gtk/gsk/gpu/shaders/gskgpublur.glsl
Benjamin Otte d11886e7ac gpu: Use variations in the blur shader
Have one variation for colorizing to a shadow color and another
variation that just blurs.
2024-01-07 07:22:53 +01:00

83 lines
2.1 KiB
GLSL

#include "common.glsl"
/* blur radius (aka in_blur_direction) 0 is NOT supported and MUST be caught before */
#define VARIATION_COLORIZE ((GSK_VARIATION & 1u) == 1u)
PASS(0) vec2 _pos;
PASS_FLAT(1) Rect _rect;
PASS_FLAT(2) vec4 _blur_color;
PASS(3) vec2 _tex_coord;
PASS_FLAT(4) vec2 _tex_blur_step;
PASS_FLAT(5) uint _samples_per_side;
PASS_FLAT(6) uint _tex_id;
PASS_FLAT(7) vec3 _initial_gaussian;
#ifdef GSK_VERTEX_SHADER
IN(0) vec4 in_rect;
IN(1) vec4 in_blur_color;
IN(2) vec4 in_tex_rect;
IN(3) vec2 in_blur_direction;
IN(4) uint in_tex_id;
void
run (out vec2 pos)
{
Rect r = rect_from_gsk (in_rect);
pos = rect_get_position (r);
_pos = pos;
_rect = r;
_blur_color = in_blur_color;
Rect tex_rect = rect_from_gsk (in_tex_rect);
_tex_coord = rect_get_coord (tex_rect, pos);
_tex_id = in_tex_id;
float blur_radius = length (GSK_GLOBAL_SCALE * in_blur_direction);
_tex_blur_step = GSK_GLOBAL_SCALE * in_blur_direction / blur_radius / rect_size (tex_rect);
_samples_per_side = uint (floor (blur_radius));
float sigma = blur_radius / 2.0;
_initial_gaussian.x = 1.0 / (sqrt (2.0 * PI) * sigma);
_initial_gaussian.y = exp (-0.5 / (sigma * sigma));
_initial_gaussian.z = _initial_gaussian.y * _initial_gaussian.y;
}
#endif
#ifdef GSK_FRAGMENT_SHADER
// Partially from http://callumhay.blogspot.com/2010/09/gaussian-blur-shader-glsl.html
void
run (out vec4 color,
out vec2 position)
{
vec3 incremental_gaussian = _initial_gaussian;
vec4 sum = gsk_texture (_tex_id, _tex_coord) * incremental_gaussian.x;
float coefficient_sum = incremental_gaussian.x;
incremental_gaussian.xy *= incremental_gaussian.yz;
vec2 p = _tex_blur_step;
for (uint i = 0u; i < _samples_per_side; i++)
{
sum += gsk_texture (_tex_id, _tex_coord - p) * incremental_gaussian.x;
sum += gsk_texture (_tex_id, _tex_coord + p) * incremental_gaussian.x;
coefficient_sum += 2.0 * incremental_gaussian.x;
incremental_gaussian.xy *= incremental_gaussian.yz;
p += _tex_blur_step;
}
if (VARIATION_COLORIZE)
color = _blur_color * sum.a / coefficient_sum;
else
color = sum / coefficient_sum;
position = _pos;
}
#endif