COMPMID-344 Updated doxygen

Change-Id: I32f7b84daa560e460b77216add529c8fa8b327ae
diff --git a/src/core/CL/cl_kernels/warp_affine.cl b/src/core/CL/cl_kernels/warp_affine.cl
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+/*
+ * Copyright (c) 2016, 2017 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "helpers.h"
+#include "warp_helpers.h"
+
+/** Returns a vector of floats contaning the matrix coefficients. */
+inline const float8 build_affine_mtx()
+{
+    return (float8)(MAT0, MAT1, MAT2, MAT3, MAT4, MAT5, 0, 0);
+}
+
+/** Transforms 4 2D coordinates using the formula:
+ *
+ *   x0 = M[1][1] * x + M[1][2] * y + M[1][3]
+ *   y0 = M[2][1] * x + M[2][2] * y + M[2][3]
+ *
+ * @param[in] coord 2D coordinate to transform.
+ * @param[in] mtx   affine matrix
+ *
+ * @return a int8 containing 4 2D transformed values.
+ */
+inline const float8 apply_affine_transform(const float2 coord, const float8 mtx)
+{
+    const float4 in_x_coords = (float4)(coord.s0, 1 + coord.s0, 2 + coord.s0, 3 + coord.s0);
+    // transform [x,x+1,x+2,x+3]
+    const float4 new_x = mad(/*A*/ in_x_coords, (float4)(mtx.s0) /*B*/, mad((float4)(coord.s1), (float4)(mtx.s2), (float4)(mtx.s4)));
+    // transform [y,y+1,y+2,y+3]
+    const float4 new_y = mad(in_x_coords, (float4)(mtx.s1), mad((float4)(coord.s1), (float4)(mtx.s3), (float4)(mtx.s5)));
+    return (float8)(new_x.s0, new_y.s0, new_x.s1, new_y.s1, new_x.s2, new_y.s2, new_x.s3, new_y.s3);
+}
+
+/** Performs an affine transform on an image interpolating with the NEAREAST NEIGHBOUR method. Input and output are single channel U8.
+ *
+ * This kernel performs an affine transform with a 2x3 Matrix M with this method of pixel coordinate translation:
+ *   x0 = M[1][1] * x + M[1][2] * y + M[1][3]
+ *   y0 = M[2][1] * x + M[2][2] * y + M[2][3]
+ *   output(x,y) = input(x0,y0)
+ *
+ * @attention The matrix coefficients need to be passed at compile time:\n
+ * const char build_options [] = "-DMAT0=1 -DMAT1=2 -DMAT2=1 -DMAT3=2 -DMAT4=4 -DMAT5=2 "\n
+ * clBuildProgram( program, 0, NULL, build_options, NULL, NULL);
+ *
+ * @param[in]  in_ptr                            Pointer to the source image. Supported data types: U8.
+ * @param[in]  in_stride_x                       Stride of the source image in X dimension (in bytes)
+ * @param[in]  in_step_x                         in_stride_x * number of elements along X processed per work item (in bytes)
+ * @param[in]  in_stride_y                       Stride of the source image in Y dimension (in bytes)
+ * @param[in]  in_step_y                         in_stride_y * number of elements along Y processed per work item (in bytes)
+ * @param[in]  in_offset_first_element_in_bytes  Offset of the first element in the source image
+ * @param[out] out_ptr                           Pointer to the destination image. Supported data types: U8.
+ * @param[in]  out_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]  out_step_x                        out_stride_x * number of elements along X processed per work item (in bytes)
+ * @param[in]  out_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]  out_step_y                        out_stride_y * number of elements along Y processed per work item (in bytes)
+ * @param[in]  out_offset_first_element_in_bytes Offset of the first element in the destination image
+ * @param[in]  width                             Width of the destination image
+ * @param[in]  height                            Height of the destination image
+ */
+__kernel void warp_affine_nearest_neighbour(
+    IMAGE_DECLARATION(in),
+    IMAGE_DECLARATION(out),
+    const int width,
+    const int height)
+{
+    Image in  = CONVERT_TO_IMAGE_STRUCT_NO_STEP(in);
+    Image out = CONVERT_TO_IMAGE_STRUCT(out);
+    vstore4(read_texels4(&in, convert_int8(clamp_to_border(apply_affine_transform(get_current_coords(), build_affine_mtx()), width, height))), 0, out.ptr);
+}
+
+/** Performs an affine transform on an image interpolating with the BILINEAR method. Input and output are single channel U8.
+ *
+ * @attention The matrix coefficients need to be passed at compile time:\n
+ * const char build_options [] = "-DMAT0=1 -DMAT1=2 -DMAT2=1 -DMAT3=2 -DMAT4=4 -DMAT5=2 "\n
+ * clBuildProgram( program, 0, NULL, build_options, NULL, NULL);
+ *
+ * @param[in]  in_ptr                            Pointer to the source image. Supported data types: U8.
+ * @param[in]  in_stride_x                       Stride of the source image in X dimension (in bytes)
+ * @param[in]  in_step_x                         in_stride_x * number of elements along X processed per work item (in bytes)
+ * @param[in]  in_stride_y                       Stride of the source image in Y dimension (in bytes)
+ * @param[in]  in_step_y                         in_stride_y * number of elements along Y processed per work item (in bytes)
+ * @param[in]  in_offset_first_element_in_bytes  Offset of the first element in the source image
+ * @param[out] out_ptr                           Pointer to the destination image. Supported data types: U8.
+ * @param[in]  out_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]  out_step_x                        out_stride_x * number of elements along X processed per work item (in bytes)
+ * @param[in]  out_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]  out_step_y                        out_stride_y * number of elements along Y processed per work item (in bytes)
+ * @param[in]  out_offset_first_element_in_bytes Offset of the first element in the destination image
+ * @param[in]  width                             Width of the destination image
+ * @param[in]  height                            Height of the destination image
+ */
+__kernel void warp_affine_bilinear(
+    IMAGE_DECLARATION(in),
+    IMAGE_DECLARATION(out),
+    const int width,
+    const int height)
+{
+    Image in  = CONVERT_TO_IMAGE_STRUCT_NO_STEP(in);
+    Image out = CONVERT_TO_IMAGE_STRUCT(out);
+    vstore4(bilinear_interpolate(&in, clamp_to_border(apply_affine_transform(get_current_coords(), build_affine_mtx()), width, height), width, height), 0, out.ptr);
+}