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avfilter/vf_v360: refactor FoV calculation for stereographic

Move in out of loop.
This commit is contained in:
Paul B Mahol 2019-09-11 16:21:25 +02:00
parent 78b86c30d3
commit 7ce7002664

View File

@ -1396,6 +1396,26 @@ static void equirect_to_xyz(const V360Context *s,
vec[2] = -cos_theta * cos_phi;
}
/**
* Prepare data for processing stereographic output format.
*
* @param ctx filter context
*
* @return error code
*/
static int prepare_stereographic_out(AVFilterContext *ctx)
{
V360Context *s = ctx->priv;
const float h_angle = tan(FFMIN(s->h_fov, 359.f) * M_PI / 720.f);
const float v_angle = tan(FFMIN(s->v_fov, 359.f) * M_PI / 720.f);
s->flat_range[0] = h_angle;
s->flat_range[1] = v_angle;
return 0;
}
/**
* Calculate 3D coordinates on sphere for corresponding frame position in stereographic format.
*
@ -1410,11 +1430,8 @@ static void stereographic_to_xyz(const V360Context *s,
int i, int j, int width, int height,
float *vec)
{
const float h_angle = tan(FFMIN(s->h_fov, 359.f) * M_PI / 720.f);
const float v_angle = tan(FFMIN(s->v_fov, 359.f) * M_PI / 720.f);
const float x = ((2.f * i) / width - 1.f) * h_angle;
const float y = ((2.f * j) / height - 1.f) * v_angle;
const float x = ((2.f * i) / width - 1.f) * s->flat_range[0];
const float y = ((2.f * j) / height - 1.f) * s->flat_range[1];
const float xy = x * x + y * y;
vec[0] = 2.f * x / (1.f + xy);
@ -2282,7 +2299,7 @@ static int config_output(AVFilterLink *outlink)
break;
case STEREOGRAPHIC:
out_transform = stereographic_to_xyz;
err = 0;
err = prepare_stereographic_out(ctx);
w = FFMAX(roundf(wf), roundf(hf));
h = w;
break;