I am trying to get a global position to the shadow map uv position for a ShadowGenerator Texture. float sampleSunShadow(vec3 pos){ vec4 posFromSun = vec4(pos, distance(sunPosition, pos)); vec3 clipSpace = posFromSun.xyz / posFromSun.w; vec2 uv = 0.5 * clipSpace.xy + vec2(0.5); i…

Here it is: https://playground.babylonjs.com/#21FNQE#16 [image] Note that shadowMapTransformMatrix was not in the uniform list passed to BABYLON.PostProcess, so you ended up with an all-0 matrix in the shader. I mostly copied what is done in the computeShadow method used by the shadow fragment s…

Did you check the shader we use for PBR or stdMat?

yeah, and when I try to duplicate it I seem to still have a sample issue. Maybe it’s the global position that I am messing up. Ill check if the PBR example helps me. hmm its the same function, and as far as I can tell I am using the same process… dang gotta figure this out.

Maybe the position or the light matrix?

Im super close, let me see if I can post a PG for it. Somebody might see what’s good right away. https://playground.babylonjs.com/#21FNQE#10 its on line 565 where I am sampling the shadowmap, I have a sneaking suspicion I am just sampling the wrong global point or the incorrect perspective amount…

why this: length(pos+sunPosition)+50./600.)

I am assuming that is the way to convert the depth of the rayPosition to the Light, but might be wrong. My shadowMin and max is 50 and 600 units Ive tried vec4(pos, distance(pos,sunPosition)); as well.

Just to be sure I understand what you want to do: You want to shadow the clouds that are hidden (blocked by geometries) from the point of view of the sun? If yes, what I don’t understand is that you take the value from the shadow map (return texture2D(sunShadowMap, uv).x;) as the light attenuation…

if we can figure this out then I will optimize the whole system to run at 60 fps, and then introduce simulation shaders to make it so we can have some real volumetric smoke and other things. I think I know what you are saying, I was mistaken about what the shadowmaps data had on it! I did not real…

wow I was doing a bunch wrong now that I am looking at it with fresh eyes.

This is the closest I have gotten now. https://playground.babylonjs.com/#21FNQE#15 And that is still off… I have tried using the lights matrix, the shadowGenerators Matrix hmmm there is gonna be an answer and once its figured out this is gonna look cool… I think it might be I am sampling the wro…

Struggling to Convert Global Position to Shadow Map position

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aFalcon November 12, 2019, 9:51pm 21

got it. Thanks for explaining @Evgeni_Popov and @Pryme8 .

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Struggling to Convert Global Position to Shadow Map position

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