SortKey.m_Blend

[SunGQ1987]

m_key.m_blend = "\x0\x2\x2\x3\x3\x2\x3\x2\x3\x2\x2\x2\x2\x2\x2\x2\x2\x2\x2"[( (blend)&0xf) + (!!blend)] + !!alphaRef;
what does this magic table means?

[bkaradzic]

Line you picked, have comment above:

bgfx/src/bgfx_p.h

Lines 2402 to 2403 in 946852c

	// transparency sort order table
	m_key.m_blend = "\x0\x2\x2\x3\x3\x2\x3\x2\x3\x2\x2\x2\x2\x2\x2\x2\x2\x2\x2"[( (blend)&0xf) + (!!blend)] + !!alphaRef;

[bkaradzic]

I added more info in code:

bgfx/src/bgfx_p.h

Lines 2403 to 2420 in 99a7af7

	// Transparency sort order table:
	//
	// +----------------------------------------- BGFX_STATE_BLEND_ZERO
	// | +-------------------------------------- BGFX_STATE_BLEND_ONE
	// | | +----------------------------------- BGFX_STATE_BLEND_SRC_COLOR
	// | | | +-------------------------------- BGFX_STATE_BLEND_INV_SRC_COLOR
	// | | | | +----------------------------- BGFX_STATE_BLEND_SRC_ALPHA
	// | | | | | +-------------------------- BGFX_STATE_BLEND_INV_SRC_ALPHA
	// | | | | | | +----------------------- BGFX_STATE_BLEND_DST_ALPHA
	// | | | | | | | +-------------------- BGFX_STATE_BLEND_INV_DST_ALPHA
	// | | | | | | | | +----------------- BGFX_STATE_BLEND_DST_COLOR
	// | | | | | | | | | +-------------- BGFX_STATE_BLEND_INV_DST_COLOR
	// | | | | | | | | | | +----------- BGFX_STATE_BLEND_SRC_ALPHA_SAT
	// | | | | | | | | | | | +-------- BGFX_STATE_BLEND_FACTOR
	// | | | | | | | | | | | | +----- BGFX_STATE_BLEND_INV_FACTOR
	// | | | | | | | | | | | | |
	// x | | | | | | | | | | | | | x x x x x
	m_key.m_blend = "\x0\x2\x2\x3\x3\x2\x3\x2\x3\x2\x2\x2\x2\x2\x2\x2\x2\x2\x2"[( (blend)&0xf) + (!!blend)] + !!alphaRef;