PixelRenderer.cc

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/*
TODO:
- Implement blinking (of page mask) in bitmap modes.
*/

#include "PixelRenderer.hh"
#include "Rasterizer.hh"
#include "PostProcessor.hh"
#include "Display.hh"
#include "VideoSystem.hh"
#include "RenderSettings.hh"
#include "VideoSourceSetting.hh"
#include "IntegerSetting.hh"
#include "VDP.hh"
#include "VDPVRAM.hh"
#include "SpriteChecker.hh"
#include "EventDistributor.hh"
#include "FinishFrameEvent.hh"
#include "RealTime.hh"
#include "MSXMotherBoard.hh"
#include "Reactor.hh"
#include "Timer.hh"
#include "unreachable.hh"
#include <algorithm>
#include <cassert>

namespace openmsx {

void PixelRenderer::draw(
        int startX, int startY, int endX, int endY, DrawType drawType, bool atEnd)
{
        if (drawType == DRAW_BORDER) {
                rasterizer->drawBorder(startX, startY, endX, endY);
        } else {
                assert(drawType == DRAW_DISPLAY);

                // Calculate display coordinates.
                int zero = vdp.getLineZero();
                int displayX = (startX - vdp.getLeftSprites()) / 2;
                int displayY = startY - zero;
                if (!vdp.getDisplayMode().isTextMode()) {
                        displayY += vdp.getVerticalScroll();
                } else {
                        // this is not what the real VDP does, but it is good
                        // enough for "Boring scroll" demo part of "Relax"
                        displayY = (displayY & 7) | (textModeCounter * 8);
                        if (atEnd && (drawType == DRAW_DISPLAY)) {
                                int low  = std::max(0, (startY - zero)) / 8;
                                int high = std::max(0, (endY   - zero)) / 8;
                                textModeCounter += (high - low);
                        }
                }

                displayY &= 255; // Page wrap.
                int displayWidth = (endX - (startX & ~1)) / 2;
                int displayHeight = endY - startY;

                assert(0 <= displayX);
                assert(displayX + displayWidth <= 512);

                rasterizer->drawDisplay(
                        startX, startY,
                        displayX - vdp.getHorizontalScrollLow() * 2, displayY,
                        displayWidth, displayHeight
                        );
                if (vdp.spritesEnabled() && !renderSettings.getDisableSprites()) {
                        rasterizer->drawSprites(
                                startX, startY,
                                displayX / 2, displayY,
                                (displayWidth + 1) / 2, displayHeight);
                }
        }
}

void PixelRenderer::subdivide(
        int startX, int startY, int endX, int endY, int clipL, int clipR,
        DrawType drawType )
{
        // Partial first line.
        if (startX > clipL) {
                bool atEnd = (startY != endY) || (endX >= clipR);
                if (startX < clipR) {
                        draw(startX, startY, (atEnd ? clipR : endX),
                             startY + 1, drawType, atEnd);
                }
                if (startY == endY) return;
                startY++;
        }
        // Partial last line.
        bool drawLast = false;
        if (endX >= clipR) {
                endY++;
        } else if (endX > clipL) {
                drawLast = true;
        }
        // Full middle lines.
        if (startY < endY) {
                draw(clipL, startY, clipR, endY, drawType, true);
        }
        // Actually draw last line if necessary.
        // The point of keeping top-to-bottom draw order is that it increases
        // the locality of memory references, which generally improves cache
        // hit rates.
        if (drawLast) draw(clipL, endY, endX, endY + 1, drawType, false);
}

PixelRenderer::PixelRenderer(VDP& vdp_, Display& display)
        : vdp(vdp_), vram(vdp.getVRAM())
        , eventDistributor(vdp.getReactor().getEventDistributor())
        , realTime(vdp.getMotherBoard().getRealTime())
        , renderSettings(display.getRenderSettings())
        , videoSourceSetting(vdp.getMotherBoard().getVideoSource())
        , spriteChecker(vdp.getSpriteChecker())
        , rasterizer(display.getVideoSystem().createRasterizer(vdp))
{
        // In case of loadstate we can't yet query any state from the VDP
        // (because that object is not yet fully deserialized). But
        // VDP::serialize() will call Renderer::reInit() again when it is
        // safe to query.
        reInit();

        finishFrameDuration = 0;
        frameSkipCounter = 999; // force drawing of frame
        prevRenderFrame = false;

        renderSettings.getMaxFrameSkipSetting().attach(*this);
        renderSettings.getMinFrameSkipSetting().attach(*this);
}

PixelRenderer::~PixelRenderer()
{
        renderSettings.getMinFrameSkipSetting().detach(*this);
        renderSettings.getMaxFrameSkipSetting().detach(*this);
}

PostProcessor* PixelRenderer::getPostProcessor() const
{
        return rasterizer->getPostProcessor();
}

void PixelRenderer::reInit()
{
        // Don't draw before frameStart() is called.
        // This for example can happen after a loadstate or after switching
        // renderer in the middle of a frame.
        renderFrame = false;

        rasterizer->reset();
        displayEnabled = vdp.isDisplayEnabled();
}

void PixelRenderer::updateDisplayEnabled(bool enabled, EmuTime::param time)
{
        sync(time, true);
        displayEnabled = enabled;
}

void PixelRenderer::frameStart(EmuTime::param time)
{
        if (!rasterizer->isActive()) {
                frameSkipCounter = 999;
                renderFrame = false;
                prevRenderFrame = false;
                return;
        }
        prevRenderFrame = renderFrame;
        if (vdp.isInterlaced() && renderSettings.getDeinterlace() &&
            vdp.getEvenOdd() && vdp.isEvenOddEnabled()) {
                // deinterlaced odd frame, do same as even frame
        } else {
                if (frameSkipCounter < renderSettings.getMinFrameSkip()) {
                        ++frameSkipCounter;
                        renderFrame = false;
                } else if (frameSkipCounter >= renderSettings.getMaxFrameSkip()) {
                        frameSkipCounter = 0;
                        renderFrame = true;
                } else {
                        ++frameSkipCounter;
                        if (rasterizer->isRecording()) {
                                renderFrame = true;
                        } else {
                                renderFrame = realTime.timeLeft(
                                        unsigned(finishFrameDuration), time);
                        }
                        if (renderFrame) {
                                frameSkipCounter = 0;
                        }
                }
        }
        if (!renderFrame) return;

        rasterizer->frameStart(time);

        accuracy = renderSettings.getAccuracy();

        nextX = 0;
        nextY = 0;
        // This is not what the real VDP does, but it is good enough
        // for the "Boring scroll" demo part of ANMA's "Relax" demo.
        textModeCounter = 0;
}

void PixelRenderer::frameEnd(EmuTime::param time)
{
        bool skipEvent = !renderFrame;
        if (renderFrame) {
                // Render changes from this last frame.
                sync(time, true);

                // Let underlying graphics system finish rendering this frame.
                auto time1 = Timer::getTime();
                rasterizer->frameEnd();
                auto time2 = Timer::getTime();
                auto current = time2 - time1;
                const float ALPHA = 0.2f;
                finishFrameDuration = finishFrameDuration * (1 - ALPHA) +
                                      current * ALPHA;

                if (vdp.isInterlaced() && vdp.isEvenOddEnabled() &&
                    renderSettings.getDeinterlace() &&
                    !prevRenderFrame) {
                        // dont send event in deinterlace mode when
                        // previous frame was not rendered
                        skipEvent = true;
                }
        }
        if (vdp.getMotherBoard().isActive() &&
            !vdp.getMotherBoard().isFastForwarding()) {
                eventDistributor.distributeEvent(
                        std::make_shared<FinishFrameEvent>(
                                rasterizer->getPostProcessor()->getVideoSource(),
                                videoSourceSetting.getSource(),
                                skipEvent));
        }
}

void PixelRenderer::updateHorizontalScrollLow(
        byte scroll, EmuTime::param time)
{
        if (displayEnabled) sync(time);
        rasterizer->setHorizontalScrollLow(scroll);
}

void PixelRenderer::updateHorizontalScrollHigh(
        byte /*scroll*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateBorderMask(
        bool masked, EmuTime::param time)
{
        if (displayEnabled) sync(time);
        rasterizer->setBorderMask(masked);
}

void PixelRenderer::updateMultiPage(
        bool /*multiPage*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateTransparency(
        bool enabled, EmuTime::param time)
{
        if (displayEnabled) sync(time);
        rasterizer->setTransparency(enabled);
}

void PixelRenderer::updateSuperimposing(
        const RawFrame* videoSource, EmuTime::param time)
{
        if (displayEnabled) sync(time);
        rasterizer->setSuperimposeVideoFrame(videoSource);
}

void PixelRenderer::updateForegroundColor(
        int /*color*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateBackgroundColor(
        int color, EmuTime::param time)
{
        sync(time);
        rasterizer->setBackgroundColor(color);
}

void PixelRenderer::updateBlinkForegroundColor(
        int /*color*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateBlinkBackgroundColor(
        int /*color*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateBlinkState(
        bool /*enabled*/, EmuTime::param /*time*/)
{
        // TODO: When the sync call is enabled, the screen flashes on
        //       every call to this method.
        //       I don't know why exactly, but it's probably related to
        //       being called at frame start.
        //sync(time);
}

void PixelRenderer::updatePalette(
        int index, int grb, EmuTime::param time)
{
        if (displayEnabled) {
                sync(time);
        } else {
                // Only sync if border color changed.
                DisplayMode mode = vdp.getDisplayMode();
                if (mode.getBase() == DisplayMode::GRAPHIC5) {
                        int bgColor = vdp.getBackgroundColor();
                        if (index == (bgColor & 3) || (index == (bgColor >> 2))) {
                                sync(time);
                        }
                } else if (mode.getByte() != DisplayMode::GRAPHIC7) {
                        if (index == vdp.getBackgroundColor()) {
                                sync(time);
                        }
                }
        }
        rasterizer->setPalette(index, grb);
}

void PixelRenderer::updateVerticalScroll(
        int /*scroll*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateHorizontalAdjust(
        int adjust, EmuTime::param time)
{
        if (displayEnabled) sync(time);
        rasterizer->setHorizontalAdjust(adjust);
}

void PixelRenderer::updateDisplayMode(
        DisplayMode mode, EmuTime::param time)
{
        // Sync if in display area or if border drawing process changes.
        DisplayMode oldMode = vdp.getDisplayMode();
        if (displayEnabled
        || oldMode.getByte() == DisplayMode::GRAPHIC5
        || oldMode.getByte() == DisplayMode::GRAPHIC7
        || mode.getByte() == DisplayMode::GRAPHIC5
        || mode.getByte() == DisplayMode::GRAPHIC7) {
                sync(time, true);
        }
        rasterizer->setDisplayMode(mode);
}

void PixelRenderer::updateNameBase(
        int /*addr*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updatePatternBase(
        int /*addr*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateColorBase(
        int /*addr*/, EmuTime::param time)
{
        if (displayEnabled) sync(time);
}

void PixelRenderer::updateSpritesEnabled(
        bool /*enabled*/, EmuTime::param time
) {
        if (displayEnabled) sync(time);
}

static inline bool overlap(
        int displayY0, // start of display region, inclusive
        int displayY1, // end of display region, exclusive
        int vramLine0, // start of VRAM region, inclusive
        int vramLine1  // end of VRAM region, exclusive
        // Note: Display region can wrap around: 256 -> 0.
        //       VRAM region cannot wrap around.
) {
        if (displayY0 <= displayY1) {
                if (vramLine1 > displayY0) {
                        if (vramLine0 <= displayY1) return true;
                }
        } else {
                if (vramLine1 > displayY0) return true;
                if (vramLine0 <= displayY1) return true;
        }
        return false;
}

inline bool PixelRenderer::checkSync(int offset, EmuTime::param time)
{
        // TODO: Because range is entire VRAM, offset == address.

        // If display is disabled, VRAM changes will not affect the
        // renderer output, therefore sync is not necessary.
        // TODO: Have bitmapVisibleWindow disabled in this case.
        if (!displayEnabled) return false;
        //if (frameSkipCounter != 0) return false; // TODO
        if (accuracy == RenderSettings::ACC_SCREEN) return false;

        // Calculate what display lines are scanned between current
        // renderer time and update-to time.
        // Note: displayY1 is inclusive.
        int deltaY = vdp.getVerticalScroll() - vdp.getLineZero();
        int limitY = vdp.getTicksThisFrame(time) / VDP::TICKS_PER_LINE;
        int displayY0 = (nextY + deltaY) & 255;
        int displayY1 = (limitY + deltaY) & 255;

        switch(vdp.getDisplayMode().getBase()) {
        case DisplayMode::GRAPHIC2:
        case DisplayMode::GRAPHIC3:
                if (vram.colorTable.isInside(offset)) {
                        int vramQuarter = (offset & 0x1800) >> 11;
                        int mask = (vram.colorTable.getMask() & 0x1800) >> 11;
                        for (int i = 0; i < 4; i++) {
                                if ( (i & mask) == vramQuarter
                                && overlap(displayY0, displayY1, i * 64, (i + 1) * 64) ) {
                                        /*fprintf(stderr,
                                                "color table: %05X %04X - quarter %d\n",
                                                offset, offset & 0x1FFF, i
                                                );*/
                                        return true;
                                }
                        }
                }
                if (vram.patternTable.isInside(offset)) {
                        int vramQuarter = (offset & 0x1800) >> 11;
                        int mask = (vram.patternTable.getMask() & 0x1800) >> 11;
                        for (int i = 0; i < 4; i++) {
                                if ( (i & mask) == vramQuarter
                                && overlap(displayY0, displayY1, i * 64, (i + 1) * 64) ) {
                                        /*fprintf(stderr,
                                                "pattern table: %05X %04X - quarter %d\n",
                                                offset, offset & 0x1FFF, i
                                                );*/
                                        return true;
                                }
                        }
                }
                if (vram.nameTable.isInside(offset)) {
                        int vramLine = ((offset & 0x3FF) / 32) * 8;
                        if (overlap(displayY0, displayY1, vramLine, vramLine + 8)) {
                                /*fprintf(stderr,
                                        "name table: %05X %03X - line %d\n",
                                        offset, offset & 0x3FF, vramLine
                                        );*/
                                return true;
                        }
                }
                return false;
        case DisplayMode::GRAPHIC4:
        case DisplayMode::GRAPHIC5: {
                // Is the address inside the visual page(s)?
                // TODO: Also look at which lines are touched inside pages.
                int visiblePage = vram.nameTable.getMask()
                        & (0x10000 | (vdp.getEvenOddMask() << 7));
                if (vdp.isMultiPageScrolling()) {
                        return (offset & 0x18000) == visiblePage
                                || (offset & 0x18000) == (visiblePage & 0x10000);
                } else {
                        return (offset & 0x18000) == visiblePage;
                }
        }
        case DisplayMode::GRAPHIC6:
        case DisplayMode::GRAPHIC7:
                return true; // TODO: Implement better detection.
        default:
                // Range unknown; assume full range.
                return vram.nameTable.isInside(offset)
                        || vram.colorTable.isInside(offset)
                        || vram.patternTable.isInside(offset);
        }
}

void PixelRenderer::updateVRAM(unsigned offset, EmuTime::param time)
{
        // Note: No need to sync if display is disabled, because then the
        //       output does not depend on VRAM (only on background color).
        if (renderFrame && displayEnabled && checkSync(offset, time)) {
                //fprintf(stderr, "vram sync @ line %d\n",
                //      vdp.getTicksThisFrame(time) / VDP::TICKS_PER_LINE);
                renderUntil(time);
        }
}

void PixelRenderer::updateWindow(bool /*enabled*/, EmuTime::param /*time*/)
{
        // The bitmapVisibleWindow has moved to a different area.
        // This update is redundant: Renderer will be notified in another way
        // as well (updateDisplayEnabled or updateNameBase, for example).
        // TODO: Can this be used as the main update method instead?
}

void PixelRenderer::sync(EmuTime::param time, bool force)
{
        if (!renderFrame) return;

        // Synchronisation is done in two phases:
        // 1. update VRAM
        // 2. update other subsystems
        // Note that as part of step 1, type 2 updates can be triggered.
        // Executing step 2 takes care of the subsystem changes that occur
        // after the last VRAM update.
        // This scheme makes sure type 2 routines such as renderUntil and
        // checkUntil are not re-entered, which was causing major pain in
        // the past.
        // TODO: I wonder if it's possible to enforce this synchronisation
        //       scheme at a higher level. Probably. But how...
        //if ((frameSkipCounter == 0) && TODO
        if (accuracy != RenderSettings::ACC_SCREEN || force) {
                vram.sync(time);
                renderUntil(time);
        }
}

void PixelRenderer::renderUntil(EmuTime::param time)
{
        // Translate from time to pixel position.
        int limitTicks = vdp.getTicksThisFrame(time);
        assert(limitTicks <= vdp.getTicksPerFrame());
        int limitX, limitY;
        switch (accuracy) {
        case RenderSettings::ACC_PIXEL: {
                limitX = limitTicks % VDP::TICKS_PER_LINE;
                limitY = limitTicks / VDP::TICKS_PER_LINE;
                break;
        }
        case RenderSettings::ACC_LINE:
        case RenderSettings::ACC_SCREEN: {
                // Note: I'm not sure the rounding point is optimal.
                //       It used to be based on the left margin, but that doesn't work
                //       because the margin can change which leads to a line being
                //       rendered even though the time doesn't advance.
                limitX = 0;
                limitY =
                        (limitTicks + VDP::TICKS_PER_LINE - 400) / VDP::TICKS_PER_LINE;
                break;
        }
        default:
                UNREACHABLE;
                limitX = limitY = 0; // avoid warning
        }

        // Stop here if there is nothing to render.
        // This ensures that no pixels are rendered in a series of updates that
        // happen at exactly the same time; the VDP subsystem states may be
        // inconsistent until all updates are performed.
        // Also it is a small performance optimisation.
        if (limitX == nextX && limitY == nextY) return;

        if (displayEnabled) {
                if (vdp.spritesEnabled()) {
                        // Update sprite checking, so that rasterizer can call getSprites.
                        spriteChecker.checkUntil(time);
                }

                // Calculate start and end of borders in ticks since start of line.
                // The 0..7 extra horizontal scroll low pixels should be drawn in
                // border color. These will be drawn together with the border,
                // but sprites above these pixels are clipped at the actual border
                // rather than the end of the border colored area.
                // TODO: Move these calculations and getDisplayLeft() to VDP.
                int borderL = vdp.getLeftBorder();
                int displayL =
                        vdp.isBorderMasked() ? borderL : vdp.getLeftBackground();
                int borderR = vdp.getRightBorder();

                // It's important that right border is drawn last (after left
                // border and display area). See comment in SDLRasterizer::drawBorder().
                // Left border.
                subdivide(nextX, nextY, limitX, limitY,
                        0, displayL, DRAW_BORDER);
                // Display area.
                subdivide(nextX, nextY, limitX, limitY,
                        displayL, borderR, DRAW_DISPLAY);
                // Right border.
                subdivide(nextX, nextY, limitX, limitY,
                        borderR, VDP::TICKS_PER_LINE, DRAW_BORDER);
        } else {
                subdivide(nextX, nextY, limitX, limitY,
                        0, VDP::TICKS_PER_LINE, DRAW_BORDER);
        }

        nextX = limitX;
        nextY = limitY;
}

void PixelRenderer::update(const Setting& setting)
{
        if (&setting == &renderSettings.getMinFrameSkipSetting() ||
            &setting == &renderSettings.getMaxFrameSkipSetting()) {
                // Force drawing of frame.
                frameSkipCounter = 999;
        } else {
                UNREACHABLE;
        }
}

} // namespace openmsx