src/gb/video.c (view raw)
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#include "video.h"
7
8#include "gb/gb.h"
9#include "gb/io.h"
10
11#include "util/memory.h"
12
13static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer);
14static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer);
15static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer);
16static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
17static void GBVideoDummyRendererDrawDot(struct GBVideoRenderer* renderer, int x, int y, struct GBObj** obj, size_t oamMax);
18static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer);
19static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
20
21static void _cleanOAM(struct GBVideo* video, int y);
22
23static struct GBVideoRenderer dummyRenderer = {
24 .init = GBVideoDummyRendererInit,
25 .reset = GBVideoDummyRendererReset,
26 .deinit = GBVideoDummyRendererDeinit,
27 .writeVideoRegister = GBVideoDummyRendererWriteVideoRegister,
28 .drawDot = GBVideoDummyRendererDrawDot,
29 .finishFrame = GBVideoDummyRendererFinishFrame,
30 .getPixels = GBVideoDummyRendererGetPixels
31};
32
33void GBVideoInit(struct GBVideo* video) {
34 video->renderer = &dummyRenderer;
35 video->vram = 0;
36 video->frameskip = 0;
37}
38
39void GBVideoReset(struct GBVideo* video) {
40 video->ly = 0;
41 video->mode = 1;
42 video->stat = 1;
43
44 video->nextEvent = INT_MAX;
45 video->eventDiff = 0;
46
47 video->nextMode = INT_MAX;
48 video->nextDot = INT_MAX;
49
50 video->frameCounter = 0;
51 video->frameskipCounter = 0;
52
53 if (video->vram) {
54 mappedMemoryFree(video->vram, GB_SIZE_VRAM);
55 }
56 video->vram = anonymousMemoryMap(GB_SIZE_VRAM);
57 video->renderer->vram = video->vram;
58 memset(&video->oam, 0, sizeof(video->oam));
59 video->renderer->oam = &video->oam;
60
61 video->renderer->deinit(video->renderer);
62 video->renderer->init(video->renderer);
63}
64
65void GBVideoDeinit(struct GBVideo* video) {
66 GBVideoAssociateRenderer(video, &dummyRenderer);
67 mappedMemoryFree(video->vram, GB_SIZE_VRAM);
68}
69
70void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer) {
71 video->renderer->deinit(video->renderer);
72 video->renderer = renderer;
73 renderer->vram = video->vram;
74 video->renderer->init(video->renderer);
75}
76
77int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles) {
78 video->eventDiff += cycles;
79 if (video->nextEvent != INT_MAX) {
80 video->nextEvent -= cycles;
81 }
82 if (video->nextEvent <= 0) {
83 if (video->nextEvent != INT_MAX) {
84 video->nextMode -= video->eventDiff;
85 video->nextDot -= video->eventDiff;
86 }
87 video->nextEvent = INT_MAX;
88 if (video->nextDot <= 0) {
89 video->renderer->drawDot(video->renderer, video->x, video->ly, video->objThisLine, video->objMax);
90 ++video->x;
91 if (video->x < GB_VIDEO_HORIZONTAL_PIXELS) {
92 video->nextDot = 1;
93 } else {
94 video->nextDot = INT_MAX;
95 }
96 }
97 if (video->nextMode <= 0) {
98 int lyc = video->p->memory.io[REG_LYC];
99 switch (video->mode) {
100 case 0:
101 ++video->ly;
102 video->p->memory.io[REG_LY] = video->ly;
103 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
104 if (video->ly < GB_VIDEO_VERTICAL_PIXELS) {
105 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
106 video->mode = 2;
107 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
108 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
109 }
110 } else {
111 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
112 video->mode = 1;
113 ++video->frameCounter;
114 video->renderer->finishFrame(video->renderer);
115 if (GBRegisterSTATIsVblankIRQ(video->stat) || GBRegisterSTATIsOAMIRQ(video->stat)) {
116 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
117 }
118 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_VBLANK);
119 }
120 if (GBRegisterSTATIsLYCIRQ(video->stat) && lyc == video->ly) {
121 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
122 }
123 GBUpdateIRQs(video->p);
124 break;
125 case 1:
126 ++video->ly;
127 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
128 if (GBRegisterSTATIsLYCIRQ(video->stat) && lyc == video->ly) {
129 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
130 }
131 if (video->ly >= GB_VIDEO_VERTICAL_TOTAL_PIXELS) {
132 video->ly = 0;
133 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
134 video->mode = 2;
135 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
136 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
137 GBUpdateIRQs(video->p);
138 }
139 } else {
140 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
141 }
142 video->p->memory.io[REG_LY] = video->ly;
143 break;
144 case 2:
145 _cleanOAM(video, video->ly);
146 video->nextDot = 1;
147 video->nextEvent = video->nextDot;
148 video->x = 0;
149 video->nextMode = GB_VIDEO_MODE_3_LENGTH_BASE + video->objMax * 8;
150 video->mode = 3;
151 break;
152 case 3:
153 video->nextMode = GB_VIDEO_MODE_0_LENGTH_BASE - video->objMax * 8;
154 video->mode = 0;
155 if (GBRegisterSTATIsHblankIRQ(video->stat)) {
156 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
157 GBUpdateIRQs(video->p);
158 }
159 break;
160 }
161 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
162 video->p->memory.io[REG_STAT] = video->stat;
163 }
164 if (video->nextDot < video->nextEvent) {
165 video->nextEvent = video->nextDot;
166 }
167 if (video->nextMode < video->nextEvent) {
168 video->nextEvent = video->nextMode;
169 }
170 video->eventDiff = 0;
171 }
172 return video->nextEvent;
173}
174
175static void _cleanOAM(struct GBVideo* video, int y) {
176 // TODO: GBC differences
177 // TODO: Optimize
178 video->objMax = 0;
179 int spriteHeight = 8;
180 if (GBRegisterLCDCIsObjSize(video->p->memory.io[REG_LCDC])) {
181 spriteHeight = 16;
182 }
183 int o = 0;
184 int i;
185 for (i = 0; i < 40; ++i) {
186 uint8_t oy = video->oam.obj[i].y;
187 if (y < oy - 16 || y >= oy - 16 + spriteHeight) {
188 continue;
189 }
190 // TODO: Sort
191 video->objThisLine[o] = &video->oam.obj[i];
192 ++o;
193 if (o == 10) {
194 break;
195 }
196 }
197 video->objMax = o;
198}
199
200void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
201 if (!GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && GBRegisterLCDCIsEnable(value)) {
202 // TODO: Does enabling the LCD start in vblank?
203 video->mode = 2;
204 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
205 video->nextEvent = video->nextMode;
206 video->eventDiff = 0;
207 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
208 video->p->memory.io[REG_STAT] = video->stat;
209 video->eventDiff = 0;
210 if (video->p->cpu->cycles + video->nextEvent < video->p->cpu->nextEvent) {
211 video->p->cpu->nextEvent = video->p->cpu->cycles + video->nextEvent;
212 }
213 return;
214 }
215 if (GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && !GBRegisterLCDCIsEnable(value)) {
216 video->mode = 0;
217 video->nextMode = INT_MAX;
218 video->nextEvent = INT_MAX;
219 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
220 video->p->memory.io[REG_STAT] = video->stat;
221 video->ly = 0;
222 video->p->memory.io[REG_LY] = 0;
223 }
224}
225
226void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value) {
227 video->stat = (video->stat & 0x7) | (value & 0x78);
228}
229
230static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer) {
231 UNUSED(renderer);
232 // Nothing to do
233}
234
235static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer) {
236 UNUSED(renderer);
237 // Nothing to do
238}
239
240static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer) {
241 UNUSED(renderer);
242 // Nothing to do
243}
244
245static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value) {
246 UNUSED(renderer);
247 UNUSED(address);
248 return value;
249}
250
251static void GBVideoDummyRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address) {
252 UNUSED(renderer);
253 UNUSED(address);
254 // Nothing to do
255}
256
257static void GBVideoDummyRendererWriteOAM(struct GBVideoRenderer* renderer, uint8_t oam) {
258 UNUSED(renderer);
259 UNUSED(oam);
260 // Nothing to do
261}
262
263static void GBVideoDummyRendererDrawDot(struct GBVideoRenderer* renderer, int x, int y, struct GBObj** obj, size_t oamMax) {
264 UNUSED(renderer);
265 UNUSED(x);
266 UNUSED(y);
267 UNUSED(obj);
268 UNUSED(oamMax);
269 // Nothing to do
270}
271
272static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer) {
273 UNUSED(renderer);
274 // Nothing to do
275}
276
277static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels) {
278 UNUSED(renderer);
279 UNUSED(stride);
280 UNUSED(pixels);
281 // Nothing to do
282}