skia2/tests/ParametricStageTest.cpp
Brian Osman 11e6aa823d Starting to hack up HDR transfer function support
Brings over skcms' encoding scheme, etc.

Change-Id: Ib8abec911acd1c50df3b201b4a9bde01b1cb123b
Bug: chromium:960620
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249000
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
2019-10-16 18:40:16 +00:00

79 lines
2.6 KiB
C++

/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/core/SkColorSpace.h"
#include "src/core/SkRasterPipeline.h"
#include "tests/Test.h"
static void check_error(skiatest::Reporter* r, float limit, skcms_TransferFunction fn) {
float in[256], out[256];
for (int i = 0; i < 256; i++) {
in [i] = i / 255.0f;
out[i] = 0.0f; // Not likely important. Just being tidy.
}
SkRasterPipeline_MemoryCtx ip = { in, 0},
op = {out, 0};
SkRasterPipeline_<256> p;
p.append(SkRasterPipeline::load_f32, &ip);
p.append_transfer_function(fn);
p.append(SkRasterPipeline::store_f32, &op);
p.run(0,0, 256/4,1);
for (int i = 0; i < 256; i++) {
float want = (in[i] <= fn.d) ? fn.c * in[i] + fn.f
: powf(in[i] * fn.a + fn.b, fn.g) + fn.e;
if (i % 4 == 3) { // alpha should stay unchanged.
want = in[i];
}
float err = fabsf(out[i] - want);
if (err > limit) {
ERRORF(r, "At %d, error was %g (got %g, want %g)", i, err, out[i], want);
}
}
}
static void check_error(skiatest::Reporter* r, float limit, float gamma) {
skcms_TransferFunction fn = {0,0,0,0,0,0,0};
fn.g = gamma;
fn.a = 1;
check_error(r, limit, fn);
}
DEF_TEST(Parametric_sRGB, r) {
// Test our good buddy the sRGB transfer function in resplendent 7-parameter glory.
check_error(r, 1/510.0f, {
2.4f,
1.0f / 1.055f,
0.055f / 1.055f,
1.0f / 12.92f,
0.04045f,
0.0f,
0.0f,
});
}
// A nice little spread of simple gammas.
DEF_TEST(Parametric_1dot0, r) { check_error(r, 1/510.0f, 1.0f); }
DEF_TEST(Parametric_1dot2, r) { check_error(r, 1/510.0f, 1.2f); }
DEF_TEST(Parametric_1dot4, r) { check_error(r, 1/510.0f, 1.4f); }
DEF_TEST(Parametric_1dot8, r) { check_error(r, 1/510.0f, 1.8f); }
DEF_TEST(Parametric_2dot0, r) { check_error(r, 1/510.0f, 2.0f); }
DEF_TEST(Parametric_2dot2, r) { check_error(r, 1/510.0f, 2.2f); }
DEF_TEST(Parametric_2dot4, r) { check_error(r, 1/510.0f, 2.4f); }
DEF_TEST(Parametric_inv_1dot2, r) { check_error(r, 1/510.0f, 1/1.2f); }
DEF_TEST(Parametric_inv_1dot4, r) { check_error(r, 1/510.0f, 1/1.4f); }
DEF_TEST(Parametric_inv_1dot8, r) { check_error(r, 1/510.0f, 1/1.8f); }
DEF_TEST(Parametric_inv_2dot0, r) { check_error(r, 1/510.0f, 1/2.0f); }
DEF_TEST(Parametric_inv_2dot2, r) { check_error(r, 1/510.0f, 1/2.2f); }
DEF_TEST(Parametric_inv_2dot4, r) { check_error(r, 1/510.0f, 1/2.4f); }