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@wwwtyro
Created March 16, 2015 05:54
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GLSL ray-sphere intersection
float raySphereIntersect(vec3 r0, vec3 rd, vec3 s0, float sr) {
// - r0: ray origin
// - rd: normalized ray direction
// - s0: sphere center
// - sr: sphere radius
// - Returns distance from r0 to first intersecion with sphere,
// or -1.0 if no intersection.
float a = dot(rd, rd);
vec3 s0_r0 = r0 - s0;
float b = 2.0 * dot(rd, s0_r0);
float c = dot(s0_r0, s0_r0) - (sr * sr);
if (b*b - 4.0*a*c < 0.0) {
return -1.0;
}
return (-b - sqrt((b*b) - 4.0*a*c))/(2.0*a);
}
@Ap0thecary
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IT DOESNT FUCKING WORK FUCK YOU

Imagine not having the problem solving skills to fix it if it didn't.

Literally worked perfectly without any major changes. Imagine being this much of a tool.
raySphereIntersect

Thanks for the snippet OP!

Looks super cool, I can't wait to try this out

@brandonhs
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brandonhs commented Mar 12, 2021

IT DOESNT FUCKING WORK FUCK YOU

M yes, I too hate it when I copy someone's code and I don't even know how to use, so I then go harrass the creator. /s

With that out of the way, the snippet works fine so thank you OP

@grigoryoskin
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In your comment it says rd: normalized ray direction, but then you compute dot(rd, rd) which is always one. So either rd should not be normalized or your code is doing unnecessary operations.

@stuw-u
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stuw-u commented Aug 5, 2022

lol are we all using this for a shader in unity

@RGBProductions
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lol are we all using this for a shader in unity

Not me, I'm using it for Love2D.

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