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More scanline changes. Try to render only what we need to see.

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2017-10-04 01:28:33 +01:00
parent d5a724fdb4
commit 2b5324cb43
1 changed files with 33 additions and 34 deletions
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67
LR35902/src/Display.cpp
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@ -22,13 +22,15 @@ void EightBit::GameBoy::Display::initialise() {
}
void EightBit::GameBoy::Display::render() {
m_control = m_bus.peekRegister(Bus::LCDC);
if (m_control & Bus::LcdEnable) {
m_scanLine = m_bus.peekRegister(Bus::LY);
if (m_control & Bus::DisplayBackground)
renderBackground();
if (m_control & Bus::ObjectEnable)
renderObjects();
m_scanLine = m_bus.peekRegister(Bus::LY);
if (m_scanLine < RasterHeight) {
m_control = m_bus.peekRegister(Bus::LCDC);
if (m_control & Bus::LcdEnable) {
if (m_control & Bus::DisplayBackground)
renderBackground();
if (m_control & Bus::ObjectEnable)
renderObjects();
}
}
}
@ -71,12 +73,13 @@ void EightBit::GameBoy::Display::renderObjects(int objBlockHeight) {
const auto& current = m_objectAttributes[i];
const auto sprite = current.pattern();
const auto spriteX = current.positionX();
const auto spriteY = current.positionY();
const auto drawY = spriteY - 16;
const auto hidden = (spriteX == 0) && (spriteY == 0);
if ((m_scanLine >= drawY) && (m_scanLine < (drawY + objBlockHeight))) {
if (!hidden) {
const auto spriteX = current.positionX();
const auto drawX = spriteX - 8;
const auto definition = CharacterDefinition(&m_bus, objDefinitionAddress + 16 * sprite, objBlockHeight);
const auto& palette = palettes[current.palette()];
@ -85,7 +88,7 @@ void EightBit::GameBoy::Display::renderObjects(int objBlockHeight) {
renderTile(
objBlockHeight,
spriteX - 8, spriteY - 16,
drawX, drawY,
flipX, flipY, true,
palette,
definition);
@ -119,10 +122,11 @@ void EightBit::GameBoy::Display::renderBackground(
const std::array<int, 4>& palette) {
const int row = (m_scanLine - offsetY) / 8;
const auto baseAddress = bgArea + row * BufferCharacterWidth;
for (int column = 0; column < BufferCharacterWidth; ++column) {
const auto address = bgArea + row * BufferCharacterWidth + column;
const auto address = baseAddress + column;
const auto character = m_bus.peek(address);
const auto definition = CharacterDefinition(&m_bus, bgCharacters + 16 * character, 8);
@ -136,9 +140,9 @@ void EightBit::GameBoy::Display::renderBackground(
}
void EightBit::GameBoy::Display::renderTile(
int height,
int drawX, int drawY,
bool flipX, bool flipY, bool allowTransparencies,
const int height,
const int drawX, const int drawY,
const bool flipX, const bool flipY, const bool allowTransparencies,
const std::array<int, 4>& palette,
const CharacterDefinition& definition) {
@ -147,30 +151,25 @@ void EightBit::GameBoy::Display::renderTile(
const auto flipMaskX = width - 1;
const auto flipMaskY = height - 1;
for (int cy = 0; cy < height; ++cy) {
const auto y = m_scanLine;
const uint8_t y = drawY + (flipY ? ~cy & flipMaskY : cy);
if (y >= RasterHeight)
continue;
auto cy = y - drawY;
if (flipY)
cy = ~cy & flipMaskY;
if (y != m_scanLine)
continue;
const auto rowDefinition = definition.get(cy);
const auto rowDefinition = definition.get(cy);
const auto lineAddress = y * RasterWidth;
for (int cx = 0; cx < width; ++cx) {
for (int cx = 0; cx < width; ++cx) {
const uint8_t x = drawX + (flipX ? ~cx & flipMaskX : cx);
if (x >= RasterWidth)
break;
const uint8_t x = drawX + (flipX ? ~cx & flipMaskX : cx);
if (x >= RasterWidth)
break;
const auto colour = rowDefinition[cx];
if (!allowTransparencies || (allowTransparencies && (colour > 0))) {
const auto outputPixel = y * RasterWidth + x;
m_pixels[outputPixel] = m_colours->getColour(palette[colour]);
}
const auto colour = rowDefinition[cx];
if (!allowTransparencies || (allowTransparencies && (colour > 0))) {
const auto outputPixel = lineAddress + x;
m_pixels[outputPixel] = m_colours->getColour(palette[colour]);
}
break;
}
}