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/**
* Camera projection / uv functions and utils.
**/
#pragma BLENDER_REQUIRE(common_math_lib.glsl)
/* -------------------------------------------------------------------- */
/** \name Panoramic Projections
*
* Adapted from Cycles to match EEVEE's coordinate system.
* \{ */
vec2 camera_equirectangular_from_direction(CameraData cam, vec3 dir)
{
float phi = atan(-dir.z, dir.x);
float theta = acos(dir.y / length(dir));
return (vec2(phi, theta) - cam.equirect_bias) * cam.equirect_scale_inv;
}
vec3 camera_equirectangular_to_direction(CameraData cam, vec2 uv)
{
uv = uv * cam.equirect_scale + cam.equirect_bias;
float phi = uv.x;
float theta = uv.y;
float sin_theta = sin(theta);
return vec3(sin_theta * cos(phi), cos(theta), -sin_theta * sin(phi));
}
vec2 camera_fisheye_from_direction(CameraData cam, vec3 dir)
{
float r = atan(length(dir.xy), -dir.z) / cam.fisheye_fov;
float phi = atan(dir.y, dir.x);
vec2 uv = r * vec2(cos(phi), sin(phi)) + 0.5;
return (uv - cam.uv_bias) / cam.uv_scale;
}
vec3 camera_fisheye_to_direction(CameraData cam, vec2 uv)
{
uv = uv * cam.uv_scale + cam.uv_bias;
uv = (uv - 0.5) * 2.0;
float r = length(uv);
if (r > 1.0) {
return vec3(0.0);
}
float phi = safe_acos(uv.x * safe_rcp(r));
float theta = r * cam.fisheye_fov * 0.5;
if (uv.y < 0.0) {
phi = -phi;
}
return vec3(cos(phi) * sin(theta), sin(phi) * sin(theta), -cos(theta));
}
vec2 camera_mirror_ball_from_direction(CameraData cam, vec3 dir)
{
dir = normalize(dir);
dir.z -= 1.0;
dir *= safe_rcp(2.0 * safe_sqrt(-0.5 * dir.z));
vec2 uv = 0.5 * dir.xy + 0.5;
return (uv - cam.uv_bias) / cam.uv_scale;
}
vec3 camera_mirror_ball_to_direction(CameraData cam, vec2 uv)
{
uv = uv * cam.uv_scale + cam.uv_bias;
vec3 dir;
dir.xy = uv * 2.0 - 1.0;
if (len_squared(dir.xy) > 1.0) {
return vec3(0.0);
}
dir.z = -safe_sqrt(1.0 - sqr(dir.x) - sqr(dir.y));
const vec3 I = vec3(0.0, 0.0, 1.0);
return reflect(I, dir);
}
/** \} */
/* -------------------------------------------------------------------- */
/** \name Regular projections
* \{ */
vec3 camera_view_from_uv(mat4 projmat, vec2 uv)
{
return project_point(projmat, vec3(uv * 2.0 - 1.0, 0.0));
}
vec2 camera_uv_from_view(mat4 projmat, bool is_persp, vec3 vV)
{
vec4 tmp = projmat * vec4(vV, 1.0);
if (is_persp && tmp.w <= 0.0) {
/* Return invalid coordinates for points behind the camera.
* This can happen with panoramic projections. */
return vec2(-1.0);
}
return (tmp.xy / tmp.w) * 0.5 + 0.5;
}
/** \} */
/* -------------------------------------------------------------------- */
/** \name General functions handling all projections
* \{ */
vec3 camera_view_from_uv(CameraData cam, vec2 uv)
{
vec3 vV;
switch (cam.type) {
default:
case CAMERA_ORTHO:
case CAMERA_PERSP:
return camera_view_from_uv(cam.wininv, uv);
case CAMERA_PANO_EQUIRECT:
vV = camera_equirectangular_to_direction(cam, uv);
break;
case CAMERA_PANO_EQUIDISTANT:
/* ATTR_FALLTHROUGH; */
case CAMERA_PANO_EQUISOLID:
vV = camera_fisheye_to_direction(cam, uv);
break;
case CAMERA_PANO_MIRROR:
vV = camera_mirror_ball_to_direction(cam, uv);
break;
}
return vV;
}
vec2 camera_uv_from_view(CameraData cam, vec3 vV)
{
switch (cam.type) {
default:
case CAMERA_ORTHO:
return camera_uv_from_view(cam.winmat, false, vV);
case CAMERA_PERSP:
return camera_uv_from_view(cam.winmat, true, vV);
case CAMERA_PANO_EQUIRECT:
return camera_equirectangular_from_direction(cam, vV);
case CAMERA_PANO_EQUISOLID:
/* ATTR_FALLTHROUGH; */
case CAMERA_PANO_EQUIDISTANT:
return camera_fisheye_from_direction(cam, vV);
case CAMERA_PANO_MIRROR:
return camera_mirror_ball_from_direction(cam, vV);
}
}
vec2 camera_uv_from_world(CameraData cam, vec3 V)
{
vec3 vV = transform_point(cam.viewmat, V);
switch (cam.type) {
default:
case CAMERA_ORTHO:
return camera_uv_from_view(cam.persmat, false, V);
case CAMERA_PERSP:
return camera_uv_from_view(cam.persmat, true, V);
case CAMERA_PANO_EQUIRECT:
return camera_equirectangular_from_direction(cam, vV);
case CAMERA_PANO_EQUISOLID:
/* ATTR_FALLTHROUGH; */
case CAMERA_PANO_EQUIDISTANT:
return camera_fisheye_from_direction(cam, vV);
case CAMERA_PANO_MIRROR:
return camera_mirror_ball_from_direction(cam, vV);
}
}
/** \} */
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