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Added an attempt at ball rendering.

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This commit is contained in:
Thomas Harte 2015-07-30 21:30:00 -04:00
parent cfe758daa0
commit 78e66d2577
1 changed files with 13 additions and 8 deletions
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21
Machines/Atari2600.cpp
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@ -48,25 +48,21 @@ void Machine::get_output_pixel(uint8_t *pixel, int offset)
69, 134, 108, 161, 186, 210, 235, 255
};
// get the playfield pixel
// get the playfield pixel and hence a proposed colour
const int x = offset >> 2;
const int mirrored = (x / 20) & (_playfieldControl&1);
const int index = mirrored ? x - 20 : 19 - (x%20);
const int byte = 2 - (index >> 3);
const int lowestBit = (byte&1)^1;
const int bit = (index & 7)^(lowestBit | (lowestBit << 1) | (lowestBit << 2));
// printf("%d -> %d -> %d -> %d/%d\n", offset, x, index, byte, bit);
uint8_t playfieldPixel = (_playfield[byte] >> bit)&1;
// TODO: almost everything!
uint8_t playfieldColour = ((_playfieldControl&6) == 2) ? _playerColour[x / 20] : _playfieldColour;
uint8_t playerPixels[2], missilePixels[2];
// get player and missile proposed pixels
uint8_t playerPixels[2], missilePixels[2];
for(int c = 0; c < 2; c++)
{
// figure out sprite colour
// figure out player colour
int flipMask = (_playerReflection[c]&0x8) ? 0 : 7;
int relativeTimer = _playerPosition[c] - _horizontalTimer;
@ -109,6 +105,14 @@ void Machine::get_output_pixel(uint8_t *pixel, int offset)
missilePixels[c] = (missileIndex >= 0 && missileIndex < missileSize && (_missileGraphicsEnable[c]&2)) ? 1 : 0;
}
// get the ball proposed colour
uint8_t ballPixel;
int ballIndex = _ballPosition - _horizontalTimer;
int ballSize = 1 << ((_playfieldControl >> 4)&3);
ballPixel = (ballIndex >= 0 && ballIndex < ballSize && (_ballGraphicsEnable&2)) ? 1 : 0;
// apply appropriate priority to pick a colour
playfieldPixel |= ballPixel;
uint8_t outputColour = playfieldPixel ? playfieldColour : _backgroundColour;
if(!(_playfieldControl&0x04) || !playfieldPixel) {
@ -116,6 +120,7 @@ void Machine::get_output_pixel(uint8_t *pixel, int offset)
if (playerPixels[0] || missilePixels[0]) outputColour = _playerColour[0];
}
// map that colour to an RGBA
pixel[0] = palette[outputColour >> 4][0];
pixel[1] = palette[outputColour >> 4][1];
pixel[2] = palette[outputColour >> 4][2];