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/constraint.h>
23 #include <dali/public-api/animation/constraints.h>
34 const std::string MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME( "uBlurTexCoordScale" );
35 const std::string MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME( "uGeometryStretchFactor" );
36 const std::string MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME( "uSpeedScalingFactor" );
37 const std::string MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME( "uObjectFadeStart" );
38 const std::string MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME( "uObjectFadeEnd" );
39 const std::string MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME( "uAlphaScale" );
40 const std::string MOTION_BLUR_NUM_SAMPLES_NAME( "uNumSamples" );
41 const std::string MOTION_BLUR_RECIP_NUM_SAMPLES_NAME( "uRecipNumSamples" );
42 const std::string MOTION_BLUR_RECIP_NUM_SAMPLES_MINUS_ONE_NAME( "uRecipNumSamplesMinusOne" );
43 const std::string MOTION_BLUR_MODEL_LASTFRAME( "uModelLastFrame" ); ///< Matrix
45 ////////////////////////////////////////////////////
47 // Motion blur shader / actor tweaking parameters
50 const unsigned int MOTION_BLUR_NUM_SAMPLES = 8;
52 // half width and half height respectively of actor, corresponding to values in vertex attribute stream
53 // 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,
54 // either in Dali or by passing uniforms which we can use to 'normalise' the verts in the vertex shader
55 const Vector2 MOTION_BLUR_ACTOR_VERTEX( 0.5f, 0.5f );
57 const float MOTION_BLUR_TEXCOORD_SCALE = 0.125f; // stretch texture reads along velocity vector, larger number means reads spaced further apart
58 const float MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR = 0.05f; // scaling factor for how much to stretch actor geom as it moves
59 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
61 const Vector2 MOTION_BLUR_OBJECT_FADE_END( MOTION_BLUR_ACTOR_VERTEX ); // distance from center at which actor fully fades to zero alpha
62 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
64 const float MOTION_BLUR_ALPHA_SCALE = 0.75f; // global scaler applied to actor alpha as it is blurred + moving
69 MotionBlurEffect::MotionBlurEffect()
73 //Call the Parent copy constructor to add reference to the implementation for this object
74 MotionBlurEffect::MotionBlurEffect( ShaderEffect handle )
75 :ShaderEffect( handle )
79 MotionBlurEffect::~MotionBlurEffect()
83 MotionBlurEffect MotionBlurEffect::Apply( RenderableActor renderable )
85 MotionBlurEffect newEffect = New( MOTION_BLUR_NUM_SAMPLES );
86 renderable.SetShaderEffect( newEffect );
88 Dali::Property::Index uModelProperty = newEffect.GetPropertyIndex( MOTION_BLUR_MODEL_LASTFRAME );
90 Constraint constraint = Constraint::New<Matrix>( newEffect, uModelProperty, EqualToConstraint() );
91 constraint.AddSource( Source( renderable, Actor::Property::WORLD_MATRIX ) );
93 // and set up constraint.
98 MotionBlurEffect MotionBlurEffect::New()
100 return New( MOTION_BLUR_NUM_SAMPLES );
103 MotionBlurEffect MotionBlurEffect::New( unsigned int numBlurSamples )
105 // Dali vertexSource prefix for reference:
106 // precision highp float;
107 // attribute vec3 aPosition;
108 // attribute vec2 aTexCoord;
109 // uniform mat4 uMvpMatrix;
110 // uniform mat4 uModelView;
111 // uniform mat3 uNormalMatrix;
112 // uniform mat4 uProjection;
113 // uniform vec4 uColor;
114 // varying vec2 vTexCoord;
115 std::string vertexSource;
117 "precision mediump float;\n"
118 "uniform mat4 uModelLastFrame;\n"
119 "uniform float uTimeDelta;\n"
121 "uniform float uGeometryStretchFactor;\n"
122 "uniform float uSpeedScalingFactor;\n"
125 "varying vec2 vModelSpaceCenterToPos;\n"
126 "varying vec2 vScreenSpaceVelocityVector;\n"
127 "varying float vSpeed;\n"
131 // get view space position of vertex this frame and last frame
132 " vec4 vertex = vec4(aPosition, 1.0);\n"
133 " vec4 viewSpaceVertex = uModelView * vertex;\n"
134 " vec4 viewSpaceVertexLastFrame = (uViewMatrix * uModelLastFrame) * vertex;\n"
135 " float reciprocalTimeDelta = 1.0 / ((uTimeDelta > 0.0) ? uTimeDelta : 0.01);\n"
137 // work out vertex's last movement in view space
138 " vec3 viewSpacePosDelta = viewSpaceVertex.xyz - viewSpaceVertexLastFrame.xyz;\n"
140 // get clip space position of vertex this frame and last frame
141 " vec4 clipSpaceVertex = uMvpMatrix * vertex;\n"
142 " vec4 clipSpaceVertexLastFrame = uProjection * viewSpaceVertexLastFrame;\n"
144 // decide how much this vertex is 'trailing', i.e. at the back of the object relative to its direction of motion. We do this
145 // 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
147 " float posDeltaLength = length(viewSpacePosDelta);\n"
148 " if(posDeltaLength > 0.001)\n" // avoid div by 0 if object has barely moved
150 " vec4 viewSpaceCenterToPos = uModelView * vec4(aPosition, 0.0);\n"
151 " float centerToVertexDist = length(viewSpaceCenterToPos);\n"
152 " if(centerToVertexDist > 0.001)\n" // avoid div by 0 if object has vertex at model space origin
154 " vec3 viewSpacePosDeltaNormalised = viewSpacePosDelta / posDeltaLength;\n"
155 " vec3 viewSpaceCenterToPosNormalised = viewSpaceCenterToPos.xyz / centerToVertexDist;\n"
156 " t = (dot(viewSpacePosDeltaNormalised, viewSpaceCenterToPosNormalised) * 0.5 ) + 0.5;\n" // scale and bias from [-1..1] to [0..1]
159 // output vertex position lerped with its last position, based on how much it is trailing,
160 // this stretches the geom back along where it has just been, giving a warping effect
161 // 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)
162 " gl_Position = mix(clipSpaceVertexLastFrame, clipSpaceVertex, t * uGeometryStretchFactor * reciprocalTimeDelta);\n"
164 // work out vertex's last movement in normalised device coordinates [-1..1] space, i.e. perspective divide
165 " vec2 ndcVertex = clipSpaceVertex.xy / clipSpaceVertex.w;\n"
166 " vec2 ndcVertexLastFrame = clipSpaceVertexLastFrame.xy / clipSpaceVertexLastFrame.w;\n"
167 // scale and bias so that a value of 1.0 corresponds to screen size (NDC is [-1..1] = 2)
168 " vScreenSpaceVelocityVector = ((ndcVertex - ndcVertexLastFrame) * 0.5 * reciprocalTimeDelta);\n"
169 " vScreenSpaceVelocityVector.y = -vScreenSpaceVelocityVector.y;\n" // TODO negated due to y being inverted in our coordinate system?
170 // calculate a scaling factor proportional to velocity, which we can use to tweak how things look
171 " vSpeed = length(vScreenSpaceVelocityVector) * uSpeedScalingFactor;\n"
172 " vSpeed = clamp(vSpeed, 0.0, 1.0);\n"
174 // 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)
175 " vModelSpaceCenterToPos = aPosition.xy;\n"
177 " vTexCoord = aTexCoord;\n"
181 // Dali fragmentSource prefix for reference:
182 // precision highp float;
183 // uniform sampler2D sTexture;
184 // uniform sampler2D sEffect;
185 // uniform vec4 uColor;
186 // varying vec2 vTexCoord;
187 std::string fragmentSource;
189 "precision mediump float;\n"
190 "uniform vec2 uObjectFadeStart;\n"
191 "uniform vec2 uObjectFadeEnd;\n"
192 "uniform float uAlphaScale;\n"
193 "uniform float uBlurTexCoordScale;\n"
194 "uniform float uNumSamples;\n"
195 "uniform float uRecipNumSamples;\n"
196 "uniform float uRecipNumSamplesMinusOne;\n"
198 "varying vec2 vModelSpaceCenterToPos;\n"
199 "varying vec2 vScreenSpaceVelocityVector;\n"
200 "varying float vSpeed;\n"
204 // 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
205 // the blurred object and the unblurred background. Use smoothstep also to hide any hard edges (discontinuities) in rate of change of this alpha gradient
206 " vec2 centerToPixel = abs(vModelSpaceCenterToPos);\n"
207 " vec2 fadeToEdges = smoothstep(0.0, 1.0, 1.0 - ((centerToPixel - uObjectFadeStart) / (uObjectFadeEnd - uObjectFadeStart)));\n"
208 " float fadeToEdgesScale = fadeToEdges.x * fadeToEdges.y * uAlphaScale;\n" // apply global scaler
209 " fadeToEdgesScale = mix(1.0, fadeToEdgesScale, vSpeed);\n" // fade proportional to speed, so opaque when at rest
211 // scale velocity vector by user requirements
212 " vec2 velocity = vScreenSpaceVelocityVector * uBlurTexCoordScale;\n"
214 // standard actor texel
215 " vec4 colActor = texture2D(sTexture, vTexCoord);\n"
217 // blurred actor - gather texture samples from the actor texture in the direction of motion
218 " vec4 col = colActor * uRecipNumSamples;\n"
219 " for(float i = 1.0; i < uNumSamples; i += 1.0)\n"
221 " float t = i * uRecipNumSamplesMinusOne;\n"
222 " col += texture2D(sTexture, vTexCoord + (velocity * t)) * uRecipNumSamples;\n"
224 " gl_FragColor = mix(colActor, col, vSpeed);\n" // lerp blurred and non-blurred actor based on speed of motion
225 " gl_FragColor.a = colActor.a * fadeToEdgesScale;\n" // fade blurred actor to its edges based on speed of motion
226 " gl_FragColor *= uColor;\n"
229 // NOTE: we must turn on alpha blending for the actor (HINT_BLENDING)
230 ShaderEffect shader = ShaderEffect::New( vertexSource, fragmentSource,
232 ShaderEffect::GeometryHints( ShaderEffect::HINT_BLENDING | ShaderEffect::HINT_GRID) );
234 MotionBlurEffect handle( shader );
237 //////////////////////////////////////
238 // Register uniform properties
242 // factors that scale the look, defaults
243 handle.SetUniform( MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME, MOTION_BLUR_TEXCOORD_SCALE );
244 handle.SetUniform( MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME, MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR );
245 handle.SetUniform( MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME, MOTION_BLUR_SPEED_SCALING_FACTOR );
246 handle.SetUniform( MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME, MOTION_BLUR_OBJECT_FADE_START );
247 handle.SetUniform( MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME, MOTION_BLUR_OBJECT_FADE_END );
248 handle.SetUniform( MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME, MOTION_BLUR_ALPHA_SCALE );
249 handle.SetUniform( MOTION_BLUR_NUM_SAMPLES_NAME, static_cast<float>( MOTION_BLUR_NUM_SAMPLES ) );
250 handle.SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_NAME, 1.0f / static_cast<float>( MOTION_BLUR_NUM_SAMPLES ) );
251 handle.SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_MINUS_ONE_NAME, 1.0f / static_cast<float>( MOTION_BLUR_NUM_SAMPLES - 1.0f ) );
252 handle.SetUniform( MOTION_BLUR_MODEL_LASTFRAME, Matrix::IDENTITY );
257 MotionBlurEffect MotionBlurEffect::DownCast( ShaderEffect shaderEffect )
259 MotionBlurEffect handle = shaderEffect;
263 void MotionBlurEffect::SetNumSamples( int numSamples )
265 SetUniform( MOTION_BLUR_NUM_SAMPLES_NAME, static_cast<float>( numSamples ) );
266 SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_NAME, 1.0f / static_cast<float>( numSamples ) );
267 SetUniform( MOTION_BLUR_RECIP_NUM_SAMPLES_MINUS_ONE_NAME, 1.0f / static_cast<float>( numSamples - 1.0f ) );
270 void MotionBlurEffect::SetTexcoordScale( float texcoordScale )
272 SetUniform( MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME, texcoordScale );
275 void MotionBlurEffect::SetGeometryStretchFactor( float scalingFactor )
277 SetUniform( MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME, scalingFactor );
280 void MotionBlurEffect::SetSpeedScalingFactor( float scalingFactor )
282 SetUniform( MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME, scalingFactor );
285 void MotionBlurEffect::SetObjectFadeStart( Vector2 displacement )
287 SetUniform( MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME, displacement );
290 void MotionBlurEffect::SetObjectFadeEnd( Vector2 displacement )
292 SetUniform( MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME, displacement );
295 void MotionBlurEffect::SetAlphaScale( float alphaScale )
297 SetUniform( MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME, alphaScale );
300 const std::string& MotionBlurEffect::GetTexcoordScalePropertyName() const
302 return MOTION_BLUR_TEXCOORD_SCALE_PROPERTY_NAME;
305 const std::string& MotionBlurEffect::GetGeometryStretchFactorPropertyName() const
307 return MOTION_BLUR_GEOM_STRETCH_SCALING_FACTOR_PROPERTY_NAME;
310 const std::string& MotionBlurEffect::GetSpeedScalingFactorPropertyName() const
312 return MOTION_BLUR_SPEED_SCALING_FACTOR_PROPERTY_NAME;
315 const std::string& MotionBlurEffect::GetObjectFadeStartPropertyName() const
317 return MOTION_BLUR_OBJECT_FADE_START_PROPERTY_NAME;
320 const std::string& MotionBlurEffect::GetObjectFadeEndPropertyName() const
322 return MOTION_BLUR_OBJECT_FADE_END_PROPERTY_NAME;
325 const std::string& MotionBlurEffect::GetAlphaScalePropertyName() const
327 return MOTION_BLUR_ALPHA_SCALE_PROPERTY_NAME;