Difference between revisions of "ShaderMirror"

Revision as of 04:23, 19 March 2007

EP0-TS2
0xCD7FE87A
0x1C0532FA
0xBAC036BC
0xFF123570
# reflection

version 4

# Shaders for mirror reflections.

# Note: These materials assume that the reflection camera uses the same handed coordinate system as 
# the main camera, with the x axis flipped. Therefore, when marking out the area in the stencil buffer 
# to be filled in the with the reflection view, the x clip coordinate of the mirror vertices is
# negated.
#
# The layer numbers for the mirror pre- and post-reflection render materials (+/-99998) are referenced
# from C++ code for the censor-in-mirror render.

set reflectionRenderTarget "ScreenReflection"

#beginshader SimpleMirrorReflection
#description Assign this material to the mirror quad to make it reflective.
#description The mirror quad needs to be centered over the origin in its local space,
#description facing positive Y. You can use a transform bone to orient the mirror
#description however you need.

set mvAspect 1


define SimpleMirrorReflection()
   material
      if (viewerRenderType = $kRenderTypeShadow)
         create StandardShaderShadow()
      else
         if (viewerRenderType = $kRenderTypeThumbnail)
            create BlankMirrorMaterial($kRenderTypeThumbnail)
         else            
            if (not $mirrorReflectionsEnabled)
               set currentType (viewerRenderType)
               create BlankMirrorMaterial($currentType)
            else
               create MirrorReflectionMaterial()
            endif            
         endif         
      endif
   end
enddef
#endshader

define BlankMirrorMaterial(renderType)
      # mirror shader for thumbnails. Output a single flat color.
      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 (0.5,0.6,0.75, 1)
            stage
               textureBlend select(colorScalar) select(colorScalar)
            end            
         end
      end      
enddef

# shader to prep stencil buffer on the rendertarget for the mirror reflection view.
# When objects are rendered from the viewpoint of the reflection camera after this shader runs, they will
# render only to the area of the rendertarget marked out in the stencil buffer by this shader.   
define MirrorReflectionMaterial()
      
      # write depth into the depth buffer as seen from the main camera. Write stencil = 1
      # if this is the mirror we are rendering the reflection for, and 0 otherwise.
      shader -layer -9998   # this material must render first
         validateRenderShaderContext -viewerRenderType $kRenderTypeMirror  # reflection render
         
         # write stencil in area occupied by mirror
         pass -renderEachFrame
            renderTarget $reflectionRenderTarget -setViewport viewportFromParentRenderContext

            # test and write depth (as seen from the main camera)
            depthTest true -enableDepthWrite true

            # This material script command means the following:
            #
            # if (renderableIsTargetBounded)
            #     set stencil test to write 1 when depth test passes
            # else
            #     set stencil test to write 0 when depth test passes
            #
            applyStencilStateForOverlappingReflections
              
            # do not write color
            #colorWriteEnable -red false -green false -blue false -alpha false
            alphaBlend srcFactor(zero) add dstFactor(one)
            
            # since we are negating clip space x below we need to prevent this quad from being culled
            cullmode none
            
            # vertex program
            shaderProgram -target vertexProgram -method assemble            
               bindConstants 0 -bindingID geomToClipFromParentView -constantCount 4 # set the matrices from the parent (i.e. the main view) so that the stencil is written to the right place
      
               shaderSource
                  vs_1_1
                  dcl_position v0
                  
                  ; color output for debugging
                  def c5, 1,0,0,1
                 
                  ; project vertex to clip coords
                  m4x4 r0,   v0,  c0
                  
                  ; flip the x coordinate so the stencil is marked in the right place
                  mov oPos.x,  -r0
                  mov oPos.yzw, r0                  
               endShaderSource
            end
         end # pass
      end # shader

      # render of the mirror from the main camera. This samples from the reflection render target texture.
      shader -layer 6  # this must be after all opaque objects (especially Sims), but before transparent objects and the censor compositing pass
         validateRenderShaderContext -viewerRenderType $kRenderTypeNormal
         
         pass -modifiedEachFrameHint  # we want the mirrors to be rendered every frame even in dirty rect mode

            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
                  
                  # project vertex to clip coords
                  m4x4 r0,   v0,  c0
                  mov oPos, r0
                  
                  # multiply 0.5 * w so homogenous divide will make it 0.5 again
                  mul r2, c9, r0.w
                  
                  # scale projected xy by .5 and re-center so it's in 0-w range
                  mad r4, r0, c8, r2
                  
                  # Try to get an exact texel to pixel mapping by shifting texture coordinates
                  # slightly.
                  # A texture coordinate of 0 must map to 1/2*(texture dimension) and a 
                  # coordinate of 1 must map to (1 - 1/2*(texture dimension)).
                  # Note: This does not seem to eliminate the wobble on the mirror
                  # reflection entirely.
                  rcp r3.x, c4.x   ;# 2/width                                    
                  rcp r3.y, c5.y   ;# 2/height
                  mov r3.zw, c9.zw ;# r3 = (2/width, 2/height, 0, 0)
                  
                  mul r3, r3, c10  ;# r3 = (1/2*width, 1/2*height, 0, 0)
                  mad r6, r0, r3, r4
                  mov oT0, r6.xyww ;# move w into z so we can divide by z in the texture stage; some cards don't handle division by w correctly
               endShaderSource               
            end
            
            stage
               textureTransformType vector3 homogeneous # divide the xy components of the texture coordinate by z
               textureAddressing clamp clamp
               texture $reflectionRenderTarget
               textureBlend select(texture) select(texture)
            end # stage
                       
         end # pass
      end # shader
      
      # this shader is in case the above case fails. This does projection per vertex.
      shader -layer 6      
         validateRenderShaderContext -viewerRenderType $kRenderTypeNormal      

         pass -modifiedEachFrameHint  # we want the mirrors to be rendered every frame even in dirty rect mode

            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
                  
                  # project vertex to clip coords
                  m4x4 r0,   v0,  c0
                  mov oPos, r0
                  
                  # multiply 0.5 * w so homogenous divide will make it 0.5 again
                  mul r2, c9, r0.w
                  
                  # scale projected xy by .5 and re-center so it's in 0-w range
                  mad r4, r0, c8, r2
                  
                  # Try to get an exact texel to pixel mapping by shifting texture coordinates
                  # slightly.
                  # A texture coordinate of 0 must map to 1/2*(texture dimension) and a 
                  # coordinate of 1 must map to (1 - 1/2*(texture dimension)).
                  # Note: This does not seem to eliminate the wobble on the mirror
                  # reflection entirely.
                  rcp r3.x, c4.x   ;# 2/width                                    
                  rcp r3.y, c5.y   ;# 2/height
                  mov r3.zw, c9.zw ;# r3 = (2/width, 2/height, 0, 0)
                  
                  mul r3, r3, c10  ;# r3 = (1/2*width, 1/2*height, 0, 0)
                                       
                  mad r1, r0, r3, r4  ; write to a temp instead of output texcoord (as above)
                  
                  rcp r1.w, r1.w    ; calc 1/w
                  
                  mul oT0.xy, r1.w, r1.xy  ; project per vertex since the intel HW (and maybe others) can't do it per pixel.
                  
               endShaderSource               
            end    #shader
            
            stage
               textureAddressing clamp clamp
               texture $reflectionRenderTarget
               textureBlend select(texture) select(texture)
            end # stage    
            
         end # pass
      end #shader   
enddef

# material to clear stencil buffer and set depth buffer to "correct" value on rendertarget.
# The depth value is the depth as seen from the main camera.

define MirrorBackClearStencilAndSetDepth()
   material
      # AV TODO: this material doesn't do anything now, so it should be removed (from go2sco as well)
      shader -layer 9998
      end # shader
   end # material
enddef

# used by the mirror render. Sets z to the specified value on the entire reflection render target.
define SetSpecifiedZOnMirrorRTT(zValue)
   material
      shader      
         pass         
            renderClipSpaceRect
            renderTarget $reflectionRenderTarget -setViewport fullRenderTargetViewport            
                        
            # turn off stencil test
            stencil false
            
            # depth test accept always, write depth
            depthTest true -enableDepthWrite true
            depthTestFunction accept
            
            # do not write color
            alphaBlend srcFactor(zero) add dstFactor(one)
            
            # vertex program
            shaderProgram -target vertexProgram -method compile -version 1_1
               bindConstants 0 -bindingID immediateData -data (0,0,&zValue, 0)
               
               shaderSource
                  float4 zValue : register(c0);
                  
                  void VertexMain(float4 position : POSITION, out float4 oPosition : POSITION)
                  {
                     oPosition = position;
                     oPosition.z = zValue.z;    // set specified z value
                  }
                  
               endShaderSource
            end
         end # pass
      end # shader
   end # material
enddef

# used by the mirror camera for dirty rect rendering
define SetNearZOnMirrorRTT()
   create SetSpecifiedZOnMirrorRTT(0)
enddef

# used by the mirror camera for non-dirty rect rendering
define SetFarZOnMirrorRTT()
   create SetSpecifiedZOnMirrorRTT(1)
enddef

# used by the censor render in the mirror. Sets stencil on the entire censor render target to 1.
define SetStencilOnCensorRTT()
   material
      shader       
         pass 
            renderClipSpaceRect
                        
            # set stencil to 1 everywhere
            stencil true
            stencilFunction accept -refValue 1
            stencilOperation -onPass writeRef
            
            # depth test accept, do not write depth
            depthTest false -enableDepthWrite false
            depthTestFunction accept
            
            # do not write color
            alphaBlend srcFactor(zero) add dstFactor(one)
            
            shaderProgram -target vertexProgram -method assemble
               shaderSource
                  vs_1_1
                  dcl_position v0
                  mov oPos, v0
               endShaderSource
            end
            
            stage
               textureBlend select(colorScalar) select(colorScalar)
            end
            
         end # pass
      end # shader
   end # material
enddef

# common state for all objects rendered with the reflection camera
defaultState $kRenderTypeMirror # reflection render
   # stencil test passes only in the areas where the reference value has been written
   stencil true
   stencilFunction acceptIfEqual -refValue 1
   stencilOperation -onPass noWrite
end

# only render where the stencil is zero in turbo rect mode
defaultState $kRenderTypeNormal # Stencil
   stencil true
   stencilFunction acceptIfEqual -refValue 0
   stencilOperation -onPass noWrite
end


# Begin DO NOT MODIFY THIS BLOCK
# Material instances bound to reflective surfaces.

# Note: The following material instances are bound to exported resources and accessed
# by runtime code. They CANNOT be deleted without changing the export program.

materialDefinition simple_mirror_reflection
   setDefinition SimpleMirrorReflection
end

materialDefinition MirrorBackPostReflectionRenderMaterial
   setDefinition MirrorBackClearStencilAndSetDepth
end

# bound to the bounding mesh around the mirror plane that prevents the mirror from being
# undesirably culled
materialDefinition MirrorBoundingBoxMaterial
   setDefinition Null
end

# used to clear the mirror render target to z = 0 wherever the stencil has been set to 1
materialDefinition ZClearToNearPlaneMaterial
   setDefinition SetNearZOnMirrorRTT
end

# used to clear the mirror render target to z = 0 wherever the stencil has been set to 1
materialDefinition ZClearToFarPlaneMaterial
   setDefinition SetFarZOnMirrorRTT
end

# bound to a compositing pass geometry that preps the stencil buffer for rendering into
# the censor render target from the mirror view
materialDefinition CensorInMirrorStencilPrepMaterial
   setDefinition SetStencilOnCensorRTT
end

# End DO NOT MODIFY THIS BLOCK