find-cbaseentity-emitsoundfilter

name	find-CBaseEntity_EmitSoundFilter
description	Find and identify the CBaseEntity_EmitSoundFilter function in CS2 binary using IDA Pro MCP. Use this skill when reverse engineering CS2 server.dll or libserver.so to locate the EmitSoundFilter function by searching for the "CT_Water.StepLeft" string reference and analyzing cross-references.
disable-model-invocation	true

Find CBaseEntity_EmitSoundFilter

Locate CBaseEntity_EmitSoundFilter in CS2 server.dll or libserver.so using IDA Pro MCP tools.

Method

1. Search for the sound string:

   mcp__ida-pro-mcp__find_regex pattern="CT_Water\.StepLeft"
   

2. Get cross-references to the string:

   mcp__ida-pro-mcp__xrefs_to addrs="<string_addr>"
   

3. Decompile the referencing function:

   mcp__ida-pro-mcp__decompile addr="<function_addr>"
   

4. Identify CBaseEntity_EmitSoundFilter from the decompiled code. Look for a function call pattern like:

   v38[0] = "CT_Water.StepLeft";
   ...
   v30 = sub_XXXXXX(qword_YYYYYY, v29, &v32);
   

   The target function is called with a global variable, an entity pointer, and a sound parameter structure.

5. Rename the function:

   mcp__ida-pro-mcp__rename batch={"func": {"addr": "<function_addr>", "name": "CBaseEntity_EmitSoundFilter"}}
   

6. Generate and validate unique signature:

   ALWAYS Use SKILL /generate-signature-for-function to generate a robust and unique signature for the function.

7. Write IDA analysis output as YAML beside the binary:

   ALWAYS Use SKILL /write-func-as-yaml to write the analysis results.

   Required parameters:

   • func_name: CBaseEntity_EmitSoundFilter
   • func_addr: The function address from step 4
   • func_sig: The validated signature from step 6

Signature Pattern

The function is called in water footstep sound handling code with the string "CT_Water.StepLeft":

v38[0] = "CT_Water.StepLeft";
v39 = v33;
v40 = v26;
v38[1] = v32;
v42 = v42 & 0xE7 | 0x10;
v30 = CBaseEntity_EmitSoundFilter(qword_XXXXXX, v29, &v32);

Function Characteristics

• Parameters: (filter_global, entity, sound_params) where filter_global is a global sound filter pointer, entity is the entity emitting the sound, sound_params contains sound parameters
• Purpose: Emits a filtered sound from an entity
• Called by: Water footstep sound handler and other sound emission code

Output YAML Format

The output YAML filename depends on the platform:

• server.dll → CBaseEntity_EmitSoundFilter.windows.yaml
• libserver.so → CBaseEntity_EmitSoundFilter.linux.yaml