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BGL Opcodes

scruffyduck

scruffyduck

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I have been working my way through the opCodes in the SDKs including the BGLFP SDK in preparation to try and render an mdl object in DirectX.

I have started to decompile the BGL section of an mdl file and come across a code which does not seem to be listed. Based on what MDL Tweaker II is telling me about the same section, it is called SET_MATRIX_INDIRECT and seems to have the opCode &HC4. It looks like it is 4 bytes long. Is there another document with further codes which contains this and other newer bgl opCodes??
 
Hi Lars and thanks. I have been using the mdl file definition document to get me started on de-compiling. AS you say it refers to some of the opCodes but not all. I am also using the BGLFP SDK and the FS2000 BGLC SDK for information. It seems that the op codes in the &HC0... range come later as they are higher than the FP codes.
 
Have you took a look at BGLC_9_Source.htm, which is included in BGLC_9 archive? There you can find some info on BGL opcodes and data formats used by compiler. Let's do some research on mentioned opcode &HC4 for example.

Search for '0C4h' string. It's found in following line:
Code: 
BGLOP_SET_MATRIX_INDIRECT           EQU         0000000c4h
Now we know the name of macro. Next we look for 'SET_MATRIX_INDIRECT' string and get following piece of code:
Code: 
BGL_SET_MATRIX_INDIRECT macro matrix_index
        local start
start  label word
        dw    BGLOP_SET_MATRIX_INDIRECT     ; opcode = BGLOP_SET_MATRIX_INDIRECT = 0C4h
        dw      matrix_index                    ; index into the object matrix list to use
      endm
From that we can conclude that the macro is 2 words (4 bytes) long. The first word contains opcode itself and the second word contains matrix index.

Is that what you're looking for?
 
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Thanks - that is what I am looking for - I did not think to look at BGLC 9 :o
 
Well that has set me off into another muddy pool of scenery design fun :) :) It is a very long time since I had anything to do with Assembler. Every time I think I am getting to the bottom of this scenery stuff something else turns up - so much still to learn!
 
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