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 GBVideoDummyRendererDrawDot(struct GBVideoRenderer* renderer, int x, int y, struct GBObj** obj, size_t oamMax);
20static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer);
21static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
22
23static void _cleanOAM(struct GBVideo* video, int y);
24
25static struct GBVideoRenderer dummyRenderer = {
26 .init = GBVideoDummyRendererInit,
27 .reset = GBVideoDummyRendererReset,
28 .deinit = GBVideoDummyRendererDeinit,
29 .writeVideoRegister = GBVideoDummyRendererWriteVideoRegister,
30 .drawDot = GBVideoDummyRendererDrawDot,
31 .finishFrame = GBVideoDummyRendererFinishFrame,
32 .getPixels = GBVideoDummyRendererGetPixels
33};
34
35void GBVideoInit(struct GBVideo* video) {
36 video->renderer = &dummyRenderer;
37 video->vram = 0;
38 video->frameskip = 0;
39}
40
41void GBVideoReset(struct GBVideo* video) {
42 video->ly = 0;
43 video->mode = 1;
44 video->stat = 1;
45
46 video->nextEvent = INT_MAX;
47 video->eventDiff = 0;
48
49 video->nextMode = INT_MAX;
50 video->nextDot = INT_MAX;
51
52 video->frameCounter = 0;
53 video->frameskipCounter = 0;
54
55 if (video->vram) {
56 mappedMemoryFree(video->vram, GB_SIZE_VRAM);
57 }
58 video->vram = anonymousMemoryMap(GB_SIZE_VRAM);
59 video->renderer->vram = video->vram;
60 memset(&video->oam, 0, sizeof(video->oam));
61 video->renderer->oam = &video->oam;
62
63 video->renderer->deinit(video->renderer);
64 video->renderer->init(video->renderer);
65}
66
67void GBVideoDeinit(struct GBVideo* video) {
68 GBVideoAssociateRenderer(video, &dummyRenderer);
69 mappedMemoryFree(video->vram, GB_SIZE_VRAM);
70}
71
72void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer) {
73 video->renderer->deinit(video->renderer);
74 video->renderer = renderer;
75 renderer->vram = video->vram;
76 video->renderer->init(video->renderer);
77}
78
79int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles) {
80 video->eventDiff += cycles;
81 if (video->nextEvent != INT_MAX) {
82 video->nextEvent -= cycles;
83 }
84 if (video->nextEvent <= 0) {
85 if (video->nextEvent != INT_MAX) {
86 video->nextMode -= video->eventDiff;
87 video->nextDot -= video->eventDiff;
88 }
89 video->nextEvent = INT_MAX;
90 if (video->nextDot <= 0) {
91 video->renderer->drawDot(video->renderer, video->x, video->ly, video->objThisLine, video->objMax);
92 ++video->x;
93 if (video->x < GB_VIDEO_HORIZONTAL_PIXELS) {
94 video->nextDot = 1;
95 } else {
96 video->nextDot = INT_MAX;
97 }
98 }
99 if (video->nextMode <= 0) {
100 int lyc = video->p->memory.io[REG_LYC];
101 switch (video->mode) {
102 case 0:
103 ++video->ly;
104 video->p->memory.io[REG_LY] = video->ly;
105 video->stat = GBRegisterSTATSetLYC(video->stat, lyc == video->ly);
106 if (video->ly < GB_VIDEO_VERTICAL_PIXELS) {
107 video->nextMode = GB_VIDEO_MODE_2_LENGTH;
108 video->mode = 2;
109 if (GBRegisterSTATIsOAMIRQ(video->stat)) {
110 video->p->memory.io[REG_IF] |= (1 << GB_IRQ_LCDSTAT);
111 }
112 } else {
113 video->nextMode = GB_VIDEO_HORIZONTAL_LENGTH;
114 video->mode = 1;
115 ++video->frameCounter;
116 video->renderer->finishFrame(video->renderer);
117 mCoreSyncPostFrame(video->p->sync);
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->nextDot = 1;
161 video->nextEvent = video->nextDot;
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->nextDot < video->nextEvent) {
179 video->nextEvent = video->nextDot;
180 }
181 if (video->nextMode < video->nextEvent) {
182 video->nextEvent = video->nextMode;
183 }
184 video->eventDiff = 0;
185 }
186 return video->nextEvent;
187}
188
189static void _cleanOAM(struct GBVideo* video, int y) {
190 // TODO: GBC differences
191 // TODO: Optimize
192 video->objMax = 0;
193 int spriteHeight = 8;
194 if (GBRegisterLCDCIsObjSize(video->p->memory.io[REG_LCDC])) {
195 spriteHeight = 16;
196 }
197 int o = 0;
198 int i;
199 for (i = 0; i < 40; ++i) {
200 uint8_t oy = video->oam.obj[i].y;
201 if (y < oy - 16 || y >= oy - 16 + spriteHeight) {
202 continue;
203 }
204 // TODO: Sort
205 video->objThisLine[o] = &video->oam.obj[i];
206 ++o;
207 if (o == 10) {
208 break;
209 }
210 }
211 video->objMax = o;
212}
213
214void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
215 if (!GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && GBRegisterLCDCIsEnable(value)) {
216 video->mode = 2;
217 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
218 video->nextEvent = video->nextMode;
219 video->eventDiff = -video->p->cpu->cycles;
220 // TODO: Does this read as 0 for 4 T-cycles?
221 video->stat = GBRegisterSTATSetMode(video->stat, 2);
222 video->p->memory.io[REG_STAT] = video->stat;
223 video->ly = 0;
224 video->p->memory.io[REG_LY] = 0;
225
226 if (video->p->cpu->cycles + video->nextEvent < video->p->cpu->nextEvent) {
227 video->p->cpu->nextEvent = video->p->cpu->cycles + video->nextEvent;
228 }
229 return;
230 }
231 if (GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && !GBRegisterLCDCIsEnable(value)) {
232 video->mode = 0;
233 video->nextMode = INT_MAX;
234 video->nextEvent = INT_MAX;
235 video->stat = GBRegisterSTATSetMode(video->stat, video->mode);
236 video->p->memory.io[REG_STAT] = video->stat;
237 video->ly = 0;
238 video->p->memory.io[REG_LY] = 0;
239 }
240}
241
242void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value) {
243 video->stat = (video->stat & 0x7) | (value & 0x78);
244}
245
246static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer) {
247 UNUSED(renderer);
248 // Nothing to do
249}
250
251static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer) {
252 UNUSED(renderer);
253 // Nothing to do
254}
255
256static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer) {
257 UNUSED(renderer);
258 // Nothing to do
259}
260
261static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value) {
262 UNUSED(renderer);
263 UNUSED(address);
264 return value;
265}
266
267static void GBVideoDummyRendererDrawDot(struct GBVideoRenderer* renderer, int x, int y, struct GBObj** obj, size_t oamMax) {
268 UNUSED(renderer);
269 UNUSED(x);
270 UNUSED(y);
271 UNUSED(obj);
272 UNUSED(oamMax);
273 // Nothing to do
274}
275
276static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer) {
277 UNUSED(renderer);
278 // Nothing to do
279}
280
281static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels) {
282 UNUSED(renderer);
283 UNUSED(stride);
284 UNUSED(pixels);
285 // Nothing to do
286}