libavfilter: Add OpenCL convolution filter

Behaves like existing convolution filter.

Signed-off-by: Mark Thompson <sw@jkqxz.net>

1 files changed, 45 insertions, 0 deletions

diff --git a/libavfilter/opencl/convolution.cl b/libavfilter/opencl/convolution.cl
new file mode 100644
index 0000000..03ef4ef
--- /dev/null
+++ b/libavfilter/opencl/convolution.cl
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018 Danil Iashchenko
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+__kernel void convolution_global(__write_only image2d_t dst,
+                                 __read_only  image2d_t src,
+                                 int coef_matrix_dim,
+                                 __constant float *coef_matrix,
+                                 float div,
+                                 float bias)
+{
+    const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
+                               CLK_ADDRESS_CLAMP_TO_EDGE   |
+                               CLK_FILTER_NEAREST);
+
+    const int half_matrix_dim = (coef_matrix_dim / 2);
+    int2 loc = (int2)(get_global_id(0), get_global_id(1));
+    float4 convPix = (float4)(0.0f, 0.0f, 0.0f, 0.0f);
+
+    for (int conv_i = -half_matrix_dim; conv_i <= half_matrix_dim; conv_i++) {
+        for (int conv_j = -half_matrix_dim; conv_j <= half_matrix_dim; conv_j++) {
+            float4 px = read_imagef(src, sampler, loc + (int2)(conv_j, conv_i));
+            convPix += px * coef_matrix[(conv_i + half_matrix_dim) * coef_matrix_dim +
+                                        (conv_j + half_matrix_dim)];
+        }
+     }
+     float4 dstPix = convPix * div + bias;
+     write_imagef(dst, loc, dstPix);
+}