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