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
|
// Screen size.
#define SCREEN_WIDTH 320
#define SCREEN_HEIGHT 240
static OSMesg retrace_msg_buf;
static OSMesgQueue retrace_msg_queue;
//
// Framebuffers.
//
u16 framebuffers[2][SCREEN_WIDTH * SCREEN_HEIGHT] __attribute__((aligned(16)));
//
// Statics.
//
static u16 pixels[SCREEN_WIDTH * SCREEN_HEIGHT] __attribute__((aligned(16)));
static int current_fb = 0;
static u16 screen_width = SCREEN_WIDTH;
static u16 screen_height = SCREEN_HEIGHT;
static u16 palette[16];
static u8 pixels_fg[SCREEN_WIDTH * SCREEN_HEIGHT] __attribute__((aligned(16)));
static u8 pixels_bg[SCREEN_WIDTH * SCREEN_HEIGHT] __attribute__((aligned(16)));
static u8 dirty_lines[SCREEN_HEIGHT];
static u8 reqdraw = 0;
static u8 blending[5][16] = {
{0, 0, 0, 0, 1, 0, 1, 1, 2, 2, 0, 2, 3, 3, 3, 0},
{0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3},
{1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1, 1, 2, 3, 1},
{2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2},
{1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0}};
u16
rgb565(u32 rgba) {
u16 r = (rgba >> 16 & 0xFF);
u16 g = (rgba >> 8 & 0xFF);
u16 b = (rgba >> 0 & 0xFF);
r = r >> 3;
g = g >> 2;
b = b >> 3;
return (r << 11) | (g << 5) | b;
}
void
redraw_screen(void) {
for (size_t j = 0; j < screen_height; j++) {
dirty_lines[j] = 1;
}
}
void
ppu_pixel(u8 *layer, u16 x, u16 y, u8 color) {
if (x >= screen_width || y >= screen_height) {
return;
}
u32 i = x + y *screen_width;
if(color != layer[i]) {
layer[i] = color;
}
dirty_lines[y] |= 1;
}
void
ppu_1bpp(u8 *layer, u16 x, u16 y, u8 *sprite, u8 color, u8 flipx, u8 flipy) {
u16 v, h;
for(v = 0; v < 8; v++)
for(h = 0; h < 8; h++) {
u8 ch1 = (sprite[v] >> (7 - h)) & 0x1;
if(ch1 || blending[4][color])
ppu_pixel(layer,
x + (flipx ? 7 - h : h),
y + (flipy ? 7 - v : v),
blending[ch1][color]);
}
}
void
ppu_2bpp(u8 *layer, u16 x, u16 y, u8 *sprite, u8 color, u8 flipx, u8 flipy) {
u16 v, h;
for(v = 0; v < 8; v++)
for(h = 0; h < 8; h++) {
u8 ch1 = ((sprite[v] >> (7 - h)) & 0x1);
u8 ch2 = ((sprite[v + 8] >> (7 - h)) & 0x1);
u8 ch = ch1 + ch2 * 2;
if(ch || blending[4][color])
ppu_pixel(layer,
x + (flipx ? 7 - h : h),
y + (flipy ? 7 - v : v),
blending[ch][color]);
}
}
void
fb_copy_test(void) {
for (size_t i = 0; i < SCREEN_HEIGHT * SCREEN_WIDTH; i++) {
framebuffers[current_fb][i] = pixels[i];
}
}
void
init_ppu(void) {
// NOTE: Test image.
for (size_t j = 0; j < SCREEN_HEIGHT; j++) {
for (size_t i = 0; i < SCREEN_WIDTH; i++) {
u16 shade_x = (float)i / (float)SCREEN_WIDTH * 255;
u16 shade_y = (float)j / (float)SCREEN_HEIGHT * 255;
u16 color = GPACK_RGBA5551(shade_x, 0, shade_y, 1);
pixels[i + j * SCREEN_WIDTH] = color;
}
}
// Clear pixel buffers and dirty lines
for (size_t i = 0; i < 16; i++) {
palette[i] = 0;
}
for (size_t i = 0; i < SCREEN_WIDTH * SCREEN_HEIGHT; i++) {
pixels_fg[i] = 0;
pixels_bg[i] = 0;
}
for (size_t i = 0; i < SCREEN_HEIGHT; i++) {
dirty_lines[i] = 0;
}
// Setup the message queues
osCreateMesgQueue(&retrace_msg_queue, &retrace_msg_buf, 1);
osViSetEvent(&retrace_msg_queue, NULL, 1);
}
void
swap_buffers(void) {
osViSwapBuffer(framebuffers[current_fb]);
// Wait for Vertical retrace to finish swap buffers.
if (MQ_IS_FULL(&retrace_msg_queue)) {
osRecvMesg(&retrace_msg_queue, NULL, OS_MESG_BLOCK);
}
osRecvMesg(&retrace_msg_queue, NULL, OS_MESG_BLOCK);
}
void
blit_framebuffer(void) {
if (reqdraw == 0) {
return;
}
for (size_t j = 0; j < screen_height; j++) {
if (dirty_lines[j] != 0) {
for (size_t i = 0; i < screen_width; i++) {
size_t idx = i + j * screen_width;
pixels[idx] = palette[pixels_fg[idx] << 2 | pixels_bg[idx]];
}
}
dirty_lines[j] = 0;
}
current_fb ^= 1;
fb_copy_test();
reqdraw = 0;
}
|
