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77 lines
2.4 KiB
JavaScript
77 lines
2.4 KiB
JavaScript
//This file is automatically rebuilt by the Cesium build process.
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export default "uniform sampler2D heights;\n\
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uniform sampler2D colors;\n\
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\n\
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// This material expects heights to be sorted from lowest to highest.\n\
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\n\
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float getHeight(int idx, float invTexSize)\n\
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{\n\
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vec2 uv = vec2((float(idx) + 0.5) * invTexSize, 0.5);\n\
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#ifdef OES_texture_float\n\
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return texture2D(heights, uv).x;\n\
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#else\n\
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return czm_unpackFloat(texture2D(heights, uv));\n\
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#endif\n\
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}\n\
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\n\
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czm_material czm_getMaterial(czm_materialInput materialInput)\n\
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{\n\
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czm_material material = czm_getDefaultMaterial(materialInput);\n\
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\n\
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float height = materialInput.height;\n\
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float invTexSize = 1.0 / float(heightsDimensions.x);\n\
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\n\
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float minHeight = getHeight(0, invTexSize);\n\
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float maxHeight = getHeight(heightsDimensions.x - 1, invTexSize);\n\
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\n\
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// early-out when outside the height range\n\
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if (height < minHeight || height > maxHeight) {\n\
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material.diffuse = vec3(0.0);\n\
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material.alpha = 0.0;\n\
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return material;\n\
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}\n\
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\n\
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// Binary search to find heights above and below.\n\
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int idxBelow = 0;\n\
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int idxAbove = heightsDimensions.x;\n\
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float heightBelow = minHeight;\n\
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float heightAbove = maxHeight;\n\
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\n\
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// while loop not allowed, so use for loop with max iterations.\n\
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// maxIterations of 16 supports a texture size up to 65536 (2^16).\n\
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const int maxIterations = 16;\n\
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for (int i = 0; i < maxIterations; i++) {\n\
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if (idxBelow >= idxAbove - 1) {\n\
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break;\n\
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}\n\
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\n\
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int idxMid = (idxBelow + idxAbove) / 2;\n\
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float heightTex = getHeight(idxMid, invTexSize);\n\
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\n\
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if (height > heightTex) {\n\
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idxBelow = idxMid;\n\
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heightBelow = heightTex;\n\
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} else {\n\
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idxAbove = idxMid;\n\
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heightAbove = heightTex;\n\
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}\n\
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}\n\
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\n\
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float lerper = heightBelow == heightAbove ? 1.0 : (height - heightBelow) / (heightAbove - heightBelow);\n\
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vec2 colorUv = vec2(invTexSize * (float(idxBelow) + 0.5 + lerper), 0.5);\n\
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vec4 color = texture2D(colors, colorUv);\n\
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\n\
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// undo preumultiplied alpha\n\
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if (color.a > 0.0) \n\
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{\n\
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color.rgb /= color.a;\n\
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}\n\
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\n\
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color.rgb = czm_gammaCorrect(color.rgb);\n\
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\n\
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material.diffuse = color.rgb;\n\
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material.alpha = color.a;\n\
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return material;\n\
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}\n\
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";
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