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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 | //This file is automatically rebuilt by the Cesium build process.
export default "// See Intersection.glsl for the definition of intersectScene\n\
// See IntersectionUtils.glsl for the definition of nextIntersection\n\
// See convertLocalToBoxUv.glsl, convertLocalToCylinderUv.glsl, or convertLocalToEllipsoidUv.glsl\n\
// for the definitions of convertLocalToShapeSpaceDerivative and getTileAndUvCoordinate. \n\
// The appropriate functions are selected based on the VoxelPrimitive shape type, \n\
// and added to the shader in Scene/VoxelRenderResources.js.\n\
// See Octree.glsl for the definitions of TraversalData, SampleData,\n\
// traverseOctreeFromBeginning, and traverseOctreeFromExisting\n\
// See Megatexture.glsl for the definition of accumulatePropertiesFromMegatexture\n\
\n\
#define STEP_COUNT_MAX 1000 // Harcoded value because GLSL doesn't like variable length loops\n\
#if defined(PICKING_VOXEL)\n\
#define ALPHA_ACCUM_MAX 0.1\n\
#else\n\
#define ALPHA_ACCUM_MAX 0.98 // Must be > 0.0 and <= 1.0\n\
#endif\n\
\n\
uniform mat4 u_transformPositionViewToLocal;\n\
uniform mat3 u_transformDirectionViewToLocal;\n\
uniform vec3 u_cameraPositionLocal;\n\
uniform vec3 u_cameraDirectionLocal;\n\
uniform float u_stepSize;\n\
\n\
#if defined(PICKING)\n\
uniform vec4 u_pickColor;\n\
#endif\n\
\n\
vec3 getSampleSize(in int level) {\n\
vec3 sampleCount = exp2(float(level)) * vec3(u_dimensions);\n\
vec3 sampleSizeUv = 1.0 / sampleCount;\n\
return scaleShapeUvToShapeSpace(sampleSizeUv);\n\
}\n\
\n\
#define MINIMUM_STEP_SCALAR (0.02)\n\
#define SHIFT_FRACTION (0.001)\n\
\n\
/**\n\
* Given a coordinate within a tile, and sample spacings along a ray through\n\
* the coordinate, find the distance to the points where the ray entered and\n\
* exited the voxel cell, along with the surface normals at those points.\n\
* The surface normals are returned in shape space coordinates.\n\
*/\n\
RayShapeIntersection getVoxelIntersection(in vec3 tileUv, in vec3 sampleSizeAlongRay) {\n\
vec3 voxelCoord = tileUv * vec3(u_dimensions);\n\
vec3 directions = sign(sampleSizeAlongRay);\n\
vec3 positiveDirections = max(directions, 0.0);\n\
vec3 entryCoord = mix(ceil(voxelCoord), floor(voxelCoord), positiveDirections);\n\
vec3 exitCoord = entryCoord + directions;\n\
\n\
vec3 distanceFromEntry = -abs((entryCoord - voxelCoord) * sampleSizeAlongRay);\n\
float lastEntry = maxComponent(distanceFromEntry);\n\
bvec3 isLastEntry = equal(distanceFromEntry, vec3(lastEntry));\n\
vec3 entryNormal = -1.0 * vec3(isLastEntry) * directions;\n\
vec4 entry = vec4(entryNormal, lastEntry);\n\
\n\
vec3 distanceToExit = abs((exitCoord - voxelCoord) * sampleSizeAlongRay);\n\
float firstExit = minComponent(distanceToExit);\n\
bvec3 isFirstExit = equal(distanceToExit, vec3(firstExit));\n\
vec3 exitNormal = vec3(isFirstExit) * directions;\n\
vec4 exit = vec4(exitNormal, firstExit);\n\
\n\
return RayShapeIntersection(entry, exit);\n\
}\n\
\n\
vec4 getStepSize(in SampleData sampleData, in Ray viewRay, in RayShapeIntersection shapeIntersection, in mat3 jacobianT, in float currentT) {\n\
vec3 gradient = viewRay.dir * jacobianT;\n\
vec3 sampleSizeAlongRay = getSampleSize(sampleData.tileCoords.w) / gradient;\n\
\n\
RayShapeIntersection voxelIntersection = getVoxelIntersection(sampleData.tileUv, sampleSizeAlongRay);\n\
\n\
// Transform normal from shape space to Cartesian space to eye space\n\
vec3 voxelNormal = jacobianT * voxelIntersection.entry.xyz;\n\
voxelNormal = normalize(czm_normal * voxelNormal);\n\
\n\
// Compare with the shape intersection, to choose the appropriate normal\n\
vec4 voxelEntry = vec4(voxelNormal, currentT + voxelIntersection.entry.w);\n\
vec4 entry = intersectionMax(shapeIntersection.entry, voxelEntry);\n\
\n\
float fixedStep = minComponent(abs(sampleSizeAlongRay)) * u_stepSize;\n\
float shift = fixedStep * SHIFT_FRACTION;\n\
float dt = voxelIntersection.exit.w + shift;\n\
if ((currentT + dt) > shapeIntersection.exit.w) {\n\
// Stop at end of shape\n\
dt = shapeIntersection.exit.w - currentT + shift;\n\
}\n\
float stepSize = clamp(dt, fixedStep * MINIMUM_STEP_SCALAR, fixedStep + shift);\n\
\n\
return vec4(entry.xyz, stepSize);\n\
}\n\
\n\
vec2 packIntToVec2(int value) {\n\
float shifted = float(value) / 255.0;\n\
float lowBits = fract(shifted);\n\
float highBits = floor(shifted) / 255.0;\n\
return vec2(highBits, lowBits);\n\
}\n\
\n\
vec2 packFloatToVec2(float value) {\n\
float lowBits = fract(value);\n\
float highBits = floor(value) / 255.0;\n\
return vec2(highBits, lowBits);\n\
}\n\
\n\
int getSampleIndex(in SampleData sampleData) {\n\
// tileUv = 1.0 is a valid coordinate but sampleIndex = u_inputDimensions is not.\n\
// (tileUv = 1.0 corresponds to the far edge of the last sample, at index = u_inputDimensions - 1).\n\
// Clamp to [0, voxelDimensions - 0.5) to avoid numerical error before flooring\n\
vec3 maxCoordinate = vec3(u_inputDimensions) - vec3(0.5);\n\
vec3 inputCoordinate = clamp(sampleData.inputCoordinate, vec3(0.0), maxCoordinate);\n\
ivec3 sampleIndex = ivec3(floor(inputCoordinate));\n\
// Convert to a 1D index for lookup in a 1D data array\n\
return sampleIndex.x + u_inputDimensions.x * (sampleIndex.y + u_inputDimensions.y * sampleIndex.z);\n\
}\n\
\n\
/**\n\
* Compute the view ray at the current fragment, in the local coordinates of the shape.\n\
*/\n\
Ray getViewRayLocal() {\n\
vec4 eyeCoordinates = czm_windowToEyeCoordinates(gl_FragCoord);\n\
vec3 origin;\n\
vec3 direction;\n\
if (czm_orthographicIn3D == 1.0) {\n\
eyeCoordinates.z = 0.0;\n\
origin = (u_transformPositionViewToLocal * eyeCoordinates).xyz;\n\
direction = u_cameraDirectionLocal;\n\
} else {\n\
origin = u_cameraPositionLocal;\n\
direction = u_transformDirectionViewToLocal * normalize(eyeCoordinates.xyz);\n\
}\n\
return Ray(origin, direction);\n\
}\n\
\n\
Ray getViewRayEC() {\n\
vec4 eyeCoordinates = czm_windowToEyeCoordinates(gl_FragCoord);\n\
vec3 viewPosEC = (czm_orthographicIn3D == 1.0)\n\
? vec3(eyeCoordinates.xy, 0.0)\n\
: vec3(0.0);\n\
vec3 viewDirEC = normalize(eyeCoordinates.xyz);\n\
return Ray(viewPosEC, viewDirEC);\n\
}\n\
\n\
void main()\n\
{\n\
Ray viewRayLocal = getViewRayLocal();\n\
Ray viewRayEC = getViewRayEC();\n\
\n\
Intersections ix;\n\
vec2 screenCoord = (gl_FragCoord.xy - czm_viewport.xy) / czm_viewport.zw; // [0,1]\n\
RayShapeIntersection shapeIntersection = intersectScene(screenCoord, viewRayLocal, viewRayEC, ix);\n\
// Exit early if the scene was completely missed.\n\
if (shapeIntersection.entry.w == NO_HIT) {\n\
discard;\n\
}\n\
\n\
float currentT = shapeIntersection.entry.w;\n\
float endT = shapeIntersection.exit.w;\n\
\n\
vec3 positionEC = viewRayEC.pos + currentT * viewRayEC.dir;\n\
TileAndUvCoordinate tileAndUv = getTileAndUvCoordinate(positionEC);\n\
vec3 positionLocal = viewRayLocal.pos + currentT * viewRayLocal.dir;\n\
mat3 jacobianT = convertLocalToShapeSpaceDerivative(positionLocal);\n\
\n\
// Traverse the tree from the start position\n\
TraversalData traversalData;\n\
SampleData sampleDatas[SAMPLE_COUNT];\n\
traverseOctreeFromBeginning(tileAndUv, traversalData, sampleDatas);\n\
vec4 step = getStepSize(sampleDatas[0], viewRayLocal, shapeIntersection, jacobianT, currentT);\n\
\n\
FragmentInput fragmentInput;\n\
#if defined(STATISTICS)\n\
setStatistics(fragmentInput.metadataStatistics);\n\
#endif\n\
\n\
czm_modelMaterial materialOutput;\n\
vec4 colorAccum = vec4(0.0);\n\
\n\
for (int stepCount = 0; stepCount < STEP_COUNT_MAX; ++stepCount) {\n\
// Read properties from the megatexture based on the traversal state\n\
Properties properties = accumulatePropertiesFromMegatexture(sampleDatas);\n\
\n\
// Prepare the custom shader inputs\n\
copyPropertiesToMetadata(properties, fragmentInput.metadata);\n\
\n\
fragmentInput.attributes.positionEC = positionEC;\n\
// Re-normalize normals: some shape intersections may have been scaled to encode positive/negative shapes\n\
fragmentInput.attributes.normalEC = normalize(step.xyz);\n\
\n\
fragmentInput.voxel.viewDirUv = viewRayLocal.dir;\n\
\n\
fragmentInput.voxel.travelDistance = step.w;\n\
fragmentInput.voxel.stepCount = stepCount;\n\
fragmentInput.voxel.tileIndex = sampleDatas[0].megatextureIndex;\n\
fragmentInput.voxel.sampleIndex = getSampleIndex(sampleDatas[0]);\n\
fragmentInput.voxel.distanceToDepthBuffer = ix.distanceToDepthBuffer - currentT;\n\
\n\
// Run the custom shader\n\
fragmentMain(fragmentInput, materialOutput);\n\
\n\
// Sanitize the custom shader output\n\
vec4 color = vec4(materialOutput.diffuse, materialOutput.alpha);\n\
color.rgb = max(color.rgb, vec3(0.0));\n\
color.a = clamp(color.a, 0.0, 1.0);\n\
\n\
// Pre-multiplied alpha blend\n\
colorAccum += (1.0 - colorAccum.a) * vec4(color.rgb * color.a, color.a);\n\
\n\
// Stop traversing if the alpha has been fully saturated\n\
if (colorAccum.a > ALPHA_ACCUM_MAX) {\n\
colorAccum.a = ALPHA_ACCUM_MAX;\n\
break;\n\
}\n\
\n\
if (step.w == 0.0) {\n\
// Shape is infinitely thin. The ray may have hit the edge of a\n\
// foreground voxel. Step ahead slightly to check for more voxels\n\
step.w == 0.00001;\n\
}\n\
\n\
// Keep raymarching\n\
currentT += step.w;\n\
// Check if there's more intersections.\n\
if (currentT > endT) {\n\
#if (INTERSECTION_COUNT == 1)\n\
break;\n\
#else\n\
shapeIntersection = nextIntersection(ix);\n\
if (shapeIntersection.entry.w == NO_HIT) {\n\
break;\n\
} else {\n\
// Found another intersection. Resume raymarching there\n\
currentT = shapeIntersection.entry.w;\n\
endT = shapeIntersection.exit.w;\n\
}\n\
#endif\n\
}\n\
positionEC = viewRayEC.pos + currentT * viewRayEC.dir;\n\
tileAndUv = getTileAndUvCoordinate(positionEC);\n\
positionLocal = viewRayLocal.pos + currentT * viewRayLocal.dir;\n\
jacobianT = convertLocalToShapeSpaceDerivative(positionLocal);\n\
\n\
// Traverse the tree from the current ray position.\n\
// This is similar to traverseOctreeFromBeginning but is faster when the ray is in the same tile as the previous step.\n\
traverseOctreeFromExisting(tileAndUv, traversalData, sampleDatas);\n\
step = getStepSize(sampleDatas[0], viewRayLocal, shapeIntersection, jacobianT, currentT);\n\
}\n\
\n\
// Convert the alpha from [0,ALPHA_ACCUM_MAX] to [0,1]\n\
colorAccum.a /= ALPHA_ACCUM_MAX;\n\
\n\
#if defined(PICKING)\n\
// If alpha is 0.0 there is nothing to pick\n\
if (colorAccum.a == 0.0) {\n\
discard;\n\
}\n\
out_FragColor = u_pickColor;\n\
#elif defined(PICKING_VOXEL)\n\
// If alpha is 0.0 there is nothing to pick\n\
if (colorAccum.a == 0.0) {\n\
discard;\n\
}\n\
vec2 megatextureId = packIntToVec2(sampleDatas[0].megatextureIndex);\n\
vec2 sampleIndex = packIntToVec2(getSampleIndex(sampleDatas[0]));\n\
out_FragColor = vec4(megatextureId, sampleIndex);\n\
#else\n\
out_FragColor = colorAccum;\n\
#endif\n\
}\n\
";
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