1/* Copyright (c) 2013-2016 Jeffrey Pfau
 2 *
 3 * This Source Code Form is subject to the terms of the Mozilla Public
 4 * License, v. 2.0. If a copy of the MPL was not distributed with this
 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 6#ifndef GB_VIDEO_H
 7#define GB_VIDEO_H
 8
 9#include "util/common.h"
10
11#include "gb/memory.h"
12
13enum {
14	GB_VIDEO_HORIZONTAL_PIXELS = 160,
15	GB_VIDEO_VERTICAL_PIXELS = 144,
16	GB_VIDEO_VBLANK_PIXELS = 10,
17	GB_VIDEO_VERTICAL_TOTAL_PIXELS = GB_VIDEO_VERTICAL_PIXELS + GB_VIDEO_VBLANK_PIXELS,
18
19	GB_VIDEO_MODE_0_LENGTH = 203, // Estimates, figure out with more precision
20	GB_VIDEO_MODE_2_LENGTH = 81,
21	GB_VIDEO_MODE_3_LENGTH = 172,
22
23	GB_VIDEO_HORIZONTAL_LENGTH = GB_VIDEO_MODE_0_LENGTH + GB_VIDEO_MODE_2_LENGTH + GB_VIDEO_MODE_3_LENGTH,
24
25	GB_VIDEO_MODE_1_LENGTH = GB_VIDEO_HORIZONTAL_LENGTH * GB_VIDEO_VBLANK_PIXELS,
26	GB_VIDEO_TOTAL_LENGTH = GB_VIDEO_HORIZONTAL_LENGTH * GB_VIDEO_VERTICAL_TOTAL_PIXELS,
27};
28
29struct GBVideoRenderer {
30	void (*init)(struct GBVideoRenderer* renderer);
31	void (*reset)(struct GBVideoRenderer* renderer);
32	void (*deinit)(struct GBVideoRenderer* renderer);
33
34	uint8_t (*writeVideoRegister)(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
35	void (*writeVRAM)(struct GBVideoRenderer* renderer, uint16_t address);
36	void (*drawScanline)(struct GBVideoRenderer* renderer, int y);
37	void (*finishFrame)(struct GBVideoRenderer* renderer);
38
39	void (*getPixels)(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
40	void (*putPixels)(struct GBVideoRenderer* renderer, unsigned stride, void* pixels);
41
42	uint8_t* vram;
43};
44
45DECL_BITFIELD(GBRegisterLCDC, uint8_t);
46DECL_BIT(GBRegisterLCDC, Enable, 7);
47
48DECL_BITFIELD(GBRegisterSTAT, uint8_t);
49DECL_BITS(GBRegisterSTAT, Mode, 0, 2);
50DECL_BIT(GBRegisterSTAT, LYC, 2);
51DECL_BIT(GBRegisterSTAT, HblankIRQ, 3);
52DECL_BIT(GBRegisterSTAT, VblankIRQ, 4);
53DECL_BIT(GBRegisterSTAT, OAMIRQ, 5);
54DECL_BIT(GBRegisterSTAT, LYCIRQ, 6);
55
56struct GBVideo {
57	struct GB* p;
58	struct GBVideoRenderer* renderer;
59
60	int ly;
61	GBRegisterSTAT stat;
62
63	int mode;
64
65	int32_t nextEvent;
66	int32_t eventDiff;
67
68	int32_t nextMode;
69
70	uint8_t* vram;
71
72	int32_t frameCounter;
73	int frameskip;
74	int frameskipCounter;
75};
76
77void GBVideoInit(struct GBVideo* video);
78void GBVideoReset(struct GBVideo* video);
79void GBVideoDeinit(struct GBVideo* video);
80void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer);
81int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles);
82
83void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value);
84void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value);
85
86#endif