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#ifndef __STABLEFLUIDS_KERNELS_CUH_
#define __STABLEFLUIDS_KERNELS_CUH_

#include "defines.h"

// Vector data type used to velocity and force fields
typedef float2 cData;

void setupTexture(int x, int y);
void updateTexture(cData *data, size_t w, size_t h, size_t pitch);
void deleteTexture(void);

// This method adds constant force vectors to the velocity field
// stored in 'v' according to v(x,t+1) = v(x,t) + dt * f.
__global__ void addForces_k(cData *v, int dx, int dy, int spx, int spy,
                            float fx, float fy, int r, size_t pitch);

// This method performs the velocity advection step, where we
// trace velocity vectors back in time to update each grid cell.
// That is, v(x,t+1) = v(p(x,-dt),t). Here we perform bilinear
// interpolation in the velocity space.
__global__ void advectVelocity_k(cData *v, float *vx, float *vy, int dx,
                                 int pdx, int dy, float dt, int lb,
                                 cudaTextureObject_t tex);

// This method performs velocity diffusion and forces mass conservation
// in the frequency domain. The inputs 'vx' and 'vy' are complex-valued
// arrays holding the Fourier coefficients of the velocity field in
// X and Y. Diffusion in this space takes a simple form described as:
// v(k,t) = v(k,t) / (1 + visc * dt * k^2), where visc is the viscosity,
// and k is the wavenumber. The projection step forces the Fourier
// velocity vectors to be orthogonal to the wave wave vectors for each
// wavenumber: v(k,t) = v(k,t) - ((k dot v(k,t) * k) / k^2.
__global__ void diffuseProject_k(cData *vx, cData *vy, int dx, int dy, float dt,
                                 float visc, int lb);

// This method updates the velocity field 'v' using the two complex
// arrays from the previous step: 'vx' and 'vy'. Here we scale the
// real components by 1/(dx*dy) to account for an unnormalized FFT.
__global__ void updateVelocity_k(cData *v, float *vx, float *vy, int dx,
                                 int pdx, int dy, int lb, size_t pitch);

// This method updates the particles by moving particle positions
// according to the velocity field and time step. That is, for each
// particle: p(t+1) = p(t) + dt * v(p(t)).
__global__ void advectParticles_k(cData *part, cData *v, int dx, int dy,
                                  float dt, int lb, size_t pitch);

#endif