mirror of https://github.com/bsnes-emu/bsnes.git
70 lines
2.4 KiB
C++
70 lines
2.4 KiB
C++
auto PPU::Screen::run(uint x, uint y) -> uint15 {
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if(ppu.blank()) return 0x7fff;
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//determine active window
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uint1 active[6] = {true, true, true, true, true, true}; //enable all layers if no windows are enabled
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if(ppu.window0.io.enable || ppu.window1.io.enable || ppu.window2.io.enable) {
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memory::copy(&active, &ppu.window3.io.active, sizeof(active));
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if(ppu.window2.io.enable && ppu.window2.output) memory::copy(&active, &ppu.window2.io.active, sizeof(active));
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if(ppu.window1.io.enable && ppu.window1.output) memory::copy(&active, &ppu.window1.io.active, sizeof(active));
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if(ppu.window0.io.enable && ppu.window0.output) memory::copy(&active, &ppu.window0.io.active, sizeof(active));
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}
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//priority sorting: find topmost two pixels
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Pixel layers[6] = {
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ppu.objects.mosaic,
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ppu.bg0.mosaic,
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ppu.bg1.mosaic,
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ppu.bg2.mosaic,
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ppu.bg3.mosaic,
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{true, 3, ppu.pram[0]},
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};
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uint aboveLayer = 5, belowLayer = 5;
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for(int priority = 3; priority >= 0; priority--) {
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for(int layer = 5; layer >= 0; layer--) {
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if(layers[layer].enable && layers[layer].priority == priority && active[layer]) {
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belowLayer = aboveLayer;
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aboveLayer = layer;
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}
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}
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}
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auto above = layers[aboveLayer];
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auto below = layers[belowLayer];
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auto eva = min(16u, (uint)io.blendEVA);
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auto evb = min(16u, (uint)io.blendEVB);
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auto evy = min(16u, (uint)io.blendEVY);
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uint15 color = above.color;
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//color blending
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if(active[SFX]) {
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if(above.translucent && io.blendBelow[belowLayer]) {
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color = blend(above.color, eva, below.color, evb);
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} else if(io.blendMode == 1 && io.blendAbove[aboveLayer] && io.blendBelow[belowLayer]) {
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color = blend(above.color, eva, below.color, evb);
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} else if(io.blendMode == 2 && io.blendAbove[aboveLayer]) {
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color = blend(above.color, 16 - evy, 0x7fff, evy);
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} else if(io.blendMode == 3 && io.blendAbove[aboveLayer]) {
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color = blend(above.color, 16 - evy, 0x0000, evy);
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}
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}
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return color;
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}
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auto PPU::Screen::blend(uint15 above, uint eva, uint15 below, uint evb) -> uint15 {
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uint5 ar = above >> 0, ag = above >> 5, ab = above >> 10;
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uint5 br = below >> 0, bg = below >> 5, bb = below >> 10;
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uint r = (ar * eva + br * evb) >> 4;
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uint g = (ag * eva + bg * evb) >> 4;
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uint b = (ab * eva + bb * evb) >> 4;
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return min(31u, r) << 0 | min(31u, g) << 5 | min(31u, b) << 10;
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}
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auto PPU::Screen::power() -> void {
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io = {};
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}
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