@xeokit/xeokit-sdk
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3D BIM IFC Viewer SDK for AEC engineering applications. Open Source JavaScript Toolkit based on pure WebGL for top performance, real-world coordinates and full double precision
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JavaScript
export const PickDepthProgram = function(programVariables, geometry, logarithmicDepthBufferEnabled) {
const far = programVariables.createUniform("float", "far", (set, state) => set(state.legacyFrameCtx.viewParams.far));
const near = programVariables.createUniform("float", "near", (set, state) => set(state.legacyFrameCtx.viewParams.near));
const vViewPosition = programVariables.createVarying("vec3", "vViewPosition", () => `${geometry.attributes.position.view}.xyz`);
const outPackedDepth = programVariables.createOutput("vec4", "outPackedDepth");
const packDepth = programVariables.createFragmentDefinition(
"packDepth",
(name, src) => {
src.push(`vec4 ${name}(const in float depth) {`);
src.push(" const vec4 bitShift = vec4(256.0*256.0*256.0, 256.0*256.0, 256.0, 1.0);");
src.push(" const vec4 bitMask = vec4(0.0, 1.0/256.0, 1.0/256.0, 1.0/256.0);");
src.push(" vec4 res = fract(depth * bitShift);");
src.push(" res -= res.xxyz * bitMask;");
src.push(" return res;");
src.push("}");
});
return {
programName: "PickDepth",
getLogDepth: logarithmicDepthBufferEnabled && (vFragDepth => vFragDepth),
renderPassFlag: 3, // PICK
incPointSizeBy10: true,
appendFragmentOutputs: (src) => {
src.push(`float zNormalizedDepth = abs((${near} + ${vViewPosition}.z) / (${far} - ${near}));`);
// isn't zNormalizedDepth the same as gl_FragDepth or gl_FragCoord.z?
src.push(`${outPackedDepth} = ${packDepth}(zNormalizedDepth);`); // Must be linear depth
// try: src.push(" outPackedDepth = vec4(zNormalizedDepth, fract(zNormalizedDepth * vec3(256.0, 256.0*256.0, 256.0*256.0*256.0)));");
}
};
};