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bilinear filter in Texture::getPixel

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This commit is contained in:
Mikulas Florek 2014-09-05 22:54:19 +02:00
parent 6dbe3f8b43
commit 246ea8eff4
2 changed files with 31 additions and 11 deletions
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40
src/graphics/texture.cpp
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@ -449,21 +449,41 @@ namespace Lumix
glBindTexture(m_is_cubemap ? GL_TEXTURE_CUBE_MAP : GL_TEXTURE_2D, m_id);
}
uint32_t Texture::getPixel(int x, int y)
uint32_t Texture::getPixel(float x, float y)
{
if(m_data.empty() || x >= m_width || y >= m_height || x < 0 || y < 0)
{
return 0;
}
switch(m_BPP)
{
case 4:
return *(uint32_t*)&m_data[(x + y * m_width) * 4];
default:
ASSERT(false);
return 0;
}
// http://fastcpp.blogspot.sk/2011/06/bilinear-pixel-interpolation-using-sse.html
int px = (int)x;
int py = (int)y;
const uint32_t* p0 = (uint32_t*)&m_data[(px + py * m_width) * 4];
const uint8_t* p1 = (uint8_t*)p0;
const uint8_t* p2 = (uint8_t*)(p0 + 1);
const uint8_t* p3 = (uint8_t*)(p0 + m_width);
const uint8_t* p4 = (uint8_t*)(p0 + 1 + m_width);
float fx = x - px;
float fy = y - py;
float fx1 = 1.0f - fx;
float fy1 = 1.0f - fy;
int w1 = (int)(fx1 * fy1 * 256.0f);
int w2 = (int)(fx * fy1 * 256.0f);
int w3 = (int)(fx1 * fy * 256.0f);
int w4 = (int)(fx * fy * 256.0f);
uint8_t res[4];
res[0] = (p1[0] * w1 + p2[0] * w2 + p3[0] * w3 + p4[0] * w4) >> 8;
res[1] = (p1[1] * w1 + p2[1] * w2 + p3[1] * w3 + p4[1] * w4) >> 8;
res[2] = (p1[2] * w1 + p2[2] * w2 + p3[2] * w3 + p4[2] * w4) >> 8;
res[3] = (p1[3] * w1 + p2[3] * w2 + p3[3] * w3 + p4[3] * w4) >> 8;
return *(uint32_t*)res;
}

2
src/graphics/texture.h
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@ -31,7 +31,7 @@ class LUMIX_ENGINE_API Texture : public Resource
void removeDataReference();
void onDataUpdated();
void save();
uint32_t getPixel(int x, int y);
uint32_t getPixel(float x, float y);
private:
void loaded(FS::IFile* file, bool success, FS::FileSystem& fs);