define TransparentMirrorReflection()

  material
     if (viewerRenderType = $kRenderTypeShadow)
        create StandardShaderShadow()
     else
        if (viewerRenderType = $kRenderTypeThumbnail)
           create TransparentBlankMirrorMaterial($kRenderTypeThumbnail)
        else            
           if (not $mirrorReflectionsEnabled)
              set currentType (viewerRenderType)
              create TransparentBlankMirrorMaterial($currentType)
           else
              create TransparentMirrorReflectionMaterial()
           endif            
        endif         
     endif
  end

enddef

define TransparentBlankMirrorMaterial(renderType)

     shader
        validateRenderShaderContext -viewerRenderType  &renderType
        
        pass             
           shaderProgram -target vertexProgram -method assemble
              bindConstants 0 -bindingID geomToClip -constantCount 4
              shaderSource
                 vs_1_1
                 dcl_position v0
                 m4x4 oPos, v0, c0
              endShaderSource
           end
           
           colorScalar (0,0,0) 0.5
           stage
              textureBlend select(colorScalar) select(colorScalar)
           end            
        end
     end      

enddef

define TransparentMirrorReflectionMaterial()

     shader -layer -9998   # this material must render first
        validateRenderShaderContext -viewerRenderType $kRenderTypeMirror  # reflection render

        pass -renderEachFrame
           renderTarget $reflectionRenderTarget -setViewport viewportFromParentRenderContext

           depthTest true -enableDepthWrite true

           applyStencilStateForOverlappingReflections

           alphaBlend srcFactor(zero) add dstFactor(one)

           cullmode none

           shaderProgram -target vertexProgram -method assemble            
              bindConstants 0 -bindingID geomToClipFromParentView -constantCount 4
              shaderSource
                 vs_1_1
                 dcl_position v0
                 def c5, 1,0,0,1
                 m4x4 r0,   v0,  c0
                 mov oPos.x,  -r0
                 mov oPos.yzw, r0                  
              endShaderSource
           end
        end
     end

     shader -layer 6
        validateRenderShaderContext -viewerRenderType $kRenderTypeNormal
        pass -modifiedEachFrameHint
           shaderProgram -target vertexProgram -method assemble            
              bindConstants 0 -bindingID geomToClip -constantCount 4
              bindConstants 4 -bindingID clipToViewTarget -constantCount 4
              shaderSource
                 vs_1_1
                 dcl_position v0
                 def c8,    -0.5, -0.5, 1, 1
                 def c9,     0.5,  0.5, 0, 0 
                 def c10,    0.25, 0.25, 0, 0
                 m4x4 r0,   v0,  c0
                 mov oPos, r0
                 mul r2, c9, r0.w
                 mad r4, r0, c8, r2
                 rcp r3.x, c4.x                                   
                 rcp r3.y, c5.y
                 mov r3.zw, c9.zw
                 mul r3, r3, c10
                 mad r6, r0, r3, r4
                 mov oT0, r6.xyww
              endShaderSource               
           end

           alphaBlend srcFactor(srcAlpha) add dstFactor(invSrcAlpha)
           depthTest true -enableDepthWrite false
           colorScalar (0,0,0) 0.25

           stage
              textureTransformType vector3 homogeneous
              textureAddressing clamp clamp
              texture $reflectionRenderTarget
              textureBlend select(texture) select(colorScalar)
           end
                      
        end
     end
     
     shader -layer 6      
        validateRenderShaderContext -viewerRenderType $kRenderTypeNormal
        pass -modifiedEachFrameHint
           shaderProgram -target vertexProgram -method assemble            
              bindConstants 0 -bindingID geomToClip -constantCount 4
              bindConstants 4 -bindingID clipToViewTarget -constantCount 4
              shaderSource
                 vs_1_1
                 dcl_position v0
                 def c8,    -0.5, -0.5, 1, 1
                 def c9,     0.5,  0.5, 0, 0
                 def c10,    0.25, 0.25, 0, 0
                 m4x4 r0,   v0,  c0
                 mov oPos, r0
                 mul r2, c9, r0.w
                 mad r4, r0, c8, r2
                 rcp r3.x, c4.x                                   
                 rcp r3.y, c5.y
                 mov r3.zw, c9.zw
                 mul r3, r3, c10
                 mad r1, r0, r3, r4
                 rcp r1.w, r1.w
                 mul oT0.xy, r1.w, r1.xy
              endShaderSource               
           end

           alphaBlend srcFactor(srcAlpha) add dstFactor(invSrcAlpha)
           depthTest true -enableDepthWrite false
           colorScalar (0,0,0) 0.25

           stage
              textureAddressing clamp clamp
              texture $reflectionRenderTarget
              textureBlend select(texture) select(colorScalar)
           end
           
        end
     end

enddef

1. ---------------------------------------------------------------------------------------------------------------#

materialDefinition transparent_mirror_reflection

  setDefinition TransparentMirrorReflection

end