVector(&ncc, cvecGetPtr(pModel->normals, triangle->v[2]));
/* normalizace normal */
coordsNormalize(&naa);
coordsNormalize(&nbb);
coordsNormalize(&ncc);
/* transformace normaly trojuhelniku matici model */
trTransformVector(&nn, cvecGetPtr(pModel->trinormals, triangle->n));
/* normalizace normaly */
coordsNormalize(&nn);
/* je troj. privraceny ke kamere, tudiz viditelny? */
if( !renCalcVisibility(pRenderer, &aa, &nn) )
{
/* odvracene troj. vubec nekreslime */
return;
}
/* rasterizace trojuhelniku */
renDrawTriangle(pRenderer,
&aa, &bb, &cc,
&naa, &nbb, &ncc,
u1, v1, u2, v2, u3, v3
);
}
int renCalcVisibility(S_Renderer *pRenderer, const S_Coords *point, const S_Coords *normal)
{
S_Coords cvec;
IZG_ASSERT(pRenderer && point && normal);
/* vektor od kamery k plosce, pozice kamery je (0, 0, -camera_dist) */
cvec = makeCoords(point->x, point->y, point->z + pRenderer->camera_dist);
coordsNormalize(&cvec);
/* test zda je normala privracena
* skalarni soucin vektoru od kamery a normaly */
return (normal->x * cvec.x + normal->y * cvec.y + normal->z * cvec.z > 0) ? 0 : 1;
}
S_RGBA renLambertianReflectance(S_Renderer *pRenderer, const S_Coords *point, const S_Coords *normal)
{
S_Coords lvec;
double diffuse, r, g, b;
S_RGBA color;
IZG_ASSERT(pRenderer && point && normal);
/* vektor ke zdroji svetla */
lvec = makeCoords(pRenderer->light_position.x - point->x,
pRenderer->light_position.y - point->y,
pRenderer->light_position.z - point->z);
coordsNormalize(&lvec);
/* ambientni cast */
r = pRenderer->light_ambient.red * pRenderer->mat_ambient.red;
g = pRenderer->light_ambient.green * pRenderer->mat_ambient.green;
b = pRenderer->light_ambient.blue * pRenderer->mat_ambient.blue;
/* difuzni cast */
diffuse = lvec.x * normal->x + lvec.y * normal->y + lvec.z * normal->z;
if( diffuse > 0 )
{
r += diffuse * pRenderer->light_diffuse.red * pRenderer->mat_diffuse.red;
g += diffuse * pRenderer->light_diffuse.green * pRenderer->mat_diffuse.green;
b += diffuse * pRenderer->light_diffuse.blue * pRenderer->mat_diffuse.blue;
}
/* saturace osvetleni*/
r = MIN(1, r);
g = MIN(1, g);
b = MIN(1, b);
/* kreslici barva */
color.red = ROUND2BYTE(255 * r);
color.green = ROUND2BYTE(255 * g);
color.blue = ROUND2BYTE(255 * b);
return color;
}
void studrenProjectTriangle(S_Renderer *pRenderer, S_Model *pModel, int i, float n)
{
S_Coords aa, bb, cc; /* souradnice vrcholu po transformaci */
S_Coords naa, nbb, ncc; /* normaly ve vrcholech po transformaci */
S_Coords nn; /* normala trojuhelniku po transformaci */
int u1, v1, u2, v2, u3, v3; /* souradnice vrcholu po projekci do roviny obrazovky */
S_Triangle * triangle;
int vertexOffset, normalOffset; /* offset pro vrcholy a normalove vektory trojuhelniku */
int i0, i1, i2, in; /* indexy vrcholu a normaly pro i-ty trojuhelnik n-teho snimku */
S_Coords aa1, bb1, cc1; /* souradnice vrcholu po transformaci */
S_Coords naa1, nbb1, ncc1; /* normaly ve vrcholech po transformaci */
S_Coords nn1; /* normala trojuhelniku po transformaci */
int vertexOffset1, normalOffset1;
int i01, i11, i21, in1; /* indexy vrcholu a normaly pro i-ty trojuhelnik (n+1)-teho snimku */
IZG_ASSERT(pRenderer && pModel && i >= 0 && i < trivecSize(pModel->triangles) && n >= 0 );
int N = (int) floor(n);
float xN = n - floor(n);
/* z modelu si vytahneme i-ty trojuhelnik */
triangle = trivecGetPtr(pModel->triangles, i);
/* ziskame offset pro vrcholy n-teho snimku */
vertexOffset = (N % pModel->frames) * pModel->verticesPerFrame;
vertexOffset1 = ((N + 1) % pModel->frames) * pModel->verticesPerFrame;
/* ziskame offset pro normaly trojuhelniku n-teho snimku */
normalOffset = (N % pModel->frames) * pModel->triangles->size;
normalOffset1 = ((N + 1) % pModel->frames) * pModel->triangles->size;
/* indexy vrcholu pro i-ty trojuhelnik n-teho snimku - pricteni offsetu */
i0 = triangle->v[ 0 ] + vertexOffset;
i1 = triangle->v[ 1 ] + vertexOffset;
i2 = triangle->v[ 2 ] + vertexOffset;
i01 = triangle->v[ 0 ] + vertexOffset1;
i11 = triangle->v[ 1 ] + vertexOffset1;
i21 = triangle->v[ 2 ] + vertexOffset1;
/* index normaloveho vektoru pro i-ty trojuhelnik n-teho snimku - pricteni offsetu */
in = triangle->n + normalOffset;
in1 = triangle->n + normalOffset1;
/* transformace vrcholu matici model */
trTransformVertex(&aa, cvecGetPtr(pModel->vertices, i0));
trTransformVertex(&bb, cvecGetPtr(pModel->vertices, i1));
trTransformVertex(&cc, cvecGetPtr(pModel->vertices, i2));
trTransformVertex(&aa1, cvecGetPtr(pModel->vertices, i01));
trTransformVertex(&bb1, cvecGetPtr(pModel->vertices, i11));
trTransformVertex(&cc1, cvecGetPtr(pModel->vertices, i21));
/* Interpolace vrcholu*/
aa.x = (1 - xN) * aa.x + xN * aa1.x;
aa.y = (1 - xN) * aa.y + xN * aa1.y;
aa.z = (1 - xN) * aa.z + xN * aa1.z;
bb.x = (1 - xN) * bb.x + xN * bb1.x;
bb.y = (1 - xN) * bb.y + xN * bb1.y;
bb.z = (1 - xN) * bb.z + xN * bb1.z;
cc.x = (1 - xN) * cc.x + xN * cc1.x;
cc.y = (1 - xN) * cc.y + xN * cc1.y;
cc.z = (1 - xN) * cc.z + xN * cc1.z;
/* promitneme vrcholy trojuhelniku na obrazovku */
double h0 = trProjectVertex(&u1, &v1, &aa);
double h1 = trProjectVertex(&u2, &v2, &bb);
double h2 = trProjectVertex(&u3, &v3, &cc);
/* pro osvetlovaci model transformujeme take normaly ve vrcholech */
trTransformVector(&naa, cvecGetPtr(pModel->normals, i0));
trTransformVector(&nbb, cvecGetPtr(pModel->normals, i1));
trTransformVector(&ncc, cvecGetPtr(pModel->normals, i2));
trTransformVector(&naa1, cvecGetPtr(pModel->normals, i01));
trTransformVector(&nbb1, cvecGetPtr(pModel->normals, i11));
trTransformVector(&ncc1, cvecGetPtr(pModel->normals, i21));
/* Interpolace normal */
naa.x = (1 - xN) * naa.x + xN * naa1.x;
naa.y = (1 - xN) * naa.y + xN * naa1.y;
naa.z = (1 - xN) * naa.z + xN * naa1.z;
nbb.x = (1 - xN) * nbb.x + xN * nbb1.x;
nbb.y = (1 - xN) * nbb.y + xN * nbb1.y;
nbb.z = (1 - xN) * nbb.z + xN * nbb1.z;
ncc.x = (1 - xN) * ncc.x + xN * ncc1.x;
ncc.y = (1 - xN) * ncc.y + xN * ncc1.y;
ncc.z = (1 - xN) * ncc.z + xN * ncc1.z;
/* normalizace normal */
coordsNormalize(&naa);
coordsNormalize(&nbb);
coordsNormalize(&ncc);
/* transformace normaly trojuhelniku matici model */
trTransformVector(&nn, cvecGetPtr(pModel->trinormals, in));
trTransformVector(&nn1, cvecGetPtr(pModel->trinormals, in1));
/* Interpolace normaly */
nn.x = (1 - xN) * nn.x + xN * nn1.x;
nn.y = (1 - xN) * nn.y + xN * nn1.y;
nn.z = (1 - xN) * nn.z + xN * nn1.z;
/* normalizace normaly */
coordsNormalize(&nn);
/* je troj. privraceny ke kamere, tudiz viditelny? */
if( !renCalcVisibility(pRenderer, &aa, &nn) )
{
/* odvracene troj. vubec nekreslime */
return;
}
S_Triangle *texture = trivecGetPtr(pModel->triangles, i);
/* rasterizace trojuhelniku */
studrenDrawTriangle(pRenderer,
&aa, &bb, &cc,
&naa, &nbb, &ncc,
&triangle->t[0], &triangle->t[1], &triangle->t[2],
u1, v1, u2, v2, u3, v3,
h0, h1, h2
);
}
S_RGBA studrenPhongReflectance(S_Renderer *pRenderer, const S_Coords *point, const S_Coords *normal)
{
S_Coords lvec, eyevec, reflect;
double diffuse, specular, reflect_scalar;
double r, g, b;
/* If = Ia + Id + Is */
S_RGBA color;
IZG_ASSERT(pRenderer && point && normal);
/* vektor ke zdroji svetla */
lvec = makeCoords(pRenderer->light_position.x - point->x,
pRenderer->light_position.y - point->y,
pRenderer->light_position.z - point->z);
coordsNormalize(&lvec);
/* vektor ke kamere */
eyevec = makeCoords(-point->x,
-point->y,
-pRenderer->camera_dist - point->z);
coordsNormalize(&eyevec);
/* ambientni cast -- Ia = (Al * Am) + (As * Am) */
/* As je barva sceny, muzeme zanedbat */
r = pRenderer->light_ambient.red * pRenderer->mat_ambient.red;
g = pRenderer->light_ambient.green * pRenderer->mat_ambient.green;
b = pRenderer->light_ambient.blue * pRenderer->mat_ambient.blue;
/* difuzni cast -- Id = Dl * Dm * LambertTerm */
/* LambertTerm = dot(N, L) */
diffuse = lvec.x * normal->x + lvec.y * normal->y + lvec.z * normal->z;
if( diffuse > 0 )
{
r += diffuse * pRenderer->light_diffuse.red * pRenderer->mat_diffuse.red;
g += diffuse * pRenderer->light_diffuse.green * pRenderer->mat_diffuse.green;
b += diffuse * pRenderer->light_diffuse.blue * pRenderer->mat_diffuse.blue;
}
/* odraziva cast -- Is = Sm * Sl * pow( max( dot(R, E), 0.0), f ) */
/* R = reflect(-L, N) = 2 * dot(N, L) * N - L */
reflect_scalar = 2 * (normal->x * lvec.x + normal->y * lvec.y + normal->z * lvec.z);
reflect.x = reflect_scalar * normal->x - lvec.x;
reflect.y = reflect_scalar * normal->y - lvec.y;
reflect.z = reflect_scalar * normal->z - lvec.z;
specular = pow(
MAX(reflect.x * eyevec.x + reflect.y * eyevec.y + reflect.z * eyevec.z, 0.0f),
((S_StudentRenderer*)pRenderer)->mat_shininess);
r += specular * pRenderer->light_specular.red * pRenderer->mat_specular.red;
g += specular * pRenderer->light_specular.green * pRenderer->mat_specular.green;
b += specular * pRenderer->light_specular.blue * pRenderer->mat_specular.blue;
/* saturace osvetleni*/
r = MIN(1, r);
g = MIN(1, g);
b = MIN(1, b);
/* kreslici barva */
color.red = ROUND2BYTE(255 * r);
color.green = ROUND2BYTE(255 * g);
color.blue = ROUND2BYTE(255 * b);
return color;
}
void studrenDrawTriangle(S_Renderer *pRenderer,
S_Coords *v1, S_Coords *v2, S_Coords *v3,
S_Coords *n1, S_Coords *n2, S_Coords *n3,
int x1, int y1,
int x2, int y2,
int x3, int y3
)
{
// oblast trojuhelniku
int min[2] = {
MIN(x1, MIN(x2, x3)),
MIN(y1, MIN(y2, y3))
};
int max[2] = {
MAX(x1, MAX(x2, x3)),
MAX(y1, MAX(y2, y3))
};
// oriznuti rozmerem okna
min[0] = MAX(min[0], 0);
min[1] = MAX(min[1], 0);
max[0] = MIN(max[0], pRenderer->frame_w - 1);
max[1] = MIN(max[1], pRenderer->frame_h - 1);
// pro urceni hranic trojuhelnika pouzijeme pineduv algoritmus
// hranova funkce je rovnice Ax + By + C = 0
// A,B je normalovy vektor primky, tzn. (-dy, dx)
// C vyjadrime jako x1y2 - x2y1
int A[3] = {
{ y1 - y2 },
{ y2 - y3 },
{ y3 - y1 }
};
int B[3] = {
{ x2 - x1 },
{ x3 - x2 },
{ x1 - x3 }
};
int C[3] = {
{ x1 * y2 - x2 * y1 },
{ x2 * y3 - x3 * y2 },
{ x3 * y1 - x1 * y3 }
};
// do hranove funkce dosadime protejsi vrcholy
// provedeme normalizaci, aby kladna strana byla uvnitr oblasti
int s0 = A[0] * x3 + B[0] * y3 + C[0];
int s1 = A[1] * x1 + B[1] * y1 + C[1];
int s2 = A[2] * x2 + B[2] * y2 + C[2];
if (s0 < 0) {
A[0] *= -1; B[0] *= -1; C[0] *= -1;
s0 *= -1;
}
if (s1 < 0) {
A[1] *= -1; B[1] *= -1; C[1] *= -1;
s1 *= -1;
}
if (s2 < 0) {
A[2] *= -1; B[2] *= -1; C[2] *= -1;
s2 *= -1;
}
double _s0 = 1.0f / (double)s0;
double _s1 = 1.0f / (double)s1;
double _s2 = 1.0f / (double)s2;
/* gourandovo stinovani */
//S_RGBA color, b1, b2, b3;
//b1 = pRenderer->calcReflectanceFunc(pRenderer, v1, n1);
//b2 = pRenderer->calcReflectanceFunc(pRenderer, v2, n2);
//b3 = pRenderer->calcReflectanceFunc(pRenderer, v3, n3);
// vyplnovani pinedovim algoritmem
for (int y = min[1]; y <= max[1]; ++y) {
int e[3] = {
A[0] * min[0] + B[0] * y + C[0],
A[1] * min[0] + B[1] * y + C[1],
A[2] * min[0] + B[2] * y + C[2]
};
for (int x = min[0]; x <= max[0]; ++x) {
// uvnitr trojuhelniku jsou cisla kladna
if (e[0] >= 0 && e[1] >= 0 && e[2] >= 0) {
// spocitame barycentricke koeficienty u,v,w
double u = e[1] * _s1;
double v = e[2] * _s2;
double w = e[0] * _s0;
// nemelo by nastat, protoze jsme uvnitr trojuhelniku
//if (u < 0.0f || u > 1.0f) continue;
//if (v < 0.0f || v > 1.0f) continue;
//if (w < 0.0f || w > 1.0f) continue;
// bod v trojuhelniku pred projekci ve 3D
S_Coords pt = makeCoords(
u * v1->x + v * v2->x + w * v3->x,
u * v1->y + v * v2->y + w * v3->y,
u * v1->z + v * v2->z + w * v3->z);
/* gourandovo stinovani */
//double r = u * b1.red + v * b2.red + w * b3.red;
//double g = u * b1.green + v * b2.green + w * b3.green;
//double b = u * b1.blue + v * b2.blue + w * b3.blue;
//double a = u * b1.alpha + v * b2.alpha + w * b3.alpha;
//r = MIN(255.0f, MAX(r, 0.0f));
//g = MIN(255.0f, MAX(g, 0.0f));
//b = MIN(255.0f, MAX(b, 0.0f));
//a = MIN(255.0f, MAX(a, 0.0f));
//color.red = ROUND2BYTE(r);
//color.green = ROUND2BYTE(g);
//color.blue = ROUND2BYTE(b);
//color.alpha = ROUND2BYTE(a);
// vektor smerujici od bodu ke kamere
S_Coords P_Cam = makeCoords(
-pt.x,
-pt.y,
-pRenderer->camera_dist - pt.z);
// vykreslime jen blizsi body
double depth = sqrt(P_Cam.x * P_Cam.x + P_Cam.y * P_Cam.y + P_Cam.z * P_Cam.z);
if (depth <= DEPTH(pRenderer, x, y))
{
// normala bodu
S_Coords n = makeCoords(
u * n1->x + v * n2->x + w * n3->x,
u * n1->y + v * n2->y + w * n3->y,
u * n1->z + v * n2->z + w * n3->z);
coordsNormalize(&n);
S_RGBA color;
color = pRenderer->calcReflectanceFunc(pRenderer, &pt, &n);
/* vybarvi objekt normalou */
//color.red = ROUND2BYTE(255.0f * (n.x / 2.0f + 0.5f));
//color.green = ROUND2BYTE(255.0f * (n.y / 2.0f + 0.5f));
//color.blue = ROUND2BYTE(255.0f * (-n.z / 2.0f + 0.5f));
//color.alpha = 255;
DEPTH(pRenderer, x, y) = depth;
PIXEL(pRenderer, x, y) = color;
}
}
// Ei(x+1,y) = Ei(x,y) + dy
e[0] += A[0];
e[1] += A[1];
e[2] += A[2];
}
}
}