// calculate response for the samples in cb and fraction time tau
// in comments Ti is input sampling period
double src::re_samp(double tau )
{
int p;
int k;
double sum,h,sample;
p = (x_cb_i)-1; // this is youngest sample index
sum=0.0;
for (k=0; k<NTaps; k++) {
if (p <0 ) { // circular buffer
p = NTaps-1;
}
h = h_t(tau+k); // k+tau represents t=k*Ti+tau
sample = x_cb[p]; // samples
sum = sum + h*sample; // the older the sample, the longer last its partial response
p = p-1; // go to older sample
}
return (sum);
}
float OceanSurface::h(float x, float z, float t) {
complex_number height;
glm::vec2 x_v = glm::vec2(x, z);
for (int i = 0; i < N; i++) {
float k_x = M_PI * (2.0f * i - N) / L_x;
for (int j = 0; j < M; j++) {
int pos = i * M + j;
float k_z = M_PI * (2.0f * j - M) / L_z;
glm::vec2 k = glm::vec2(k_x, k_z); // k is wavevector
float d = glm::dot(k, x_v);
complex_number h_0_t = h_t(i, j, t);
complex_number c1(cos(d), sin(d));
height = height + c1 * h_0_t;
}
}
return height.re;
}
void OceanSurface::updateOcean(float t) {
if (!gpu) {
for (int i = 0; i < N; i++) {
float k_x = float(M_PI) * (2.0f * i - N) / L_x; // x-coordinate of wavevector at 'pos'
for (int j = 0; j < M; j++) {
int pos = i * M + j;
float k_z = M_PI * (2.0f * j - M) / L_z; // z-coordinate of wavevector at 'pos'
float k_length = sqrtf(k_x * k_x + k_z * k_z); // length of wavevector 'k'
// calc all complex amplitudes in time t
h_fft[pos] = h_t(i, j, t);
// calc all displacements in time t
if (k_length < 0.000001) { // ignore small wavevectors, put (0, 0) displacement
dx_fft[pos] = complex_number();
dz_fft[pos] = complex_number();
}
else { // calculate displacement via formula
dx_fft[pos] = complex_number(0.0f, -k_x / k_length) * h_fft[pos];
dz_fft[pos] = complex_number(0.0f, -k_z / k_length) * h_fft[pos];
}
// calc x-, and z- component of gradient of h_fft
gradient_x[pos] = complex_number(0.0f, k_x) * h_fft[pos];
gradient_z[pos] = complex_number(0.0f, k_z) * h_fft[pos];
}
}
// row flipping
/*/complex_number *h_fft_2 = new complex_number[N * N];
for (int i = 0; i < N; i++) {
for (int j = 0; j < M; j++) {
int pos_1 = i * M + j;
int pos_2 = (N - i - 1) * M + j;
h_fft_2[pos_2] = h_fft[pos_1];
}
}*/
}
else {
// first update height map with time amplitudes (and displacement map with gradient map);
glUseProgram(upd_height_program);
glUniform1f(total_time_location, t);
// height map
glBindImageTexture(0, texture_H_t0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, texture_H_t0_cc, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(2, texture_H_t, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
// displacement map
glBindImageTexture(3, texture_Dx, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glBindImageTexture(4, texture_Dz, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
// gradient map
glBindImageTexture(5, texture_Gradx, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glBindImageTexture(6, texture_Gradz, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(N, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
glUseProgram(0);
// fft in compute shader
glUseProgram(fft_comp_program);
// update texture
/*glBindTexture(GL_TEXTURE_2D, texture_H_t);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, N, N, GL_RG, GL_FLOAT, h_fft);
//glTexImage2D(GL_TEXTURE_2D, 0, GL_RG32F, N, N, 0, GL_RG, GL_FLOAT, h_fft);
glBindTexture(GL_TEXTURE_2D, 0);*/
// bind reverse indices
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 2, rev_ind_buffer);
/*______________HEIGHT MAP FFT________________*/
// fft per rows
glUniform1i(fft_column_location, 0);
glBindImageTexture(0, texture_H_t, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, texture_H_fft_t_row, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
// fft per columns
glUniform1i(fft_column_location, 1);
glBindImageTexture(0, texture_H_fft_t_row, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, texture_H_fft_t_col, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
/*______________DISPLACEMENT-X MAP FFT________________*/
// fft per rows
glUniform1i(fft_column_location, 0);
glBindImageTexture(0, texture_Dx, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_dx_fft_row, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
// fft per columns
glUniform1i(fft_column_location, 1);
glBindImageTexture(0, tex_dx_fft_row, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_dx_fft, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
/*______________DISPLACEMENT-Z MAP FFT________________*/
// fft per rows
glUniform1i(fft_column_location, 0);
glBindImageTexture(0, texture_Dz, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_dz_fft_row, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
// fft per columns
glUniform1i(fft_column_location, 1);
glBindImageTexture(0, tex_dz_fft_row, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_dz_fft, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
/*______________GRADIENT-X MAP FFT________________*/
// fft per rows
glUniform1i(fft_column_location, 0);
glBindImageTexture(0, texture_Gradx, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_gradx_fft_row, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
// fft per columns
glUniform1i(fft_column_location, 1);
glBindImageTexture(0, tex_gradx_fft_row, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_gradx_fft, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
/*______________GRADIENT-Z MAP FFT________________*/
// fft per rows
glUniform1i(fft_column_location, 0);
glBindImageTexture(0, texture_Gradz, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_gradz_fft_row, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
// fft per columns
glUniform1i(fft_column_location, 1);
glBindImageTexture(0, tex_gradz_fft_row, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RG32F);
glBindImageTexture(1, tex_gradz_fft, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RG32F);
glDispatchCompute(1, N, 1);
glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
glUseProgram(0);
}
int error = glGetError();
if (error != GL_NO_ERROR) {
int b = 4;
}
if (gpu) {
return;
}
for (unsigned int i = 0; i < N; i++) { // horizontal fft for rows
/*fft->fft(h_fft, h_fft, 1, i * M);
fft->fft(dx_fft, dx_fft, 1, i * M);
fft->fft(dz_fft, dz_fft, 1, i * M);
fft->fft(gradient_x, gradient_x, 1, i * M);
fft->fft(gradient_z, gradient_z, 1, i * M);*/
myFFT->processVertical(h_fft, 1, i * M);
myFFT->processVertical(dx_fft, 1, i * M);
myFFT->processVertical(dz_fft, 1, i * M);
myFFT->processVertical(gradient_x, 1, i * M);
myFFT->processVertical(gradient_z, 1, i * M);
}
for (unsigned int j = 0; j < M; j++) { // vertical fft for columns
/*fft->fft(h_fft, h_fft, M, j);
fft->fft(dx_fft, dx_fft, M, j);
fft->fft(dz_fft, dz_fft, M, j);
fft->fft(gradient_x, gradient_x, M, j);
fft->fft(gradient_z, gradient_z, M, j);*/
myFFT->processHorizontal(h_fft, M, j);
myFFT->processHorizontal(dx_fft, M, j);
myFFT->processHorizontal(dz_fft, M, j);
myFFT->processHorizontal(gradient_x, M, j);
myFFT->processHorizontal(gradient_z, M, j);
}
glm::vec3 normal; // temp variable for normal calculation
int sign;
float signs[] = { 1.0f, -1.0f };
for (int i = 0; i < N; i++) {
for (int j = 0; j < M; j++) {
int pos = i * M + j;
// flip sign for height
sign = signs[(i + j) & 1];
grid[pos].y = h_fft[pos].re * sign;
// flip sign for displacement
dx_fft[pos] = dx_fft[pos] * sign;
dz_fft[pos] = dz_fft[pos] * sign;
// then calc displacement for original position in grid
//grid[pos].x = init_positions[pos].x + lambda * dx_fft[pos].re;
//grid[pos].z = init_positions[pos].z + lambda * dz_fft[pos].re;
// flip sign for gradient component;
gradient_x[pos] = gradient_x[pos] * sign;
gradient_z[pos] = gradient_z[pos] * sign;
// then calculate normal of vertex and normalize it
normal = glm::vec3(-gradient_x[pos].re, 1.0f, -gradient_z[pos].re);
normal = glm::normalize(normal);
// and save it to vertex structure
grid[pos].normal_x = normal.x;
grid[pos].normal_y = normal.y;
grid[pos].normal_z = normal.z;
}
}
}