Add logencode filter.

cuburn/code/filters.py

@@ -77,6 +77,19 @@ yuv_to_rgb(float4 *dst, const float4 *src) {
 }
 ''')
 
+logencodelib = devlib(defs=r'''
+__global__ void
+logencode(float4 *dst, const float4 *src, float degamma) {
+    GET_IDX(i);
+    float4 pix = src[i];
+    pix.x = log2f(powf(pix.x, degamma)) / 12.0f + 1.0f;
+    pix.y = log2f(powf(pix.y, degamma)) / 12.0f + 1.0f;
+    pix.z = log2f(powf(pix.z, degamma)) / 12.0f + 1.0f;
+    pix.w = log2f(powf(pix.w, degamma)) / 12.0f + 1.0f;
+    dst[i] = pix;
+}
+''')
+
 denblurlib = devlib(deps=[texshearlib], decls='''
 texture<float4, cudaTextureType2D> chan4_src;
 texture<float,  cudaTextureType2D> chan1_src;

cuburn/filters.py

@@ -180,6 +180,17 @@ class ColorClip(Filter, ClsMod):
         launch2('colorclip', self.mod, stream, dim,
                 fb.d_front, vib, hipow, gam, lin, lingam)
 
+
+@Filter.register('logencode')
+class LogEncode(Filter, ClsMod):
+    lib = code.filters.logencodelib
+    def apply(self, fb, gprof, params, dim, tc, stream=None):
+        degamma = f32(params.degamma(tc))
+
+        launch2('logencode', self.mod, stream, dim,
+                fb.d_back, fb.d_front, degamma)
+        fb.flip()
+
 def create(gprof):
     order = ['yuv'] + gprof.filter_order
     return [Filter.filter_map[f]() for f in order]

cuburn/genome/specs.py

@@ -54,6 +54,7 @@ filters = (
   , 'haloclip': {}
   , 'smearclip': {'width': scalespline(0.7, d='Spatial stdev of filter')}
   , 'logscale': {'brightness': scalespline(4, d='Log-scale brightness')}
+  , 'logencode': {'degamma': scalespline(2.2)}
   , 'yuv': {}
   })