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Make Sun customizable!

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numzero 2025-03-29 00:45:45 +03:00
parent c1b3e862d6
commit 9a9a88360a
1 changed files with 16 additions and 2 deletions
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18
src/trace.wgsl
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@ -104,8 +104,22 @@ fn trace_fragment(in: Varying) -> vec3f {
if (sphere == -1) {
let theta = dot(ray, normalize(vec3(0., 0., 1.)));
var env: vec3f; // in kilonits
if (theta > 0.999988647254458) {
env = vec3(1.6e6, 1.5e6, 1.0e6);
const ILLUMINANCE_LUX = 1e5;
const ANGULAR_DIAMETER_DEG = 0.5; // Sun: 0.5°
const PI = 3.141592653589793;
const ANGULAR_DIAMETER_RAD = PI / 180.0 * ANGULAR_DIAMETER_DEG;
const THETA = 0.5 * ANGULAR_DIAMETER_RAD;
const COS_THETA = 1.0 - 0.5 * THETA * THETA; // approximately
const SOLID_ANGLE_SR = PI * THETA * THETA; // approximately
const LUMINANCE_NIT = ILLUMINANCE_LUX / SOLID_ANGLE_SR;
const LUMINANCE_KNIT = 1e-3 * LUMINANCE_NIT;
if (theta > COS_THETA) {
env = vec3(1.0, 0.9, 0.6) * LUMINANCE_KNIT;
} else {
env = mix(vec3(0.5, 1.0, 2.0), vec3(2.0, 3.0, 4.0), 0.5 * theta + 0.5);
}