RECV MODDING BASICS - TEXTURES - Ch.1 (By CBNJ)

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PREVIOUS CHAPTER: RECV MODDING BASICS - TEXTURES - INTRODUCTION
https://www.dreamcast-talk.com/forum/vi ... 48#p181148
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Since we already opened our pl00.ald file in the hex viewer and we already located ourselfs on the texture caller bits, lets give that claire shield a new look by remap the texture it uses, this is the texture list for claire body specified in her body texture table set 1 at the start of her model.
cl01
cl02
cl03
cl1_01
cl1_02

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This is the same list in the same order but now visually

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Now you can clearly see texture 1 is the claire upper body as i mentioned before, next comes her head, then the face, later her pants and finally the shoes for a total of 5 textures.

Since i want claire shield to be unique lets remap claire face texture to wrap it, changing that texture 1 for texture 3 in the texture caller bits, to tell the game we want texture 3 to be mapped onto claire shield we will change the double 00 to be 02, in case we would like to use other texture, the limit will be 04 (claire shoes), since her texture table only have 5 textures.

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Save the changes, rebuild your system.afs using our modified file and rebuild your GDI, then when you enter to game you will be welcome whit this!

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Her shield now uses claire face texture and not only that... her shield is alive too!
You can see how the shield blinks!!!.

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Some models even being basic can use múltiple textures, in this cases we can modify all of them to call a diferent texture but the texture caller bytes will be sparced across the whole triangle strip table and we should locate them manually, i will use claire body as an example of this.
Open your pl00.ald file, do a string search for MDL and next locate the start of the triangle strip table by eye, then locate the caller texture byte wich is located after the twin bytes following to the 13250400 byte, you should be at offset 0CC4 if you did it correctly.

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You will quickly notice below this point and not very far away another 13250400 and another pair of twin bytes, following the hierarchy we know until now there should be another texture caller byte rigth after this twin bytes, wich as you see is true, this is located at offset 0DA0.

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You would be thinking , great i can do a search for 13250400 or for 7F7F7FFF to locate this byte easy, but nope, you cannot, and the reason i already gave it to you, the twin bytes values can and will change and the 13250400 only appears once per model, i wont explain the reason why there are two In this model rigth now, in the advanced guide you will discover why this is happening here, the important area to focus is the texture byte caller, this texture byte will be the same for every one we can find in this model because is a single mesh and thus recieve the same material/poligon properties for the whole model (if this model were constructed by many pieces each body piece would have diferent material/poligon properties byte values for each piece), this eases our work since this value will remain constant whit the only variant of the texture number wich is being called.
Using this at our favor we should make a hex value search for 0834, and then by eye check if the byte where we landded follows the texture byte estructure, showing the value in the third pair of bits into a aceptable range of thexture number (from 00 to 04 in this case since claire body only uses 5 textures) and finishing whit the value 40 on the 4th pair of bits, if any of this two rules break, it means that byte is not a texture caller and we can proceed to do the next 0834 value search.

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Doing the search in such way we will quickly find the next texture caller bytes for claire body.

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Changing the texture caller bits in those bytes we can make each part of claire body uses a diferent texture to be wrapped whit it.
END OF CHAPTER.

NEXT GUIDE: RECV MODDING BASICS - TEXTURES - Ch.2
https://www.dreamcast-talk.com/forum/vi ... 54#p181154