Drake has wrong body skin color

[AmProsius]

Describe the bug
Drake's body skin color does not match his head.

Expected behavior
Drake's body skin color now matches his head.

Additional context
Instance Grd_260_Drake.

[szapp]

Similar to #124. No, see below.

[szapp]

gothic-1-community-patch/scriptbase/_work/Data/Scripts/Content/Story/NPC/GRD_260_Drake.d

Lines 20 to 28 in 56e45df

	//-------- visuals --------
	// animations
	Mdl_SetVisual (self,"HUMANS.MDS");
	Mdl_ApplyOverlayMds (self,"Humans_Militia.mds");
	// body mesh ,bdytex,skin,head mesh ,1headtex,teethtex,ruestung
	Mdl_SetVisualBody (self,"hum_body_Naked0", 0, 3,"Hum_Head_Fighter",110 , 1, GRD_ARMOR_M);
	B_Scale (self);
	Mdl_SetModelFatness(self,0);

The forth argument passed to the function Mdl_SetVisualBody has to be adjusted. I don't know by heart to what number. To replace it the function call and its arguments need to be identified within the instance function.

[AmProsius]

The forth argument passed to the function Mdl_SetVisualBody has to be adjusted.

We want to change the body texture, so it's actually the second argument.

[szapp]

No, the second argument is the body mesh.

Gothic refers to a 3D model as mesh and a surface color/pattern/image as texture.

Parameters of Mdl_SetVisualBody:

1. NPC instance
2. Body mesh (= 3D model of the body, for humans either "hum_body_Naked0" or "Bab_body_Naked0")
3. Body texture (= Image placed on the mesh)
4. Body skin color (= Texture variation)
5. Head mesh
6. Head texture
7. Teeth texture
8. Armor

Here, Drake's body skin has a darker shade than his head does. (I will update the title and description of this issue.)

changed to

Provided Fix

gothic-1-community-patch/scriptbase/_work/Data/Scripts/Content/Story/NPC/GRD_260_Drake.d

Lines 20 to 28 in 56e45df

	//-------- visuals --------
	// animations
	Mdl_SetVisual (self,"HUMANS.MDS");
	Mdl_ApplyOverlayMds (self,"Humans_Militia.mds");
	// body mesh ,bdytex,skin,head mesh ,1headtex,teethtex,ruestung
	Mdl_SetVisualBody (self,"hum_body_Naked0", 0, 3,"Hum_Head_Fighter",110 , 1, GRD_ARMOR_M);
	B_Scale (self);
	Mdl_SetModelFatness(self,0);

changed to

    //-------- visuals --------
    //          animations
    Mdl_SetVisual       (self,"HUMANS.MDS");
    Mdl_ApplyOverlayMds (self,"Humans_Militia.mds");
    //          body mesh     ,bdytex,skin,head mesh     ,1headtex,teethtex,ruestung
    Mdl_SetVisualBody (self,"hum_body_Naked0", 0, 1,"Hum_Head_Fighter",110 ,  1, GRD_ARMOR_M);

    B_Scale (self);
        Mdl_SetModelFatness(self,0);

Since the NPC appearance is not loaded from the savegame but set by the NPC's instance function, this fix does not have to be reverted. Instead, the instance function will be modified to replace the forth argument to the function call. The way I would implement it is by finding the last call to Mdl_SetVisualBody in the function (zPAR_TOK_CALLEXTERN MEM_GetFuncID(Mdl_SetVisualBody)). From the address of the call, go 25 bytes back (5 bytes for each of the last 5 pushed arguments). Then, check against zPAR_TOK_PUSHINT 3 or zPAR_TOK_PUSHVAR some variable with content 3. If so, replace it by zPAR_TOK_PUSHINT 1 and mark the fix as applied.

---

This is a draft for the implementation:

/*
 * #129 Drake has wrong body skin color
 */
func int G1CP_149_DrakeBodySkin() {
    var int applied; applied = FALSE;

    // Get necessary symbol indices
    var int symbId; symbId = G1CP_GetNpcInstID("Grd_260_Drake");
    if (symbId == -1) {
        return FALSE;
    };

    // Find call to "Mdl_SetVisualBody"
    const int bytes[2] = {zPAR_TOK_CALLEXTERNAL<<24, -1};
    bytes[1] = MEM_GetFuncID(Mdl_SetVisualBody);
    var int matches; matches = G1CP_FindInFunc(symbId, _@(bytes)+3, 5);

    // Check for last occurrence
    if (MEM_ArraySize(matches) > 0) {
        var int pos; pos = MEM_ArrayLast(matches);

        // Get the necessary pushed arguments
        var int arg6; arg6 = MEM_ReadInt(pos-14);
        var int arg4; arg4 = MEM_ReadInt(pos-24);
        if (MEM_ReadByte(pos-15) == zPAR_TOK_PUSHVAR) {
            arg6 = G1CP_GetIntI(arg6, 0, arg6);
        };
        if (MEM_ReadByte(pos-25) == zPAR_TOK_PUSHVAR) {
            arg4 = G1CP_GetIntI(arg4, 0, arg4);
        };

        // Confirm head texture and body skin color
        if (arg6 == 110) && (arg4 == 3) {
            // Write the correct byte code for the forth argument
            MEMINT_OverrideFunc_Ptr = pos-25;
            MEMINT_OFTokPar(zPAR_TOK_PUSHINT, 1);
            applied = TRUE;
        };
    };

    // Free the array
    MEM_ArrayFree(matches);

    return applied;
};

As for a test, create a manual one, that teleports the player to the waypoint in front of Drake. There is example code on how to auto-trigger changing the world. See the test regarding the Free Mine.

[szapp]

@AmProsius I noted a slight improvement. Otherwise all good.

[szapp]

Thanks to more recent changes we can replace these three lines by just one:

// Find call to "Mdl_SetVisualBody"
var int matches; matches = G1CP_FindCall(symbId, 0, MEM_GetFuncID(Mdl_SetVisualBody));

It may be even possible to omit the call to MEM_GetFuncID - that should be tested.