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 GBAVideoRendererInit(struct GBAVideoRenderer* renderer);
 10
 11static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer);
 12static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value);
 13static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y);
 14static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer);
 15
 16static struct GBAVideoRenderer dummyRenderer = {
 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
 46int32_t GBAVideoProcessEvents(struct GBAVideo* video, int32_t cycles) {
 47	video->nextEvent -= cycles;
 48	if (video->nextEvent <= 0) {
 49		video->lastHblank -= video->eventDiff;
 50		video->nextHblank -= video->eventDiff;
 51		video->nextHblankIRQ -= video->eventDiff;
 52		video->nextVcounterIRQ -= video->eventDiff;
 53
 54		if (video->inHblank) {
 55			// End Hblank
 56			video->inHblank = 0;
 57			video->nextEvent = video->nextHblank;
 58
 59			++video->vcount;
 60			video->p->memory.io[REG_VCOUNT >> 1] = video->vcount;
 61
 62			switch (video->vcount) {
 63			case VIDEO_VERTICAL_PIXELS:
 64				video->inVblank = 1;
 65				video->renderer->finishFrame(video->renderer);
 66				video->nextVblankIRQ = video->nextEvent + VIDEO_TOTAL_LENGTH;
 67				//video->cpu.mmu.runVblankDmas();
 68				if (video->vblankIRQ) {
 69					GBARaiseIRQ(video->p, IRQ_VBLANK);
 70				}
 71				//video->vblankCallback();
 72				break;
 73			case VIDEO_VERTICAL_TOTAL_PIXELS - 1:
 74				video->inVblank = 0;
 75				break;
 76			case VIDEO_VERTICAL_TOTAL_PIXELS:
 77				video->vcount = 0;
 78				//video->renderPath.startDraw();
 79				break;
 80			}
 81
 82			video->vcounter = video->vcount == video->vcountSetting;
 83			if (video->vcounter && video->vcounterIRQ) {
 84				GBARaiseIRQ(video->p, IRQ_VCOUNTER);
 85				video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
 86			}
 87
 88			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
 89				video->renderer->drawScanline(video->renderer, video->vcount);
 90			}
 91		} else {
 92			// Begin Hblank
 93			video->inHblank = 1;
 94			video->lastHblank = video->nextHblank;
 95			video->nextEvent = video->lastHblank + VIDEO_HBLANK_LENGTH;
 96			video->nextHblank = video->nextEvent + VIDEO_HDRAW_LENGTH;
 97			video->nextHblankIRQ = video->nextHblank;
 98
 99			if (video->vcount < VIDEO_VERTICAL_PIXELS) {
100				//video->cpu.mmu.runHblankDmas();
101			}
102			if (video->hblankIRQ) {
103				GBARaiseIRQ(video->p, IRQ_HBLANK);
104			}
105		}
106
107		video->eventDiff = video->nextEvent;
108	}
109	return video->nextEvent;
110}
111
112void GBAVideoWriteDISPSTAT(struct GBAVideo* video, uint16_t value) {
113	video->vblankIRQ = value & 0x0008;
114	video->hblankIRQ = value & 0x0010;
115	video->vcounterIRQ = value & 0x0020;
116	video->vcountSetting = (value & 0xFF00) >> 8;
117
118	if (video->vcounterIRQ) {
119		// FIXME: this can be too late if we're in the middle of an Hblank
120		video->nextVcounterIRQ = video->nextHblank + VIDEO_HBLANK_LENGTH + (video->vcountSetting - video->vcount) * VIDEO_HORIZONTAL_LENGTH;
121		if (video->nextVcounterIRQ < video->nextEvent) {
122			video->nextVcounterIRQ += VIDEO_TOTAL_LENGTH;
123		}
124	}
125}
126
127uint16_t GBAVideoReadDISPSTAT(struct GBAVideo* video) {
128	return (video->inVblank) | (video->inHblank << 1) | (video->vcounter << 2);
129}
130
131static void GBAVideoRendererInit(struct GBAVideoRenderer* renderer) {
132	memset(renderer->palette, 0, sizeof(renderer->palette));
133	memset(renderer->vram, 0, sizeof(renderer->vram));
134	memset(&renderer->oam, 0, sizeof(renderer->oam));
135}
136
137static void GBAVideoDummyRendererDeinit(struct GBAVideoRenderer* renderer) {
138	(void)(renderer);
139	// Nothing to do
140}
141static uint16_t GBAVideoDummyRendererWriteVideoRegister(struct GBAVideoRenderer* renderer, uint32_t address, uint16_t value) {
142	(void)(renderer);
143	(void)(address);
144	return value;
145}
146
147static void GBAVideoDummyRendererDrawScanline(struct GBAVideoRenderer* renderer, int y) {
148	(void)(renderer);
149	(void)(y);
150	// Nothing to do
151}
152
153static void GBAVideoDummyRendererFinishFrame(struct GBAVideoRenderer* renderer) {
154	(void)(renderer);
155	printf("Drawing a frame\n");
156	// Nothing to do
157}