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Diffstat (limited to 'source/blender/draw/engines/eevee/shaders/effect_velocity_tile_frag.glsl')
| -rw-r--r-- | source/blender/draw/engines/eevee/shaders/effect_velocity_tile_frag.glsl | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/source/blender/draw/engines/eevee/shaders/effect_velocity_tile_frag.glsl b/source/blender/draw/engines/eevee/shaders/effect_velocity_tile_frag.glsl new file mode 100644 index 00000000000..0eb598521af --- /dev/null +++ b/source/blender/draw/engines/eevee/shaders/effect_velocity_tile_frag.glsl @@ -0,0 +1,151 @@ +/** + * Shaders that down-sample velocity buffer, + * + * Based on: + * A Fast and Stable Feature-Aware Motion Blur Filter + * by Jean-Philippe Guertin, Morgan McGuire, Derek Nowrouzezahrai + * + * Adapted from G3D Innovation Engine implementation. + */ + +uniform sampler2D velocityBuffer; +uniform vec2 viewportSize; +uniform vec2 viewportSizeInv; +uniform ivec2 velocityBufferSize; + +out vec4 tileMaxVelocity; + +vec4 sample_velocity(ivec2 texel) +{ + texel = clamp(texel, ivec2(0), velocityBufferSize - 1); + vec4 data = texelFetch(velocityBuffer, texel, 0); + /* Decode data. */ + return (data * 2.0 - 1.0) * viewportSize.xyxy; +} + +vec4 encode_velocity(vec4 velocity) +{ + return velocity * viewportSizeInv.xyxy * 0.5 + 0.5; +} + +#ifdef TILE_GATHER + +uniform ivec2 gatherStep; + +void main() +{ + vec4 max_motion = vec4(0.0); + float max_motion_len_sqr_prev = 0.0; + float max_motion_len_sqr_next = 0.0; + ivec2 texel = ivec2(gl_FragCoord.xy); + texel = texel * gatherStep.yx + texel * EEVEE_VELOCITY_TILE_SIZE * gatherStep; + + for (int i = 0; i < EEVEE_VELOCITY_TILE_SIZE; ++i) { + vec4 motion = sample_velocity(texel + i * gatherStep); + float motion_len_sqr_prev = dot(motion.xy, motion.xy); + float motion_len_sqr_next = dot(motion.zw, motion.zw); + + if (motion_len_sqr_prev > max_motion_len_sqr_prev) { + max_motion_len_sqr_prev = motion_len_sqr_prev; + max_motion.xy = motion.xy; + } + if (motion_len_sqr_next > max_motion_len_sqr_next) { + max_motion_len_sqr_next = motion_len_sqr_next; + max_motion.zw = motion.zw; + } + } + + tileMaxVelocity = encode_velocity(max_motion); +} + +#else /* TILE_EXPANSION */ + +bool neighbor_affect_this_tile(ivec2 offset, vec2 velocity) +{ + /* Manhattan distance to the tiles, which is used for + * differentiating corners versus middle blocks */ + float displacement = float(abs(offset.x) + abs(offset.y)); + /** + * Relative sign on each axis of the offset compared + * to the velocity for that tile. In order for a tile + * to affect the center tile, it must have a + * neighborhood velocity in which x and y both have + * identical or both have opposite signs relative to + * offset. If the offset coordinate is zero then + * velocity is irrelevant. + **/ + vec2 point = sign(offset * velocity); + + float dist = (point.x + point.y); + /** + * Here's an example of the logic for this code. + * In this diagram, the upper-left tile has offset = (-1, -1). + * V1 is velocity = (1, -2). point in this case = (-1, 1), and therefore dist = 0, + * so the upper-left tile does not affect the center. + * + * Now, look at another case. V2 = (-1, -2). point = (1, 1), so dist = 2 and the tile + * does affect the center. + * + * V2(-1,-2) V1(1, -2) + * \ / + * \ / + * \/___ ____ ____ + * (-1, -1)| | | | + * |____|____|____| + * | | | | + * |____|____|____| + * | | | | + * |____|____|____| + **/ + return (abs(dist) == displacement); +} + +/** + * Only gather neighborhood velocity into tiles that could be affected by it. + * In the general case, only six of the eight neighbors contribute: + * + * This tile can't possibly be affected by the center one + * | + * v + * ____ ____ ____ + * | | ///|/// | + * |____|////|//__| + * | |////|/ | + * |___/|////|____| + * | //|////| | <--- This tile can't possibly be affected by the center one + * |_///|///_|____| + **/ +void main() +{ + vec4 max_motion = vec4(0.0); + float max_motion_len_sqr_prev = -1.0; + float max_motion_len_sqr_next = -1.0; + + ivec2 tile = ivec2(gl_FragCoord.xy); + ivec2 offset = ivec2(0); + for (offset.y = -1; offset.y <= 1; ++offset.y) { + for (offset.x = -1; offset.x <= 1; ++offset.x) { + vec4 motion = sample_velocity(tile + offset); + float motion_len_sqr_prev = dot(motion.xy, motion.xy); + float motion_len_sqr_next = dot(motion.zw, motion.zw); + + if (motion_len_sqr_prev > max_motion_len_sqr_prev) { + if (neighbor_affect_this_tile(offset, motion.xy)) { + max_motion_len_sqr_prev = motion_len_sqr_prev; + max_motion.xy = motion.xy; + } + } + + if (motion_len_sqr_next > max_motion_len_sqr_next) { + if (neighbor_affect_this_tile(offset, motion.zw)) { + max_motion_len_sqr_next = motion_len_sqr_next; + max_motion.zw = motion.zw; + } + } + } + } + + tileMaxVelocity = encode_velocity(max_motion); +} + +#endif
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