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86 lines
3.3 KiB
GLSL

attribute vec3 startEllipsoidNormal;
attribute vec3 endEllipsoidNormal;
attribute vec4 startPositionAndHeight;
attribute vec4 endPositionAndHeight;
attribute vec4 startFaceNormalAndVertexCorner;
attribute vec4 endFaceNormalAndHalfWidth;
attribute float a_batchId;
uniform mat4 u_modifiedModelView;
uniform vec2 u_minimumMaximumVectorHeights;
varying vec4 v_startPlaneEC;
varying vec4 v_endPlaneEC;
varying vec4 v_rightPlaneEC;
varying float v_halfWidth;
varying vec3 v_volumeUpEC;
void main()
{
// vertex corner IDs
// 3-----------7
// /| left /|
// / | 1 / |
// 2-----------6 5 end
// | / | /
// start |/ right |/
// 0-----------4
//
float isEnd = floor(startFaceNormalAndVertexCorner.w * 0.251); // 0 for front, 1 for end
float isTop = floor(startFaceNormalAndVertexCorner.w * mix(0.51, 0.19, isEnd)); // 0 for bottom, 1 for top
vec3 forward = endPositionAndHeight.xyz - startPositionAndHeight.xyz;
vec3 right = normalize(cross(forward, startEllipsoidNormal));
vec4 position = vec4(startPositionAndHeight.xyz, 1.0);
position.xyz += forward * isEnd;
v_volumeUpEC = czm_normal * normalize(cross(right, forward));
// Push for volume height
float offset;
vec3 ellipsoidNormal = mix(startEllipsoidNormal, endEllipsoidNormal, isEnd);
// offset height to create volume
offset = mix(startPositionAndHeight.w, endPositionAndHeight.w, isEnd);
offset = mix(u_minimumMaximumVectorHeights.y, u_minimumMaximumVectorHeights.x, isTop) - offset;
position.xyz += offset * ellipsoidNormal;
// move from RTC to EC
position = u_modifiedModelView * position;
right = czm_normal * right;
// Push for width in a direction that is in the start or end plane and in a plane with right
// N = normalEC ("right-facing" direction for push)
// R = right
// p = angle between N and R
// w = distance to push along R if R == N
// d = distance to push along N
//
// N R
// { \ p| } * cos(p) = dot(N, R) = w / d
// d\ \ | |w * d = w / dot(N, R)
// { \| }
// o---------- polyline segment ---->
//
vec3 scratchNormal = mix(-startFaceNormalAndVertexCorner.xyz, endFaceNormalAndHalfWidth.xyz, isEnd);
scratchNormal = cross(scratchNormal, mix(startEllipsoidNormal, endEllipsoidNormal, isEnd));
vec3 miterPushNormal = czm_normal * normalize(scratchNormal);
offset = 2.0 * endFaceNormalAndHalfWidth.w * max(0.0, czm_metersPerPixel(position)); // offset = widthEC
offset = offset / dot(miterPushNormal, right);
position.xyz += miterPushNormal * (offset * sign(0.5 - mod(startFaceNormalAndVertexCorner.w, 2.0)));
gl_Position = czm_depthClamp(czm_projection * position);
position = u_modifiedModelView * vec4(startPositionAndHeight.xyz, 1.0);
vec3 startNormalEC = czm_normal * startFaceNormalAndVertexCorner.xyz;
v_startPlaneEC = vec4(startNormalEC, -dot(startNormalEC, position.xyz));
v_rightPlaneEC = vec4(right, -dot(right, position.xyz));
position = u_modifiedModelView * vec4(endPositionAndHeight.xyz, 1.0);
vec3 endNormalEC = czm_normal * endFaceNormalAndHalfWidth.xyz;
v_endPlaneEC = vec4(endNormalEC, -dot(endNormalEC, position.xyz));
v_halfWidth = endFaceNormalAndHalfWidth.w;
}