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 "core/sync.h"
9#include "core/thread.h"
10#include "gb/gb.h"
11#include "gb/io.h"
12
13#include "util/memory.h"
14
15static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer);
16static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer);
17static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer);
18static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
19static void GBVideoDummyRendererDrawRange(struct GBVideoRenderer* renderer, int startX, int endX, int y, struct GBObj** obj, size_t oamMax);
20static void GBVideoDummyRendererFinishScanline(struct GBVideoRenderer* renderer, int y);
21static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer);
22static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
23
24static void _cleanOAM(struct GBVideo* video, int y);
25
26static struct GBVideoRenderer dummyRenderer = {
27 .init = GBVideoDummyRendererInit,
28 .reset = GBVideoDummyRendererReset,
29 .deinit = GBVideoDummyRendererDeinit,
30 .writeVideoRegister = GBVideoDummyRendererWriteVideoRegister,
31 .drawRange = GBVideoDummyRendererDrawRange,
32 .finishScanline = GBVideoDummyRendererFinishScanline,
33 .finishFrame = GBVideoDummyRendererFinishFrame,
34 .getPixels = GBVideoDummyRendererGetPixels
35};
36
37void GBVideoInit(struct GBVideo* video) {
38 video->renderer = &dummyRenderer;
39 video->vram = 0;
40 video->frameskip = 0;
41}
42
43void GBVideoReset(struct GBVideo* video) {
44 video->ly = 0;
45 video->mode = 1;
46 video->stat = 1;
47
48 video->nextEvent = INT_MAX;
49 video->eventDiff = 0;
50
51 video->nextMode = INT_MAX;
52 video->dotCounter = INT_MIN;
53
54 video->frameCounter = 0;
55 video->frameskipCounter = 0;
56
57 if (video->vram) {
58 mappedMemoryFree(video->vram, GB_SIZE_VRAM);
59 }
60 video->vram = anonymousMemoryMap(GB_SIZE_VRAM);
61 video->renderer->vram = video->vram;
62 memset(&video->oam, 0, sizeof(video->oam));
63 video->renderer->oam = &video->oam;
64
65 video->renderer->deinit(video->renderer);
66 video->renderer->init(video->renderer);
67}
68
69void GBVideoDeinit(struct GBVideo* video) {
70 GBVideoAssociateRenderer(video, &dummyRenderer);
71 mappedMemoryFree(video->vram, GB_SIZE_VRAM);
72}
73
74void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer) {
75 video->renderer->deinit(video->renderer);
76 video->renderer = renderer;
77 renderer->vram = video->vram;
78 video->renderer->init(video->renderer);
79}
80
81int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles) {
82 video->eventDiff += cycles;
83 if (video->nextEvent != INT_MAX) {
84 video->nextEvent -= cycles;
85 }
86 if (video->nextEvent <= 0) {
87 if (video->nextEvent != INT_MAX) {
88 video->nextMode -= video->eventDiff;
89 }
90 video->nextEvent = INT_MAX;
91 GBVideoProcessDots(video);
92 if (video->nextMode <= 0) {
93 int lyc = video->p->memory.io[REG_LYC];
94 switch (video->mode) {
95 case 0:
96 if (video->frameskipCounter <= 0) {
97 video->renderer->finishScanline(video->renderer, video->ly);
98 }
99 ++video->ly;
100 video->p->memory.io[REG_LY] = video->ly;
101 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
102 if (video->ly < GB_VIDEO_VERTICAL_PIXELS) {
103 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
104 video->mode = 2;
105 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
106 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
107 }
108 } else {
109 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
110 video->mode = 1;
111 --video->frameskipCounter;
112 if (video->frameskipCounter < 0) {
113 video->renderer->finishFrame(video->renderer);
114 mCoreSyncPostFrame(video->p->sync);
115 video->frameskipCounter = video->frameskip;
116 }
117 ++video->frameCounter;
118
119 struct mCoreThread* thread = mCoreThreadGet();
120 if (thread && thread->frameCallback) {
121 thread->frameCallback(thread);
122 }
123
124 if (GBRegisterSTATIsVblankIRQ(video->stat) || GBRegisterSTATIsOAMIRQ(video->stat)) {
125 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
126 }
127 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_VBLANK);
128 }
129 if (GBRegisterSTATIsLYCIRQ(video->stat) && lyc == video->ly) {
130 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
131 }
132 GBUpdateIRQs(video->p);
133 break;
134 case 1:
135 // TODO: One M-cycle delay
136 ++video->ly;
137 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
138 if (video->ly == GB_VIDEO_VERTICAL_TOTAL_PIXELS) {
139 video->ly = 0;
140 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
141 video->mode = 2;
142 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
143 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
144 }
145 } else {
146 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
147 }
148 if (video->ly == GB_VIDEO_VERTICAL_TOTAL_PIXELS - 1) {
149 video->p->memory.io[REG_LY] = 0;
150 } else {
151 video->p->memory.io[REG_LY] = video->ly;
152 }
153 if (GBRegisterSTATIsLYCIRQ(video->stat) && lyc == video->ly) {
154 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
155 }
156 GBUpdateIRQs(video->p);
157 break;
158 case 2:
159 _cleanOAM(video, video->ly);
160 video->dotCounter = 0;
161 video->nextEvent = GB_VIDEO_HORIZONTAL_LENGTH;
162 video->x = 0;
163 video->nextMode = GB_VIDEO_MODE_3_LENGTH_BASE + video->objMax * 8;
164 video->mode = 3;
165 break;
166 case 3:
167 video->nextMode = GB_VIDEO_MODE_0_LENGTH_BASE - video->objMax * 8;
168 video->mode = 0;
169 if (GBRegisterSTATIsHblankIRQ(video->stat)) {
170 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
171 GBUpdateIRQs(video->p);
172 }
173 break;
174 }
175 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
176 video->p->memory.io[REG_STAT] = video->stat;
177 }
178 if (video->nextMode < video->nextEvent) {
179 video->nextEvent = video->nextMode;
180 }
181 video->eventDiff = 0;
182 }
183 return video->nextEvent;
184}
185
186static void _cleanOAM(struct GBVideo* video, int y) {
187 // TODO: GBC differences
188 // TODO: Optimize
189 video->objMax = 0;
190 int spriteHeight = 8;
191 if (GBRegisterLCDCIsObjSize(video->p->memory.io[REG_LCDC])) {
192 spriteHeight = 16;
193 }
194 int o = 0;
195 int i;
196 for (i = 0; i < 40; ++i) {
197 uint8_t oy = video->oam.obj[i].y;
198 if (y < oy - 16 || y >= oy - 16 + spriteHeight) {
199 continue;
200 }
201 // TODO: Sort
202 video->objThisLine[o] = &video->oam.obj[i];
203 ++o;
204 if (o == 10) {
205 break;
206 }
207 }
208 video->objMax = o;
209}
210
211void GBVideoProcessDots(struct GBVideo* video) {
212 if (video->mode != 3 || video->dotCounter < 0) {
213 return;
214 }
215 int oldX = video->x;
216 video->x = video->dotCounter + video->eventDiff + video->p->cpu->cycles;
217 if (video->x > GB_VIDEO_HORIZONTAL_PIXELS) {
218 video->x = GB_VIDEO_HORIZONTAL_PIXELS;
219 }
220 if (video->x == GB_VIDEO_HORIZONTAL_PIXELS) {
221 video->dotCounter = INT_MIN;
222 }
223 if (video->frameskipCounter <= 0) {
224 video->renderer->drawRange(video->renderer, oldX, video->x, video->ly, video->objThisLine, video->objMax);
225 }
226}
227
228void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
229 if (!GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && GBRegisterLCDCIsEnable(value)) {
230 video->mode = 2;
231 video->nextMode = GB_VIDEO_MODE_2_LENGTH - 5; // TODO: Why is this fudge factor needed? Might be related to T-cycles for load/store differing
232 video->nextEvent = video->nextMode;
233 video->eventDiff = -video->p->cpu->cycles;
234 // TODO: Does this read as 0 for 4 T-cycles?
235 video->stat = GBRegisterSTATSetMode(video->stat, 2);
236 video->p->memory.io[REG_STAT] = video->stat;
237 video->ly = 0;
238 video->p->memory.io[REG_LY] = 0;
239
240 if (video->p->cpu->cycles + video->nextEvent < video->p->cpu->nextEvent) {
241 video->p->cpu->nextEvent = video->p->cpu->cycles + video->nextEvent;
242 }
243 return;
244 }
245 if (GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && !GBRegisterLCDCIsEnable(value)) {
246 video->mode = 0;
247 video->nextMode = INT_MAX;
248 video->nextEvent = INT_MAX;
249 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
250 video->p->memory.io[REG_STAT] = video->stat;
251 video->ly = 0;
252 video->p->memory.io[REG_LY] = 0;
253 }
254}
255
256void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value) {
257 video->stat = (video->stat & 0x7) | (value & 0x78);
258}
259
260static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer) {
261 UNUSED(renderer);
262 // Nothing to do
263}
264
265static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer) {
266 UNUSED(renderer);
267 // Nothing to do
268}
269
270static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer) {
271 UNUSED(renderer);
272 // Nothing to do
273}
274
275static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value) {
276 UNUSED(renderer);
277 UNUSED(address);
278 return value;
279}
280
281static void GBVideoDummyRendererDrawRange(struct GBVideoRenderer* renderer, int startX, int endX, int y, struct GBObj** obj, size_t oamMax) {
282 UNUSED(renderer);
283 UNUSED(endX);
284 UNUSED(startX);
285 UNUSED(y);
286 UNUSED(obj);
287 UNUSED(oamMax);
288 // Nothing to do
289}
290
291static void GBVideoDummyRendererFinishScanline(struct GBVideoRenderer* renderer, int y) {
292 UNUSED(renderer);
293 UNUSED(y);
294 // Nothing to do
295}
296
297static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer) {
298 UNUSED(renderer);
299 // Nothing to do
300}
301
302static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels) {
303 UNUSED(renderer);
304 UNUSED(stride);
305 UNUSED(pixels);
306 // Nothing to do
307}