reznez 0.0.0

The high accuracy NES Emulator
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172

use enum_iterator::IntoEnumIterator;
use num_traits::FromPrimitive;

use crate::ppu::palette::palette_table::PaletteTable;
use crate::ppu::palette::rgbt::Rgbt;
use crate::ppu::pattern_table::{PatternIndex, PatternTable, Tile};
use crate::ppu::pixel_index::{ColumnInTile, PixelColumn, PixelRow, RowInTile};
use crate::ppu::render::frame::Frame;
use crate::ppu::sprite::sprite_attributes::{SpriteAttributes, Priority};
use crate::ppu::sprite::sprite_half::SpriteHalf;
use crate::ppu::sprite::sprite_height::SpriteHeight;
use crate::ppu::sprite::sprite_y::SpriteY;

#[derive(Clone, Copy, Debug)]
pub struct Sprite {
    x_coordinate: PixelColumn,
    y_coordinate: SpriteY,
    pattern_index: PatternIndex,
    attributes: SpriteAttributes,
}

impl Sprite {
    #[inline]
    pub fn from_u32(value: u32) -> Sprite {
        let [y_coordinate, raw_pattern_index, attributes, x_coordinate] =
            value.to_be_bytes();

        Sprite {
            x_coordinate: PixelColumn::new(x_coordinate),
            y_coordinate: SpriteY::new(y_coordinate),
            pattern_index: PatternIndex::new(raw_pattern_index),
            attributes: SpriteAttributes::from_u8(attributes),
        }
    }

    pub fn priority(self) -> Priority {
        self.attributes.priority()
    }

    pub fn pattern_index(self) -> PatternIndex {
        self.pattern_index
    }

    // For debug screens only.
    pub fn render_normal_height(
        self,
        pattern_table: &PatternTable,
        palette_table: &PaletteTable,
    ) -> Tile {
        self.render_tile(
            SpriteHeight::Normal,
            SpriteHalf::Top,
            pattern_table,
            palette_table,
        )
    }

    // For debug screens only.
    pub fn render_tall(
        self,
        pattern_table: &PatternTable,
        palette_table: &PaletteTable,
    ) -> (Tile, Tile) {
        use SpriteHalf::*;
        use SpriteHeight::Tall;
        (
            self.render_tile(Tall, Top, pattern_table, palette_table),
            self.render_tile(Tall, Bottom, pattern_table, palette_table),
        )
    }

    pub fn render_sliver(
        self,
        row: PixelRow,
        sprite_height: SpriteHeight,
        pattern_table: &PatternTable,
        palette_table: &PaletteTable,
        is_sprite_0: bool,
        frame: &mut Frame,
    ) {
        let Some((sprite_half, row_in_half, _visible)) =
            self.y_coordinate.row_in_sprite(self.attributes.flip_vertically(), sprite_height, row) else {

            return;
        };

        let mut sprite_sliver = [Rgbt::Transparent; 8];
        self.render_sliver_from_sprite_half(
            sprite_height,
            sprite_half,
            row_in_half,
            pattern_table,
            palette_table,
            &mut sprite_sliver,
        );

        for (column_in_sprite, &pixel) in sprite_sliver.iter().enumerate() {
            let column_in_sprite = ColumnInTile::from_usize(column_in_sprite).unwrap();
            if let Rgbt::Opaque(_) = pixel {
                if let Some(column) =
                    self.x_coordinate.add_column_in_tile(column_in_sprite)
                {
                    frame.set_sprite_pixel(
                        column,
                        row,
                        pixel,
                        self.priority(),
                        is_sprite_0,
                    );
                }
            }
        }
    }

    fn render_tile(
        self,
        sprite_height: SpriteHeight,
        sprite_half: SpriteHalf,
        pattern_table: &PatternTable,
        palette_table: &PaletteTable,
    ) -> Tile {
        let mut tile = Tile::new();
        for row in RowInTile::into_enum_iter() {
            self.render_sliver_from_sprite_half(
                sprite_height,
                sprite_half,
                row,
                pattern_table,
                palette_table,
                tile.row_mut(row),
            );
        }

        tile
    }

    fn render_sliver_from_sprite_half(
        self,
        sprite_height: SpriteHeight,
        sprite_half: SpriteHalf,
        mut row_in_half: RowInTile,
        pattern_table: &PatternTable,
        palette_table: &PaletteTable,
        sprite_sliver: &mut [Rgbt; 8],
    ) {
        #[rustfmt::skip]
        let pattern_index = match (sprite_height, sprite_half) {
            (SpriteHeight::Normal, SpriteHalf::Top) => self.pattern_index,
            (SpriteHeight::Normal, SpriteHalf::Bottom) => unreachable!(),
            (SpriteHeight::Tall,   SpriteHalf::Top) => self.pattern_index.to_tall_indexes().0,
            (SpriteHeight::Tall,   SpriteHalf::Bottom) => self.pattern_index.to_tall_indexes().1,
        };

        if self.attributes.flip_vertically() {
            row_in_half = row_in_half.flip();
        }

        let sprite_palette = palette_table.sprite_palette(self.attributes.palette_table_index());
        pattern_table.render_pixel_sliver(
            pattern_index,
            row_in_half,
            sprite_palette,
            sprite_sliver,
        );

        if self.attributes.flip_horizontally() {
            for i in 0..sprite_sliver.len() / 2 {
                sprite_sliver.swap(i, 7 - i);
            }
        }
    }
}