84 lines
2 KiB
Text
84 lines
2 KiB
Text
#version 460
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#extension GL_EXT_ray_tracing : require
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#extension GL_EXT_nonuniform_qualifier : enable
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#extension GL_EXT_scalar_block_layout : enable
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#extension GL_GOOGLE_include_directive : enable
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#include "raycommon.glsl"
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#include "wavefront.glsl"
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hitAttributeEXT vec3 HitAttribute;
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layout(binding = 7, set = 1, scalar) buffer allSpheres_
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{
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Sphere i[];
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}
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allSpheres;
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struct Ray
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{
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vec3 origin;
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vec3 direction;
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};
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// Ray-Sphere intersection
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// http://viclw17.github.io/2018/07/16/raytracing-ray-sphere-intersection/
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float hitSphere(const Sphere s, const Ray r)
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{
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vec3 oc = r.origin - s.center;
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float a = dot(r.direction, r.direction);
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float b = 2.0 * dot(oc, r.direction);
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float c = dot(oc, oc) - s.radius * s.radius;
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float discriminant = b * b - 4 * a * c;
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if(discriminant < 0)
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{
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return -1.0;
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}
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else
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{
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return (-b - sqrt(discriminant)) / (2.0 * a);
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}
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}
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// Ray-AABB intersection
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float hitAabb(const Aabb aabb, const Ray r)
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{
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vec3 invDir = 1.0 / r.direction;
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vec3 tbot = invDir * (aabb.minimum - r.origin);
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vec3 ttop = invDir * (aabb.maximum - r.origin);
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vec3 tmin = min(ttop, tbot);
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vec3 tmax = max(ttop, tbot);
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float t0 = max(tmin.x, max(tmin.y, tmin.z));
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float t1 = min(tmax.x, min(tmax.y, tmax.z));
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return t1 > max(t0, 0.0) ? t0 : -1.0;
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}
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void main()
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{
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Ray ray;
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ray.origin = gl_WorldRayOriginEXT;
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ray.direction = gl_WorldRayDirectionEXT;
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// Sphere data
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Sphere sphere = allSpheres.i[gl_PrimitiveID];
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float tHit = -1;
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int hitKind = gl_PrimitiveID % 2 == 0 ? KIND_SPHERE : KIND_CUBE;
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if(hitKind == KIND_SPHERE)
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{
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// Sphere intersection
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tHit = hitSphere(sphere, ray);
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}
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else
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{
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// AABB intersection
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Aabb aabb;
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aabb.minimum = sphere.center - vec3(sphere.radius);
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aabb.maximum = sphere.center + vec3(sphere.radius);
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tHit = hitAabb(aabb, ray);
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}
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// Report hit point
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if(tHit > 0)
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reportIntersectionEXT(tHit, hitKind);
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}
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