void InitializeForms()
{
// build color table:
for (unsigned int i = 0; i < 256; i++)
{
float rr, gg, bb;
//
// generic Hue profile as deduced from true-color imaging for spirals
// Hue in degrees
float hue = (i < 28)? 25 * tanh(0.0615f * (27 - i)): 25 * tanh(0.0615f * (27 - i)) + 220;
//convert Hue to RGB
DeepSkyObject::hsv2rgb(&rr, &gg, &bb, hue, 0.20f, 1.0f);
colorTable[i] = Color(rr, gg, bb);
}
// Spiral Galaxies, 7 classical Hubble types
spiralForms = new GalacticForm*[7];
spiralForms[Galaxy::S0] = buildGalacticForms("models/S0.png");
spiralForms[Galaxy::Sa] = buildGalacticForms("models/Sa.png");
spiralForms[Galaxy::Sb] = buildGalacticForms("models/Sb.png");
spiralForms[Galaxy::Sc] = buildGalacticForms("models/Sc.png");
spiralForms[Galaxy::SBa] = buildGalacticForms("models/SBa.png");
spiralForms[Galaxy::SBb] = buildGalacticForms("models/SBb.png");
spiralForms[Galaxy::SBc] = buildGalacticForms("models/SBc.png");
// Elliptical Galaxies , 8 classical Hubble types, E0..E7,
//
// To save space: generate spherical E0 template from S0 disk
// via rescaling by (1.0f, 3.8f, 1.0f).
ellipticalForms = new GalacticForm*[8];
for (unsigned int eform = 0; eform <= 7; ++eform)
{
float ell = 1.0f - (float) eform / 8.0f;
// note the correct x,y-alignment of 'ell' scaling!!
// build all elliptical templates from rescaling E0
ellipticalForms[eform] = buildGalacticForms("models/E0.png");
if (*ellipticalForms)
ellipticalForms[eform]->scale = Vec3f(ell, ell, 1.0f);
// account for reddening of ellipticals rel.to spirals
if (*ellipticalForms)
{
unsigned int nPoints = (unsigned int) (ellipticalForms[eform]->blobs->size());
for (unsigned int i = 0; i < nPoints; ++i)
{
(*ellipticalForms[eform]->blobs)[i].colorIndex = (unsigned int) ceil(0.76f * (*ellipticalForms[eform]->blobs)[i].colorIndex);
}
}
}
//Irregular Galaxies
unsigned int galaxySize = GALAXY_POINTS, ip = 0;
Blob b;
Point3f p;
vector<Blob>* irregularPoints = new vector<Blob>;
irregularPoints->reserve(galaxySize);
while (ip < galaxySize)
{
p = Point3f(Mathf::sfrand(), Mathf::sfrand(), Mathf::sfrand());
float r = p.distanceFromOrigin();
if (r < 1)
{
float prob = (1 - r) * (fractalsum(Point3f(p.x + 5, p.y + 5, p.z + 5), 8) + 1) * 0.5f;
if (Mathf::frand() < prob)
{
b.position = p;
b.brightness = 64u;
unsigned int rr = (unsigned int) (r * 511);
b.colorIndex = rr < 256? rr: 255;
irregularPoints->push_back(b);
++ip;
}
}
}
irregularForm = new GalacticForm();
irregularForm->blobs = irregularPoints;
irregularForm->scale = Vec3f(0.5f, 0.5f, 0.5f);
formsInitialized = true;
}
void Galaxy::renderGalaxyPointSprites(const GLContext&,
const Vec3f& offset,
const Quatf& viewerOrientation,
float brightness,
float pixelSize)
{
if (form == NULL)
return;
/* We'll first see if the galaxy's apparent size is big enough to
be noticeable on screen; if it's not we'll break right here,
avoiding all the overhead of the matrix transformations and
GL state changes: */
float distanceToDSO = offset.length() - getRadius();
if (distanceToDSO < 0)
distanceToDSO = 0;
float minimumFeatureSize = pixelSize * distanceToDSO;
float size = 2 * getRadius();
if (size < minimumFeatureSize)
return;
if (galaxyTex == NULL)
{
galaxyTex = CreateProceduralTexture(width, height, GL_RGBA,
GalaxyTextureEval);
}
assert(galaxyTex != NULL);
glEnable(GL_TEXTURE_2D);
galaxyTex->bind();
Mat3f viewMat = viewerOrientation.toMatrix3();
Vec3f v0 = Vec3f(-1, -1, 0) * viewMat;
Vec3f v1 = Vec3f( 1, -1, 0) * viewMat;
Vec3f v2 = Vec3f( 1, 1, 0) * viewMat;
Vec3f v3 = Vec3f(-1, 1, 0) * viewMat;
//Mat4f m = (getOrientation().toMatrix4() *
// Mat4f::scaling(form->scale) *
// Mat4f::scaling(getRadius()));
Mat3f m =
Mat3f::scaling(form->scale)*getOrientation().toMatrix3()*Mat3f::scaling(size);
// Note: fixed missing factor of 2 in getRadius() scaling of galaxy diameter!
// Note: fixed correct ordering of (non-commuting) operations!
int pow2 = 1;
vector<Blob>* points = form->blobs;
unsigned int nPoints = (unsigned int) (points->size() * clamp(getDetail()));
// corrections to avoid excessive brightening if viewed e.g. edge-on
float brightness_corr = 1.0f;
float cosi;
if (type < E0 || type > E3) //all galaxies, except ~round elliptics
{
cosi = Vec3f(0,1,0) * getOrientation().toMatrix3()
* offset/offset.length();
brightness_corr = (float) sqrt(abs(cosi));
if (brightness_corr < 0.2f)
brightness_corr = 0.2f;
}
if (type > E3) // only elliptics with higher ellipticities
{
cosi = Vec3f(1,0,0) * getOrientation().toMatrix3()
* offset/offset.length();
brightness_corr = brightness_corr * (float) abs((cosi));
if (brightness_corr < 0.45f)
brightness_corr = 0.45f;
}
glBegin(GL_QUADS);
for (unsigned int i = 0; i < nPoints; ++i)
{
if ((i & pow2) != 0)
{
pow2 <<= 1;
size /= 1.55f;
if (size < minimumFeatureSize)
break;
}
Blob b = (*points)[i];
Point3f p = b.position * m;
float br = b.brightness / 255.0f;
Color c = colorTable[b.colorIndex]; // lookup static color table
Point3f relPos = p + offset;
float screenFrac = size / relPos.distanceFromOrigin();
if (screenFrac < 0.1f)
{
float btot = ((type > SBc) && (type < Irr))? 2.5f: 5.0f;
float a = btot * (0.1f - screenFrac) * brightness_corr * brightness * br;
glColor4f(c.red(), c.green(), c.blue(), (4.0f*lightGain + 1.0f)*a);
glTexCoord2f(0, 0); glVertex(p + (v0 * size));
glTexCoord2f(1, 0); glVertex(p + (v1 * size));
glTexCoord2f(1, 1); glVertex(p + (v2 * size));
glTexCoord2f(0, 1); glVertex(p + (v3 * size));
}
}
glEnd();
}
