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Implement bump-mapping in pcg

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This commit is contained in:
Nikita Lisitsa 2020-12-13 16:10:40 +03:00
parent e1b1030160
commit 2a3337a912
1 changed files with 50 additions and 0 deletions
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libs/pcg/include/psemek/pcg/bump.hpp Normal file
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#pragma once
#include <psemek/pcg/seamless.hpp>
#include <psemek/gfx/pixmap.hpp>
namespace psemek::pcg
{
inline gfx::basic_pixmap<geom::vector<float, 3>> bump(gfx::pixmap_float const & height_map, seamless_tag)
{
gfx::basic_pixmap<geom::vector<float, 3>> result(height_map.dims());
float const dx = 1.f / result.width();
float const dy = 1.f / result.height();
for (auto i : result.indices())
{
auto ix0 = i;
ix0[0] = (ix0[0] + result.width() - 1) % result.width();
auto ix1 = i;
ix1[0] = (ix1[0] + 1) % result.width();
auto iy0 = i;
iy0[1] = (iy0[1] + result.height() - 1) % result.height();
auto iy1 = i;
iy1[1] = (iy1[1] + 1) % result.height();
float h = height_map(i);
float hx0 = height_map(ix0);
float hx1 = height_map(ix1);
float hy0 = height_map(iy0);
float hy1 = height_map(iy1);
auto n = geom::vector<float, 3>::zero();
n += geom::normalized(geom::vector{hx0 - h, 0.f, dx});
n += geom::normalized(geom::vector{h - hx1, 0.f, dx});
n += geom::normalized(geom::vector{0.f, hy0 - h, dy});
n += geom::normalized(geom::vector{0.f, h - hy1, dy});
result(i) = geom::normalized(n);
}
return result;
}
}