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about tile priority and colors

vbt - Aug 14, 2014

		vbt	Aug 14, 2014
		i have some troubles with emulation on saturn and i think it can be solved. on some games tiles from the same layer(map) have a priority over sprites. normally it's possible to do the same on saturn but i didn't find the good way. does someone knows how to do that ? another boring thing is transparent color. if i enable transparency when i allocate color for a layer, there is always transparency, on some cases it should not be transparent (it dépends on palette in fact). is possible to enable/disable transparency in the tile attributes ? good examples are vigilante and ghost n goblins on vigilante titles it uses 2 palettes, on with black as transparent, another palette with black visible with maybe not same tile. if i disable transparency i don't see the background, on the other case, i see the complete background (it should be in a window) about priorities, sprites must be behind tires. see pictures attached [attachment=4410][a ttachment=4412][atta chment=4413]

		vbt	Aug 17, 2014
		about priority, surix helped me : special priority bit must be used, in order to work : - sprites and nbg must have same priority (sprite will be displayed over tiles) - special priority mode must be set to 1 - set 1 to SP in the cell SS_SET_S0PRIN(4); // sprite priority SS_SET_N0PRIN(4); // nbg priority SS_SET_N0SPRM(1); // 1 for special priority map[0] = map[0x2000] = Colour + 0x2000; // 0x2000 sets the special priority bit map[1] = map[0x2001] = Tile; about color transparency, some help of Guillaume(yabause) but not yet working as expected (or yabause supports modes partially). i can't test on saturn. so it could be done with special color calculation. to set it up : - color calculation ratio mode bit set to 0 - color calculation mode bit set to 0 - enable color calculation - set color calculation mode to 1 or 2 (by tile or dot) - set color calculation ration 0 to 31 (31 = transparent) - set special code to ??? 1 maybe (if using mode 2) - set special code selection to a color number 0 ??? (if using mode 2) - special code values are unclear in the doc - set 1 to CC in the cell SS_SET_CCRTMD(0); // color calc ratio mode bit SS_SET_CCMD(0); // color calc mode bit SS_SET_N0CCEN(1); // color calc enable SS_SET_N0SCCM(2); // color calc mode 1 on tile, 2 by dot, 3 color data with msb SS_SET_N0CCRT(10); // color calc ratio ss_regs->specialcode=1; // 1 for mode 2 ss_regs->special code_sel=0; map[0] = map[0x2000] = Colour + 0x1000; // 0x1000 sets the special color calculation map[1] = map[0x2001] = Tile; on yabause mode 1,2 &3 give same result maybe my setup is wrong, i thought the mode 2 (by dot) would set transparency only to the dots with color 0 [attachment=4414][a ttachment=4415][atta chment=4416]

		vbt	Aug 29, 2014
		correct transparency on ssf (on dot)     SS_SET_CCRTMD(0); // color calc ratio mode bit SS_SET_CCMD(0); // color calc mode bit SS_SET_N0CCEN(1); // color calc enable SS_SET_N0SCCM(2); // color calc mode 1 on tile, 2 by dot, 3 color data with msb SS_SET_N0CCRT(31); // color calc ratio ss_regs->specialcode=0x0001; // sfcode, upper 8bits, function b, lower 8bits function a // 1=> transparency applied on color 0 & 1 ss_regs->specialcode_sel=0; // sfsel, bit 0 for nbg0 // 1 sfcs, bit 0 = 1 for funcion code b, 0 for function code a [attachment=4420]

		vbt	Nov 10, 2014
		well, i give up with that game, now it's working well in yabause. Thanks to Guillaume (Yabause team) who has fixed color calculaton mode 2 emulation in yabause =) vigilante runs correctly without sound but looses lot of speed with ym2151 emulation. also sound support is partially working.