Tutorial - Rendering A Shadow Map

[Motoboss]

Blur in PS is your friend....

[RFX_corentin_12]

Hi, I'm doing well as it should, but when I get to step 6, I click on the run button but its brand me this:



I do how?

thank you;)

[yz171kx12]

Hi, I'm doing well as it should, but when I get to step 6, I click on the run button but its brand me this:



I do how?

thank you;)

I normally just delete the startgate shadows. You can just delete the super thin objects from track.pov if it says they're missing a texture because it probably won't render shadows for them anyways.

[barrington314]

I noticed that some people turn the pgm into a png and place it in as one big decal. Is there a benefit to that, maybe with load times or frame rate? Im sure it wouldnt be much but some tracks are coming to the point that any extra resource help is nice to use.

[MotoX745]

idk might make it easier to line up shadows i'm having trouble with the PGM's on lining up shadows

[jlv]

It won't be lit correctly that way. It'll just be darker instead of being lit by ambient only. It won't be any faster.

[barrington314]

Is there a trick to doing shadows for supercross, since it needs to be cast from multiple angles? Render it 6 - 8 separate times?

[jlv]

Yes, it's six renders blended together. I use this shell script to automate it.

Code: Select all

#!/bin/bash

sed 's/image_map[^}]*}/Black/g' <track.pov >trackstripped.pov

scale=$(awk '{print $2}' <terrain.hf)

n=0
grep flare_point <lighting | sed 's/[][]//g' |
while read flare_point x y z rest
do
        nice -19 /opt/povray/bin/povray -D -w2050 -h2050 \
         Declare=SCALE=$scale \
         Declare=LIGHTX=$x \
         Declare=LIGHTY=$y \
         Declare=LIGHTZ=$z shadows.pov || break
        mv shadows.png shadow$n.png
        n=$((n+1)) # this is in a subshell and doesn't update the outer scope
done

n=$(ls shadow[0-9].png | wc -l)

scale=$(bc <<<"scale=5;1/$n")
pngtopnm <shadow0.png | pamfunc -multiplier $scale >s.ppm
for ((i=1;i<n;i++))
do
        echo combine $i
        pngtopnm <shadow$i.png | pamfunc -multiplier $scale >t.ppm
        pamarith -add s.ppm t.ppm >u.ppm
        mv u.ppm s.ppm
done

ppmtopgm s.ppm | pamscale -xysize 1025 1025 >shadows.pgm

[twistmoto]

Yes, it's six renders blended together. I use this shell script to automate it.

Code: Select all

#!/bin/bash

sed 's/image_map[^}]*}/Black/g' <track.pov >trackstripped.pov

scale=$(awk '{print $2}' <terrain.hf)

n=0
grep flare_point <lighting | sed 's/[][]//g' |
while read flare_point x y z rest
do
        nice -19 /opt/povray/bin/povray -D -w2050 -h2050 \
         Declare=SCALE=$scale \
         Declare=LIGHTX=$x \
         Declare=LIGHTY=$y \
         Declare=LIGHTZ=$z shadows.pov || break
        mv shadows.png shadow$n.png
        n=$((n+1)) # this is in a subshell and doesn't update the outer scope
done

n=$(ls shadow[0-9].png | wc -l)

scale=$(bc <<<"scale=5;1/$n")
pngtopnm <shadow0.png | pamfunc -multiplier $scale >s.ppm
for ((i=1;i<n;i++))
do
        echo combine $i
        pngtopnm <shadow$i.png | pamfunc -multiplier $scale >t.ppm
        pamarith -add s.ppm t.ppm >u.ppm
        mv u.ppm s.ppm
done

ppmtopgm s.ppm | pamscale -xysize 1025 1025 >shadows.pgm

I was working on a SX night track recently (I had ten lights... ) and could not for the life of me remember how to correctly code a batch file to accomplish this, and an hour in Linux reminded me of everything I have forgot about it so I made some adjustments to the shadows.pov.
I set it up to use spotlights and render all of the lights at once. Maybe this will help somebody out when they are trying to setup their shadow map. If you get stuck there are instructions in the file, and you will need to follow DJs basic instructions.
http://www.mediafire.com/download/gvrpb ... shadows.7z

[Maczust63]

I got this error and dont know where to begin im not good with this so be kinda and any help would be great

[twistmoto]

You have to remove the startgate.ppm lines from your track pov file, before you run the shadows.pov. Also make sure there are no billboard lines in your tracks pov cause that will be the next error.

[barrington314]

You have to remove the startgate.ppm lines from your track pov file, before you run the shadows.pov. Also make sure there are no billboard lines in your tracks pov cause that will be the next error.

Or just make a ppm image in photoshop thats a solid color and save it as startgate.ppm and put that in the render folder.

[Maczust63]

okay ill try that thanks

[jlv]

sed 's/image_map[^}]*}/Black/g' <track.pov >trackstripped.pov

Unix makes life easier!

If you're on Windows you want to replace all image_map sections with "Black". So if you have this:

texture { uv_mapping pigment { image_map { png "sx2013/scorehousemotooption.png"} } scale <1,-1,1> }

You want to edit it to this:

texture { uv_mapping pigment { Black } scale <1,-1,1> }

[Maczust63]

thanks ill try this stuff when im less frustrated with new programs haha