diff options
Diffstat (limited to 'src/modules')
| -rw-r--r-- | src/modules/flui2d/flui2d.c | 52 |
1 files changed, 44 insertions, 8 deletions
diff --git a/src/modules/flui2d/flui2d.c b/src/modules/flui2d/flui2d.c index 388bb7f..5fb6087 100644 --- a/src/modules/flui2d/flui2d.c +++ b/src/modules/flui2d/flui2d.c @@ -1,3 +1,4 @@ +#include <errno.h> #include <stdint.h> #include <inttypes.h> #include <math.h> @@ -19,6 +20,7 @@ /* These knobs affect how the simulated fluid behaves */ #define DEFAULT_VISCOSITY .000000001 #define DEFAULT_DIFFUSION .00001 +#define DEFAULT_DECAY .0001 #define ROOT 128 // Change this to vary the density field resolution #define SIZE ((ROOT + 2) * (ROOT + 2)) @@ -27,11 +29,12 @@ static float flui2d_viscosity = DEFAULT_VISCOSITY; static float flui2d_diffusion = DEFAULT_DIFFUSION; +static float flui2d_decay = DEFAULT_DECAY; typedef struct flui2d_t { float u[SIZE], v[SIZE], u_prev[SIZE], v_prev[SIZE]; float dens[SIZE], dens_prev[SIZE]; - float visc, diff; + float visc, diff, decay; } flui2d_t; static void set_bnd(int N, int b, float *x) @@ -57,7 +60,7 @@ static void add_source(int N, float *x, float *s, float dt) x[i] += dt * s[i]; } -static void diffuse(int N, int b, float *x, float *x0, float diff, float dt) +static void diffuse(int N, int b, float *x, float *x0, float diff, float decay, float dt) { float a = dt * diff * (float)N * (float)N; int i, j, k; @@ -66,7 +69,7 @@ static void diffuse(int N, int b, float *x, float *x0, float diff, float dt) for (k = 0; k < 20; k++) { for (i = 1; i <= N; i++) { for (j = 1; j <= N; j++) { - x[IX(i, j)] = (x0[IX(i, j)] + a * (x[IX(i - 1, j)] + x[IX(i + 1, j)] + x[IX(i, j - 1)] + x[IX(i, j + 1)])) * z; + x[IX(i, j)] = (x0[IX(i, j)] + a * (x[IX(i - 1, j)] + x[IX(i + 1, j)] + x[IX(i, j - 1)] + x[IX(i, j + 1)])) * z * (1.f - decay); } } set_bnd(N, b, x); @@ -146,7 +149,7 @@ static void project(int N, float *u, float *v, float *p, float *div) set_bnd(N, 2, v); } -static void dens_step(int N, float *x, float *x0, float *u, float *v, float diff, float dt) +static void dens_step(int N, float *x, float *x0, float *u, float *v, float diff, float decay, float dt) { /* @@ -154,7 +157,7 @@ static void dens_step(int N, float *x, float *x0, float *u, float *v, float diff * add_source(N, x, x0, dt); * SWAP(x0, x); */ - diffuse(N, 0, x, x0, diff, dt); + diffuse(N, 0, x, x0, diff, decay, dt); SWAP(x0, x); advect(N, 0, x, x0, u, v, dt); } @@ -164,9 +167,9 @@ static void vel_step(int N, float *u, float *v, float *u0, float *v0, float visc add_source(N, u, u0, dt); add_source(N, v, v0, dt); SWAP(u0, u); - diffuse(N, 1, u, u0, visc, dt); + diffuse(N, 1, u, u0, visc, 0.f, dt); SWAP(v0, v); - diffuse(N, 2, v, v0, visc, dt); + diffuse(N, 2, v, v0, visc, 0.f, dt); project(N, u, v, u0, v0); SWAP(u0, u); SWAP(v0, v); @@ -192,6 +195,7 @@ static void * flui2d_create_context(unsigned ticks, unsigned num_cpus) ctxt->fluid.visc = flui2d_viscosity; ctxt->fluid.diff = flui2d_diffusion; + ctxt->fluid.decay = flui2d_decay; return ctxt; } @@ -234,7 +238,7 @@ static void flui2d_prepare_frame(void *context, unsigned ticks, unsigned n_cpus, * a GLSL implementation for a fragment shader. */ vel_step(ROOT, ctxt->fluid.u, ctxt->fluid.v, ctxt->fluid.u_prev, ctxt->fluid.v_prev, ctxt->fluid.visc, .1f); - dens_step(ROOT, ctxt->fluid.dens, ctxt->fluid.dens_prev, ctxt->fluid.u, ctxt->fluid.v, ctxt->fluid.diff, .1f); + dens_step(ROOT, ctxt->fluid.dens, ctxt->fluid.dens_prev, ctxt->fluid.u, ctxt->fluid.v, ctxt->fluid.diff, ctxt->fluid.decay, .1f); ctxt->xf = 1.f / fragment->frame_width; ctxt->yf = 1.f / fragment->frame_height; @@ -294,6 +298,15 @@ static int flui2d_setup(const til_settings_t *settings, til_setting_desc_t **nex ".0001", NULL }; + const char *decay; + const char *decay_values[] = { + ".000001", + ".00001", + ".0001", + ".001", + ".01", + NULL + }; viscosity = til_settings_get_value(settings, "viscosity"); @@ -332,9 +345,32 @@ static int flui2d_setup(const til_settings_t *settings, til_setting_desc_t **nex return 1; } + decay = til_settings_get_value(settings, "decay"); + if (!decay) { + int r; + + r = til_setting_desc_clone(&(til_setting_desc_t){ + .name = "Fluid Decay", + .key = "decay", + .regex = "\\.[0-9]+", + .preferred = TIL_SETTINGS_STR(DEFAULT_DECAY), + .values = decay_values, + .annotations = NULL + }, next_setting); + if (r < 0) + return r; + + return 1; + } + /* TODO: return -EINVAL on parse errors? */ sscanf(viscosity, "%f", &flui2d_viscosity); sscanf(diffusion, "%f", &flui2d_diffusion); + sscanf(decay, "%f", &flui2d_decay); + + /* prevent overflow in case an explicit out of range setting is supplied */ + if (flui2d_decay > 1.f || flui2d_decay < 0.f) + return -EINVAL; return 0; } |