nerdcruft/libcruft-util
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noise-tool: interpolate the gradient colour

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This commit is contained in:
Danny Robson 2015-06-03 17:35:58 +10:00
parent 34406dc244
commit effecbf117
1 changed files with 12 additions and 9 deletions
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21
tools/noise.cpp
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@ -76,7 +76,7 @@ main (void)
std::transform (img.begin (), img.end (), img.begin (), [offset,div] (auto i) { return (i - offset) / div; });
// create colour data
// create a coloured map with this gradient
static const struct {
float scale;
util::colour3u value;
@ -89,22 +89,25 @@ main (void)
{ 22 / 32.f, { 224, 224, 0 } },
{ 28 / 32.f, { 128, 128, 128 } },
{ 32 / 32.f, { 255, 255, 255 } },
{ 32 / 32.f, { 255, 255, 255 } }
{ 1000000.f, { 255, 255, 255 } },
};
std::unique_ptr<uint8_t[]> coloured (new uint8_t[size.area () * 3]);
for (size_t i = 0; i < size.area (); ++i) {
auto v = img.data ()[i] + +8/32.f;
auto c0 = std::lower_bound (std::begin (GRADPOINT),
auto v = img.data ()[i] + 0/32.f;
auto c1 = std::upper_bound (std::begin (GRADPOINT),
std::end (GRADPOINT),
v,
[] (auto a, auto b) { return a.scale < b; });
auto c1 = c0+1;
[] (auto a, auto b) { return a < b.scale; });
auto c0 = c1-1;
CHECK_GE (v, c0->scale);
CHECK_LT (v, c1->scale);
float t = (v - c0->scale) / (c1->scale - c0->scale);
CHECK_LIMIT (t, 0, 1);
auto c = (
(c0->value.template cast<float> () +
c1->value.template cast<float> ()
) / 2.f
(1 - t) * c0->value.template cast<float> () +
( t) * c1->value.template cast<float> ()
).template cast<uint8_t> ();
coloured[i*3+0] = c[0];