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 video->renderer->finishScanline(video->renderer, video->ly);
97 ++video->ly;
98 video->p->memory.io[REG_LY] = video->ly;
99 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
100 if (video->ly < GB_VIDEO_VERTICAL_PIXELS) {
101 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
102 video->mode = 2;
103 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
104 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
105 }
106 } else {
107 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
108 video->mode = 1;
109 ++video->frameCounter;
110 video->renderer->finishFrame(video->renderer);
111 mCoreSyncPostFrame(video->p->sync);
112
113 struct mCoreThread* thread = mCoreThreadGet();
114 if (thread && thread->frameCallback) {
115 thread->frameCallback(thread);
116 }
117
118 if (GBRegisterSTATIsVblankIRQ(video->stat) || GBRegisterSTATIsOAMIRQ(video->stat)) {
119 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
120 }
121 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_VBLANK);
122 }
123 if (GBRegisterSTATIsLYCIRQ(video->stat) && lyc == video->ly) {
124 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
125 }
126 GBUpdateIRQs(video->p);
127 break;
128 case 1:
129 // TODO: One M-cycle delay
130 ++video->ly;
131 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
132 if (video->ly == GB_VIDEO_VERTICAL_TOTAL_PIXELS) {
133 video->ly = 0;
134 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
135 video->mode = 2;
136 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
137 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
138 }
139 } else {
140 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
141 }
142 if (video->ly == GB_VIDEO_VERTICAL_TOTAL_PIXELS - 1) {
143 video->p->memory.io[REG_LY] = 0;
144 } else {
145 video->p->memory.io[REG_LY] = video->ly;
146 }
147 if (GBRegisterSTATIsLYCIRQ(video->stat) && lyc == video->ly) {
148 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
149 }
150 GBUpdateIRQs(video->p);
151 break;
152 case 2:
153 _cleanOAM(video, video->ly);
154 video->dotCounter = 0;
155 video->nextEvent = GB_VIDEO_HORIZONTAL_LENGTH;
156 video->x = 0;
157 video->nextMode = GB_VIDEO_MODE_3_LENGTH_BASE + video->objMax * 8;
158 video->mode = 3;
159 break;
160 case 3:
161 video->nextMode = GB_VIDEO_MODE_0_LENGTH_BASE - video->objMax * 8;
162 video->mode = 0;
163 if (GBRegisterSTATIsHblankIRQ(video->stat)) {
164 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
165 GBUpdateIRQs(video->p);
166 }
167 break;
168 }
169 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
170 video->p->memory.io[REG_STAT] = video->stat;
171 }
172 if (video->nextMode < video->nextEvent) {
173 video->nextEvent = video->nextMode;
174 }
175 video->eventDiff = 0;
176 }
177 return video->nextEvent;
178}
179
180static void _cleanOAM(struct GBVideo* video, int y) {
181 // TODO: GBC differences
182 // TODO: Optimize
183 video->objMax = 0;
184 int spriteHeight = 8;
185 if (GBRegisterLCDCIsObjSize(video->p->memory.io[REG_LCDC])) {
186 spriteHeight = 16;
187 }
188 int o = 0;
189 int i;
190 for (i = 0; i < 40; ++i) {
191 uint8_t oy = video->oam.obj[i].y;
192 if (y < oy - 16 || y >= oy - 16 + spriteHeight) {
193 continue;
194 }
195 // TODO: Sort
196 video->objThisLine[o] = &video->oam.obj[i];
197 ++o;
198 if (o == 10) {
199 break;
200 }
201 }
202 video->objMax = o;
203}
204
205void GBVideoProcessDots(struct GBVideo* video) {
206 if (video->mode != 3 || video->dotCounter < 0) {
207 return;
208 }
209 int oldX = video->x;
210 video->x = video->dotCounter + video->eventDiff + video->p->cpu->cycles;
211 if (video->x > GB_VIDEO_HORIZONTAL_PIXELS) {
212 video->x = GB_VIDEO_HORIZONTAL_PIXELS;
213 }
214 if (video->x == GB_VIDEO_HORIZONTAL_PIXELS) {
215 video->dotCounter = INT_MIN;
216 }
217 video->renderer->drawRange(video->renderer, oldX, video->x, video->ly, video->objThisLine, video->objMax);
218}
219
220void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
221 if (!GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && GBRegisterLCDCIsEnable(value)) {
222 video->mode = 2;
223 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
224 video->nextEvent = video->nextMode;
225 video->eventDiff = -video->p->cpu->cycles;
226 // TODO: Does this read as 0 for 4 T-cycles?
227 video->stat = GBRegisterSTATSetMode(video->stat, 2);
228 video->p->memory.io[REG_STAT] = video->stat;
229 video->ly = 0;
230 video->p->memory.io[REG_LY] = 0;
231
232 if (video->p->cpu->cycles + video->nextEvent < video->p->cpu->nextEvent) {
233 video->p->cpu->nextEvent = video->p->cpu->cycles + video->nextEvent;
234 }
235 return;
236 }
237 if (GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && !GBRegisterLCDCIsEnable(value)) {
238 video->mode = 0;
239 video->nextMode = INT_MAX;
240 video->nextEvent = INT_MAX;
241 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
242 video->p->memory.io[REG_STAT] = video->stat;
243 video->ly = 0;
244 video->p->memory.io[REG_LY] = 0;
245 }
246}
247
248void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value) {
249 video->stat = (video->stat & 0x7) | (value & 0x78);
250}
251
252static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer) {
253 UNUSED(renderer);
254 // Nothing to do
255}
256
257static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer) {
258 UNUSED(renderer);
259 // Nothing to do
260}
261
262static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer) {
263 UNUSED(renderer);
264 // Nothing to do
265}
266
267static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value) {
268 UNUSED(renderer);
269 UNUSED(address);
270 return value;
271}
272
273static void GBVideoDummyRendererDrawRange(struct GBVideoRenderer* renderer, int startX, int endX, int y, struct GBObj** obj, size_t oamMax) {
274 UNUSED(renderer);
275 UNUSED(endX);
276 UNUSED(startX);
277 UNUSED(y);
278 UNUSED(obj);
279 UNUSED(oamMax);
280 // Nothing to do
281}
282
283static void GBVideoDummyRendererFinishScanline(struct GBVideoRenderer* renderer, int y) {
284 UNUSED(renderer);
285 UNUSED(y);
286 // Nothing to do
287}
288
289static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer) {
290 UNUSED(renderer);
291 // Nothing to do
292}
293
294static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels) {
295 UNUSED(renderer);
296 UNUSED(stride);
297 UNUSED(pixels);
298 // Nothing to do
299}