Added new blend source options that allow a blend mask to be used together with depth based blending.

Scripts/ExpectedScreenshots/StandardMultilayerPBR/003_debug_blendweights.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f31975d4e3a3f0d2cd56885d4862ffa4da361a515992b8ca6d5aa8d3b8662ffc
+size 247964

Scripts/ExpectedScreenshots/StandardMultilayerPBR/004_usevertexcolors_modelhasnovertexcolors.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:e6d5b550ee48e9ad9142e8420e808f2b190f738001c9c213acbc85bfe99dd0dd
-size 952801
+oid sha256:f44e4255da1ff534cf43f4076864e38535016ad55955eccbf203a49c18e93157
+size 1138758

Scripts/ExpectedScreenshots/StandardMultilayerPBR/005_usedisplacement.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:54905abbe18a04626b677460e02510f4a047b327346c7e0aa4798c86f60b380f
+size 1961020

Scripts/ExpectedScreenshots/StandardMultilayerPBR/005_usedisplacement_with_blendmasktexture.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:effffd169392698b72add5c4d7960dc08c35130e4364ecb39fa86563981a1077
+size 1561600

Scripts/ExpectedScreenshots/StandardMultilayerPBR/005_usedisplacement_with_blendmaskvertexcolors.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:53610e7bcfe7b37c7a59cf9bada458b3bbc479bca6026c34b95ba648cd9ecf14
+size 1690263

Scripts/MaterialScreenshotTests.bv.lua

@@ -166,6 +166,9 @@ GenerateMaterialScreenshot('Level G', '003_Debug_Displacement', {model=g_cubeMod
 GenerateMaterialScreenshot('Level G', '003_Debug_BlendWeights', {model=g_cubeModel})
 GenerateMaterialScreenshot('Level I', '004_UseVertexColors', {model=g_modelWithLayerMask, cameraHeading=0.0, cameraPitch=45.0, cameraDistance=30.0})
 GenerateMaterialScreenshot('Level I', '004_UseVertexColors', {model=g_modelWithoutLayerMask, cameraHeading=145.0, cameraPitch=7.0, cameraZ=-0.1, cameraDistance=3.0, screenshotFilename="004_UseVertexColors_modelHasNoVertexColors"})
+GenerateMaterialScreenshot('Level I', '005_UseDisplacement',                            {lighting="Blouberg Sunrise 1 (Alt)", model=g_modelWithLayerMask, cameraHeading=-35.0, cameraPitch=33.0, cameraDistance=9.0, cameraZ=0.9})
+GenerateMaterialScreenshot('Level I', '005_UseDisplacement_With_BlendMaskTexture',      {lighting="Blouberg Sunrise 1 (Alt)", model=g_modelWithLayerMask, cameraHeading=180.0, cameraPitch=45.0, cameraDistance=20.0, cameraZ=-0.5})
+GenerateMaterialScreenshot('Level I', '005_UseDisplacement_With_BlendMaskVertexColors', {lighting="Blouberg Sunrise 1 (Alt)", model=g_modelWithLayerMask, cameraHeading=0.0, cameraPitch=80.0, cameraDistance=27.0})
 
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 -- Skin Materials...