46 lines
1.4 KiB
JavaScript
46 lines
1.4 KiB
JavaScript
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//This file is automatically rebuilt by the Cesium build process.
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define(function() {
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'use strict';
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return "/**\n\
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* Computes the size of a pixel in meters at a distance from the eye.\n\
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\n\
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* @name czm_metersPerPixel\n\
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* @glslFunction\n\
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*\n\
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* @param {vec3} positionEC The position to get the meters per pixel in eye coordinates.\n\
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*\n\
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* @returns {float} The meters per pixel at positionEC.\n\
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*/\n\
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float czm_metersPerPixel(vec4 positionEC)\n\
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{\n\
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float width = czm_viewport.z;\n\
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float height = czm_viewport.w;\n\
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float pixelWidth;\n\
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float pixelHeight;\n\
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\n\
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float top = czm_frustumPlanes.x;\n\
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float bottom = czm_frustumPlanes.y;\n\
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float left = czm_frustumPlanes.z;\n\
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float right = czm_frustumPlanes.w;\n\
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\n\
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if (czm_sceneMode == czm_sceneMode2D || czm_orthographicIn3D == 1.0)\n\
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{\n\
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float frustumWidth = right - left;\n\
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float frustumHeight = top - bottom;\n\
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pixelWidth = frustumWidth / width;\n\
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pixelHeight = frustumHeight / height;\n\
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}\n\
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else\n\
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{\n\
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float distanceToPixel = -positionEC.z;\n\
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float inverseNear = 1.0 / czm_currentFrustum.x;\n\
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float tanTheta = top * inverseNear;\n\
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pixelHeight = 2.0 * distanceToPixel * tanTheta / height;\n\
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tanTheta = right * inverseNear;\n\
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pixelWidth = 2.0 * distanceToPixel * tanTheta / width;\n\
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}\n\
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\n\
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return max(pixelWidth, pixelHeight);\n\
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}\n\
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";
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});
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