src/gba/gba-video.c (view raw)
1#include "gba-video.h"
2
3#include "gba.h"
4#include "gba-io.h"
5#include "gba-serialize.h"
6#include "gba-thread.h"
7#include "memory.h"
8
9#include <limits.h>
10#include <string.h>
11
12static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer);
13static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer);
14static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value);
15static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y);
16static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer);
17
18static struct GBAVideoRenderer dummyRenderer = {
19 .init = GBAVideoDummyRendererInit,
20 .deinit = GBAVideoDummyRendererDeinit,
21 .writeVideoRegister = GBAVideoDummyRendererWriteVideoRegister,
22 .drawScanline = GBAVideoDummyRendererDrawScanline,
23 .finishFrame = GBAVideoDummyRendererFinishFrame
24};
25
26void GBAVideoInit(struct GBAVideo* video) {
27 video->renderer = &dummyRenderer;
28
29 video->inHblank = 0;
30 video->inVblank = 0;
31 video->vcounter = 0;
32 video->vblankIRQ = 0;
33 video->hblankIRQ = 0;
34 video->vcounterIRQ = 0;
35 video->vcountSetting = 0;
36
37 video->vcount = -1;
38
39 video->lastHblank = 0;
40 video->nextHblank = VIDEO_HDRAW_LENGTH;
41 video->nextEvent = video->nextHblank;
42 video->eventDiff = video->nextEvent;
43
44 video->nextHblankIRQ = 0;
45 video->nextVblankIRQ = 0;
46 video->nextVcounterIRQ = 0;
47
48 video->vram = anonymousMemoryMap(SIZE_VRAM);
49
50 int i;
51 for (i = 0; i < 128; ++i) {
52 video->oam.obj[i].disable = 1;
53 }
54}
55
56void GBAVideoDeinit(struct GBAVideo* video) {
57 GBAVideoAssociateRenderer(video, &dummyRenderer);
58 mappedMemoryFree(video->vram, SIZE_VRAM);
59}
60
61void GBAVideoAssociateRenderer(struct GBAVideo* video, struct GBAVideoRenderer* renderer) {
62 video->renderer->deinit(video->renderer);
63 video->renderer = renderer;
64 renderer->palette = video->palette;
65 renderer->vram = video->vram;
66 renderer->oam = &video->oam;
67 video->renderer->init(video->renderer);
68}
69
70int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
71 video->nextEvent -= cycles;
72 video->eventDiff += cycles;
73 if (video->nextEvent <= 0) {
74 int32_t lastEvent = video->nextEvent;
75 video->lastHblank -= video->eventDiff;
76 video->nextHblank -= video->eventDiff;
77 video->nextHblankIRQ -= video->eventDiff;
78 video->nextVcounterIRQ -= video->eventDiff;
79
80 if (video->inHblank) {
81 // End Hblank
82 video->inHblank = 0;
83 video->nextEvent = video->nextHblank;
84
85 ++video->vcount;
86 video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
87
88 switch (video->vcount) {
89 case VIDEO_VERTICAL_PIXELS:
90 video->inVblank = 1;
91 if (GBASyncDrawingFrame(video->p->sync)) {
92 video->renderer->finishFrame(video->renderer);
93 }
94 video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
95 GBAMemoryRunVblankDMAs(&video->p->memory, lastEvent);
96 if (video->vblankIRQ) {
97 GBARaiseIRQ(video->p, IRQ_VBLANK);
98 }
99 GBASyncPostFrame(video->p->sync);
100 break;
101 case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
102 video->inVblank = 0;
103 break;
104 case VIDEO_VERTICAL_TOTAL_PIXELS:
105 video->vcount = 0;
106 video->p->memory.io[REG_VCOUNT >> 1] = 0;
107 break;
108 }
109
110 video->vcounter = video->vcount == video->vcountSetting;
111 if (video->vcounter && video->vcounterIRQ) {
112 GBARaiseIRQ(video->p, IRQ_VCOUNTER);
113 video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
114 }
115
116 if (video->vcount < VIDEO_VERTICAL_PIXELS && GBASyncDrawingFrame(video->p->sync)) {
117 video->renderer->drawScanline(video->renderer, video->vcount);
118 }
119 } else {
120 // Begin Hblank
121 video->inHblank = 1;
122 video->lastHblank = video->nextHblank;
123 video->nextEvent = video->lastHblank + VIDEO_HBLANK_LENGTH;
124 video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
125 video->nextHblankIRQ = video->nextHblank;
126
127 if (video->vcount < VIDEO_VERTICAL_PIXELS) {
128 GBAMemoryRunHblankDMAs(&video->p->memory, lastEvent);
129 }
130 if (video->hblankIRQ) {
131 GBARaiseIRQ(video->p, IRQ_HBLANK);
132 }
133 }
134
135 video->eventDiff = 0;
136 }
137 return video->nextEvent;
138}
139
140void GBAVideoWriteDISPSTAT(struct GBAVideo* video, uint16_t value) {
141 union GBARegisterDISPSTAT dispstat;
142 dispstat.packed = value;
143 video->vblankIRQ = dispstat.vblankIRQ;
144 video->hblankIRQ = dispstat.hblankIRQ;
145 video->vcounterIRQ = dispstat.vcounterIRQ;
146 video->vcountSetting = dispstat.vcountSetting;
147
148 if (video->vcounterIRQ) {
149 // FIXME: this can be too late if we're in the middle of an Hblank
150 video->nextVcounterIRQ = video->nextHblank + VIDEO_HBLANK_LENGTH + (video->vcountSetting - video->vcount) * VIDEO_HORIZONTAL_LENGTH;
151 if (video->nextVcounterIRQ < video->nextEvent) {
152 video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
153 }
154 }
155}
156
157uint16_t GBAVideoReadDISPSTAT(struct GBAVideo* video) {
158 return (video->inVblank) | (video->inHblank << 1) | (video->vcounter << 2);
159}
160
161static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer) {
162 (void)(renderer);
163 // Nothing to do
164}
165
166static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
167 (void)(renderer);
168 // Nothing to do
169}
170
171static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
172 (void)(renderer);
173 (void)(address);
174 return value;
175}
176
177static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y) {
178 (void)(renderer);
179 (void)(y);
180 // Nothing to do
181}
182
183static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer) {
184 (void)(renderer);
185 // Nothing to do
186}
187
188void GBAVideoSerialize(struct GBAVideo* video, struct GBASerializedState* state) {
189 memcpy(state->vram, video->renderer->vram, SIZE_VRAM);
190 memcpy(state->oam, video->oam.raw, SIZE_OAM);
191 memcpy(state->pram, video->palette, SIZE_PALETTE_RAM);
192 union GBARegisterDISPSTAT dispstat;
193 dispstat.inVblank = video->inVblank;
194 dispstat.inHblank = video->inHblank;
195 dispstat.vcounter = video->vcounter;
196 dispstat.vblankIRQ = video->vblankIRQ;
197 dispstat.hblankIRQ = video->hblankIRQ;
198 dispstat.vcounterIRQ = video->vcounterIRQ;
199 dispstat.vcountSetting = video->vcountSetting;
200 state->io[REG_DISPSTAT >> 1] = dispstat.packed;
201 state->video.nextEvent = video->nextEvent;
202 state->video.eventDiff = video->eventDiff;
203 state->video.lastHblank = video->lastHblank;
204 state->video.nextHblank = video->nextHblank;
205 state->video.nextHblankIRQ = video->nextHblankIRQ;
206 state->video.nextVblankIRQ = video->nextVblankIRQ;
207 state->video.nextVcounterIRQ = video->nextVcounterIRQ;
208}
209
210void GBAVideoDeserialize(struct GBAVideo* video, struct GBASerializedState* state) {
211 memcpy(video->renderer->vram, state->vram, SIZE_VRAM);
212 int i;
213 for (i = 0; i < SIZE_OAM; i += 2) {
214 GBAStore16(&video->p->memory.d, BASE_OAM | i, state->oam[i >> 1], 0);
215 }
216 for (i = 0; i < SIZE_PALETTE_RAM; i += 2) {
217 GBAStore16(&video->p->memory.d, BASE_PALETTE_RAM | i, state->pram[i >> 1], 0);
218 }
219 union GBARegisterDISPSTAT dispstat;
220 dispstat.packed = state->io[REG_DISPSTAT >> 1];
221 video->inVblank = dispstat.inVblank;
222 video->inHblank = dispstat.inHblank;
223 video->vcounter = dispstat.vcounter;
224 video->vblankIRQ = dispstat.vblankIRQ;
225 video->hblankIRQ = dispstat.hblankIRQ;
226 video->vcounterIRQ = dispstat.vcounterIRQ;
227 video->vcountSetting = dispstat.vcountSetting;
228 video->nextEvent = state->video.nextEvent;
229 video->eventDiff = state->video.eventDiff;
230 video->lastHblank = state->video.lastHblank;
231 video->nextHblank = state->video.nextHblank;
232 video->nextHblankIRQ = state->video.nextHblankIRQ;
233 video->nextVblankIRQ = state->video.nextVblankIRQ;
234 video->nextVcounterIRQ = state->video.nextVcounterIRQ;
235 video->vcount = state->io[REG_VCOUNT >> 1];
236}