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fix world-space coords of DEVICE vertex domain at infinity

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In device vertex domain it is easy to specify infinite world-space
coordinated (e.g. with the skybox), this results in complications
everywhere. We were mitigating this by essentially moving these
coordinates to around 16000 (give or take depending on the near plane),
but that was way too small.
Now we move them around 1e19, which seems to work. It's important with
applications rendering very large scenes to not use too small of a value.
This commit is contained in:
Mathias Agopian
2023-03-20 23:52:01 -07:00
committed by Mathias Agopian
parent 331af7bf35
commit 3ec704b91c
1 changed files with 6 additions and 2 deletions
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8
shaders/src/getters.vs
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@@ -185,8 +185,12 @@ vec4 computeWorldPosition() {
// GL convention to inverted DX convention
p.z = p.z * -0.5 + 0.5;
vec4 position = transform * p;
if (abs(position.w) < MEDIUMP_FLT_MIN) {
position.w = position.w < 0.0 ? -MEDIUMP_FLT_MIN : MEDIUMP_FLT_MIN;
// w could be zero (e.g.: with the skybox) which corresponds to an infinite distance in
// world-space. However, we want to avoid infinites and divides-by-zero, so we use a very
// small number instead in that case (2^-63 seem to work well).
const highp float ALMOST_ZERO_FLT = 1.08420217249e-19f;
if (abs(position.w) < ALMOST_ZERO_FLT) {
position.w = position.w < 0.0 ? -ALMOST_ZERO_FLT : ALMOST_ZERO_FLT;
}
return position * (1.0 / position.w);
#else