@cesium/engine/Source/Shaders/Voxels/IntersectCylinder.js

CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.

//This file is automatically rebuilt by the Cesium build process.
export default "// See IntersectionUtils.glsl for the definitions of Ray, NO_HIT, Intersections,\n\
// RayShapeIntersection, setSurfaceIntersection, setShapeIntersection,\n\
// intersectIntersections\n\
// See IntersectLongitude.glsl for the definitions of intersectHalfPlane,\n\
// intersectFlippedWedge, intersectRegularWedge\n\
\n\
/* Cylinder defines (set in Scene/VoxelCylinderShape.js)\n\
#define CYLINDER_HAS_RENDER_BOUNDS_RADIUS_MIN\n\
#define CYLINDER_HAS_RENDER_BOUNDS_RADIUS_FLAT\n\
#define CYLINDER_HAS_RENDER_BOUNDS_ANGLE\n\
#define CYLINDER_HAS_RENDER_BOUNDS_ANGLE_RANGE_UNDER_HALF\n\
#define CYLINDER_HAS_RENDER_BOUNDS_ANGLE_RANGE_OVER_HALF\n\
#define CYLINDER_HAS_RENDER_BOUNDS_ANGLE_RANGE_EQUAL_ZERO\n\
\n\
#define CYLINDER_INTERSECTION_INDEX_RADIUS_MAX\n\
#define CYLINDER_INTERSECTION_INDEX_RADIUS_MIN\n\
#define CYLINDER_INTERSECTION_INDEX_ANGLE\n\
*/\n\
\n\
// Cylinder uniforms\n\
uniform vec2 u_cylinderRenderRadiusMinMax;\n\
#if defined(CYLINDER_HAS_RENDER_BOUNDS_ANGLE)\n\
    uniform vec2 u_cylinderRenderAngleMinMax;\n\
#endif\n\
\n\
uniform sampler2D u_renderBoundPlanesTexture;\n\
\n\
RayShapeIntersection intersectBoundPlanes(in Ray ray) {\n\
    vec4 lastEntry = vec4(ray.dir, -INF_HIT);\n\
    vec4 firstExit = vec4(-ray.dir, +INF_HIT);\n\
    for (int i = 0; i < 2; i++) {\n\
        vec4 boundPlane = getBoundPlane(u_renderBoundPlanesTexture, i);\n\
        vec4 intersection = intersectPlane(ray, boundPlane);\n\
        if (dot(ray.dir, boundPlane.xyz) < 0.0) {\n\
            lastEntry = intersection.w > lastEntry.w ? intersection : lastEntry;\n\
        } else {\n\
            firstExit = intersection.w < firstExit.w ? intersection: firstExit;\n\
        }\n\
    }\n\
\n\
    if (lastEntry.w < firstExit.w) {\n\
        return RayShapeIntersection(lastEntry, firstExit);\n\
    } else {\n\
        return RayShapeIntersection(vec4(-ray.dir, NO_HIT), vec4(ray.dir, NO_HIT));\n\
    }\n\
}\n\
\n\
/**\n\
 * Find the intersection of a ray with a right cylindrical surface of a given radius\n\
 * about the z-axis.\n\
 */\n\
RayShapeIntersection intersectCylinder(in Ray ray, in float radius, in bool convex)\n\
{\n\
    vec2 position = ray.pos.xy;\n\
    vec2 direction = ray.dir.xy;\n\
\n\
    float a = dot(direction, direction);\n\
    float b = dot(position, direction);\n\
    float c = dot(position, position) - radius * radius;\n\
    float determinant = b * b - a * c;\n\
\n\
    if (determinant < 0.0) {\n\
        vec4 miss = vec4(normalize(ray.dir), NO_HIT);\n\
        return RayShapeIntersection(miss, miss);\n\
    }\n\
\n\
    determinant = sqrt(determinant);\n\
    float t1 = (-b - determinant) / a;\n\
    float t2 = (-b + determinant) / a;\n\
    float signFlip = convex ? 1.0 : -1.0;\n\
    vec3 normal1 = vec3((position + t1 * direction) * signFlip, 0.0);\n\
    vec3 normal2 = vec3((position + t2 * direction) * signFlip, 0.0);\n\
    // Return normals in eye coordinates\n\
    vec4 intersect1 = vec4(normalize(czm_normal * normal1), t1);\n\
    vec4 intersect2 = vec4(normalize(czm_normal * normal2), t2);\n\
\n\
    return RayShapeIntersection(intersect1, intersect2);\n\
}\n\
\n\
/**\n\
 * Find the intersection of a ray with a right cylindrical solid of given\n\
 * radius and height bounds. NOTE: The shape is assumed to be convex.\n\
 */\n\
RayShapeIntersection intersectBoundedCylinder(in Ray ray, in Ray rayEC, in float radius)\n\
{\n\
    RayShapeIntersection cylinderIntersection = intersectCylinder(ray, radius, true);\n\
    RayShapeIntersection heightBoundsIntersection = intersectBoundPlanes(rayEC);\n\
    return intersectIntersections(ray, cylinderIntersection, heightBoundsIntersection);\n\
}\n\
\n\
void intersectShape(in Ray ray, in Ray rayEC, inout Intersections ix)\n\
{\n\
    RayShapeIntersection outerIntersect = intersectBoundedCylinder(ray, rayEC, u_cylinderRenderRadiusMinMax.y);\n\
\n\
    setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_RADIUS_MAX, outerIntersect);\n\
\n\
    if (outerIntersect.entry.w == NO_HIT) {\n\
        return;\n\
    }\n\
\n\
    #if defined(CYLINDER_HAS_RENDER_BOUNDS_RADIUS_FLAT)\n\
        // When the cylinder is perfectly thin it's necessary to sandwich the\n\
        // inner cylinder intersection inside the outer cylinder intersection.\n\
\n\
        // Without this special case,\n\
        // [outerMin, outerMax, innerMin, innerMax] will bubble sort to\n\
        // [outerMin, innerMin, outerMax, innerMax] which will cause the back\n\
        // side of the cylinder to be invisible because it will think the ray\n\
        // is still inside the inner (negative) cylinder after exiting the\n\
        // outer (positive) cylinder.\n\
\n\
        // With this special case,\n\
        // [outerMin, innerMin, innerMax, outerMax] will bubble sort to\n\
        // [outerMin, innerMin, innerMax, outerMax] which will work correctly.\n\
\n\
        // Note: If initializeIntersections() changes its sorting function\n\
        // from bubble sort to something else, this code may need to change.\n\
        RayShapeIntersection innerIntersect = intersectCylinder(ray, 1.0, false);\n\
        setSurfaceIntersection(ix, 0, outerIntersect.entry, true, true);  // positive, enter\n\
        setSurfaceIntersection(ix, 1, innerIntersect.entry, false, true); // negative, enter\n\
        setSurfaceIntersection(ix, 2, innerIntersect.exit, false, false); // negative, exit\n\
        setSurfaceIntersection(ix, 3, outerIntersect.exit, true, false);  // positive, exit\n\
    #elif defined(CYLINDER_HAS_RENDER_BOUNDS_RADIUS_MIN)\n\
        RayShapeIntersection innerIntersect = intersectCylinder(ray, u_cylinderRenderRadiusMinMax.x, false);\n\
        setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_RADIUS_MIN, innerIntersect);\n\
    #endif\n\
\n\
    #if defined(CYLINDER_HAS_RENDER_BOUNDS_ANGLE_RANGE_UNDER_HALF)\n\
        RayShapeIntersection wedgeIntersect = intersectRegularWedge(ray, u_cylinderRenderAngleMinMax);\n\
        setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_ANGLE, wedgeIntersect);\n\
    #elif defined(CYLINDER_HAS_RENDER_BOUNDS_ANGLE_RANGE_OVER_HALF)\n\
        RayShapeIntersection wedgeIntersects[2];\n\
        intersectFlippedWedge(ray, u_cylinderRenderAngleMinMax, wedgeIntersects);\n\
        setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_ANGLE + 0, wedgeIntersects[0]);\n\
        setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_ANGLE + 1, wedgeIntersects[1]);\n\
    #elif defined(CYLINDER_HAS_RENDER_BOUNDS_ANGLE_RANGE_EQUAL_ZERO)\n\
        RayShapeIntersection wedgeIntersects[2];\n\
        intersectHalfPlane(ray, u_cylinderRenderAngleMinMax.x, wedgeIntersects);\n\
        setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_ANGLE + 0, wedgeIntersects[0]);\n\
        setShapeIntersection(ix, CYLINDER_INTERSECTION_INDEX_ANGLE + 1, wedgeIntersects[1]);\n\
    #endif\n\
}\n\
";