1#include "gba-video.h"
  2
  3#include "gba.h"
  4#include "gba-io.h"
  5
  6#include <limits.h>
  7#include <string.h>
  8
  9static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer);
 10static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer);
 11static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value);
 12static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y);
 13static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer);
 14
 15static struct GBAVideoRenderer dummyRenderer = {
 16	.init = GBAVideoDummyRendererInit,
 17	.deinit = GBAVideoDummyRendererDeinit,
 18	.writeVideoRegister = GBAVideoDummyRendererWriteVideoRegister,
 19	.drawScanline = GBAVideoDummyRendererDrawScanline,
 20	.finishFrame = GBAVideoDummyRendererFinishFrame
 21};
 22
 23void GBAVideoInit(struct GBAVideo* video) {
 24	video->renderer = &dummyRenderer;
 25
 26	video->inHblank = 0;
 27	video->inVblank = 0;
 28	video->vcounter = 0;
 29	video->vblankIRQ = 0;
 30	video->hblankIRQ = 0;
 31	video->vcounterIRQ = 0;
 32	video->vcountSetting = 0;
 33
 34	video->vcount = -1;
 35
 36	video->lastHblank = 0;
 37	video->nextHblank = VIDEO_HDRAW_LENGTH;
 38	video->nextEvent = video->nextHblank;
 39	video->eventDiff = video->nextEvent;
 40
 41	video->nextHblankIRQ = 0;
 42	video->nextVblankIRQ = 0;
 43	video->nextVcounterIRQ = 0;
 44}
 45
 46void GBAVideoAssociateRenderer(struct GBAVideo* video, struct GBAVideoRenderer* renderer) {
 47	video->renderer->deinit(video->renderer);
 48	video->renderer = renderer;
 49	renderer->palette = video->palette;
 50	renderer->vram = video->vram;
 51	renderer->oam = &video->oam;
 52	video->renderer->init(video->renderer);
 53}
 54
 55int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 56	video->nextEvent -= cycles;
 57	if (video->nextEvent <= 0) {
 58		video->lastHblank -= video->eventDiff;
 59		video->nextHblank -= video->eventDiff;
 60		video->nextHblankIRQ -= video->eventDiff;
 61		video->nextVcounterIRQ -= video->eventDiff;
 62
 63		if (video->inHblank) {
 64			// End Hblank
 65			video->inHblank = 0;
 66			video->nextEvent = video->nextHblank;
 67
 68			++video->vcount;
 69			video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 70
 71			switch (video->vcount) {
 72			case VIDEO_VERTICAL_PIXELS:
 73				video->inVblank = 1;
 74				video->renderer->finishFrame(video->renderer);
 75				video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
 76				GBAMemoryRunVblankDMAs(&video->p->memory);
 77				if (video->vblankIRQ) {
 78					GBARaiseIRQ(video->p, IRQ_VBLANK);
 79				}
 80				//video->vblankCallback();
 81				break;
 82			case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
 83				video->inVblank = 0;
 84				break;
 85			case VIDEO_VERTICAL_TOTAL_PIXELS:
 86				video->vcount = 0;
 87				//video->renderPath.startDraw();
 88				break;
 89			}
 90
 91			video->vcounter = video->vcount == video->vcountSetting;
 92			if (video->vcounter && video->vcounterIRQ) {
 93				GBARaiseIRQ(video->p, IRQ_VCOUNTER);
 94				video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
 95			}
 96
 97			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
 98				video->renderer->drawScanline(video->renderer, video->vcount);
 99			}
100		} else {
101			// Begin Hblank
102			video->inHblank = 1;
103			video->lastHblank = video->nextHblank;
104			video->nextEvent = video->lastHblank + VIDEO_HBLANK_LENGTH;
105			video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
106			video->nextHblankIRQ = video->nextHblank;
107
108			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
109				GBAMemoryRunHblankDMAs(&video->p->memory);
110			}
111			if (video->hblankIRQ) {
112				GBARaiseIRQ(video->p, IRQ_HBLANK);
113			}
114		}
115
116		video->eventDiff = video->nextEvent;
117	}
118	return video->nextEvent;
119}
120
121void GBAVideoWriteDISPSTAT(struct GBAVideo* video, uint16_t value) {
122	video->vblankIRQ = value & 0x0008;
123	video->hblankIRQ = value & 0x0010;
124	video->vcounterIRQ = value & 0x0020;
125	video->vcountSetting = (value & 0xFF00) >> 8;
126
127	if (video->vcounterIRQ) {
128		// FIXME: this can be too late if we're in the middle of an Hblank
129		video->nextVcounterIRQ = video->nextHblank + VIDEO_HBLANK_LENGTH + (video->vcountSetting - video->vcount) * VIDEO_HORIZONTAL_LENGTH;
130		if (video->nextVcounterIRQ < video->nextEvent) {
131			video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
132		}
133	}
134}
135
136uint16_t GBAVideoReadDISPSTAT(struct GBAVideo* video) {
137	return (video->inVblank) | (video->inHblank << 1) | (video->vcounter << 2);
138}
139
140static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer) {
141	(void)(renderer);
142	// Nothing to do
143}
144
145static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
146	(void)(renderer);
147	// Nothing to do
148}
149
150static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
151	(void)(renderer);
152	(void)(address);
153	return value;
154}
155
156static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y) {
157	(void)(renderer);
158	(void)(y);
159	// Nothing to do
160}
161
162static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer) {
163	(void)(renderer);
164	// Nothing to do
165}