Masterthatsnotmaster (#421)

* glsl complains that lerp is deprecated, and tells us to use mix instead (equivalent)

* some nice and useful brushes for pretty painting

* one more brush

Author: Beherith

scen_edit/gfx/shaders.lua

@@ -22,12 +22,12 @@ function getPenShader(mode)
             ["Darken"] = [[mix(min(mapColor,color),mapColor,color.a);]],
             ["Difference"] = [[mix(abs(color-mapColor),mapColor,color.a);]],
             ["Exclusion"] = [[mix(color+mapColor-(2.0*color*mapColor),mapColor,color.a);]],
-            ["HardLight"] = [[mix(lerp(2.0 * mapColor * color,1.0 - 2.0*(1.0-color)*(1.0-mapColor),min(1.0,max(0.0,10.0*(dot(vec4(0.25,0.65,0.1,0.0),color)- 0.45)))),mapColor,color.a);]],
+            ["HardLight"] = [[mix(mix(2.0 * mapColor * color,1.0 - 2.0*(1.0-color)*(1.0-mapColor),min(1.0,max(0.0,10.0*(dot(vec4(0.25,0.65,0.1,0.0),color)- 0.45)))),mapColor,color.a);]],
             ["InverseDifference"] = [[mix(1.0-abs(mapColor-color),mapColor,color.a);]],
             ["Lighten"] = [[mix(max(color,mapColor),mapColor,color.a);]],
             ["Luminance"] = [[mix(dot(color,vec4(0.25,0.65,0.1,0.0))*normalize(mapColor),mapColor,color.a);]],
             ["Multiply"] = [[mix(color*mapColor,mapColor,color.a);]],
-            ["Overlay"] = [[mix(lerp(2.0 * mapColor * color,1.0 - 2.0*(1.0-color)*(1.0-mapColor),min(1.0,max(0.0,10.0*(dot(vec4(0.25,0.65,0.1,0.0),mapColor)- 0.45)))),mapColor,color.a);]],
+            ["Overlay"] = [[mix(mix(2.0 * mapColor * color,1.0 - 2.0*(1.0-color)*(1.0-mapColor),min(1.0,max(0.0,10.0*(dot(vec4(0.25,0.65,0.1,0.0),mapColor)- 0.45)))),mapColor,color.a);]],
             ["Premultiplied"] = [[vec4(color.rgb + (1.0-color.a)*mapColor.rgb, (color.a+mapColor.a));]],
             ["Screen"] = [[mix(1.0-(1.0-mapColor)*(1.0-color),mapColor,color.a);]],
             ["SoftLight"] = [[mix(2.0*mapColor*color+mapColor*mapColor-2.0*mapColor*mapColor*color,mapColor,color.a);]],