Files
choco-chip8/DisplaySDL.cpp

109 lines
3.0 KiB
C++

#include "DisplaySDL.hpp"
#include "Peripherals.hpp"
#include <SDL2/SDL_surface.h>
#include <stdexcept>
DisplaySDL::DisplaySDL(int w, int h, uint32_t fgColor, uint32_t bgColor):
mpFramebuffer{std::make_unique<Framebuffer>()},
mpDisplayState{std::make_unique<Framebuffer>()},
mDoClear{true} {
// Create SDL Window
mpWindow = SDL_CreateWindow(
"ChocoChip-8",
SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
w, h,
0
);
if(mpWindow == NULL) {
throw std::runtime_error(SDL_GetError());
}
// Convert our foreground/background colors to the format expected by SDL
SDL_PixelFormat *fmt = SDL_AllocFormat(SDL_GetWindowPixelFormat(mpWindow));
mFgColor = SDL_MapRGB(
fmt,
(fgColor & 0x00FF0000) >> 16,
(fgColor & 0x0000FF00) >> 8,
(fgColor & 0x000000FF)
);
mBgColor = SDL_MapRGB(
fmt,
(bgColor & 0x00FF0000) >> 16,
(bgColor & 0x0000FF00) >> 8,
(bgColor & 0x000000FF)
);
SDL_FreeFormat(fmt);
};
DisplaySDL::~DisplaySDL() {
SDL_DestroyWindow(mpWindow);
}
void DisplaySDL::clear() {
for(auto &scanline : *mpFramebuffer) {
scanline.reset();
}
mDoClear = true;
}
int DisplaySDL::blit(const chocochip8::Scanline &spriteScanline, int y) {
using chocochip8::Scanline;
Scanline &targetScanline = mpFramebuffer->at(y);
bool collision = (spriteScanline & targetScanline).any();
targetScanline ^= spriteScanline;
return collision;
}
void DisplaySDL::updateWindow(bool doWindowUpdate) const {
using chocochip8::Scanline;
SDL_Surface *pSurface = SDL_GetWindowSurface(mpWindow);
if(mDoClear) {
for(auto &scanline : *mpDisplayState) {
scanline.reset();
}
SDL_FillRect(pSurface, NULL, mBgColor);
mDoClear = false;
doWindowUpdate = true;
}
for(int y = 0; y < mpFramebuffer->size(); y++) {
Scanline &rNewScanline = (*mpFramebuffer)[y];
Scanline &rOldScanline = (*mpDisplayState)[y];
if(rNewScanline == rOldScanline) {
// Skip scanlines that haven't changed since the last update
continue;
}
for(int x = 0; x < rNewScanline.size(); x++) {
bool isSet = rNewScanline._Unchecked_test(x);
bool wasSet = rOldScanline._Unchecked_test(x);
if(isSet == wasSet) {
continue;
}
// Map framebuffer pixel to SDL surface rectangle,
// note that the MSB of an scanline's bitset is the leftmost pixel.
int z = (chocochip8::gcWidth - 1) - x;
int x1 = ( z * pSurface->w) / chocochip8::gcWidth;
int x2 = ((z + 1) * pSurface->w) / chocochip8::gcWidth;
int y1 = ( y * pSurface->h) / chocochip8::gcHeight;
int y2 = ((y + 1) * pSurface->h) / chocochip8::gcHeight;
SDL_Rect rect;
rect.x = x1;
rect.y = y1;
rect.w = x2 - x1;
rect.h = y2 - y1;
Uint32 color = (isSet ? mFgColor : mBgColor);
SDL_FillRect(pSurface, &rect, color);
doWindowUpdate = true;
}
}
if(doWindowUpdate) {
*mpDisplayState = *mpFramebuffer;
SDL_UpdateWindowSurface(mpWindow);
}
}