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/**
* The resources expected to be defined are:
* - probes_buf
* - lightprobe_grid_tx
* - grids
*/
#pragma BLENDER_REQUIRE(common_math_geom_lib.glsl)
#pragma BLENDER_REQUIRE(eevee_irradiance_lib.glsl)
float lightprobe_grid_weight(GridData grid, vec3 P)
{
vec3 lP = transform_point(grid.local_mat, P);
vec3 pos_to_edge = max(vec3(0.0), abs(lP) - 1.0);
float fade = length(pos_to_edge);
return saturate(-fade * grid.attenuation_scale + grid.attenuation_bias);
}
vec3 lightprobe_grid_evaluate(
GridInfoData info, sampler2DArray grid_tx, GridData grid, vec3 P, vec3 N)
{
vec3 lP = transform_point(grid.local_mat, P) * 0.5 + 0.5;
lP = lP * vec3(grid.resolution) - 0.5;
ivec3 lP_floored = ivec3(floor(lP));
vec3 trilinear_weight = fract(lP);
if (grid.offset == 0) {
N = transform_direction(info.lookdev_rotation, N);
}
float weight_accum = 0.0;
vec3 irradiance_accum = vec3(0.0);
/* For each neighbor cells */
for (int i = 0; i < 8; i++) {
ivec3 offset = ivec3(i, i >> 1, i >> 2) & ivec3(1);
ivec3 cell_coord = clamp(lP_floored + offset, ivec3(0), grid.resolution - 1);
/* Skip cells not yet rendered during baking. */
cell_coord = (cell_coord / grid.level_skip) * grid.level_skip;
/* Keep in sync with update_irradiance_probe. */
int cell_id = grid.offset + cell_coord.z + cell_coord.y * grid.resolution.z +
cell_coord.x * grid.resolution.z * grid.resolution.y;
vec3 color = irradiance_load_cell(info, grid_tx, cell_id, N);
/* We need this because we render probes in world space (so we need light vector in WS).
* And rendering them in local probe space is too much problem. */
mat4 cell_to_world = mat4(vec4(grid.increment_x, 0.0),
vec4(grid.increment_y, 0.0),
vec4(grid.increment_z, 0.0),
vec4(grid.corner, 1.0));
vec3 ws_cell_location = transform_point(cell_to_world, vec3(cell_coord));
vec3 ws_point_to_cell = ws_cell_location - P;
float ws_dist_point_to_cell = length(ws_point_to_cell);
vec3 ws_light = ws_point_to_cell / ws_dist_point_to_cell;
/* Smooth backface test. */
float weight = saturate(dot(ws_light, N));
/* Precomputed visibility. */
weight *= visibility_load_cell(info,
grid_tx,
cell_id,
ws_light,
ws_dist_point_to_cell,
grid.visibility_bias,
grid.visibility_bleed,
grid.visibility_range);
/* Smoother transition. */
weight += info.irradiance_smooth;
/* Trilinear weights. */
vec3 trilinear = mix(1.0 - trilinear_weight, trilinear_weight, offset);
weight *= trilinear.x * trilinear.y * trilinear.z;
/* Avoid zero weight. */
weight = max(0.00001, weight);
weight_accum += weight;
irradiance_accum += color * weight;
}
return irradiance_accum / weight_accum;
}
vec3 lightprobe_grid_eval(vec3 P, vec3 N, float random_threshold)
{
/* Go through all grids, computing and adding their weights for this pixel
* until reaching a random threshold. */
float weight = 0.0;
int grid_index = probes_buf.grids_info.grid_count - 1;
for (; grid_index > 0; grid_index--) {
weight += lightprobe_grid_weight(grids_buf[grid_index], P);
if (weight >= random_threshold) {
break;
}
}
return lightprobe_grid_evaluate(
probes_buf.grids_info, lightprobe_grid_tx, grids_buf[grid_index], P, N);
}
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