PulseStudio/VoxelEngine
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reimplement bicubic interpolation

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This commit is contained in:
MihailRis 2024-10-28 01:38:34 +03:00
parent 78fcc46f79
commit 99d9533453
1 changed files with 32 additions and 5 deletions
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37
src/maths/Heightmap.cpp
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@ -5,10 +5,6 @@
#include <stdexcept>
#include <glm/glm.hpp>
static inline float smootherstep(float x) {
return glm::smoothstep(std::floor(x), std::floor(x)+1, x);
}
static inline float sample_at(
const float* buffer,
uint width,
@ -17,6 +13,27 @@ static inline float sample_at(
return buffer[y*width+x];
}
static inline float sample_at(
const float* buffer,
uint width, uint height,
uint x, uint y
) {
return buffer[(y >= height ? height-1 : y)*width+(x >= width ? width-1 : x)];
}
static inline float interpolate_cubic(float p[4], float x) {
return p[1] + 0.5 * x*(p[2] - p[0] + x*(2.0*p[0] - 5.0*p[1] + 4.0*p[2] -
p[3] + x*(3.0*(p[1] - p[2]) + p[3] - p[0])));
}
static inline float interpolate_bicubic(float p[4][4], float x, float y) {
float q[4];
for (int i = 0; i < 4; i++) {
q[i] = interpolate_cubic(p[i], y);
}
return interpolate_cubic(q, x);
}
static inline float sample_at(
const float* buffer,
uint width, uint height,
@ -50,7 +67,17 @@ static inline float sample_at(
return a00 + a10*tx + a01*ty + a11*tx*ty;
}
// TODO: implement CUBIC (Bicubic) interpolation
case InterpolationType::CUBIC: {
float p[4][4];
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
p[i][j] = sample_at(
buffer, width, height, ix + j - 1, iy + i - 1
);
}
}
return interpolate_bicubic(p, ty, tx);
}
default:
throw std::runtime_error("interpolation type is not implemented");
}