126 lines
3.0 KiB
C++
126 lines
3.0 KiB
C++
/*
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epple2
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Copyright (C) 2008 by Christopher A. Mosher <cmosher01@gmail.com>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY, without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "video.h"
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#include "e2const.h"
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#include "videoaddressing.h"
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#include "videomode.h"
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#include "addressbus.h"
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#include "picturegenerator.h"
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#include "textcharacters.h"
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static const int FLASH_HALF_PERIOD = E2Const::AVG_CPU_HZ/4; // 2 Hz period = 4 Hz half-period
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Video::Video(VideoMode& mode, AddressBus& addressBus, PictureGenerator& picgen, TextCharacters& textRows):
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mode(mode), addressBus(addressBus), picgen(picgen), textRows(textRows)
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{
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VideoAddressing::buildLUT(TEXT_BASE_1,TEXT_LEN,lutTEXT[0]);
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VideoAddressing::buildLUT(TEXT_BASE_2,TEXT_LEN,lutTEXT[1]);
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VideoAddressing::buildLUT(HRES_BASE_1,HRES_LEN,lutHRES[0]);
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VideoAddressing::buildLUT(HRES_BASE_2,HRES_LEN,lutHRES[1]);
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}
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Video::~Video()
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{
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}
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void Video::powerOn()
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{
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this->t = 0;
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this->flash = false;
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this->cflash = 0;
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}
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void Video::tick()
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{
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const unsigned char data = getDataByte();
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const unsigned char rowToPlot = getRowToPlot(data);
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this->picgen.tick(this->t,rowToPlot);
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updateFlash();
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++this->t;
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if (this->t >= E2Const::BYTES_PER_FIELD)
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{
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this->t = 0;
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}
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}
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void Video::updateFlash()
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{
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++this->cflash;
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if (this->cflash >= FLASH_HALF_PERIOD)
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{
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this->flash = !this->flash;
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this->cflash = 0;
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}
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}
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unsigned char Video::getDataByte()
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{
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// TODO should fix the mixed-mode scanning during VBL (see U.A.][, p. 5-13)
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std::vector<unsigned short>& lut =
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(this->mode.isDisplayingText(this->t) || !this->mode.isHiRes())
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?
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this->lutTEXT[this->mode.getPage()]
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:
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this->lutHRES[this->mode.getPage()];
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return this->addressBus.read(lut[this->t]);
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}
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unsigned char Video::getRowToPlot(unsigned char d)
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{
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if (this->mode.isDisplayingText(this->t))
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{
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const bool inverse = inverseChar(d);
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const int y = this->t / E2Const::BYTES_PER_ROW;
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d = this->textRows.get(((d & 0x3F) << 3) | (y & 0x07));
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if (inverse)
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{
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d = ~d & 0x7F;
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}
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}
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return d;
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}
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bool Video::inverseChar(const unsigned char d)
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{
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bool inverse;
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const unsigned char cs = (d >> 6) & 3;
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if (cs == 0)
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{
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inverse = true;
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}
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else if (cs == 1)
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{
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inverse = this->flash;
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}
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else
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{
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inverse = false;
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}
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return inverse;
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}
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