gl_spharmonics.h
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#ifndef STIM_GL_SPHARMONICS_H
#define STIM_GL_SPHARMONICS_H
#include <stim/math/spharmonics.h>
#include <stim/gl/error.h>
#include <stim/math/vec3.h>
#include <stim/math/constants.h>
#include <stim/visualization/colormap.h>
namespace stim {
template<typename T>
class gl_spharmonics {
GLuint dlist;
GLuint tex;
bool displacement;
bool colormap;
bool magnitude;
void init_tex() {
T* sfunc = (T*)malloc(N * N * sizeof(T)); //create a 2D array to store the spherical function
Sc.get_func(sfunc, N, N); //generate the spherical function based on the Sc coefficients
unsigned char* tex_buffer = (unsigned char*)malloc(3 * N * N); //create a buffer to store the texture map
stim::cpu2cpu<T>(sfunc, tex_buffer, N * N, stim::cmBrewer); //create a Brewer colormap based on the spherical function
stim::buffer2image(tex_buffer, "sfunc.ppm", N, N);
if (tex) glDeleteTextures(1, &tex); //if a texture already exists, delete it
glGenTextures(1, &tex); //create a new texture and store the ID
glBindTexture(GL_TEXTURE_2D, tex); //bind the texture
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, N, N, 0, GL_RGB, GL_UNSIGNED_BYTE, tex_buffer); //copy the color data from the buffer to the GPU
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); //initialize all of the texture parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
}
public:
stim::spharmonics<T> Sc; //spherical harmonic representing the color component
stim::spharmonics<T> Sd; //spherical harmonic representing the displacement component
size_t N;
gl_spharmonics(size_t slices) {
N = slices;
dlist = 0; //initialize the display list index to zero (no list)
tex = 0; //initialize the texture index to zero (no texture)
displacement = true;
colormap = true;
magnitude = true;
}
~gl_spharmonics() {
if (dlist) glDeleteLists(dlist, 1); //delete the display list when the object is destroyed
}
/// This function renders the spherical harmonic to the current OpenGL context
void render() {
//glShadeModel(GL_FLAT);
glPushAttrib(GL_ENABLE_BIT);
glDisable(GL_CULL_FACE);
if (!tex) {
init_tex();
}
if (colormap) {
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, tex);
}
if (!dlist) {
dlist = glGenLists(1);
glNewList(dlist, GL_COMPILE);
glPushAttrib(GL_ENABLE_BIT);
glEnable(GL_NORMALIZE);
//Draw the Sphere
size_t theta_i, phi_i;
T d_theta = (T)stim::TAU / (T)N;
T d_phi = (T)stim::PI / (T)(N-1);
for (phi_i = 1; phi_i < N; phi_i++) {
T phi = phi_i * d_phi;
glBegin(GL_QUAD_STRIP);
for (theta_i = 0; theta_i <= N; theta_i++) {
T theta = (N - theta_i) * d_theta;
float theta_t = 1 - (float)theta_i / (float)N;
T r;
if (!displacement) r = 1; //if no displacement, set the r value to 1 (renders a unit sphere)
else r = Sd(theta, phi); //otherwise calculate the displacement value
glColor3f(1.0f, 1.0f, 1.0f);
if (!colormap) { //if no colormap is being rendered
if (r < 0) glColor3f(1.0, 0.0, 0.0); //if r is negative, render it red
else glColor3f(0.0, 1.0, 0.0); //otherwise render in green
}
if (magnitude) { //if the magnitude is being displaced, calculate the magnitude of r
if (r < 0) r = -r;
}
stim::vec3<T> s(r, theta, phi);
stim::vec3<T> c = s.sph2cart();
stim::vec3<T> n; //allocate a value to store the normal
if (!displacement) n = c; //if there is no displacement, the normal is spherical
else n = Sd.dphi(theta, phi).cross(Sd.dtheta(theta, phi)); //otherwise calculate the normal as the cross product of derivatives
glTexCoord2f(theta_t, (float)phi_i / (float)N);
//std::cout << theta_t <<" "<<(float)phi_i / (float)N << "----------------";
glNormal3f(n[0], n[1], n[2]);
glVertex3f(c[0], c[1], c[2]);
T r1;
if (!displacement) r1 = 1;
else r1 = Sd(theta, phi - d_phi);
if (!colormap) { //if no colormap is being rendered
if (r1 < 0) glColor3f(1.0, 0.0, 0.0); //if r1 is negative, render it red
else glColor3f(0.0, 1.0, 0.0); //otherwise render in green
}
if (magnitude) { //if the magnitude is being rendered, calculate the magnitude of r
if (r1 < 0) r1 = -r1;
}
stim::vec3<T> s1(r1, theta, phi - d_phi);
stim::vec3<T> c1 = s1.sph2cart();
stim::vec3<T> n1;
if (!displacement) n1 = c1;
else n1 = Sd.dphi(theta, phi - d_phi).cross(Sd.dtheta(theta, phi - d_phi));
//std::cout << theta_t << " " << (float)(phi_i - 1) / (float)N << std::endl;
glTexCoord2f(theta_t, 1.0/(2*(N)) + (float)(phi_i-1) / (float)N);
glNormal3f(n1[0], n1[1], n1[2]);
glVertex3f(c1[0], c1[1], c1[2]);
}
glEnd();
}
glPopAttrib();
glEndList();
}
glCallList(dlist); //call the display list to render
glPopAttrib();
}
/// Push a coefficient to the spherical harmonic - by default, push applies the component to both the displacement and color SH
void push(T coeff) {
Sd.push(coeff);
Sc.push(coeff);
}
/// Resize the spherical harmonic coefficient array
void resize(size_t s) {
Sd.resize(s);
Sc.resize(s);
}
/// Set a spherical harmonic coefficient to the given value
void setc(unsigned int c, T value) {
Sd.setc(c, value);
Sc.setc(c, value);
}
void project(T* data, size_t x, size_t y, size_t nc) {
Sd.project(data, x, y, nc);
Sc = Sd;
}
/// Project a set of samples onto the basis
void project(std::vector<vec3<float>>& vlist, size_t nc) {
Sd.project(vlist, nc);
Sc = Sd;
}
/// Calculate a density function from a list of points in spherical coordinates
void pdf(std::vector<stim::vec3<T>>& vlist, size_t nc) {
Sd.pdf(vlist, nc);
Sc = Sd;
}
void slices(size_t s) {
N = s;
}
size_t slices() {
return N;
}
void rendermode(bool displace, bool color, bool mag = true) {
displacement = displace;
colormap = color;
magnitude = mag;
}
};
}
#endif