//This file is automatically rebuilt by the Cesium build process.
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export default "#ifdef LOG_DEPTH\n\
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varying float v_depthFromNearPlusOne;\n\
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\n\
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#ifdef POLYGON_OFFSET\n\
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uniform vec2 u_polygonOffset;\n\
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#endif\n\
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\n\
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#endif\n\
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\n\
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/**\n\
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* Writes the fragment depth to the logarithmic depth buffer.\n\
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* <p>\n\
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* Use this when the vertex shader does not call {@link czm_vertexlogDepth}, for example, when\n\
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* ray-casting geometry using a full screen quad.\n\
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* </p>\n\
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* @name czm_writeLogDepth\n\
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* @glslFunction\n\
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*\n\
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* @param {float} depth The depth coordinate, where 1.0 is on the near plane and\n\
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* depth increases in eye-space units from there\n\
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*\n\
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* @example\n\
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* czm_writeLogDepth((czm_projection * v_positionEyeCoordinates).w + 1.0);\n\
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*/\n\
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void czm_writeLogDepth(float depth)\n\
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{\n\
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#if defined(GL_EXT_frag_depth) && defined(LOG_DEPTH)\n\
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// Discard the vertex if it's not between the near and far planes.\n\
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// We allow a bit of epsilon on the near plane comparison because a 1.0\n\
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// from the vertex shader (indicating the vertex should be _on_ the near\n\
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// plane) will not necessarily come here as exactly 1.0.\n\
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if (depth <= 0.9999999 || depth > czm_farDepthFromNearPlusOne) {\n\
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discard;\n\
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}\n\
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\n\
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#ifdef POLYGON_OFFSET\n\
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// Polygon offset: m * factor + r * units\n\
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float factor = u_polygonOffset[0];\n\
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float units = u_polygonOffset[1];\n\
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\n\
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// If we can't compute derivatives, just leave out the factor I guess?\n\
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#ifdef GL_OES_standard_derivatives\n\
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// m = sqrt(dZdX^2 + dZdY^2);\n\
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float x = dFdx(depth);\n\
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float y = dFdy(depth);\n\
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float m = sqrt(x * x + y * y);\n\
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\n\
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// Apply the factor before computing the log depth.\n\
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depth += m * factor;\n\
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#endif\n\
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\n\
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#endif\n\
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\n\
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gl_FragDepthEXT = log2(depth) * czm_oneOverLog2FarDepthFromNearPlusOne;\n\
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\n\
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#ifdef POLYGON_OFFSET\n\
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// Apply the units after the log depth.\n\
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gl_FragDepthEXT += czm_epsilon7 * units;\n\
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#endif\n\
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\n\
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#endif\n\
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}\n\
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\n\
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/**\n\
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* Writes the fragment depth to the logarithmic depth buffer.\n\
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* <p>\n\
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* Use this when the vertex shader calls {@link czm_vertexlogDepth}.\n\
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* </p>\n\
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*\n\
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* @name czm_writeLogDepth\n\
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* @glslFunction\n\
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*/\n\
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void czm_writeLogDepth() {\n\
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#ifdef LOG_DEPTH\n\
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czm_writeLogDepth(v_depthFromNearPlusOne);\n\
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#endif\n\
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}\n\
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";
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