Edge Clamp Texture Addressing for T3D Materials

By default, all standard T3D materials use GFXAddressWrap as their texture coordinate address mode. This is suitable for most uses, but if you try and take advantage of the rotation animation setting for a material you will get artifacts at the edges of the material that you may not like.

This resource allows you to force a material texture stage to use GFXAddressClamp for the address mode, which will remove these artifacts.

If the above explanation makes no sense, take a look at this video which shows a rotating texture using T3D's normal settings, then with the GFXAddressClamp enabled.


Engine Modifications
Luckily, there are only a few small changes to be made to the engine.

file: engine\materials\materialDefinition.h
after:

bool mUseAnisotropic[MAX_STAGES];

add:

// GUY - texture address clamping >>  
   bool mAddressModeClamp[MAX_STAGES];  
   // GUY - texture address clamping <<

file: engine\materials\materialDefinition.cpp
function: Material::Material()
after:

mSeqSegSize[i] = 0.0f;

add:

// GUY - texture address clamping >>  
   mAddressModeClamp[i] = false;  
   // GUY - texture address clamping <<

file: engine\materials\materialDefinition.cpp
function: Material::initPersistFields()
after:

addProtectedField("colorMultiply",  TypeColorF,          Offset(mDiffuse, Material),  
         defaultProtectedSetNotEmptyFn, emptyStringProtectedGetFn, MAX_STAGES,  
         "For backwards compatibility.\n@see diffuseColor\n");

add:

// GUY - texture address clamping >>  
   addField("edgeClamp",            TypeBool,            Offset(mAddressModeClamp, Material), MAX_STAGES,  
         "Forces the materials texture coordinates to clamp instead of wrap." );  
   // GUY - texture address clamping <<

file: engine\materials\processedMaterial.cpp
function: ProcessedMaterial::_initPassStateBlock( RenderPassData *rpd, GFXStateBlockDesc & result )
change:

default:  
{  
   result.samplers[i].textureColorOp = GFXTOPModulate;  
   result.samplers[i].addressModeU = GFXAddressWrap;  
   result.samplers[i].addressModeV = GFXAddressWrap;

to:

default:  
{  
   result.samplers[i].textureColorOp = GFXTOPModulate;  
  
   // GUY - texture address clamping >>  
   //result.samplers[i].addressModeU = GFXAddressWrap;  
   //result.samplers[i].addressModeV = GFXAddressWrap;  
   result.samplers[i].addressModeU = mMaterial->mAddressModeClamp[i] ? GFXAddressClamp : GFXAddressWrap;  
   result.samplers[i].addressModeV = result.samplers[i].addressModeU;  
   // GUY - texture address clamping <<

Script changes to the material editor
To add the check box for enabling edge clamp for a texture stage, we need to make a couple of small modifications to the material editor scripts.

file: game\tools\materialEditor\gui\guiMaterialPropertiesWindow.ed.gui
around line 657,
after:

new GuiBitmapButtonCtrl() {  
                           canSaveDynamicFields = "0";  
                           Enabled = "1";  
                           isContainer = "0";  
                           Profile = "GuiDefaultProfile";  
                           HorizSizing = "left";  
                           VertSizing = "bottom";  
                           position = "177 34";  
                           Extent = "16 16";  
                           MinExtent = "8 2";  
                           canSave = "1";  
                           Visible = "1";  
                           Command = "MaterialEditorGui.updateSpecMap(0);";  
                           hovertime = "1000";  
                           groupNum = "-1";  
                           buttonType = "PushButton";  
                           useMouseEvents = "0";  
                           bitmap = "tools/gui/images/delete";  
                        };  
                     };

add:

new GuiBitmapCtrl(){  
                        position="6 0";  
                        extent ="175 2";  
                        HorizSizing = "width";  
                        bitmap ="core/art/gui/images/separator-v";   
                     };  
                     new GuiCheckBoxCtrl() {  
                        text = "Edge Clamp";  
                        groupNum = "-1";  
                        buttonType = "ToggleButton";  
                        useMouseEvents = "0";  
                        position = "5 5";  
                        extent = "74 16";  
                        minExtent = "8 2";  
                        horizSizing = "right";  
                        vertSizing = "bottom";  
                        profile = "GuiCheckBoxProfile";  
                        visible = "1";  
                        active = "1";  
                        Command = "MaterialEditorGui.updateEdgeClamp($ThisControl.getValue());";  
                        tooltipProfile = "GuiDefaultProfile";  
                        tooltip = "Sets texture address mode to clamp.";  
                        hovertime = "1000";  
                        isContainer = "0";  
                        internalName = "edgeClampCheckbox";  
                     };

file: game\tools\materialEditor\scripts\materialEditor.ed.cs
add this function:

function MaterialEditorGui::updateEdgeClamp(%this, %clamp)  
{  
   %layer = MaterialEditorGui.currentLayer;  
   MaterialEditorGui.updateActiveMaterial("edgeClamp[" @ %layer @ "]", %clamp);  
}

file: game\tools\materialEditor\scripts\materialEditor.ed.cs
in function: MaterialEditorGui::guiSync( %this, %material )

after:

MaterialEditorPropertiesWindow-->minnaertTextEdit.setText((%material).minnaertConstant[%layer]);

add:

MaterialEditorPropertiesWindow-->edgeClampCheckbox.setValue((%material).edgeClamp[%layer]);

enjoy.