dali-toolkit/internal/shader-effects/page-turn-effect-impl.cpp

   1 /*
   2  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  *
  16  */
  17
  18 // CLASS HEADER
  19 #include "page-turn-effect-impl.h"
  20
  21 // EXTERNAL HEADERS
  22 #include <sstream>
  23 #include <dali/public-api/common/stage.h>
  24
  25 namespace Dali
  26 {
  27
  28 namespace Toolkit
  29 {
  30
  31 namespace Internal
  32 {
  33
  34 namespace
  35 {
  36 #define MAKE_STRING(A)#A
  37
  38 const std::string CURRENT_CENTER_PROPERTY_NAME("uCurrentCenter");
  39 const std::string ORIGINAL_CENTER_PROPERTY_NAME("uOriginalCenter");
  40 const std::string PAGE_SIZE_PROPERTY_NAME("uPageSize");
  41 const std::string IS_TURNING_BACK_PROPERTY_NAME("uIsTurningBack");
  42 const std::string SHADOW_WIDTH_PROPERTY_NAME("uShadowWidth");
  43 const std::string SPINE_SHADOW_PARAMETER_PROPERTY_NAME("uSpineShadowParameter");
  44
  45 // fake shadow is used to enhance the effect, with its default maximum width to be pageSize * 0.15
  46 const float DEFAULT_SHADOW_WIDTH(0.15f);
  47
  48 // the major&minor radius (in pixels) to form an ellipse shape
  49 // the top-left quarter of this ellipse is used to calculate spine normal for simulating shadow
  50 const Vector2 DEFAULT_SPINE_SHADOW_PARAMETER(50.0f, 20.0f);
  51
  52 // when the vanishing point is very far away(pageHeight*THRESHOLD), make it infinitely, in this case, the page bent horizontally
  53 const float THRESHOLD(20.0);
  54
  55 struct CommonParametersConstraint
  56 {
  57   Matrix operator()( const Matrix& current,
  58                      const PropertyInput& originalCenterProperty,
  59                      const PropertyInput& currentCenterProperty,
  60                      const PropertyInput& pageSizeProperty)
  61   {
  62     const Vector2& originalCenter = originalCenterProperty.GetVector2();
  63     Vector2 currentCenter = currentCenterProperty.GetVector2();
  64     const Vector2& pageSize = pageSizeProperty.GetVector2();
  65
  66     // calculate the curve direction and the vanishing point
  67     // here, the vanishing point is the intersection of spine with the line passing through original center and vertical to curve direction
  68     Vector2 curveDirection( currentCenter - originalCenter );
  69     curveDirection.Normalize();
  70     if( fabs(curveDirection.y) < 0.01f) // eliminate the possibility of division by zero in the next step
  71     {
  72       curveDirection.y = 0.01f;
  73     }
  74     float vanishingPointY = originalCenter.y + curveDirection.x * originalCenter.x / curveDirection.y;
  75
  76     float curveEndY, cosTheta ,sinTheta ,translateX, translateY;
  77     // when the vanishing point is very far away, make it infinitely, in this case, the page bent horizontally
  78     if( fabs(vanishingPointY-pageSize.y*0.5f) >= pageSize.y*THRESHOLD )
  79     {
  80       curveDirection = Vector2(-1.f,0.f);
  81       currentCenter.y = originalCenter.y;
  82
  83       curveEndY = originalCenter.y;
  84       cosTheta = 1.f;
  85       sinTheta = 0.f;
  86       translateX = currentCenter.x - originalCenter.x;
  87       translateY = vanishingPointY;
  88     }
  89     else
  90     {
  91       curveEndY = currentCenter.y - curveDirection.y * (currentCenter.x/curveDirection.x) ;
  92       Vector2 v1( currentCenter.x, currentCenter.y - vanishingPointY );
  93       v1.Normalize();
  94       Vector2 v2( originalCenter.x, originalCenter.y - vanishingPointY );
  95       v2.Normalize();
  96       cosTheta = v1.x*v2.x + v1.y*v2.y;
  97       sinTheta = ( vanishingPointY > pageSize.y*0.5f ) ? sqrt(1.0-cosTheta*cosTheta) : -sqrt(1.0-cosTheta*cosTheta);
  98       translateX = currentCenter.x - cosTheta*originalCenter.x - sinTheta*( originalCenter.y-vanishingPointY );
  99       translateY = currentCenter.y + sinTheta*originalCenter.x - cosTheta*( originalCenter.y-vanishingPointY );
 100     }
 101
 102     float originalLength = fabs(originalCenter.x/curveDirection.x);
 103     float currentLength = fabs(currentCenter.x/curveDirection.x);
 104     float curveHeight = 0.45f*sqrt(originalLength*originalLength - currentLength*currentLength);
 105
 106     Matrix commonParameters( false );
 107     float* parameterArray = commonParameters.AsFloat();
 108     parameterArray[0] = cosTheta;
 109     parameterArray[1] = -sinTheta;
 110     parameterArray[2] = originalCenter.x;
 111     parameterArray[3] = originalCenter.y;
 112     parameterArray[4] = sinTheta;
 113     parameterArray[5] = cosTheta;
 114     parameterArray[6] = currentCenter.x;
 115     parameterArray[7] = currentCenter.y;
 116     parameterArray[8] = translateX;
 117     parameterArray[9] = translateY;
 118     parameterArray[10] = vanishingPointY;
 119     parameterArray[11] = curveEndY;
 120     parameterArray[12] = curveDirection.x;
 121     parameterArray[13] = curveDirection.y;
 122     parameterArray[14] = curveHeight;
 123     parameterArray[15] = currentLength;
 124
 125     return commonParameters;
 126   }
 127 };
 128
 129 }//namespace
 130
 131 PageTurnEffect::PageTurnEffect()
 132 : mOriginalCenterPropertyIndex(Property::INVALID_INDEX),
 133   mCurrentCenterPropertyIndex(Property::INVALID_INDEX)
 134 {
 135 }
 136
 137 PageTurnEffect::~PageTurnEffect()
 138 {
 139 }
 140
 141 Toolkit::PageTurnEffect PageTurnEffect::CreateShaderEffect( bool enableBlending )
 142 {
 143   std::string vertexShader = MAKE_STRING(
 144     /*
 145      * The common parameters for all the vertices, calculate in CPU then pass into the shader as uniforms
 146      *
 147      *  first part of the page, (outside the the line passing through original center and vertical to curve direction)
 148      * no Z change, only 2D rotation and translation
 149      * ([0][0],[0][1],[1][0],[1][1]) mat2 rotateMatrix
 150      * ([2][0],[2][1]) vec2 translationVector
 151      *
 152      * ([0][2],[0][3]) vec2 originalCenter: Typically the press down position of the Pan Gesture
 153      * ([1][2],[1][3]) vec2 currentCenter: Typically the current position of the Pan Gesture
 154      * ([3][0],[3][1]) vec2 curveDirection: The normalized vector pointing from original center to current center
 155      * ([2][2]) float vanishingPointY: The Y coordinate of the intersection of the spine
 156      *                                 and the line which goes through the original center and is vertical to the curveDirection
 157      * ([2][3]) float curveEndY: The Y coordinate of intersection of the spine and the line through both original and current center
 158      * ([3][2]) float curveHeight: The height of the interpolated hermite curve.
 159      * ([3][3]) float currentLength: The length from the current center to the curveEnd.
 160      */
 161     precision mediump float;\n
 162     uniform mat4 uCommonParameters;\n
 163     \n
 164     uniform vec2 uPageSize;\n
 165     uniform float uIsTurningBack;\n
 166     uniform float uShadowWidth;\n
 167     varying vec3 vNormal;\n
 168     varying vec4 vPosition;\n
 169     varying float vEdgeShadow;\n
 170     \n
 171     void main()\n
 172     {\n
 173       vec4 position = vec4( aPosition.xy, 0.0, 1.0);\n
 174       vec2 currentCenter = vec2( uCommonParameters[1][2], uCommonParameters[1][3]);\n
 175       vec2 originalCenter = vec2( uCommonParameters[0][2], uCommonParameters[0][3]);\n
 176       vec3 normal = vec3(0.0,0.0,1.0);\n
 177       \n
 178       if(currentCenter.x < originalCenter.x)\n
 179       {\n
 180         // change the coordinate origin from the center of the page to its top-left
 181         position.xy += uPageSize * 0.5;\n
 182         vec2 curveDirection = vec2( uCommonParameters[3]);\n
 183         vec3 vanishingPoint = vec3(0.0, uCommonParameters[2][2], 0.0);\n
 184         // first part of the page, (outside the the line passing through original center and vertical to curve direction)
 185         //no Z change, only 2D rotation and translation
 186         if( dot(curveDirection, position.xy - originalCenter) < 0.0 )
 187         {\n
 188           position.y -= vanishingPoint.y;\n
 189           position.xy = mat2(uCommonParameters)*position.xy + vec2( uCommonParameters[2]);\n
 190         }\n
 191          // second part of the page, bent as a ruled surface
 192         else\n
 193         {\n
 194           // calculate on the flat plane, between
 195           // the first line passing through current vertex and vanishing point
 196           // the second line passing through original center and current center
 197           vec2 curveEnd = vec2( 0.0, uCommonParameters[2][3] );\n
 198           vec2 curFlatDirection = vec2(0.0,1.0);\n
 199           float lengthFromCurve = position.y - originalCenter.y;\n
 200           float lengthOnCurve = position.x;\n
 201           if(currentCenter.y != originalCenter.y)\n
 202           {\n
 203             curFlatDirection = normalize(position.xy - vanishingPoint.xy);\n
 204             lengthFromCurve = (curveEnd.x*curveDirection.y-curveEnd.y*curveDirection.x-position.x*curveDirection.y+position.y*curveDirection.x)
 205                             / (curFlatDirection.x*curveDirection.y-curFlatDirection.y*curveDirection.x);\n
 206             lengthOnCurve = length(position.xy+lengthFromCurve*curFlatDirection-curveEnd);\n
 207           }\n
 208           \n
 209           // define the control points of hermite curve, composed with two segments
 210           // calulation is carried out on the 2D plane which is passing through both current and original center and vertical to the image plane
 211           float currentLength = uCommonParameters[3][3];\n
 212           float originalLength =  abs(originalCenter.x/curveDirection.x);\n
 213           float height = uCommonParameters[3][2];\n
 214           float percentage = currentLength/originalLength;\n
 215           //vec2 SegmentOneControlPoint0 = vec2(0.0, 0.0);
 216           vec2 SegmentOneControlPoint1 = vec2((0.65*percentage - 0.15)*originalLength, (0.8 + 0.2 * percentage)*height); \n
 217           vec2 SegmentTwoControlPoint0 = SegmentOneControlPoint1;\n
 218           vec2 SegmentTwoControlPoint1 = vec2(currentLength, 0.0); \n
 219           vec2 SegmentOneTangentVector0 = SegmentOneControlPoint1;\n
 220           vec2 SegmentOneTangentVector1 = vec2(0.5*originalLength,0.0);\n
 221           vec2 SegmentTwoTangentVector0 = SegmentOneTangentVector1;\n
 222           vec2 SegmentTwoTangentVector1 = SegmentOneTangentVector1;\n
 223           \n
 224           // calulate the corresponding curve point position and its tangent vector
 225           // it is a linear mapping onto nonlinear curves, might cause some unwanted deformation
 226           // but as there are no analytical method to calculate the curve length on arbitrary segment
 227           // no efficient way to solve this nonlinear mapping, Numerical approximation would cost too much computation in shader
 228           vec2 curvePoint2D;\n
 229           vec2 tangent;\n
 230           float t0 = lengthOnCurve / originalLength;\n
 231           if(t0<=0.5)\n
 232           {\n
 233             float t = 2.0*t0;\n
 234             float t_2 = t*t;\n
 235             float t_3 = t*t_2;\n
 236             curvePoint2D = (-2.0*t_3+3.0*t_2)*SegmentOneControlPoint1
 237                          + (t_3-2.0*t_2+t)*SegmentOneTangentVector0 + (t_3-t_2)*SegmentOneTangentVector1;\n
 238             tangent = (-6.0*t_2+6.0*t)*SegmentOneControlPoint1
 239                     + (3.0*t_2-4.0*t+1.0)*SegmentOneTangentVector0 + (3.0*t_2-2.0*t)*SegmentOneTangentVector1;\n
 240           }\n
 241           else\n
 242           {\n
 243             float t = 2.0*t0-1.0;\n
 244             float t_2 = t*t;\n
 245             float t_3 = t*t_2;\n
 246             curvePoint2D = (2.0*t_3-3.0*t_2+1.0)*SegmentTwoControlPoint0 + (-2.0*t_3+3.0*t_2)*SegmentTwoControlPoint1
 247                          + (t_3-2.0*t_2+t)*SegmentTwoTangentVector0 + (t_3-t_2)*SegmentTwoTangentVector1;\n
 248             tangent = (6.0*t_2-6.0*t)*SegmentTwoControlPoint0 + (-6.0*t_2+6.0*t)*SegmentTwoControlPoint1
 249                     + (3.0*t_2-4.0*t+1.0)*SegmentTwoTangentVector0 + (3.0*t_2-2.0*t)*SegmentTwoTangentVector1;\n
 250             // a trick to eliminate some optical illusion caused by the gradient matter of normal in per-fragment shading
 251             // which is caused by linear interpolation of normal vs. nonlinear lighting
 252             // will notice some artifact in the areas with dramatically normal changes, so compress the normal differences here
 253             tangent.y *=  min(1.0, length(position.xyz - vanishingPoint) / uPageSize.y ); \n
 254           }\n
 255           vec3 curvePoint = vec3(curveEnd - curvePoint2D.x*curveDirection,max(0.0,curvePoint2D.y));\n
 256           vec3 tangentVector = vec3(-tangent.x*curveDirection,tangent.y);\n
 257           \n
 258           // locate the new vertex position on the line passing through both vanishing point and the calculated curve point position
 259           vec3 curLiftDirection = vec3(0.0,-1.0,0.0);\n
 260           if(currentCenter.y != originalCenter.y)\n
 261           {\n
 262             curLiftDirection = normalize(curvePoint - vanishingPoint);\n
 263             tangentVector *= (curveDirection.y > 0.0) ? -1.0 : 1.0;\n
 264           // an heuristic adjustment here, to compensate the linear parameter mapping onto the nonlinear curve
 265             float Y0 = position.y - curveDirection.y * (position.x/curveDirection.x); \n
 266             float proportion;
 267             float refLength;\n
 268             if(abs(Y0-vanishingPoint.y) > abs(curveEnd.y-vanishingPoint.y)) \n
 269             {\n
 270               proportion = abs(curveEnd.y - Y0) / (abs(curveEnd.y-Y0)+abs(curveEnd.y - vanishingPoint.y)); \n
 271               refLength = proportion*length(originalCenter-vanishingPoint.xy) / (proportion-1.0); \n
 272             }\n
 273             else\n
 274             {\n
 275               proportion = abs(curveEnd.y - Y0) / abs(curveEnd.y - vanishingPoint.y);\n
 276               refLength = proportion*length(originalCenter-vanishingPoint.xy); \n
 277             }\n
 278             float Y1 = currentCenter.y - (normalize(currentCenter-vanishingPoint.xy)).y * refLength; \n
 279             position.y = mix(Y0, Y1, t0); \n
 280           }\n
 281           position.xz = curvePoint.xz - lengthFromCurve*curLiftDirection.xz;\n
 282           // calculate the normal vector, will be used for lighting
 283           normal = cross(curLiftDirection, normalize(tangentVector));\n
 284           // the signature of Z is decided by the page turning direction:
 285           // from left to right(negative); from right to left (positive)
 286           position.z *= -uIsTurningBack;\n
 287           normal.xy *= -uIsTurningBack;\n
 288         }\n
 289         // change the coordinate origin from the top-left of the page to its center
 290         position.xy -= uPageSize * 0.5; \n
 291       }\n
 292       position.z += aPosition.z;\n
 293       gl_Position = uMvpMatrix * position;\n
 294      // varying parameters for fragment shader
 295       vTexCoord = aTexCoord;
 296       vNormal = uNormalMatrix*normal;\n
 297       vPosition = uModelView * position;\n
 298   );
 299
 300   std::string vertexShaderWithFakedShadow = MAKE_STRING(
 301       // display shadow, the fake shadow value is calculated according to the height and the distance from page edge
 302       vTexCoord.x = (aTexCoord.x-sTextureRect.s) /( 1.0 - uShadowWidth ) + sTextureRect.s;\n
 303       vTexCoord.y = ( aTexCoord.y-sTextureRect.t-0.5*uShadowWidth*(sTextureRect.q-sTextureRect.t) )/( 1.0 - uShadowWidth ) + sTextureRect.t;\n
 304       float heightCoef = (1.0 + position.z*uIsTurningBack*3.0 / uPageSize.x) * 0.6;
 305       vEdgeShadow = clamp(0.9 - heightCoef, 0.0, 0.9 ); \n
 306       if( vTexCoord.y >= sTextureRect.q || vTexCoord.y <= sTextureRect.t || vTexCoord.x >= sTextureRect.p  )\n
 307       {\n
 308         float inversedShadowWidth = (1.0-uShadowWidth) / uShadowWidth ;\n
 309         float alpha1 = (vTexCoord.x-sTextureRect.p) * inversedShadowWidth / (sTextureRect.p - sTextureRect.s);\n
 310         inversedShadowWidth = 2.0 * inversedShadowWidth  / (sTextureRect.q - sTextureRect.t); \n
 311         float alpha2 = (vTexCoord.y-sTextureRect.q) * inversedShadowWidth;\n
 312         float alpha3 = (sTextureRect.t-vTexCoord.y) * inversedShadowWidth;\n
 313         float alpha;\n
 314         if(alpha1 > 0.0 && alpha2 > 0.0) alpha = sqrt(alpha2*alpha2+alpha1*alpha1)/sqrt(1.0 + max(alpha1,alpha2)*max(alpha1,alpha2));\n //bottom-right corner
 315         else if(alpha1 > 0.0 && alpha3 > 0.0) alpha = sqrt(alpha3*alpha3+alpha1*alpha1)/sqrt(1.0+max(alpha1,alpha3)*max(alpha1,alpha3));\n //top-right corner
 316         else alpha = max(alpha1,max(alpha2,alpha3)); \n
 317         alpha = 0.9 - alpha*0.9;\n
 318         vEdgeShadow = clamp(alpha - heightCoef, 0.0, 0.9 ); \n
 319       }\n
 320   );
 321
 322   std::string vertexShaderEnd("}");
 323
 324   std::string fragmentShaderPartOne = MAKE_STRING(
 325     precision mediump float;\n
 326     uniform vec2 uPageSize;\n
 327     uniform vec2 uSpineShadowParameter;\n
 328     varying vec3 vNormal;\n
 329     varying vec4 vPosition;\n
 330     varying float vEdgeShadow;\n
 331     \n
 332     void main()\n
 333     {\n
 334       // need to re-normalize the interpolated normal
 335       vec3 normal = normalize(vNormal);\n
 336       vec4 texel;\n
 337       float spineShadowCoef = 1.0; \n
 338    );
 339
 340   std::string fragmentShaderWithFakedShadow = MAKE_STRING(
 341       if( vTexCoord.y > sTextureRect.q || vTexCoord.y < sTextureRect.t || vTexCoord.x > sTextureRect.p  )\n
 342          texel = vec4(0.0,0.0,0.0,vEdgeShadow);
 343       else \n
 344   );
 345
 346   std::string fragmentShaderPartTwo = MAKE_STRING(
 347       { \n
 348         // display page content
 349         // display back image of the page, flip the texture
 350         if(  dot(vPosition.xyz, normal) > 0.0 ) texel = texture2D( sTexture, vec2( sTextureRect.p+sTextureRect.s-vTexCoord.x, vTexCoord.y ) );\n
 351         // display front image of the page
 352         else texel = texture2D( sTexture, vTexCoord );\n
 353         // display book spine, a stripe of shadowed texture
 354         float pixelPos = (vTexCoord.x-sTextureRect.s)*uPageSize.x; \n
 355         if(pixelPos < uSpineShadowParameter.x) \n
 356         {\n
 357           float x = pixelPos - uSpineShadowParameter.x;\n
 358           float y = sqrt( uSpineShadowParameter.x*uSpineShadowParameter.x - x*x);\n
 359           spineShadowCoef = normalize( vec2( uSpineShadowParameter.y*x/uSpineShadowParameter.x, y ) ).y;\n
 360         }\n
 361       }\n
 362     // calculate the lighting
 363     // set the ambient color as vec3(0.4);
 364       float lightColor = abs( normal.z ) * 0.6 + 0.4;\n
 365       gl_FragColor = vec4( ( spineShadowCoef* lightColor)* texel.rgb , texel.a ) * uColor;\n
 366     }
 367   );
 368
 369   // Create the implementation, temporarily owned on stack,
 370   Dali::ShaderEffect shaderEffectCustom;
 371   std::ostringstream vertexShaderStringStream;
 372   std::ostringstream fragmentShaderStringStream;
 373   if( enableBlending )
 374   {
 375     vertexShaderStringStream<< vertexShader << vertexShaderWithFakedShadow << vertexShaderEnd;
 376     fragmentShaderStringStream<< fragmentShaderPartOne << fragmentShaderWithFakedShadow << fragmentShaderPartTwo;
 377     shaderEffectCustom = Dali::ShaderEffect::New( vertexShaderStringStream.str(), fragmentShaderStringStream.str(), GeometryType( GEOMETRY_TYPE_IMAGE ),
 378             ShaderEffect::GeometryHints( ShaderEffect::HINT_GRID | ShaderEffect::HINT_DEPTH_BUFFER | ShaderEffect::HINT_BLENDING) );
 379   }
 380   else
 381   {
 382     vertexShaderStringStream<< vertexShader << vertexShaderEnd;
 383     fragmentShaderStringStream<< fragmentShaderPartOne << fragmentShaderPartTwo;
 384     shaderEffectCustom = Dali::ShaderEffect::New( vertexShaderStringStream.str(), fragmentShaderStringStream.str(), GeometryType( GEOMETRY_TYPE_IMAGE ),
 385             ShaderEffect::GeometryHints( ShaderEffect::HINT_GRID | ShaderEffect::HINT_DEPTH_BUFFER ) );
 386   }
 387
 388   PageTurnEffect* shaderImpl = new PageTurnEffect();
 389   Dali::Toolkit::PageTurnEffect handle = Toolkit::PageTurnEffect( shaderEffectCustom, shaderImpl );
 390
 391   shaderImpl->Initialize( handle );
 392
 393   Vector2 defaultPageSize = Dali::Stage::GetCurrent().GetSize();
 394   Matrix zeroMatrix(true);
 395   handle.SetUniform( "uCommonParameters", zeroMatrix );
 396   handle.SetUniform( PAGE_SIZE_PROPERTY_NAME, defaultPageSize/(1.f-DEFAULT_SHADOW_WIDTH) );
 397   handle.SetUniform( SHADOW_WIDTH_PROPERTY_NAME, DEFAULT_SHADOW_WIDTH );
 398   handle.SetUniform( SPINE_SHADOW_PARAMETER_PROPERTY_NAME, DEFAULT_SPINE_SHADOW_PARAMETER );
 399
 400   shaderImpl->mOriginalCenterPropertyIndex = handle.RegisterProperty( ORIGINAL_CENTER_PROPERTY_NAME, Vector2( defaultPageSize[0], defaultPageSize[1]*0.5f ) );
 401   shaderImpl->mCurrentCenterPropertyIndex = handle.RegisterProperty( CURRENT_CENTER_PROPERTY_NAME, Vector2( defaultPageSize[0], defaultPageSize[1]*0.5f ) );
 402   shaderImpl->mInternalConstraint = Constraint::New<Matrix>( handle.GetPropertyIndex( "uCommonParameters" ),
 403                                                         LocalSource( shaderImpl->mOriginalCenterPropertyIndex ),
 404                                                         LocalSource( shaderImpl->mCurrentCenterPropertyIndex ),
 405                                                         LocalSource( handle.GetPropertyIndex( PAGE_SIZE_PROPERTY_NAME ) ),
 406                                                         CommonParametersConstraint() );
 407   handle.ApplyConstraint( shaderImpl->mInternalConstraint );
 408
 409   // setting isTurningBack to -1.0f here means turning page forward
 410   handle.SetUniform( IS_TURNING_BACK_PROPERTY_NAME, -1.0f );
 411
 412   return handle;
 413 }
 414
 415 void PageTurnEffect::SetPageSize(const Vector2& pageSize)
 416 {
 417   mShaderEffect.SetUniform(PAGE_SIZE_PROPERTY_NAME, pageSize);
 418 }
 419
 420 void PageTurnEffect::SetOriginalCenter(const Vector2& originalCenter)
 421 {
 422   mShaderEffect.SetProperty( mOriginalCenterPropertyIndex, originalCenter );
 423 }
 424
 425 void PageTurnEffect::SetCurrentCenter(const Vector2& currentCenter)
 426 {
 427   mShaderEffect.SetProperty( mCurrentCenterPropertyIndex, currentCenter );
 428 }
 429
 430 void PageTurnEffect::SetIsTurningBack(bool isTurningBack)
 431 {
 432   float direction = isTurningBack ? 1.0f : -1.0f;
 433   mShaderEffect.SetUniform(IS_TURNING_BACK_PROPERTY_NAME, direction);
 434 }
 435
 436 void PageTurnEffect::SetShadowWidth(float shadowWidth)
 437 {
 438   mShaderEffect.SetUniform( SHADOW_WIDTH_PROPERTY_NAME, shadowWidth );
 439 }
 440
 441 void PageTurnEffect::SetSpineShadowParameter(const Vector2& spineShadowParameter)
 442 {
 443   mShaderEffect.SetUniform( SPINE_SHADOW_PARAMETER_PROPERTY_NAME, spineShadowParameter);
 444 }
 445
 446 void PageTurnEffect::ApplyInternalConstraint()
 447 {
 448   mShaderEffect.ApplyConstraint( mInternalConstraint );
 449 }
 450
 451 const std::string& PageTurnEffect::GetPageSizePropertyName() const
 452 {
 453   return PAGE_SIZE_PROPERTY_NAME;
 454 }
 455
 456 const std::string& PageTurnEffect::GetOriginalCenterPropertyName() const
 457 {
 458   return ORIGINAL_CENTER_PROPERTY_NAME;
 459 }
 460
 461 const std::string& PageTurnEffect::GetCurrentCenterPropertyName() const
 462 {
 463   return CURRENT_CENTER_PROPERTY_NAME;
 464 }
 465
 466 void PageTurnEffect::Initialize( Dali::ShaderEffect shaderEffect )
 467 {
 468   // Save a reference to the shader handle
 469   mShaderEffect = shaderEffect;
 470 }
 471
 472 } // namespace Internal
 473
 474 } // namespace Toolkit
 475
 476 } // namespace Dali