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/**
* Bokeh Look Up Table: This outputs a radius multiplier to shape the sampling in gather pass or
* the scatter sprite appearance. This is only used if bokeh shape is either anamorphic or is not
* a perfect circle.
* We correct samples spacing for polygonal bokeh shapes. However, we do not for anamorphic bokeh
* as it is way more complex and expensive to do.
*/
#pragma BLENDER_REQUIRE(effect_dof_lib.glsl)
uniform float bokehSides;
uniform float bokehRotation;
uniform vec2 bokehAnisotropyInv;
in vec4 uvcoordsvar;
layout(location = 0) out vec2 outGatherLut;
layout(location = 1) out float outScatterLut;
layout(location = 2) out float outResolveLut;
float polygon_sides_length(float sides_count)
{
return 2.0 * sin(M_PI / sides_count);
}
/* Returns intersection ratio between the radius edge at theta and the polygon edge.
* Start first corners at theta == 0. */
float circle_to_polygon_radius(float sides_count, float theta)
{
/* From Graphics Gems from CryENGINE 3 (Siggraph 2013) by Tiago Sousa (slide 36). */
float side_angle = M_2PI / sides_count;
float halfside_angle = side_angle * 0.5;
return cos(side_angle * 0.5) /
cos(theta - side_angle * floor((sides_count * theta + M_PI) / M_2PI));
}
/* Remap input angle to have homogenous spacing of points along a polygon edge.
* Expect theta to be in [0..2pi] range. */
float circle_to_polygon_angle(float sides_count, float theta)
{
float side_angle = M_2PI / sides_count;
float halfside_angle = side_angle * 0.5;
float side = floor(theta / side_angle);
/* Length of segment from center to the middle of polygon side. */
float adjacent = circle_to_polygon_radius(sides_count, 0.0);
/* This is the relative position of the sample on the polygon half side. */
float local_theta = theta - side * side_angle;
float ratio = (local_theta - halfside_angle) / halfside_angle;
float halfside_len = polygon_sides_length(sides_count) * 0.5;
float opposite = ratio * halfside_len;
/* NOTE: atan(y_over_x) has output range [-M_PI_2..M_PI_2]. */
float final_local_theta = atan(opposite / adjacent);
return side * side_angle + final_local_theta;
}
void main()
{
/* Center uv in range [-1..1]. */
vec2 uv = uvcoordsvar.xy * 2.0 - 1.0;
float radius = length(uv);
vec2 texel = floor(gl_FragCoord.xy) - float(DOF_MAX_SLIGHT_FOCUS_RADIUS);
if (bokehSides > 0.0) {
/* NOTE: atan(y,x) has output range [-M_PI..M_PI], so add 2pi to avoid negative angles. */
float theta = atan(uv.y, uv.x) + M_2PI;
float r = length(uv);
radius /= circle_to_polygon_radius(bokehSides, theta - bokehRotation);
float theta_new = circle_to_polygon_angle(bokehSides, theta);
float r_new = circle_to_polygon_radius(bokehSides, theta_new);
theta_new -= bokehRotation;
uv = r_new * vec2(-cos(theta_new), sin(theta_new));
{
/* Slight focus distance */
texel *= bokehAnisotropyInv;
float theta = atan(texel.y, -texel.x) + M_2PI;
texel /= circle_to_polygon_radius(bokehSides, theta + bokehRotation);
}
}
else {
uv *= safe_rcp(length(uv));
}
/* For gather store the normalized UV. */
outGatherLut = uv;
/* For scatter store distance. */
outScatterLut = radius;
/* For slight focus gather store pixel perfect distance. */
outResolveLut = length(texel);
}
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