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 <dali-toolkit/public-api/shader-effects/motion-blur-effect.h>
22 #include <dali/public-api/animation/active-constraint.h>
23 #include <dali/public-api/animation/constraint.h>
24 #include <dali/public-api/animation/constraints.h>
35 const std::string MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME( "uBlurTexCoordScale" );
36 const std::string MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME( "uGeometryStretchFactor" );
37 const std::string MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME( "uSpeedScalingFactor" );
38 const std::string MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME( "uObjectFadeStart" );
39 const std::string MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME( "uObjectFadeEnd" );
40 const std::string MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME( "uAlphaScale" );
41 const std::string MOTION_BLUR_NUM_SAMPLES_NAME( "uNumSamples" );
42 const std::string MOTION_BLUR_RECIP_NUM_SAMPLES_NAME( "uRecipNumSamples" );
43 const std::string MOTION_BLUR_RECIP_NUM_SAMPLES_MINUS_ONE_NAME( "uRecipNumSamplesMinusOne" );
44 const std::string MOTION_BLUR_MODEL_LASTFRAME( "uModelLastFrame" ); ///< Matrix
46 ////////////////////////////////////////////////////
48 // Motion blur shader / actor tweaking parameters
51 const unsigned int MOTION_BLUR_NUM_SAMPLES = 8;
53 // half width and half height respectively of actor, corresponding to values in vertex attribute stream
54 // TODO: Note that these values work for normal image actor (verts +/- 0.5) but a grid or a nine square seems to have verts in pixel space (e.g. 256,256). Need to fix this somehow,
55 // either in Dali or by passing uniforms which we can use to 'normalise' the verts in the vertex shader
56 const Vector2 MOTION_BLUR_ACTOR_VERTEX( 0.5f, 0.5f );
58 const float MOTION_BLUR_TEXCOORD_SCALE = 0.125f; // stretch texture reads along velocity vector, larger number means reads spaced further apart
59 const float MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR = 0.05f; // scaling factor for how much to stretch actor geom as it moves
60 const float MOTION_BLUR_SPEED_SCALING_FACTOR = 0.5f; // scales the speed, producing a number affecting how much the actor blurs & fades at the edges
62 const Vector2 MOTION_BLUR_OBJECT_FADE_END( MOTION_BLUR_ACTOR_VERTEX ); // distance from center at which actor fully fades to zero alpha
63 const Vector2 MOTION_BLUR_OBJECT_FADE_START( MOTION_BLUR_OBJECT_FADE_END * 0.5f ); // distance from center at which actor start to fade from full alpha
65 const float MOTION_BLUR_ALPHA_SCALE = 0.75f; // global scaler applied to actor alpha as it is blurred + moving
70 MotionBlurEffect::MotionBlurEffect()
74 //Call the Parent copy constructor to add reference to the implementation for this object
75 MotionBlurEffect::MotionBlurEffect( ShaderEffect handle )
76 :ShaderEffect( handle )
80 MotionBlurEffect::~MotionBlurEffect()
84 MotionBlurEffect MotionBlurEffect::Apply( RenderableActor renderable )
86 MotionBlurEffect newEffect = New( MOTION_BLUR_NUM_SAMPLES );
87 renderable.SetShaderEffect( newEffect );
89 Dali::Property::Index uModelProperty = newEffect.GetPropertyIndex( MOTION_BLUR_MODEL_LASTFRAME );
91 Constraint constraint = Constraint::New<Matrix>( uModelProperty,
92 Source( renderable, Actor::Property::WorldMatrix ),
93 EqualToConstraint() );
95 // and set up constraint.
96 newEffect.ApplyConstraint( constraint );
100 MotionBlurEffect MotionBlurEffect::New()
102 return New( MOTION_BLUR_NUM_SAMPLES );
105 MotionBlurEffect MotionBlurEffect::New( unsigned int numBlurSamples )
107 // Dali vertexSource prefix for reference:
108 // precision highp float;
109 // attribute vec3 aPosition;
110 // attribute vec2 aTexCoord;
111 // uniform mat4 uMvpMatrix;
112 // uniform mat4 uModelView;
113 // uniform mat3 uNormalMatrix;
114 // uniform mat4 uProjection;
115 // uniform vec4 uColor;
116 // varying vec2 vTexCoord;
117 std::string vertexSource;
119 "precision mediump float;\n"
120 "uniform mat4 uModelLastFrame;\n"
121 "uniform float uTimeDelta;\n"
123 "uniform float uGeometryStretchFactor;\n"
124 "uniform float uSpeedScalingFactor;\n"
127 "varying vec2 vModelSpaceCenterToPos;\n"
128 "varying vec2 vScreenSpaceVelocityVector;\n"
129 "varying float vSpeed;\n"
133 // get view space position of vertex this frame and last frame
134 " vec4 vertex = vec4(aPosition, 1.0);\n"
135 " vec4 viewSpaceVertex = uModelView * vertex;\n"
136 " vec4 viewSpaceVertexLastFrame = (uViewMatrix * uModelLastFrame) * vertex;\n"
137 " float reciprocalTimeDelta = 1.0 / ((uTimeDelta > 0.0) ? uTimeDelta : 0.01);\n"
139 // work out vertex's last movement in view space
140 " vec3 viewSpacePosDelta = viewSpaceVertex.xyz - viewSpaceVertexLastFrame.xyz;\n"
142 // get clip space position of vertex this frame and last frame
143 " vec4 clipSpaceVertex = uMvpMatrix * vertex;\n"
144 " vec4 clipSpaceVertexLastFrame = uProjection * viewSpaceVertexLastFrame;\n"
146 // decide how much this vertex is 'trailing', i.e. at the back of the object relative to its direction of motion. We do this
147 // by assuming the objects model space origin is at its center and taking the dot product of the vector from center to vertex with the motion direction
149 " float posDeltaLength = length(viewSpacePosDelta);\n"
150 " if(posDeltaLength > 0.001)\n" // avoid div by 0 if object has barely moved
152 " vec4 viewSpaceCenterToPos = uModelView * vec4(aPosition, 0.0);\n"
153 " float centerToVertexDist = length(viewSpaceCenterToPos);\n"
154 " if(centerToVertexDist > 0.001)\n" // avoid div by 0 if object has vertex at model space origin
156 " vec3 viewSpacePosDeltaNormalised = viewSpacePosDelta / posDeltaLength;\n"
157 " vec3 viewSpaceCenterToPosNormalised = viewSpaceCenterToPos.xyz / centerToVertexDist;\n"
158 " t = (dot(viewSpacePosDeltaNormalised, viewSpaceCenterToPosNormalised) * 0.5 ) + 0.5;\n" // scale and bias from [-1..1] to [0..1]
161 // output vertex position lerped with its last position, based on how much it is trailing,
162 // this stretches the geom back along where it has just been, giving a warping effect
163 // Note: we must take account of time delta to convert position delta into a velocity, so changes are smooth (take into account frame time correctly)
164 " gl_Position = mix(clipSpaceVertexLastFrame, clipSpaceVertex, t * uGeometryStretchFactor * reciprocalTimeDelta);\n"
166 // work out vertex's last movement in normalised device coordinates [-1..1] space, i.e. perspective divide
167 " vec2 ndcVertex = clipSpaceVertex.xy / clipSpaceVertex.w;\n"
168 " vec2 ndcVertexLastFrame = clipSpaceVertexLastFrame.xy / clipSpaceVertexLastFrame.w;\n"
169 // scale and bias so that a value of 1.0 corresponds to screen size (NDC is [-1..1] = 2)
170 " vScreenSpaceVelocityVector = ((ndcVertex - ndcVertexLastFrame) * 0.5 * reciprocalTimeDelta);\n"
171 " vScreenSpaceVelocityVector.y = -vScreenSpaceVelocityVector.y;\n" // TODO negated due to y being inverted in our coordinate system?
172 // calculate a scaling factor proportional to velocity, which we can use to tweak how things look
173 " vSpeed = length(vScreenSpaceVelocityVector) * uSpeedScalingFactor;\n"
174 " vSpeed = clamp(vSpeed, 0.0, 1.0);\n"
176 // provide fragment shader with vector from center of object to pixel (assumes the objects model space origin is at its center and verts have same z)
177 " vModelSpaceCenterToPos = aPosition.xy;\n"
179 " vTexCoord = aTexCoord;\n"
183 // Dali fragmentSource prefix for reference:
184 // precision highp float;
185 // uniform sampler2D sTexture;
186 // uniform sampler2D sEffect;
187 // uniform vec4 uColor;
188 // varying vec2 vTexCoord;
189 std::string fragmentSource;
191 "precision mediump float;\n"
192 "uniform vec2 uObjectFadeStart;\n"
193 "uniform vec2 uObjectFadeEnd;\n"
194 "uniform float uAlphaScale;\n"
195 "uniform float uBlurTexCoordScale;\n"
196 "uniform float uNumSamples;\n"
197 "uniform float uRecipNumSamples;\n"
198 "uniform float uRecipNumSamplesMinusOne;\n"
200 "varying vec2 vModelSpaceCenterToPos;\n"
201 "varying vec2 vScreenSpaceVelocityVector;\n"
202 "varying float vSpeed;\n"
206 // calculate an alpha value that will fade the object towards its extremities, we need this to avoid an unsightly hard edge between color values of
207 // the blurred object and the unblurred background. Use smoothstep also to hide any hard edges (discontinuities) in rate of change of this alpha gradient
208 " vec2 centerToPixel = abs(vModelSpaceCenterToPos);\n"
209 " vec2 fadeToEdges = smoothstep(0.0, 1.0, 1.0 - ((centerToPixel - uObjectFadeStart) / (uObjectFadeEnd - uObjectFadeStart)));\n"
210 " float fadeToEdgesScale = fadeToEdges.x * fadeToEdges.y * uAlphaScale;\n" // apply global scaler
211 " fadeToEdgesScale = mix(1.0, fadeToEdgesScale, vSpeed);\n" // fade proportional to speed, so opaque when at rest
213 // scale velocity vector by user requirements
214 " vec2 velocity = vScreenSpaceVelocityVector * uBlurTexCoordScale;\n"
216 // standard actor texel
217 " vec4 colActor = texture2D(sTexture, vTexCoord);\n"
219 // blurred actor - gather texture samples from the actor texture in the direction of motion
220 " vec4 col = colActor * uRecipNumSamples;\n"
221 " for(float i = 1.0; i < uNumSamples; i += 1.0)\n"
223 " float t = i * uRecipNumSamplesMinusOne;\n"
224 " col += texture2D(sTexture, vTexCoord + (velocity * t)) * uRecipNumSamples;\n"
226 " gl_FragColor = mix(colActor, col, vSpeed);\n" // lerp blurred and non-blurred actor based on speed of motion
227 " gl_FragColor.a = colActor.a * fadeToEdgesScale;\n" // fade blurred actor to its edges based on speed of motion
228 " gl_FragColor *= uColor;\n"
231 // NOTE: we must turn on alpha blending for the actor (HINT_BLENDING)
232 ShaderEffect shader = ShaderEffect::New( vertexSource, fragmentSource,
234 ShaderEffect::GeometryHints( ShaderEffect::HINT_BLENDING | ShaderEffect::HINT_GRID) );
236 MotionBlurEffect handle( shader );
239 //////////////////////////////////////
240 // Register uniform properties
244 // factors that scale the look, defaults
245 handle.SetUniform( MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME, MOTION_BLUR_TEXCOORD_SCALE );
246 handle.SetUniform( MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME, MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR );
247 handle.SetUniform( MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME, MOTION_BLUR_SPEED_SCALING_FACTOR );
248 handle.SetUniform( MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME, MOTION_BLUR_OBJECT_FADE_START );
249 handle.SetUniform( MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME, MOTION_BLUR_OBJECT_FADE_END );
250 handle.SetUniform( MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME, MOTION_BLUR_ALPHA_SCALE );
251 handle.SetUniform( MOTION_BLUR_NUM_SAMPLES_NAME, static_cast<float>( MOTION_BLUR_NUM_SAMPLES ) );
252 handle.SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_NAME, 1.0f / static_cast<float>( MOTION_BLUR_NUM_SAMPLES ) );
253 handle.SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_MINUS_ONE_NAME, 1.0f / static_cast<float>( MOTION_BLUR_NUM_SAMPLES - 1.0f ) );
254 handle.SetUniform( MOTION_BLUR_MODEL_LASTFRAME, Matrix::IDENTITY );
259 MotionBlurEffect MotionBlurEffect::DownCast( ShaderEffect shaderEffect )
261 MotionBlurEffect handle = shaderEffect;
265 void MotionBlurEffect::SetNumSamples( int numSamples )
267 SetUniform( MOTION_BLUR_NUM_SAMPLES_NAME, static_cast<float>( numSamples ) );
268 SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_NAME, 1.0f / static_cast<float>( numSamples ) );
269 SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_MINUS_ONE_NAME, 1.0f / static_cast<float>( numSamples - 1.0f ) );
272 void MotionBlurEffect::SetTexcoordScale( float texcoordScale )
274 SetUniform( MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME, texcoordScale );
277 void MotionBlurEffect::SetGeometryStretchFactor( float scalingFactor )
279 SetUniform( MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME, scalingFactor );
282 void MotionBlurEffect::SetSpeedScalingFactor( float scalingFactor )
284 SetUniform( MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME, scalingFactor );
287 void MotionBlurEffect::SetObjectFadeStart( Vector2 displacement )
289 SetUniform( MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME, displacement );
292 void MotionBlurEffect::SetObjectFadeEnd( Vector2 displacement )
294 SetUniform( MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME, displacement );
297 void MotionBlurEffect::SetAlphaScale( float alphaScale )
299 SetUniform( MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME, alphaScale );
302 const std::string& MotionBlurEffect::GetTexcoordScalePropertyName() const
304 return MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME;
307 const std::string& MotionBlurEffect::GetGeometryStretchFactorPropertyName() const
309 return MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME;
312 const std::string& MotionBlurEffect::GetSpeedScalingFactorPropertyName() const
314 return MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME;
317 const std::string& MotionBlurEffect::GetObjectFadeStartPropertyName() const
319 return MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME;
322 const std::string& MotionBlurEffect::GetObjectFadeEndPropertyName() const
324 return MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME;
327 const std::string& MotionBlurEffect::GetAlphaScalePropertyName() const
329 return MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME;