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 = renderer;
 48	renderer->palette = video->palette;
 49	renderer->vram = video->vram;
 50	renderer->oam = &video->oam;
 51}
 52
 53int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 54	video->nextEvent -= cycles;
 55	if (video->nextEvent <= 0) {
 56		video->lastHblank -= video->eventDiff;
 57		video->nextHblank -= video->eventDiff;
 58		video->nextHblankIRQ -= video->eventDiff;
 59		video->nextVcounterIRQ -= video->eventDiff;
 60
 61		if (video->inHblank) {
 62			// End Hblank
 63			video->inHblank = 0;
 64			video->nextEvent = video->nextHblank;
 65
 66			++video->vcount;
 67			video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 68
 69			switch (video->vcount) {
 70			case VIDEO_VERTICAL_PIXELS:
 71				video->inVblank = 1;
 72				video->renderer->finishFrame(video->renderer);
 73				video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
 74				//video->cpu.mmu.runVblankDmas();
 75				if (video->vblankIRQ) {
 76					GBARaiseIRQ(video->p, IRQ_VBLANK);
 77				}
 78				//video->vblankCallback();
 79				break;
 80			case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
 81				video->inVblank = 0;
 82				break;
 83			case VIDEO_VERTICAL_TOTAL_PIXELS:
 84				video->vcount = 0;
 85				//video->renderPath.startDraw();
 86				break;
 87			}
 88
 89			video->vcounter = video->vcount == video->vcountSetting;
 90			if (video->vcounter && video->vcounterIRQ) {
 91				GBARaiseIRQ(video->p, IRQ_VCOUNTER);
 92				video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
 93			}
 94
 95			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
 96				video->renderer->drawScanline(video->renderer, video->vcount);
 97			}
 98		} else {
 99			// Begin Hblank
100			video->inHblank = 1;
101			video->lastHblank = video->nextHblank;
102			video->nextEvent = video->lastHblank + VIDEO_HBLANK_LENGTH;
103			video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
104			video->nextHblankIRQ = video->nextHblank;
105
106			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
107				//video->cpu.mmu.runHblankDmas();
108			}
109			if (video->hblankIRQ) {
110				GBARaiseIRQ(video->p, IRQ_HBLANK);
111			}
112		}
113
114		video->eventDiff = video->nextEvent;
115	}
116	return video->nextEvent;
117}
118
119void GBAVideoWriteDISPSTAT(struct GBAVideo* video, uint16_t value) {
120	video->vblankIRQ = value & 0x0008;
121	video->hblankIRQ = value & 0x0010;
122	video->vcounterIRQ = value & 0x0020;
123	video->vcountSetting = (value & 0xFF00) >> 8;
124
125	if (video->vcounterIRQ) {
126		// FIXME: this can be too late if we're in the middle of an Hblank
127		video->nextVcounterIRQ = video->nextHblank + VIDEO_HBLANK_LENGTH + (video->vcountSetting - video->vcount) * VIDEO_HORIZONTAL_LENGTH;
128		if (video->nextVcounterIRQ < video->nextEvent) {
129			video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
130		}
131	}
132}
133
134uint16_t GBAVideoReadDISPSTAT(struct GBAVideo* video) {
135	return (video->inVblank) | (video->inHblank << 1) | (video->vcounter << 2);
136}
137
138static void GBAVideoDummyRendererInit(struct GBAVideoRenderer* renderer) {
139	(void)(renderer);
140	// Nothing to do
141}
142
143static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
144	(void)(renderer);
145	// Nothing to do
146}
147
148static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
149	(void)(renderer);
150	(void)(address);
151	return value;
152}
153
154static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y) {
155	(void)(renderer);
156	(void)(y);
157	// Nothing to do
158}
159
160static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer) {
161	(void)(renderer);
162	printf("Drawing a frame\n");
163	// Nothing to do
164}