all repos — mgba @ 0cf9bf75e28e632ca071bb59a15e4f1afa4b4b9c

mGBA Game Boy Advance Emulator

src/ds/gx/software.c (view raw)

  1/* Copyright (c) 2013-2017 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 <mgba/internal/ds/gx/software.h>
  7
  8#include <mgba-util/memory.h>
  9#include "gba/renderers/software-private.h"
 10
 11DEFINE_VECTOR(DSGXSoftwarePolygonList, struct DSGXSoftwarePolygon);
 12DEFINE_VECTOR(DSGXSoftwareEdgeList, struct DSGXSoftwareEdge);
 13DEFINE_VECTOR(DSGXSoftwareSpanList, struct DSGXSoftwareSpan);
 14
 15static void DSGXSoftwareRendererInit(struct DSGXRenderer* renderer);
 16static void DSGXSoftwareRendererReset(struct DSGXRenderer* renderer);
 17static void DSGXSoftwareRendererDeinit(struct DSGXRenderer* renderer);
 18static void DSGXSoftwareRendererInvalidateTex(struct DSGXRenderer* renderer, int slot);
 19static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSGXVertex* verts, struct DSGXPolygon* polys, unsigned polyCount, bool wSort);
 20static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y);
 21static void DSGXSoftwareRendererGetScanline(struct DSGXRenderer* renderer, int y, const color_t** output);
 22
 23static void _expandColor(uint16_t c15, uint8_t* r, uint8_t* g, uint8_t* b) {
 24	*r = ((c15 << 1) & 0x3E) | 1;
 25	*g = ((c15 >> 4) & 0x3E) | 1;
 26	*b = ((c15 >> 9) & 0x3E) | 1;
 27}
 28
 29static color_t _finishColor(uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
 30#ifndef COLOR_16_BIT
 31	color_t rgba = (r << 2) & 0xFC;
 32	rgba |= (g << 10) & 0xFC00;
 33	rgba |= (b << 18) & 0xFC0000;
 34	rgba |= (a << 26) & 0xF8000000;
 35	return rgba;
 36#else
 37#error Unsupported color depth
 38#endif
 39}
 40
 41static unsigned _mix32(int weightA, unsigned colorA, int weightB, unsigned colorB) {
 42	unsigned c = 0;
 43	unsigned a, b;
 44#ifdef COLOR_16_BIT
 45#error Unsupported color depth
 46#else
 47	a = colorA & 0xFF;
 48	b = colorB & 0xFF;
 49	c |= ((a * weightA + b * weightB) / 32) & 0x1FF;
 50	if (c & 0x00000100) {
 51		c = 0x000000FF;
 52	}
 53
 54	a = colorA & 0xFF00;
 55	b = colorB & 0xFF00;
 56	c |= ((a * weightA + b * weightB) / 32) & 0x1FF00;
 57	if (c & 0x00010000) {
 58		c = (c & 0x000000FF) | 0x0000FF00;
 59	}
 60
 61	a = colorA & 0xFF0000;
 62	b = colorB & 0xFF0000;
 63	c |= ((a * weightA + b * weightB) / 32) & 0x1FF0000;
 64	if (c & 0x01000000) {
 65		c = (c & 0x0000FFFF) | 0x00FF0000;
 66	}
 67#endif
 68	return c;
 69}
 70
 71static unsigned _mixTexels(int weightA, unsigned colorA, int weightB, unsigned colorB) {
 72	unsigned c = 0;
 73	unsigned a, b;
 74	a = colorA & 0x7C1F;
 75	b = colorB & 0x7C1F;
 76	a |= (colorA & 0x3E0) << 16;
 77	b |= (colorB & 0x3E0) << 16;
 78	c = ((a * weightA + b * weightB) / 8);
 79	if (c & 0x04000000) {
 80		c = (c & ~0x07E00000) | 0x03E00000;
 81	}
 82	if (c & 0x0020) {
 83		c = (c & ~0x003F) | 0x001F;
 84	}
 85	if (c & 0x8000) {
 86		c = (c & ~0xF800) | 0x7C00;
 87	}
 88	c = (c & 0x7C1F) | ((c >> 16) & 0x03E0);
 89	return c;
 90}
 91
 92static color_t _lookupColor(struct DSGXSoftwareRenderer* renderer, struct DSGXSoftwareEndpoint* ep, struct DSGXSoftwarePolygon* poly) {
 93	if (!poly->texBase && poly->texFormat) {
 94		return 0;
 95	}
 96	// TODO: Optimize
 97	uint16_t texel;
 98
 99	int16_t s = ep->s >> 4;
100	int16_t t = ep->t >> 4;
101	if (!DSGXTexParamsIsSRepeat(poly->poly->texParams)) {
102		if (s < 0) {
103			s = 0;
104		} else if (s >= poly->texW) {
105			s = poly->texW - 1;
106		}
107	} else if (DSGXTexParamsIsSMirror(poly->poly->texParams)) {
108		if (s & poly->texW) {
109			s = poly->texW - s - 1;
110		}
111		s &= poly->texW - 1;
112	} else {
113		s &= poly->texW - 1;
114	}
115	if (!DSGXTexParamsIsTRepeat(poly->poly->texParams)) {
116		if (t < 0) {
117			t = 0;
118		} else if (t >= poly->texH) {
119			t = poly->texW - 1;
120		}
121	} else if (DSGXTexParamsIsTMirror(poly->poly->texParams)) {
122		if (t & poly->texH) {
123			t = poly->texH - t - 1;
124		}
125		t &= poly->texH - 1;
126	} else {
127		t &= poly->texH - 1;
128	}
129
130	uint16_t texelCoord = s + t * poly->texW;
131	uint8_t ta = 0x1F;
132	uint8_t pa = DSGXPolygonAttrsGetAlpha(poly->poly->polyParams);
133	if (pa) {
134		pa = (pa << 1) + 1;
135	}
136	switch (poly->texFormat) {
137	case 0:
138	default:
139		return _finishColor(ep->cr, ep->cg, ep->cb, pa);
140	case 1:
141		texel = ((uint8_t*) poly->texBase)[texelCoord];
142		ta = (texel >> 5) & 0x7;
143		ta = (ta << 2) + (ta >> 1);
144		texel &= 0x1F;
145		break;
146	case 2:
147		texel = ((uint8_t*) poly->texBase)[texelCoord >> 2];
148		if (texelCoord & 0x3) {
149			texel >>= 2 * texel & 3;
150		}
151		texel &= 0x3;
152		break;
153	case 3:
154		texel = ((uint8_t*) poly->texBase)[texelCoord >> 1];
155		if (texelCoord & 0x1) {
156			texel >>= 4;
157		}
158		texel &= 0xF;
159		break;
160	case 4:
161		texel = ((uint8_t*) poly->texBase)[texelCoord];
162		break;
163	case 5:
164		texelCoord = (s & ~3) + (t & 3) + (t >> 2) * poly->texW;
165		texel = ((uint8_t*) poly->texBase)[texelCoord];
166		texel >>= (s & 3) * 2;
167		texel &= 3;
168		break;
169	case 6:
170		texel = ((uint8_t*) poly->texBase)[texelCoord];
171		ta = (texel >> 3) & 0x1F;
172		texel &= 0x7;
173		break;
174	case 7:
175		return _finishColor(0x3F, 0x3F, 0x3F, pa);
176	}
177	uint8_t r, g, b;
178	unsigned wr, wg, wb, wa;
179	if (poly->texFormat == 5) {
180		// TODO: Slot 2 uses upper half
181		uint16_t half = DSGXTexParamsGetVRAMBase(poly->poly->texParams) & 0x8000;
182		uint32_t slot1Base = (DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 1) + (texelCoord >> 2) + half;
183		uint16_t texel2 = renderer->d.tex[1][slot1Base];
184		uint16_t texel2Base = (texel2 & 0x3FFF) << 1;
185		int a = 0x8;
186		int b = 0;
187		switch (texel2 >> 14) {
188		case 0:
189			if (texel == 3) {
190				ta = 0;
191			}
192			texel = poly->palBase[texel + texel2Base];
193			break;
194		case 1:
195			if (texel == 3) {
196				ta = 0;
197			}
198			if (texel != 2) {
199				texel = poly->palBase[texel + texel2Base];
200			} else {
201				texel = poly->palBase[texel2Base];
202				texel2 = poly->palBase[texel2Base + 1];
203				a = 4;
204				b = 4;
205			}
206			break;
207		case 2:
208			texel = poly->palBase[texel + texel2Base];
209			break;
210		case 3:
211			switch (texel) {
212			case 0:
213			case 1:
214				texel = poly->palBase[texel + texel2Base];
215				break;
216			case 2:
217				texel = poly->palBase[texel2Base];
218				texel2 = poly->palBase[texel2Base + 1];
219				a = 5;
220				b = 3;
221				break;
222			case 3:
223				texel = poly->palBase[texel2Base];
224				texel2 = poly->palBase[texel2Base + 1];
225				a = 3;
226				b = 5;
227				break;
228			}
229			break;
230		}
231		if (b) {
232			texel = _mixTexels(a, texel, b, texel2);
233		}
234	} else {
235		if (poly->texFormat < 5 && poly->texFormat > 1 && DSGXTexParamsIs0Transparent(poly->poly->texParams) && !texel) {
236			return 0;
237		}
238		texel = poly->palBase[texel];
239	}
240	_expandColor(texel, &r, &g, &b);
241	if (ta) {
242		ta = (ta << 1) + 1;
243	}
244	switch (poly->blendFormat) {
245	default:
246		// TODO: Alpha
247		return _finishColor(r, g, b, pa);
248	case 1:
249		wr = (r * ta + ep->cr * (63 - ta)) >> 6;
250		wg = (g * ta + ep->cg * (63 - ta)) >> 6;
251		wb = (b * ta + ep->cb * (63 - ta)) >> 6;
252		return _finishColor(wr, wg, wb, pa);
253	case 0:
254		wr = ((r + 1) * (ep->cr + 1) - 1) >> 6;
255		wg = ((g + 1) * (ep->cg + 1) - 1) >> 6;
256		wb = ((b + 1) * (ep->cb + 1) - 1) >> 6;
257		wa = ((ta + 1) * (pa + 1) - 1) >> 6;
258		return _finishColor(wr, wg, wb, wa);
259	}
260}
261
262static inline int32_t _interpolate(int32_t x0, int32_t x1, int64_t w0, int64_t w1, int64_t w, int32_t qr) {
263	// 32-bit -> 96-bit
264	int64_t x0b = (w0 & 0xFFFFFFFF) * x0;
265	int64_t x0t = (w0 >> 32) * x0;
266	int64_t x1b = (w1 & 0xFFFFFFFF) * x1;
267	int64_t x1t = (w1 >> 32) * x1;
268	// 96-bit -> 64-bit
269	int64_t xx0 = (x0t << 32) + x0b;
270	int64_t xx1 = (x1t << 32) + x1b;
271	xx1 -= xx0;
272	xx1 >>= 12;
273
274	int64_t qrb = xx1 * qr;
275	qrb += xx0;
276
277	return qrb / w;
278}
279
280static inline int32_t _divideBy(int64_t x, int32_t recip) {
281	int64_t x0 = (x & 0xFFFFFFFF) * recip;
282	int64_t x1 = (x >> 32) * recip;
283	x1 += x0 >> 32;
284	return x1 >> 31;
285}
286
287static bool _edgeToSpan(struct DSGXSoftwareSpan* span, const struct DSGXSoftwareEdge* edge, int index, int32_t y) {
288	int32_t height = edge->y1 - edge->y0;
289	int64_t yw = y - edge->y0;
290	if (!height) {
291		return false;
292	}
293	// Clamp to bounds
294	if (yw < 0) {
295		return false;
296	} else if (yw > height) {
297		return false;
298	}
299
300	span->ep[index].x = (((int64_t) (edge->x1 - edge->x0) * yw) / height) + edge->x0;
301
302	if (index) {
303		if (span->ep[0].x == span->ep[index].x) {
304			return false;
305		}
306		if (span->ep[0].x > span->ep[index].x) {
307			int32_t temp = span->ep[index].x;
308			span->ep[index] = span->ep[0];
309			span->ep[0].x = temp;
310			index = 0;
311		}
312	}
313
314	int64_t w0 = 0x7FFFFFFFFFFFFFFF / edge->w0;
315	int64_t w1 = 0x7FFFFFFFFFFFFFFF / edge->w1;
316	int64_t w = w1 - w0;
317
318	// Losslessly interpolate two 64-bit values
319	int64_t wb = (w & 0xFFFFFFFF) * yw;
320	int64_t wt = (w >> 32) * yw;
321	int64_t div = wt / height;
322	int64_t rem = wt % height;
323	w = div << 32;
324	wb += rem << 32;
325	div = wb / height;
326	w += div;
327	w += w0;
328
329	span->ep[index].w = 0x7FFFFFFFFFFFFFFF / w;
330	span->ep[index].wRecip = w;
331	int32_t qr = (yw << 12) / height;
332
333	span->ep[index].z  = _interpolate(edge->z0, edge->z1, w0, w1, w, qr);
334	span->ep[index].cr = _interpolate(edge->cr0, edge->cr1, w0, w1, w, qr);
335	span->ep[index].cg = _interpolate(edge->cg0, edge->cg1, w0, w1, w, qr);
336	span->ep[index].cb = _interpolate(edge->cb0, edge->cb1, w0, w1, w, qr);
337	span->ep[index].s  = _interpolate(edge->s0, edge->s1, w0, w1, w, qr);
338	span->ep[index].t  = _interpolate(edge->t0, edge->t1, w0, w1, w, qr);
339
340	return true;
341}
342
343static void _createStep(struct DSGXSoftwareSpan* span) {
344	int32_t width = (span->ep[1].x - span->ep[0].x) >> 12;
345
346	span->ep[0].stepW = span->ep[0].wRecip;
347	span->ep[0].stepZ = span->ep[0].z  * span->ep[0].wRecip;
348	span->ep[0].stepR = span->ep[0].cr * span->ep[0].wRecip;
349	span->ep[0].stepG = span->ep[0].cg * span->ep[0].wRecip;
350	span->ep[0].stepB = span->ep[0].cb * span->ep[0].wRecip;
351	span->ep[0].stepS = span->ep[0].s  * span->ep[0].wRecip;
352	span->ep[0].stepT = span->ep[0].t  * span->ep[0].wRecip;
353
354	span->ep[1].stepW = span->ep[1].wRecip;
355	span->ep[1].stepZ = span->ep[1].z  * span->ep[1].wRecip;
356	span->ep[1].stepR = span->ep[1].cr * span->ep[1].wRecip;
357	span->ep[1].stepG = span->ep[1].cg * span->ep[1].wRecip;
358	span->ep[1].stepB = span->ep[1].cb * span->ep[1].wRecip;
359	span->ep[1].stepS = span->ep[1].s  * span->ep[1].wRecip;
360	span->ep[1].stepT = span->ep[1].t  * span->ep[1].wRecip;
361
362	if (!width) {	
363		return;
364	}
365	span->step.stepW = (span->ep[1].stepW - span->ep[0].stepW) / width;
366	span->step.stepZ = (span->ep[1].stepZ - span->ep[0].stepZ) / width;
367	span->step.stepR = (span->ep[1].stepR - span->ep[0].stepR) / width;
368	span->step.stepG = (span->ep[1].stepG - span->ep[0].stepG) / width;
369	span->step.stepB = (span->ep[1].stepB - span->ep[0].stepB) / width;
370	span->step.stepS = (span->ep[1].stepS - span->ep[0].stepS) / width;
371	span->step.stepT = (span->ep[1].stepT - span->ep[0].stepT) / width;
372}
373
374static void _stepEndpoint(struct DSGXSoftwareSpan* span) {
375	span->ep[0].wRecip += span->step.stepW;
376	span->ep[0].w = (0x7FFFFFFFFFFFFFFF / span->ep[0].wRecip) + 1;
377
378	span->ep[0].stepZ += span->step.stepZ;
379	span->ep[0].z = _divideBy(span->ep[0].stepZ, span->ep[0].w);
380
381	span->ep[0].stepR += span->step.stepR;
382	span->ep[0].cr = _divideBy(span->ep[0].stepR, span->ep[0].w);
383
384	span->ep[0].stepG += span->step.stepG;
385	span->ep[0].cg = _divideBy(span->ep[0].stepG, span->ep[0].w);
386
387	span->ep[0].stepB += span->step.stepB;
388	span->ep[0].cb = _divideBy(span->ep[0].stepB, span->ep[0].w);
389
390	span->ep[0].stepS += span->step.stepS;
391	span->ep[0].s = _divideBy(span->ep[0].stepS, span->ep[0].w);
392
393	span->ep[0].stepT += span->step.stepT;
394	span->ep[0].t = _divideBy(span->ep[0].stepT, span->ep[0].w);
395}
396
397void DSGXSoftwareRendererCreate(struct DSGXSoftwareRenderer* renderer) {
398	renderer->d.init = DSGXSoftwareRendererInit;
399	renderer->d.reset = DSGXSoftwareRendererReset;
400	renderer->d.deinit = DSGXSoftwareRendererDeinit;
401	renderer->d.invalidateTex = DSGXSoftwareRendererInvalidateTex;
402	renderer->d.setRAM = DSGXSoftwareRendererSetRAM;
403	renderer->d.drawScanline = DSGXSoftwareRendererDrawScanline;
404	renderer->d.getScanline = DSGXSoftwareRendererGetScanline;
405}
406
407static void DSGXSoftwareRendererInit(struct DSGXRenderer* renderer) {
408	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
409	DSGXSoftwarePolygonListInit(&softwareRenderer->activePolys, DS_GX_POLYGON_BUFFER_SIZE / 4);
410	DSGXSoftwareEdgeListInit(&softwareRenderer->activeEdges, DS_GX_POLYGON_BUFFER_SIZE);
411	DSGXSoftwareSpanListInit(&softwareRenderer->activeSpans, DS_GX_POLYGON_BUFFER_SIZE / 2);
412	softwareRenderer->bucket = anonymousMemoryMap(sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
413	softwareRenderer->scanlineCache = anonymousMemoryMap(sizeof(color_t) * DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS);
414}
415
416static void DSGXSoftwareRendererReset(struct DSGXRenderer* renderer) {
417	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
418	softwareRenderer->flushPending = false;
419}
420
421static void DSGXSoftwareRendererDeinit(struct DSGXRenderer* renderer) {
422	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
423	DSGXSoftwarePolygonListDeinit(&softwareRenderer->activePolys);
424	DSGXSoftwareEdgeListDeinit(&softwareRenderer->activeEdges);	
425	DSGXSoftwareSpanListDeinit(&softwareRenderer->activeSpans);
426	mappedMemoryFree(softwareRenderer->bucket, sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
427	mappedMemoryFree(softwareRenderer->scanlineCache, sizeof(color_t) * DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS);
428}
429
430static void DSGXSoftwareRendererInvalidateTex(struct DSGXRenderer* renderer, int slot) {
431	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
432	// TODO
433}
434
435static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSGXVertex* verts, struct DSGXPolygon* polys, unsigned polyCount, bool wSort) {
436	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
437
438	softwareRenderer->flushPending = true;
439	softwareRenderer->wSort = wSort;
440	softwareRenderer->verts = verts;
441	DSGXSoftwarePolygonListClear(&softwareRenderer->activePolys);
442	DSGXSoftwareEdgeListClear(&softwareRenderer->activeEdges);
443	unsigned i;
444	for (i = 0; i < polyCount; ++i) {
445		struct DSGXSoftwarePolygon* poly = DSGXSoftwarePolygonListAppend(&softwareRenderer->activePolys);
446		struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
447		poly->poly = &polys[i];
448		poly->texFormat = DSGXTexParamsGetFormat(poly->poly->texParams);
449		poly->blendFormat = DSGXPolygonAttrsGetMode(poly->poly->polyParams);
450		poly->texW = 8 << DSGXTexParamsGetSSize(poly->poly->texParams);
451		poly->texH = 8 << DSGXTexParamsGetTSize(poly->poly->texParams);
452		if (!renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET]) {
453			poly->texBase = NULL;
454			poly->palBase = NULL;
455		} else {
456			switch (poly->texFormat) {
457			case 0:
458			case 7:
459				poly->texBase = NULL;
460				poly->palBase = NULL;
461				break;
462			case 2:
463				poly->texBase = &renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET][(DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 2) & 0xFFFF];
464				poly->palBase = &renderer->texPal[poly->poly->palBase >> 11][(poly->poly->palBase << 2) & 0x1FFF];
465				break;
466			default:
467				poly->texBase = &renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET][(DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 2) & 0xFFFF];
468				poly->palBase = &renderer->texPal[poly->poly->palBase >> 10][(poly->poly->palBase << 3) & 0x1FFF];
469				break;
470			}
471		}
472		edge->polyId = i;
473
474		struct DSGXVertex* v0 = &verts[poly->poly->vertIds[0]];
475		struct DSGXVertex* v1;
476
477		int32_t v0x = (v0->vx + v0->vw) * (int64_t) (renderer->viewportWidth << 12) / (v0->vw * 2) + (renderer->viewportX << 12);
478		int32_t v0y = (-v0->vy + v0->vw) * (int64_t) (renderer->viewportHeight << 12) / (v0->vw * 2) + (renderer->viewportY << 12);
479
480		int v;
481		for (v = 1; v < poly->poly->verts; ++v) {
482			v1 = &verts[poly->poly->vertIds[v]];
483			int32_t v1x = (v1->vx + v1->vw) * (int64_t) (renderer->viewportWidth << 12) / (v1->vw * 2) + (renderer->viewportX << 12);
484			int32_t v1y = (-v1->vy + v1->vw) * (int64_t) (renderer->viewportHeight << 12) / (v1->vw * 2) + (renderer->viewportY << 12);
485
486			if (v0y <= v1y) {
487				edge->y0 = v0y;
488				edge->x0 = v0x;
489				edge->z0 = v0->vz;
490				edge->w0 = v0->vw;
491				_expandColor(v0->color, &edge->cr0, &edge->cg0, &edge->cb0);
492				edge->s0 = v0->vs;
493				edge->t0 = v0->vt;
494
495				edge->y1 = v1y;
496				edge->x1 = v1x;
497				edge->z1 = v1->vz;
498				edge->w1 = v1->vw;
499				_expandColor(v1->color, &edge->cr1, &edge->cg1, &edge->cb1);
500				edge->s1 = v1->vs;
501				edge->t1 = v1->vt;
502			} else {
503				edge->y0 = v1y;
504				edge->x0 = v1x;
505				edge->z0 = v1->vz;
506				edge->w0 = v1->vw;
507				_expandColor(v1->color, &edge->cr0, &edge->cg0, &edge->cb0);
508				edge->s0 = v1->vs;
509				edge->t0 = v1->vt;
510
511				edge->y1 = v0y;
512				edge->x1 = v0x;
513				edge->z1 = v0->vz;
514				edge->w1 = v0->vw;
515				_expandColor(v0->color, &edge->cr1, &edge->cg1, &edge->cb1);
516				edge->s1 = v0->vs;
517				edge->t1 = v0->vt;
518			}
519
520			edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
521			edge->polyId = i;
522			v0 = v1;
523			v0x = v1x;
524			v0y = v1y;
525		}
526
527		v1 = &verts[poly->poly->vertIds[0]];
528		int32_t v1x = (v1->vx + v1->vw) * (int64_t) (renderer->viewportWidth << 12) / (v1->vw * 2) + (renderer->viewportX << 12);
529		int32_t v1y = (-v1->vy + v1->vw) * (int64_t) (renderer->viewportHeight << 12) / (v1->vw * 2) + (renderer->viewportY << 12);
530
531		if (v0y <= v1y) {
532			edge->y0 = v0y;
533			edge->x0 = v0x;
534			edge->z0 = v0->vz;
535			edge->w0 = v0->vw;
536			_expandColor(v0->color, &edge->cr0, &edge->cg0, &edge->cb0);
537			edge->s0 = v0->vs;
538			edge->t0 = v0->vt;
539
540			edge->y1 = v1y;
541			edge->x1 = v1x;
542			edge->z1 = v1->vz;
543			edge->w1 = v1->vw;
544			_expandColor(v1->color, &edge->cr1, &edge->cg1, &edge->cb1);
545			edge->s1 = v1->vs;
546			edge->t1 = v1->vt;
547		} else {
548			edge->y0 = v1y;
549			edge->x0 = v1x;
550			edge->z0 = v1->vz;
551			edge->w0 = v1->vw;
552			_expandColor(v1->color, &edge->cr0, &edge->cg0, &edge->cb0);
553			edge->s0 = v1->vs;
554			edge->t0 = v1->vt;
555
556			edge->y1 = v0y;
557			edge->x1 = v0x;
558			edge->z1 = v0->vz;
559			edge->w1 = v0->vw;
560			_expandColor(v0->color, &edge->cr1, &edge->cg1, &edge->cb1);
561			edge->s1 = v0->vs;
562			edge->t1 = v0->vt;
563		}
564	}
565}
566
567static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y) {
568	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
569	if (!softwareRenderer->flushPending) {
570		return;
571	}
572	DSGXSoftwareSpanListClear(&softwareRenderer->activeSpans);
573	memset(softwareRenderer->bucket, 0, sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
574	size_t i;
575	for (i = 0; i < DSGXSoftwareEdgeListSize(&softwareRenderer->activeEdges); ++i) {
576		struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListGetPointer(&softwareRenderer->activeEdges, i);
577		if (edge->y1 < (y << 12)) {
578			continue;
579		} else if (edge->y0 > (y << 12)) {
580			continue;
581		}
582
583		unsigned poly = edge->polyId;
584		struct DSGXSoftwareSpan* span = softwareRenderer->bucket[poly];
585		if (span && !span->ep[1].w) {
586			if (_edgeToSpan(span, edge, 1, y << 12)) {
587				_createStep(span);
588				softwareRenderer->bucket[poly] = NULL;
589			}
590		} else if (!span) {
591			span = DSGXSoftwareSpanListAppend(&softwareRenderer->activeSpans);
592			memset(&span->ep[1], 0, sizeof(span->ep[1]));
593			span->poly = DSGXSoftwarePolygonListGetPointer(&softwareRenderer->activePolys, poly);
594			if (!_edgeToSpan(span, edge, 0, y << 12)) {
595				// Horizontal line
596				DSGXSoftwareSpanListShift(&softwareRenderer->activeSpans, DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans) - 1, 1);
597			} else {
598				softwareRenderer->bucket[poly] = span;
599			}
600		}
601	}
602
603	color_t* scanline = &softwareRenderer->scanlineCache[DS_VIDEO_HORIZONTAL_PIXELS * y];
604	memset(scanline, 0, sizeof(color_t) * DS_VIDEO_HORIZONTAL_PIXELS);
605	for (i = 0; i < DS_VIDEO_HORIZONTAL_PIXELS; i += 4) {
606		softwareRenderer->depthBuffer[i] = INT32_MAX;
607		softwareRenderer->depthBuffer[i + 1] = INT32_MAX;
608		softwareRenderer->depthBuffer[i + 2] = INT32_MAX;
609		softwareRenderer->depthBuffer[i + 3] = INT32_MAX;
610	}
611
612	for (i = 0; i < DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans); ++i) {
613		struct DSGXSoftwareSpan* span = DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, i);
614
615		int32_t x = span->ep[0].x >> 12;
616		if (x < 0) {
617			x = 0;
618		}
619		for (; x < (span->ep[1].x >> 12) && x < DS_VIDEO_HORIZONTAL_PIXELS; ++x) {
620			color_t color = _lookupColor(softwareRenderer, &span->ep[0], span->poly);
621			_stepEndpoint(span);
622			unsigned a = color >> 27;
623			unsigned current = scanline[x];
624			unsigned b = current >> 27;
625			unsigned ab = a;
626			if (b > ab) {
627				ab = b;
628			}
629			if (a == 0x1F) {
630				if (softwareRenderer->wSort) {
631					if (span->ep[0].w < softwareRenderer->depthBuffer[x]) {
632						softwareRenderer->depthBuffer[x] = span->ep[0].w;
633						scanline[x] = color;
634					}
635				} else {
636					if (span->ep[0].z < softwareRenderer->depthBuffer[x]) {
637						softwareRenderer->depthBuffer[x] = span->ep[0].z;
638						scanline[x] = color;
639					}
640				}
641			} else if (a) {
642				// TODO: Disable alpha?
643				if (b) {
644					color = _mix32(a, color, 0x1F - a, current);
645					color |= ab << 27;
646				}
647				if (softwareRenderer->wSort) {
648					if (span->ep[0].w < softwareRenderer->depthBuffer[x]) {
649						if (DSGXPolygonAttrsIsUpdateDepth(span->poly->poly->polyParams)) {
650							softwareRenderer->depthBuffer[x] = span->ep[0].w;
651						}
652						scanline[x] = color;
653					}
654				} else {
655					if (span->ep[0].z < softwareRenderer->depthBuffer[x]) {
656						if (DSGXPolygonAttrsIsUpdateDepth(span->poly->poly->polyParams)) {
657							softwareRenderer->depthBuffer[x] = span->ep[0].z;
658						}
659						scanline[x] = color;
660					}
661				}
662			}
663		}
664	}
665
666	if (y == DS_VIDEO_VERTICAL_PIXELS - 1) {
667		softwareRenderer->flushPending = false;
668	}
669}
670
671static void DSGXSoftwareRendererGetScanline(struct DSGXRenderer* renderer, int y, const color_t** output) {
672	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
673	*output = &softwareRenderer->scanlineCache[DS_VIDEO_HORIZONTAL_PIXELS * y];
674}