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More restructuring code.

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This commit is contained in:
David Williams 2014-07-24 15:40:03 +02:00
parent 972bc3a456
commit 98e722271e
1 changed files with 24 additions and 60 deletions
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84
library/PolyVoxCore/include/PolyVoxCore/MarchingCubesSurfaceExtractor.h
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@ -64,60 +64,6 @@ namespace PolyVox
return result; return result;
} }
// Returns ±1
float signNotZero(float v)
{
return v >= 0.0f ? +1.0f : -1.0f;
}
// Assume normalized input. Output is on [-1, 1] for each component.
Vector2DFloat float32x3_to_oct(Vector3DFloat v)
{
// Get the input components
float vx = v.getX();
float vy = v.getY();
float vz = v.getZ();
// Project the sphere onto the octahedron, and then onto the xy plane
float px = vx * (1.0f / (abs(vx) + abs(vy) + abs(vz)));
float py = vy * (1.0f / (abs(vx) + abs(vy) + abs(vz)));
// Reflect the folds of the lower hemisphere over the diagonals
if (vz <= 0.0f)
{
float refx = ((1.0f - abs(py)) * signNotZero(px));
float refy = ((1.0f - abs(px)) * signNotZero(py));
px = refx;
py = refy;
}
Vector2DFloat p(px, py);
// Reflect the folds of the lower hemisphere over the diagonals
return p;
}
Vector3DFloat oct_to_float32x3(Vector2DFloat e)
{
Vector3DFloat v = Vector3DFloat(e.getX(), e.getY(), 1.0 - abs(e.getX()) - abs(e.getY()));
float refX = ((1.0f - abs(v.getY())) * signNotZero(v.getX()));
float refY = ((1.0f - abs(v.getX())) * signNotZero(v.getY()));
Vector2DFloat ref(refX, refY);
if (v.getZ() < 0.0f)
{
//v.xy = (1.0 - abs(v.yx)) * signNotZero(v.xy);
v.setX(refX);
v.setY(refY);
}
v.normalise();
return v;
}
inline uint16_t encodeNormal(const Vector3DFloat& normal) inline uint16_t encodeNormal(const Vector3DFloat& normal)
{ {
// The first part of this function is based off the code in Listing 1 of http://jcgt.org/published/0003/02/01/ // The first part of this function is based off the code in Listing 1 of http://jcgt.org/published/0003/02/01/
@ -163,14 +109,32 @@ namespace PolyVox
inline Vector3DFloat decode(const uint16_t& encodedNormal) inline Vector3DFloat decode(const uint16_t& encodedNormal)
{ {
uint16_t x = (encodedNormal >> 8) & 0xFF; // Extract the two bytes from the uint16_t.
uint16_t y = (encodedNormal ) & 0xFF; uint16_t ux = (encodedNormal >> 8) & 0xFF;
Vector2DFloat floatNormal(x, y); uint16_t uy = (encodedNormal ) & 0xFF;
floatNormal /= Vector2DFloat(127.5f, 127.5f); // Convert to floats in the range [-1.0f, +1.0f].
floatNormal -= Vector2DFloat(1.0f, 1.0f); float ex = ux / 127.5f - 1.0f;
float ey = uy / 127.5f - 1.0f;
return oct_to_float32x3(floatNormal); // Reconstruct the origninal vector. This is a C++ implementation
// of Listing 2 of http://jcgt.org/published/0003/02/01/
float vx = ex;
float vy = ey;
float vz = 1.0f - abs(ex) - abs(ey);
if (vz < 0.0f)
{
float refX = ((1.0f - abs(vy)) * (vx >= 0.0f ? +1.0f : -1.0f));
float refY = ((1.0f - abs(vx)) * (vy >= 0.0f ? +1.0f : -1.0f));
vx = refX;
vy = refY;
}
// Normalise and return the result.
Vector3DFloat v(vx, vy, vz);
v.normalise();
return v;
} }
/// Decodes a MarchingCubesVertex by converting it into a regular Vertex which can then be directly used for rendering. /// Decodes a MarchingCubesVertex by converting it into a regular Vertex which can then be directly used for rendering.