all repos — mgba @ 498aa541fc660c8755cda99cf8889171b3bd5381

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
 11#define SCREEN_SIZE (DS_VIDEO_VERTICAL_PIXELS << 12)
 12
 13DEFINE_VECTOR(DSGXSoftwarePolygonList, struct DSGXSoftwarePolygon);
 14DEFINE_VECTOR(DSGXSoftwareEdgeList, struct DSGXSoftwareEdge);
 15DEFINE_VECTOR(DSGXSoftwareSpanList, struct DSGXSoftwareSpan);
 16
 17static void DSGXSoftwareRendererInit(struct DSGXRenderer* renderer);
 18static void DSGXSoftwareRendererReset(struct DSGXRenderer* renderer);
 19static void DSGXSoftwareRendererDeinit(struct DSGXRenderer* renderer);
 20static void DSGXSoftwareRendererInvalidateTex(struct DSGXRenderer* renderer, int slot);
 21static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSGXVertex* verts, struct DSGXPolygon* polys, unsigned polyCount, bool wSort);
 22static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y);
 23static void DSGXSoftwareRendererGetScanline(struct DSGXRenderer* renderer, int y, const color_t** output);
 24
 25static void _expandColor(uint16_t c15, uint8_t* r, uint8_t* g, uint8_t* b) {
 26	*r = ((c15 << 1) & 0x3E) | 1;
 27	*g = ((c15 >> 4) & 0x3E) | 1;
 28	*b = ((c15 >> 9) & 0x3E) | 1;
 29}
 30
 31static color_t _finishColor(uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
 32#ifndef COLOR_16_BIT
 33	color_t rgba = (r << 2) & 0xF8;
 34	rgba |= (g << 10) & 0xF800;
 35	rgba |= (b << 18) & 0xF80000;
 36	rgba |= (a << 27) & 0xF8000000;
 37	return rgba;
 38#else
 39#error Unsupported color depth
 40#endif
 41}
 42
 43static unsigned _mix32(int weightA, unsigned colorA, int weightB, unsigned colorB) {
 44	unsigned c = 0;
 45	unsigned a, b;
 46#ifdef COLOR_16_BIT
 47#error Unsupported color depth
 48#else
 49	a = colorA & 0xFF;
 50	b = colorB & 0xFF;
 51	c |= ((a * weightA + b * weightB) / 32) & 0x1FF;
 52	if (c & 0x00000100) {
 53		c = 0x000000FF;
 54	}
 55
 56	a = colorA & 0xFF00;
 57	b = colorB & 0xFF00;
 58	c |= ((a * weightA + b * weightB) / 32) & 0x1FF00;
 59	if (c & 0x00010000) {
 60		c = (c & 0x000000FF) | 0x0000FF00;
 61	}
 62
 63	a = colorA & 0xFF0000;
 64	b = colorB & 0xFF0000;
 65	c |= ((a * weightA + b * weightB) / 32) & 0x1FF0000;
 66	if (c & 0x01000000) {
 67		c = (c & 0x0000FFFF) | 0x00FF0000;
 68	}
 69#endif
 70	return c;
 71}
 72
 73static unsigned _mixTexels(int weightA, unsigned colorA, int weightB, unsigned colorB) {
 74	unsigned c = 0;
 75	unsigned a, b;
 76	a = colorA & 0x7C1F;
 77	b = colorB & 0x7C1F;
 78	a |= (colorA & 0x3E0) << 16;
 79	b |= (colorB & 0x3E0) << 16;
 80	c = ((a * weightA + b * weightB) / 8);
 81	if (c & 0x04000000) {
 82		c = (c & ~0x07E00000) | 0x03E00000;
 83	}
 84	if (c & 0x0020) {
 85		c = (c & ~0x003F) | 0x001F;
 86	}
 87	if (c & 0x8000) {
 88		c = (c & ~0xF800) | 0x7C00;
 89	}
 90	c = (c & 0x7C1F) | ((c >> 16) & 0x03E0);
 91	return c;
 92}
 93
 94static color_t _lookupColor(struct DSGXSoftwareRenderer* renderer, struct DSGXSoftwareEndpoint* ep, struct DSGXSoftwarePolygon* poly) {
 95	// TODO: Optimize
 96	uint16_t texel;
 97
 98	int16_t s = ep->s >> 4;
 99	int16_t t = ep->t >> 4;
100	if (!DSGXTexParamsIsSRepeat(poly->poly->texParams)) {
101		if (s < 0) {
102			s = 0;
103		} else if (s >= poly->texW) {
104			s = poly->texW - 1;
105		}
106	} else if (DSGXTexParamsIsSMirror(poly->poly->texParams)) {
107		if (s & poly->texW) {
108			s = poly->texW - s;
109		}
110		s &= poly->texW - 1;
111	} else {
112		s &= poly->texW - 1;
113	}
114	if (!DSGXTexParamsIsTRepeat(poly->poly->texParams)) {
115		if (t < 0) {
116			t = 0;
117		} else if (t >= poly->texH) {
118			t = poly->texW - 1;
119		}
120	} else if (DSGXTexParamsIsTMirror(poly->poly->texParams)) {
121		if (t & poly->texH) {
122			t = poly->texH - t;
123		}
124		t &= poly->texH - 1;
125	} else {
126		t &= poly->texH - 1;
127	}
128
129	uint16_t texelCoord = s + t * poly->texW;
130	uint8_t a = DSGXPolygonAttrsGetAlpha(poly->poly->polyParams);
131	switch (poly->texFormat) {
132	case 0:
133	default:
134		return _finishColor(ep->cr, ep->cg, ep->cb, a);
135	case 1:
136		texel = ((uint8_t*) poly->texBase)[texelCoord];
137		a = (texel >> 5) & 0x7;
138		a = (a << 2) + (a >> 1);
139		texel &= 0x1F;
140		break;
141	case 2:
142		texel = ((uint8_t*) poly->texBase)[texelCoord >> 2];
143		if (texelCoord & 0x3) {
144			texel >>= 2 * texel & 3;
145		}
146		texel &= 0x3;
147		break;
148	case 3:
149		texel = ((uint8_t*) poly->texBase)[texelCoord >> 1];
150		if (texelCoord & 0x1) {
151			texel >>= 4;
152		}
153		texel &= 0xF;
154		break;
155	case 4:
156		texel = ((uint8_t*) poly->texBase)[texelCoord];
157		break;
158	case 5:
159		texelCoord = (s & ~3) + (t & 3) + (t >> 2) * poly->texW;
160		texel = ((uint8_t*) poly->texBase)[texelCoord];
161		texel >>= (s & 3) * 2;
162		texel &= 3;
163		break;
164	case 6:
165		texel = ((uint8_t*) poly->texBase)[texelCoord];
166		a = (texel >> 3) & 0x1F;
167		texel &= 0x7;
168		break;
169	case 7:
170		return _finishColor(0x3F, 0x3F, 0x3F, 0x1F);
171	}
172	uint8_t r, g, b;
173	unsigned wr, wg, wb;
174	if (poly->texFormat == 5) {
175		// TODO: Slot 2 uses upper half
176		uint16_t texel2 = renderer->d.tex[1][texelCoord >> 1];
177		int a = 0x8;
178		int b = 0;
179		switch (texel2 >> 14) {
180		case 0:
181			if (texel == 3) {
182				return 0;
183			}
184			texel = poly->palBase[texel + (texel2 & 0x3FFF) * 2];
185			break;
186		case 1:
187			if (texel == 3) {
188				return 0;
189			}
190			if (texel != 2) {
191				texel = poly->palBase[texel + (texel2 & 0x3FFF) * 2];
192			} else {
193				texel = poly->palBase[(texel2 & 0x3FFF) * 2];
194				texel2 = poly->palBase[(texel2 & 0x3FFF) * 2 + 1];
195				a = 4;
196				b = 4;
197			}
198			break;
199		case 2:
200			texel = poly->palBase[texel + (texel2 & 0x3FFF) * 2];
201			break;
202		case 3:
203			switch (texel) {
204			case 0:
205			case 1:
206				texel = poly->palBase[texel + (texel2 & 0x3FFF) * 2];
207				break;
208			case 2:
209				texel = poly->palBase[(texel2 & 0x3FFF) * 2];
210				texel2 = poly->palBase[(texel2 & 0x3FFF) * 2 + 1];
211				a = 5;
212				b = 3;
213				break;
214			case 3:
215				texel = poly->palBase[(texel2 & 0x3FFF) * 2];
216				texel2 = poly->palBase[(texel2 & 0x3FFF) * 2 + 1];
217				a = 3;
218				b = 5;
219				break;
220			}
221			break;
222		}
223		if (b) {
224			texel = _mixTexels(a, texel, b, texel2);
225		}
226	} else {
227		if (DSGXTexParamsIs0Transparent(poly->poly->texParams) && !texel) {
228			return 0;
229		}
230		texel = poly->palBase[texel];
231	}
232	_expandColor(texel, &r, &g, &b);
233	switch (poly->blendFormat) {
234	case 1:
235	default:
236		// TODO: Alpha
237		return _finishColor(r, g, b, a);
238	case 0:
239		wr = ((r + 1) * (ep->cr + 1) - 1) >> 6;
240		wg = ((g + 1) * (ep->cg + 1) - 1) >> 6;
241		wb = ((b + 1) * (ep->cb + 1) - 1) >> 6;
242		return _finishColor(wr, wg, wb, a);
243	}
244}
245
246static bool _edgeToSpan(struct DSGXSoftwareSpan* span, const struct DSGXSoftwareEdge* edge, int index, int32_t y) {
247	int32_t height = edge->y1 - edge->y0;
248	int64_t yw = (y << 12) - edge->y0;
249	if (!height) {
250		return false;
251	}
252	// Clamp to bounds
253	if (yw < 0) {
254		return false;
255	} else if (yw > height) {
256		return false;
257	}
258	yw *= 0x100000000LL / height;
259
260	span->ep[index].x = (((int64_t) (edge->x1 - edge->x0) * yw) >> 32) + edge->x0;
261
262	if (index && span->ep[0].x > span->ep[index].x) {
263		int32_t temp = span->ep[index].x;
264		span->ep[index] = span->ep[0];
265		span->ep[0].x = temp;
266		index = 0;
267	}
268	int32_t w0 = edge->w0;
269	int32_t w1 = edge->w1;
270	int32_t w = (((int64_t) (edge->w1 - edge->w0) * yw) >> 32) + edge->w0;
271	int64_t wRecip;// = 0x1000000000000LL / w;
272	// XXX: Disable perspective correction until I figure out how to fix it
273	wRecip = 0x100000000;
274	w0 = 0x10000;
275	w1 = 0x10000;
276	span->ep[index].w = w;
277	span->ep[index].z = (((edge->z1 - edge->z0) * yw) >> 32) + edge->z0;
278	span->ep[index].cr = (((((edge->cr1 * (int64_t) w1 - edge->cr0 * (int64_t) w0) * yw) >> 32) + edge->cr0 * (int64_t) w0) * wRecip) >> 48;
279	span->ep[index].cg = (((((edge->cg1 * (int64_t) w1 - edge->cg0 * (int64_t) w0) * yw) >> 32) + edge->cg0 * (int64_t) w0) * wRecip) >> 48;
280	span->ep[index].cb = (((((edge->cb1 * (int64_t) w1 - edge->cb0 * (int64_t) w0) * yw) >> 32) + edge->cb0 * (int64_t) w0) * wRecip) >> 48;
281	span->ep[index].s = (((((edge->s1 * (int64_t) w1 - edge->s0 * (int64_t) w0) * yw) >> 32) + edge->s0 * (int64_t) w0) * wRecip) >> 48;
282	span->ep[index].t = (((((edge->t1 * (int64_t) w1 - edge->t0 * (int64_t) w0) * yw) >> 32) + edge->t0 * (int64_t) w0) * wRecip) >> 48;
283
284	return true;
285}
286
287static void _lerpEndpoint(const struct DSGXSoftwareSpan* span, struct DSGXSoftwareEndpoint* ep, unsigned x) {
288	int64_t width = span->ep[1].x - span->ep[0].x;
289	int64_t xw = ((uint64_t) x << 12) - span->ep[0].x;
290	if (!width) {
291		return; // TODO?
292	}
293	// Clamp to bounds
294	if (xw < 0) {
295		xw = 0;
296	} else if (xw > width) {
297		xw = width;
298	}
299	xw *= 0x100000000LL / width;
300	int32_t w0 = span->ep[0].w;
301	int32_t w1 = span->ep[1].w;
302	int64_t w = (((int64_t) (w1 - w0) * xw) >> 32) + w0;
303	int64_t wRecip;// = 0x1000000000000LL / w;
304	ep->w = w;
305	// XXX: Disable perspective correction until I figure out how to fix it
306	wRecip = 0x100000000;
307	w0 = 0x10000;
308	w1 = 0x10000;
309
310	ep->z = (((span->ep[1].z - span->ep[0].z) * xw) >> 32) + span->ep[0].z;
311
312	uint64_t r = (((span->ep[1].cr * (int64_t) w1 - span->ep[0].cr * (int64_t) w0) * xw) >> 32) + span->ep[0].cr * (int64_t) w0;
313	uint64_t g = (((span->ep[1].cg * (int64_t) w1 - span->ep[0].cg * (int64_t) w0) * xw) >> 32) + span->ep[0].cg * (int64_t) w0;
314	uint64_t b = (((span->ep[1].cb * (int64_t) w1 - span->ep[0].cb * (int64_t) w0) * xw) >> 32) + span->ep[0].cb * (int64_t) w0;
315	ep->cr = (r * wRecip) >> 48;
316	ep->cg = (g * wRecip) >> 48;
317	ep->cb = (b * wRecip) >> 48;
318
319	int32_t s = (((span->ep[1].s * (int64_t) w1 - span->ep[0].s * (int64_t) w0) * xw) >> 32) + span->ep[0].s * (int64_t) w0;
320	int32_t t = (((span->ep[1].t * (int64_t) w1 - span->ep[0].t * (int64_t) w0) * xw) >> 32) + span->ep[0].t * (int64_t) w0;
321	ep->s = (s * wRecip) >> 48;
322	ep->t = (t * wRecip) >> 48;
323}
324
325void DSGXSoftwareRendererCreate(struct DSGXSoftwareRenderer* renderer) {
326	renderer->d.init = DSGXSoftwareRendererInit;
327	renderer->d.reset = DSGXSoftwareRendererReset;
328	renderer->d.deinit = DSGXSoftwareRendererDeinit;
329	renderer->d.invalidateTex = DSGXSoftwareRendererInvalidateTex;
330	renderer->d.setRAM = DSGXSoftwareRendererSetRAM;
331	renderer->d.drawScanline = DSGXSoftwareRendererDrawScanline;
332	renderer->d.getScanline = DSGXSoftwareRendererGetScanline;
333}
334
335static void DSGXSoftwareRendererInit(struct DSGXRenderer* renderer) {
336	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
337	DSGXSoftwarePolygonListInit(&softwareRenderer->activePolys, DS_GX_POLYGON_BUFFER_SIZE / 4);
338	DSGXSoftwareEdgeListInit(&softwareRenderer->activeEdges, DS_GX_POLYGON_BUFFER_SIZE);
339	DSGXSoftwareSpanListInit(&softwareRenderer->activeSpans, DS_GX_POLYGON_BUFFER_SIZE / 2);
340	softwareRenderer->bucket = anonymousMemoryMap(sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
341	softwareRenderer->scanlineCache = anonymousMemoryMap(sizeof(color_t) * DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS);
342}
343
344static void DSGXSoftwareRendererReset(struct DSGXRenderer* renderer) {
345	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
346	softwareRenderer->flushPending = false;
347}
348
349static void DSGXSoftwareRendererDeinit(struct DSGXRenderer* renderer) {
350	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
351	DSGXSoftwarePolygonListDeinit(&softwareRenderer->activePolys);
352	DSGXSoftwareEdgeListDeinit(&softwareRenderer->activeEdges);	
353	DSGXSoftwareSpanListDeinit(&softwareRenderer->activeSpans);
354	mappedMemoryFree(softwareRenderer->bucket, sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
355	mappedMemoryFree(softwareRenderer->scanlineCache, sizeof(color_t) * DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS);
356}
357
358static void DSGXSoftwareRendererInvalidateTex(struct DSGXRenderer* renderer, int slot) {
359	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
360	// TODO
361}
362
363static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSGXVertex* verts, struct DSGXPolygon* polys, unsigned polyCount, bool wSort) {
364	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
365
366	softwareRenderer->flushPending = true;
367	softwareRenderer->wSort = wSort;
368	softwareRenderer->verts = verts;
369	DSGXSoftwarePolygonListClear(&softwareRenderer->activePolys);
370	DSGXSoftwareEdgeListClear(&softwareRenderer->activeEdges);
371	unsigned i;
372	for (i = 0; i < polyCount; ++i) {
373		struct DSGXSoftwarePolygon* poly = DSGXSoftwarePolygonListAppend(&softwareRenderer->activePolys);
374		struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
375		poly->poly = &polys[i];
376		poly->texFormat = DSGXTexParamsGetFormat(poly->poly->texParams);
377		poly->blendFormat = DSGXPolygonAttrsGetMode(poly->poly->polyParams);
378		poly->texW = 8 << DSGXTexParamsGetSSize(poly->poly->texParams);
379		poly->texH = 8 << DSGXTexParamsGetTSize(poly->poly->texParams);
380		switch (poly->texFormat) {
381		case 0:
382		case 7:
383			poly->texBase = NULL;
384			poly->palBase = NULL;
385			break;
386		case 2:
387			poly->texBase = &renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET][(DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 2) & 0xFFFF];
388			poly->palBase = &renderer->texPal[poly->poly->palBase >> 12][(poly->poly->palBase << 2) & 0x1FFF];
389			break;
390		default:
391			poly->texBase = &renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET][(DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 2) & 0xFFFF];
392			poly->palBase = &renderer->texPal[poly->poly->palBase >> 11][(poly->poly->palBase << 3) & 0x1FFF];
393			break;
394		}
395		edge->polyId = i;
396
397		struct DSGXVertex* v0 = &verts[poly->poly->vertIds[0]];
398		struct DSGXVertex* v1;
399
400		int v;
401		for (v = 1; v < poly->poly->verts; ++v) {
402			v1 = &verts[poly->poly->vertIds[v]];
403			if (v0->vy >= v1->vy) {
404				edge->y0 = SCREEN_SIZE - v0->vy;
405				edge->x0 = v0->vx;
406				edge->z0 = v0->vz;
407				edge->w0 = v0->vw;
408				_expandColor(v0->color, &edge->cr0, &edge->cg0, &edge->cb0);
409				edge->s0 = v0->vs;
410				edge->t0 = v0->vt;
411
412				edge->y1 = SCREEN_SIZE - v1->vy;
413				edge->x1 = v1->vx;
414				edge->z1 = v1->vz;
415				edge->w1 = v1->vw;
416				_expandColor(v1->color, &edge->cr1, &edge->cg1, &edge->cb1);
417				edge->s1 = v1->vs;
418				edge->t1 = v1->vt;
419			} else {
420				edge->y0 = SCREEN_SIZE - v1->vy;
421				edge->x0 = v1->vx;
422				edge->z0 = v1->vz;
423				edge->w0 = v1->vw;
424				_expandColor(v1->color, &edge->cr0, &edge->cg0, &edge->cb0);
425				edge->s0 = v1->vs;
426				edge->t0 = v1->vt;
427
428				edge->y1 = SCREEN_SIZE - v0->vy;
429				edge->x1 = v0->vx;
430				edge->z1 = v0->vz;
431				edge->w1 = v0->vw;
432				_expandColor(v0->color, &edge->cr1, &edge->cg1, &edge->cb1);
433				edge->s1 = v0->vs;
434				edge->t1 = v0->vt;
435			}
436
437			edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
438			edge->polyId = i;
439			v0 = v1;
440		}
441
442		v1 = &verts[poly->poly->vertIds[0]];
443		if (v0->vy >= v1->vy) {
444			edge->y0 = SCREEN_SIZE - v0->vy;
445			edge->x0 = v0->vx;
446			edge->z0 = v0->vz;
447			edge->w0 = v0->vw;
448			_expandColor(v0->color, &edge->cr0, &edge->cg0, &edge->cb0);
449			edge->s0 = v0->vs;
450			edge->t0 = v0->vt;
451
452			edge->y1 = SCREEN_SIZE - v1->vy;
453			edge->x1 = v1->vx;
454			edge->z1 = v1->vz;
455			edge->w1 = v1->vw;
456			_expandColor(v1->color, &edge->cr1, &edge->cg1, &edge->cb1);
457			edge->s1 = v1->vs;
458			edge->t1 = v1->vt;
459		} else {
460			edge->y0 = SCREEN_SIZE - v1->vy;
461			edge->x0 = v1->vx;
462			edge->w0 = v1->vw;
463			edge->z0 = v1->vz;
464			_expandColor(v1->color, &edge->cr0, &edge->cg0, &edge->cb0);
465			edge->s0 = v1->vs;
466			edge->t0 = v1->vt;
467
468			edge->y1 = SCREEN_SIZE - v0->vy;
469			edge->x1 = v0->vx;
470			edge->z1 = v0->vz;
471			edge->w1 = v0->vw;
472			_expandColor(v0->color, &edge->cr1, &edge->cg1, &edge->cb1);
473			edge->s1 = v0->vs;
474			edge->t1 = v0->vt;
475		}
476	}
477}
478
479static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y) {
480	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
481	if (!softwareRenderer->flushPending) {
482		return;
483	}
484	DSGXSoftwareSpanListClear(&softwareRenderer->activeSpans);
485	memset(softwareRenderer->bucket, 0, sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
486	size_t i;
487	for (i = 0; i < DSGXSoftwareEdgeListSize(&softwareRenderer->activeEdges); ++i) {
488		struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListGetPointer(&softwareRenderer->activeEdges, i);
489		if (edge->y1 >> 12 < y) {
490			continue;
491		} else if (edge->y0 >> 12 > y) {
492			continue;
493		}
494
495		unsigned poly = edge->polyId;
496		struct DSGXSoftwareSpan* span = softwareRenderer->bucket[poly];
497		if (span && !span->ep[1].w) {
498			if (_edgeToSpan(span, edge, 1, y)) {
499				softwareRenderer->bucket[poly] = NULL;
500			}
501		} else if (!span) {
502			span = DSGXSoftwareSpanListAppend(&softwareRenderer->activeSpans);
503			memset(&span->ep[1], 0, sizeof(span->ep[1]));
504			span->poly = DSGXSoftwarePolygonListGetPointer(&softwareRenderer->activePolys, poly);
505			if (!_edgeToSpan(span, edge, 0, y)) {
506				// Horizontal line
507				DSGXSoftwareSpanListShift(&softwareRenderer->activeSpans, DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans) - 1, 1);
508			} else {
509				softwareRenderer->bucket[poly] = span;
510			}
511		}
512	}
513
514	color_t* scanline = &softwareRenderer->scanlineCache[DS_VIDEO_HORIZONTAL_PIXELS * y];
515	memset(scanline, 0, sizeof(color_t) * DS_VIDEO_HORIZONTAL_PIXELS);
516	for (i = 0; i < DS_VIDEO_HORIZONTAL_PIXELS; i += 4) {
517		softwareRenderer->depthBuffer[i] = INT32_MAX;
518		softwareRenderer->depthBuffer[i + 1] = INT32_MAX;
519		softwareRenderer->depthBuffer[i + 2] = INT32_MAX;
520		softwareRenderer->depthBuffer[i + 3] = INT32_MAX;
521	}
522
523	for (i = 0; i < DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans); ++i) {
524		struct DSGXSoftwareSpan* span = DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, i);
525
526		int32_t x = span->ep[0].x >> 12;
527		if (x < 0) {
528			x = 0;
529		}
530		for (; x < span->ep[1].x >> 12 && x < DS_VIDEO_HORIZONTAL_PIXELS; ++x) {
531			struct DSGXSoftwareEndpoint ep;
532			_lerpEndpoint(span, &ep, x);
533			color_t color = _lookupColor(softwareRenderer, &ep, span->poly);
534			unsigned a = color >> 27;
535			if (a == 0x1F) {
536				if (softwareRenderer->wSort) {
537					if (ep.w < softwareRenderer->depthBuffer[x]) {
538						softwareRenderer->depthBuffer[x] = ep.w;
539						scanline[x] = color;
540					}
541				} else {
542					if (ep.z < softwareRenderer->depthBuffer[x]) {
543						softwareRenderer->depthBuffer[x] = ep.z;
544						scanline[x] = color;
545					}
546				}
547			} else if (a) {
548				// TODO: Disable alpha?
549				color = _mix32(a, color, 0x1F - a, scanline[x]);
550				if (scanline[x] >> 27 > a) {
551					a = scanline[x] >> 27;
552				}
553				color |= a << 27;
554				if (softwareRenderer->wSort) {
555					if (ep.w < softwareRenderer->depthBuffer[x]) {
556						softwareRenderer->depthBuffer[x] = ep.w;
557						scanline[x] = color;
558					}
559				} else {
560					if (ep.z < softwareRenderer->depthBuffer[x]) {
561						softwareRenderer->depthBuffer[x] = ep.z;
562						scanline[x] = color;
563					}
564				}
565			}
566		}
567	}
568
569	if (y == DS_VIDEO_VERTICAL_PIXELS - 1) {
570		softwareRenderer->flushPending = false;
571	}
572}
573
574static void DSGXSoftwareRendererGetScanline(struct DSGXRenderer* renderer, int y, const color_t** output) {
575	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
576	*output = &softwareRenderer->scanlineCache[DS_VIDEO_HORIZONTAL_PIXELS * y];
577}