Method initTexCoordsWithRect

core/2d/ParticleSystemQuad.cpp:149–211

pointRect should be in Texture coordinates, not pixel coordinates

// pointRect should be in Texture coordinates, not pixel coordinates
void ParticleSystemQuad::initTexCoordsWithRect(const Rect& pointRect)
{
    // convert to Tex coords

    Rect rect =
        Rect(pointRect.origin.x * AX_CONTENT_SCALE_FACTOR(), pointRect.origin.y * AX_CONTENT_SCALE_FACTOR(),
             pointRect.size.width * AX_CONTENT_SCALE_FACTOR(), pointRect.size.height * AX_CONTENT_SCALE_FACTOR());

    float wide = (float)pointRect.size.width;
    float high = (float)pointRect.size.height;

    if (_texture)
    {
        wide = (float)_texture->getPixelsWide();
        high = (float)_texture->getPixelsHigh();
    }

#if AX_FIX_ARTIFACTS_BY_STRECHING_TEXEL
    float left   = (rect.origin.x * 2 + 1) / (wide * 2);
    float bottom = (rect.origin.y * 2 + 1) / (high * 2);
    float right  = left + (rect.size.width * 2 - 2) / (wide * 2);
    float top    = bottom + (rect.size.height * 2 - 2) / (high * 2);
#else
    float left   = rect.origin.x / wide;
    float bottom = rect.origin.y / high;
    float right  = left + rect.size.width / wide;
    float top    = bottom + rect.size.height / high;
#endif  // ! AX_FIX_ARTIFACTS_BY_STRECHING_TEXEL

    // Important. Texture in axmol are inverted, so the Y component should be inverted
    std::swap(top, bottom);

    V3F_C4B_T2F_Quad* quads = nullptr;
    unsigned int start = 0, end = 0;
    if (_batchNode)
    {
        quads = _batchNode->getTextureAtlas()->getQuads();
        start = _atlasIndex;
        end   = _atlasIndex + _totalParticles;
    }
    else
    {
        quads = _quads;
        start = 0;
        end   = _totalParticles;
    }

    for (unsigned int i = start; i < end; i++)
    {
        // bottom-left vertex:
        quads[i].bl.texCoords.u = left;
        quads[i].bl.texCoords.v = bottom;
        // bottom-right vertex:
        quads[i].br.texCoords.u = right;
        quads[i].br.texCoords.v = bottom;
        // top-left vertex:
        quads[i].tl.texCoords.u = left;
        quads[i].tl.texCoords.v = top;