()
| 612 | } |
| 613 | |
| 614 | func (ppu *PPU) evaluateSprites() { |
| 615 | var h int |
| 616 | if ppu.flagSpriteSize == 0 { |
| 617 | h = 8 |
| 618 | } else { |
| 619 | h = 16 |
| 620 | } |
| 621 | count := 0 |
| 622 | for i := 0; i < 64; i++ { |
| 623 | y := ppu.oamData[i*4+0] |
| 624 | a := ppu.oamData[i*4+2] |
| 625 | x := ppu.oamData[i*4+3] |
| 626 | row := ppu.ScanLine - int(y) |
| 627 | if row < 0 || row >= h { |
| 628 | continue |
| 629 | } |
| 630 | if count < 8 { |
| 631 | ppu.spritePatterns[count] = ppu.fetchSpritePattern(i, row) |
| 632 | ppu.spritePositions[count] = x |
| 633 | ppu.spritePriorities[count] = (a >> 5) & 1 |
| 634 | ppu.spriteIndexes[count] = byte(i) |
| 635 | } |
| 636 | count++ |
| 637 | } |
| 638 | if count > 8 { |
| 639 | count = 8 |
| 640 | ppu.flagSpriteOverflow = 1 |
| 641 | } |
| 642 | ppu.spriteCount = count |
| 643 | } |
| 644 | |
| 645 | // tick updates Cycle, ScanLine and Frame counters |
| 646 | func (ppu *PPU) tick() { |
no test coverage detected