2 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
19 #include "page-turn-effect-impl.h"
23 #include <dali/public-api/common/stage.h>
36 #define MAKE_STRING(A)#A
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");
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);
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);
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);
55 struct CommonParametersConstraint
57 Matrix operator()( const Matrix& current,
58 const PropertyInput& originalCenterProperty,
59 const PropertyInput& currentCenterProperty,
60 const PropertyInput& pageSizeProperty)
62 const Vector2& originalCenter = originalCenterProperty.GetVector2();
63 Vector2 currentCenter = currentCenterProperty.GetVector2();
64 const Vector2& pageSize = pageSizeProperty.GetVector2();
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
72 curveDirection.y = 0.01f;
74 float vanishingPointY = originalCenter.y + curveDirection.x * originalCenter.x / curveDirection.y;
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 )
80 curveDirection = Vector2(-1.f,0.f);
81 currentCenter.y = originalCenter.y;
83 curveEndY = originalCenter.y;
86 translateX = currentCenter.x - originalCenter.x;
87 translateY = vanishingPointY;
91 curveEndY = currentCenter.y - curveDirection.y * (currentCenter.x/curveDirection.x) ;
92 Vector2 v1( currentCenter.x, currentCenter.y - vanishingPointY );
94 Vector2 v2( originalCenter.x, originalCenter.y - vanishingPointY );
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 );
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);
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;
125 return commonParameters;
131 PageTurnEffect::PageTurnEffect()
132 : mOriginalCenterPropertyIndex(Property::INVALID_INDEX),
133 mCurrentCenterPropertyIndex(Property::INVALID_INDEX)
137 PageTurnEffect::~PageTurnEffect()
141 Toolkit::PageTurnEffect PageTurnEffect::CreateShaderEffect( bool enableBlending )
143 std::string vertexShader = MAKE_STRING(
145 * The common parameters for all the vertices, calculate in CPU then pass into the shader as uniforms
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
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.
161 precision mediump float;\n
162 uniform mat4 uCommonParameters;\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
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
178 if(currentCenter.x < originalCenter.x)\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 )
188 position.y -= vanishingPoint.y;\n
189 position.xy = mat2(uCommonParameters)*position.xy + vec2( uCommonParameters[2]);\n
191 // second part of the page, bent as a ruled surface
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
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
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
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
230 float t0 = lengthOnCurve / originalLength;\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
243 float t = 2.0*t0-1.0;\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
255 vec3 curvePoint = vec3(curveEnd - curvePoint2D.x*curveDirection,max(0.0,curvePoint2D.y));\n
256 vec3 tangentVector = vec3(-tangent.x*curveDirection,tangent.y);\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
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
268 if(abs(Y0-vanishingPoint.y) > abs(curveEnd.y-vanishingPoint.y)) \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
275 proportion = abs(curveEnd.y - Y0) / abs(curveEnd.y - vanishingPoint.y);\n
276 refLength = proportion*length(originalCenter-vanishingPoint.xy); \n
278 float Y1 = currentCenter.y - (normalize(currentCenter-vanishingPoint.xy)).y * refLength; \n
279 position.y = mix(Y0, Y1, t0); \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
289 // change the coordinate origin from the top-left of the page to its center
290 position.xy -= uPageSize * 0.5; \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
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
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
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
322 std::string vertexShaderEnd("}");
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
334 // need to re-normalize the interpolated normal
335 vec3 normal = normalize(vNormal);\n
337 float spineShadowCoef = 1.0; \n
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);
346 std::string fragmentShaderPartTwo = MAKE_STRING(
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
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
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
369 // Create the implementation, temporarily owned on stack,
370 Dali::ShaderEffect shaderEffectCustom;
371 std::ostringstream vertexShaderStringStream;
372 std::ostringstream fragmentShaderStringStream;
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) );
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 ) );
388 PageTurnEffect* shaderImpl = new PageTurnEffect();
389 Dali::Toolkit::PageTurnEffect handle = Toolkit::PageTurnEffect( shaderEffectCustom, shaderImpl );
391 shaderImpl->Initialize( handle );
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 );
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 );
409 // setting isTurningBack to -1.0f here means turning page forward
410 handle.SetUniform( IS_TURNING_BACK_PROPERTY_NAME, -1.0f );
415 void PageTurnEffect::SetPageSize(const Vector2& pageSize)
417 mShaderEffect.SetUniform(PAGE_SIZE_PROPERTY_NAME, pageSize);
420 void PageTurnEffect::SetOriginalCenter(const Vector2& originalCenter)
422 mShaderEffect.SetProperty( mOriginalCenterPropertyIndex, originalCenter );
425 void PageTurnEffect::SetCurrentCenter(const Vector2& currentCenter)
427 mShaderEffect.SetProperty( mCurrentCenterPropertyIndex, currentCenter );
430 void PageTurnEffect::SetIsTurningBack(bool isTurningBack)
432 float direction = isTurningBack ? 1.0f : -1.0f;
433 mShaderEffect.SetUniform(IS_TURNING_BACK_PROPERTY_NAME, direction);
436 void PageTurnEffect::SetShadowWidth(float shadowWidth)
438 mShaderEffect.SetUniform( SHADOW_WIDTH_PROPERTY_NAME, shadowWidth );
441 void PageTurnEffect::SetSpineShadowParameter(const Vector2& spineShadowParameter)
443 mShaderEffect.SetUniform( SPINE_SHADOW_PARAMETER_PROPERTY_NAME, spineShadowParameter);
446 void PageTurnEffect::ApplyInternalConstraint()
448 mShaderEffect.ApplyConstraint( mInternalConstraint );
451 const std::string& PageTurnEffect::GetPageSizePropertyName() const
453 return PAGE_SIZE_PROPERTY_NAME;
456 const std::string& PageTurnEffect::GetOriginalCenterPropertyName() const
458 return ORIGINAL_CENTER_PROPERTY_NAME;
461 const std::string& PageTurnEffect::GetCurrentCenterPropertyName() const
463 return CURRENT_CENTER_PROPERTY_NAME;
466 void PageTurnEffect::Initialize( Dali::ShaderEffect shaderEffect )
468 // Save a reference to the shader handle
469 mShaderEffect = shaderEffect;
472 } // namespace Internal
474 } // namespace Toolkit