/usr/include/movit/complex_modulate_effect.h is in libmovit-dev 1.3.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | #ifndef _MOVIT_COMPLEX_MODULATE_EFFECT_H
#define _MOVIT_COMPLEX_MODULATE_EFFECT_H 1
// An effect that treats each pixel as two complex numbers (xy and zw),
// and multiplies it with some other complex number (xy and xy, so the
// same in both cases). The latter can be repeated both horizontally and
// vertically if desired.
//
// The typical use is to implement convolution by way of FFT; since
// FFT(A ⊙ B) = FFT(A) * FFT(B), you can FFT both inputs (where B
// would often even be a constant, so you'd only need to do FFT once),
// multiply them together and then IFFT the result to get a convolution.
//
// It is in a sense “wrong” to do this directly on pixels, since the color
// channels are independent and real-valued (ie., not complex numbers), but
// since convolution is a linear operation, it's unproblematic to treat R + Gi
// as a single complex number and B + Ai and another one; barring numerical
// errors, there should be no leakage between the channels as long as you're
// convolving with a real quantity. (There are more sophisticated ways of doing
// two real FFTs with a single complex one, but we won't need them, as we
// don't care about the actual FFT result, just that the convolution property
// holds.)
#include <epoxy/gl.h>
#include <string>
#include "effect.h"
namespace movit {
class EffectChain;
class ComplexModulateEffect : public Effect {
public:
ComplexModulateEffect();
virtual std::string effect_type_id() const { return "ComplexModulateEffect"; }
std::string output_fragment_shader();
// Technically we only need texture bounce for the second input
// (to be allowed to mess with its sampler state), but there's
// no way of expressing that currently.
virtual bool needs_texture_bounce() const { return true; }
virtual bool changes_output_size() const { return true; }
virtual bool sets_virtual_output_size() const { return false; }
virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
virtual void get_output_size(unsigned *width, unsigned *height,
unsigned *virtual_width, unsigned *virtual_height) const;
virtual unsigned num_inputs() const { return 2; }
virtual void inform_added(EffectChain *chain) { this->chain = chain; }
void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
private:
EffectChain *chain;
int primary_input_width, primary_input_height;
int num_repeats_x, num_repeats_y;
float uniform_num_repeats[2];
};
} // namespace movit
#endif // !defined(_MOVIT_COMPLEX_MODULATE_EFFECT_H)
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