Stacktrace in my original post is from unminified version and I am not getting an actual error message - it is empty (see attached screenshot). The best I can get is fragment shader source code itself - here it goes:
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
uniform vec2 czm_currentFrustum;
const float czm_sceneMode2D = 2.0;
uniform float czm_sceneMode;
uniform vec4 czm_frustumPlanes;
uniform vec4 czm_viewport;
uniform mat4 czm_inverseProjection;
uniform mat4 czm_viewportTransformation;
float czm_metersPerPixel(vec4 positionEC)
{
float width = czm_viewport.z;
float height = czm_viewport.w;
float pixelWidth;
float pixelHeight;
float top = czm_frustumPlanes.x;
float bottom = czm_frustumPlanes.y;
float left = czm_frustumPlanes.z;
float right = czm_frustumPlanes.w;
if (czm_sceneMode == czm_sceneMode2D)
{
float frustumWidth = right - left;
float frustumHeight = top - bottom;
pixelWidth = frustumWidth / width;
pixelHeight = frustumHeight / height;
}
else
{
float distanceToPixel = -positionEC.z;
float inverseNear = 1.0 / czm_currentFrustum.x;
float tanTheta = top * inverseNear;
pixelHeight = 2.0 * distanceToPixel * tanTheta / height;
tanTheta = right * inverseNear;
pixelWidth = 2.0 * distanceToPixel * tanTheta / width;
}
return max(pixelWidth, pixelHeight);
}
vec4 czm_windowToEyeCoordinates(vec4 fragmentCoordinate)
{
float x = 2.0 * (fragmentCoordinate.x - czm_viewport.x) / czm_viewport.z - 1.0;
float y = 2.0 * (fragmentCoordinate.y - czm_viewport.y) / czm_viewport.w - 1.0;
float z = (fragmentCoordinate.z - czm_viewportTransformation[3][2]) / czm_viewportTransformation[2][2];
vec4 q = vec4(x, y, z, 1.0);
q /= fragmentCoordinate.w;
if (czm_inverseProjection != mat4(0.0)) {
q = czm_inverseProjection * q;
} else {
float top = czm_frustumPlanes.x;
float bottom = czm_frustumPlanes.y;
float left = czm_frustumPlanes.z;
float right = czm_frustumPlanes.w;
float near = czm_currentFrustum.x;
float far = czm_currentFrustum.y;
q.x = (q.x * (right - left) + left + right) * 0.5;
q.y = (q.y * (top - bottom) + bottom + top) * 0.5;
q.z = (q.z * (near - far) - near - far) * 0.5;
q.w = 1.0;
}
return q;
}
const int czm_maxClippingPlanes = 6;
float czm_discardIfClippedWithIntersect(vec4 clippingPlanes[czm_maxClippingPlanes], int clippingPlanesLength)
{
if (clippingPlanesLength > 0)
{
bool clipped = true;
vec4 position = czm_windowToEyeCoordinates(gl_FragCoord);
vec3 clipNormal = vec3(0.0);
vec3 clipPosition = vec3(0.0);
float clipAmount = 0.0;
float pixelWidth = czm_metersPerPixel(position);
for (int i = 0; i < czm_maxClippingPlanes; ++i)
{
if (i == clippingPlanesLength)
{
break;
}
clipNormal = clippingPlanes[i].xyz;
clipPosition = -clippingPlanes[i].w * clipNormal;
float amount = dot(clipNormal, (position.xyz - clipPosition)) / pixelWidth;
clipAmount = max(amount, clipAmount);
clipped = clipped && (amount <= 0.0);
}
if (clipped)
{
discard;
}
return clipAmount;
}
return 0.0;
}
float czm_discardIfClippedWithUnion(vec4 clippingPlanes[czm_maxClippingPlanes], int clippingPlanesLength)
{
if (clippingPlanesLength > 0)
{
vec4 position = czm_windowToEyeCoordinates(gl_FragCoord);
vec3 clipNormal = vec3(0.0);
vec3 clipPosition = vec3(0.0);
float clipAmount = 0.0;
float pixelWidth = czm_metersPerPixel(position);
for (int i = 0; i < czm_maxClippingPlanes; ++i)
{
if (i == clippingPlanesLength)
{
break;
}
clipNormal = clippingPlanes[i].xyz;
clipPosition = -clippingPlanes[i].w * clipNormal;
float amount = dot(clipNormal, (position.xyz - clipPosition)) / pixelWidth;
clipAmount = max(amount, clipAmount);
if (amount <= 0.0)
{
discard;
}
}
return clipAmount;
}
return 0.0;
}
#line 0
#line 0
varying vec3 v_normal;
uniform vec4 u_ambient;
uniform vec4 u_diffuse;
uniform vec4 u_emission;
uniform vec4 u_specular;
uniform float u_shininess;
void gltf_blend_main() {
vec3 normal = normalize(v_normal);
vec4 color = vec4(0., 0., 0., 0.);
vec4 diffuse = vec4(0., 0., 0., 1.);
vec4 emission;
vec4 ambient;
vec4 specular;
ambient = u_ambient;
diffuse = u_diffuse;
emission = u_emission;
specular = u_specular;
diffuse.xyz *= max(dot(normal,vec3(0.,0.,1.)), 0.);
color.xyz += diffuse.xyz;
color.xyz += emission.xyz;
color = vec4(color.rgb * diffuse.a, diffuse.a);
gl_FragColor = color;
}
uniform vec4 gltf_color;
uniform float gltf_colorBlend;
void gltf_clip_main()
{
gltf_blend_main();
float alpha = 1.0 - ceil(gl_FragColor.a) + gl_FragColor.a;
gl_FragColor.rgb /= alpha;
gl_FragColor.rgb = mix(gl_FragColor.rgb, gltf_color.rgb, gltf_colorBlend);
float highlight = ceil(gltf_colorBlend);
gl_FragColor.rgb *= mix(gltf_color.rgb, vec3(1.0), highlight);
gl_FragColor.a *= gltf_color.a;
}
uniform int gltf_clippingPlanesLength;
uniform bool gltf_clippingPlanesUnionRegions;
uniform vec4 gltf_clippingPlanes[czm_maxClippingPlanes];
uniform vec4 gltf_clippingPlanesEdgeStyle;
void main()
{
gltf_clip_main();
if (gltf_clippingPlanesLength > 0)
{
float clipDistance;
if (gltf_clippingPlanesUnionRegions)
{
clipDistance = czm_discardIfClippedWithUnion(gltf_clippingPlanes, gltf_clippingPlanesLength);
}
else
{
clipDistance = czm_discardIfClippedWithIntersect(gltf_clippingPlanes, gltf_clippingPlanesLength);
}
vec4 clippingPlanesEdgeColor = vec4(1.0);
clippingPlanesEdgeColor.rgb = gltf_clippingPlanesEdgeStyle.rgb;
float clippingPlanesEdgeWidth = gltf_clippingPlanesEdgeStyle.a;
if (clipDistance > 0.0 && clipDistance < clippingPlanesEdgeWidth)
{
gl_FragColor = clippingPlanesEdgeColor;
}
}
}
``
