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, 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) {
32#ifndef COLOR_16_BIT
33 color_t rgb = (r << 2) & 0xF8;
34 rgb |= (g << 10) & 0xF800;
35 rgb |= (b << 18) & 0xF80000;
36 return rgb;
37#else
38#error Unsupported color depth
39#endif
40}
41
42static color_t _lookupColor(struct DSGXSoftwareEndpoint* ep, struct DSGXSoftwarePolygon* poly) {
43 // TODO: Optimize
44 uint16_t texel;
45
46 int16_t s = ep->s >> 4;
47 int16_t t = ep->t >> 4;
48 if (!DSGXTexParamsIsSRepeat(poly->poly->texParams)) {
49 if (s < 0) {
50 s = 0;
51 } else if (s >= poly->texW) {
52 s = poly->texW - 1;
53 }
54 } else if (DSGXTexParamsIsSMirror(poly->poly->texParams)) {
55 if (s & poly->texW) {
56 s = poly->texW - s;
57 }
58 s &= poly->texW - 1;
59 } else {
60 s &= poly->texW - 1;
61 }
62 if (!DSGXTexParamsIsTRepeat(poly->poly->texParams)) {
63 if (t < 0) {
64 t = 0;
65 } else if (t >= poly->texH) {
66 t = poly->texW - 1;
67 }
68 } else if (DSGXTexParamsIsTMirror(poly->poly->texParams)) {
69 if (t & poly->texH) {
70 t = poly->texH - t;
71 }
72 t &= poly->texH - 1;
73 } else {
74 t &= poly->texH - 1;
75 }
76
77 uint16_t texelCoord = s + t * poly->texW;
78 switch (poly->texFormat) {
79 case 0:
80 default:
81 return _finishColor(ep->cr, ep->cg, ep->cb);
82 case 1:
83 return _finishColor(0, 0, 0x3F);
84 case 2:
85 texel = ((uint8_t*) poly->texBase)[texelCoord >> 2];
86 if (texelCoord & 0x3) {
87 texel >>= 2 * texel & 3;
88 }
89 texel &= 0x3;
90 break;
91 case 3:
92 texel = ((uint8_t*) poly->texBase)[texelCoord >> 1];
93 if (texelCoord & 0x1) {
94 texel >>= 4;
95 }
96 texel &= 0xF;
97 break;
98 case 4:
99 texel = ((uint8_t*) poly->texBase)[texelCoord];
100 break;
101 case 5:
102 return _finishColor(0x3F, 0, 0x3F);
103 case 6:
104 return _finishColor(0x3F, 0x3F, 0);
105 case 7:
106 return _finishColor(0x3F, 0x3F, 0x3F);
107 }
108 if (DSGXTexParamsIs0Transparent(poly->poly->texParams) && !texel) {
109 return FLAG_UNWRITTEN;
110 }
111 uint8_t r, g, b;
112 texel = poly->palBase[texel];
113 _expandColor(texel, &r, &g, &b);
114 return _finishColor(r, g, b);
115}
116
117static int _edgeSort(const void* a, const void* b) {
118 const struct DSGXSoftwareEdge* ea = a;
119 const struct DSGXSoftwareEdge* eb = b;
120
121 // Sort upside down
122 if (ea->y0 < eb->y0) {
123 return 1;
124 }
125 if (ea->y0 > eb->y0) {
126 return -1;
127 }
128 if (ea->y1 < eb->y1) {
129 return 1;
130 }
131 if (ea->y1 > eb->y1) {
132 return -1;
133 }
134 return 0;
135}
136
137static bool _edgeToSpan(struct DSGXSoftwareSpan* span, const struct DSGXSoftwareEdge* edge, int index, int32_t y) {
138 int32_t height = edge->y1 - edge->y0;
139 int64_t yw = (y << 12) - edge->y0;
140 if (!height) {
141 return false;
142 }
143 // Clamp to bounds
144 if (yw < 0) {
145 yw = 0;
146 } else if (yw > height) {
147 yw = height;
148 }
149 yw *= 0x100000000LL / height;
150
151 span->ep[index].x = (((int64_t) (edge->x1 - edge->x0) * yw) >> 32) + edge->x0;
152
153 if (index && span->ep[0].x > span->ep[index].x) {
154 int32_t temp = span->ep[index].x;
155 span->ep[index] = span->ep[0];
156 span->ep[0].x = temp;
157 index = 0;
158 }
159 int32_t w0 = edge->w0;
160 int32_t w1 = edge->w1;
161 int32_t w = (((int64_t) (edge->w1 - edge->w0) * yw) >> 32) + edge->w0;
162 int64_t wRecip;// = 0x1000000000000LL / w;
163 // XXX: Disable perspective correction until I figure out how to fix it
164 wRecip = 0x100000000;
165 w0 = 0x10000;
166 w1 = 0x10000;
167 span->ep[index].w = w;
168 span->ep[index].z = (((edge->z1 - edge->z0) * yw) >> 32) + edge->z0;
169 span->ep[index].cr = (((((edge->cr1 * (int64_t) w1 - edge->cr0 * (int64_t) w0) * yw) >> 32) + edge->cr0 * (int64_t) w0) * wRecip) >> 48;
170 span->ep[index].cg = (((((edge->cg1 * (int64_t) w1 - edge->cg0 * (int64_t) w0) * yw) >> 32) + edge->cg0 * (int64_t) w0) * wRecip) >> 48;
171 span->ep[index].cb = (((((edge->cb1 * (int64_t) w1 - edge->cb0 * (int64_t) w0) * yw) >> 32) + edge->cb0 * (int64_t) w0) * wRecip) >> 48;
172 span->ep[index].s = (((((edge->s1 * (int64_t) w1 - edge->s0 * (int64_t) w0) * yw) >> 32) + edge->s0 * (int64_t) w0) * wRecip) >> 48;
173 span->ep[index].t = (((((edge->t1 * (int64_t) w1 - edge->t0 * (int64_t) w0) * yw) >> 32) + edge->t0 * (int64_t) w0) * wRecip) >> 48;
174
175 return true;
176}
177
178static int _spanSort(const void* a, const void* b) {
179 const struct DSGXSoftwareSpan* sa = a;
180 const struct DSGXSoftwareSpan* sb = b;
181
182 // Sort backwards
183 if (sa->ep[0].x < sb->ep[0].x) {
184 return 1;
185 }
186 if (sa->ep[0].x > sb->ep[0].x) {
187 return -1;
188 }
189 if (sa->ep[0].w < sb->ep[0].w) {
190 return 1;
191 }
192 if (sa->ep[0].w > sb->ep[0].w) {
193 return -1;
194 }
195 return 0;
196}
197
198static void _lerpEndpoint(const struct DSGXSoftwareSpan* span, struct DSGXSoftwareEndpoint* ep, unsigned x) {
199 int64_t width = span->ep[1].x - span->ep[0].x;
200 int64_t xw = ((uint64_t) x << 12) - span->ep[0].x;
201 if (!width) {
202 return; // TODO?
203 }
204 // Clamp to bounds
205 if (xw < 0) {
206 xw = 0;
207 } else if (xw > width) {
208 xw = width;
209 }
210 xw *= 0x100000000LL / width;
211 int32_t w0 = span->ep[0].w;
212 int32_t w1 = span->ep[1].w;
213 int64_t w = (((int64_t) (w1 - w0) * xw) >> 32) + w0;
214 int64_t wRecip;// = 0x1000000000000LL / w;
215 ep->w = w;
216 // XXX: Disable perspective correction until I figure out how to fix it
217 wRecip = 0x100000000;
218 w0 = 0x10000;
219 w1 = 0x10000;
220
221 ep->z = (((span->ep[1].z - span->ep[0].z) * xw) >> 32) + span->ep[0].z;
222
223 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;
224 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;
225 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;
226 ep->cr = (r * wRecip) >> 48;
227 ep->cg = (g * wRecip) >> 48;
228 ep->cb = (b * wRecip) >> 48;
229
230 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;
231 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;
232 ep->s = (s * wRecip) >> 48;
233 ep->t = (t * wRecip) >> 48;
234}
235
236void DSGXSoftwareRendererCreate(struct DSGXSoftwareRenderer* renderer) {
237 renderer->d.init = DSGXSoftwareRendererInit;
238 renderer->d.reset = DSGXSoftwareRendererReset;
239 renderer->d.deinit = DSGXSoftwareRendererDeinit;
240 renderer->d.invalidateTex = DSGXSoftwareRendererInvalidateTex;
241 renderer->d.setRAM = DSGXSoftwareRendererSetRAM;
242 renderer->d.drawScanline = DSGXSoftwareRendererDrawScanline;
243 renderer->d.getScanline = DSGXSoftwareRendererGetScanline;
244}
245
246static void DSGXSoftwareRendererInit(struct DSGXRenderer* renderer) {
247 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
248 DSGXSoftwarePolygonListInit(&softwareRenderer->activePolys, DS_GX_POLYGON_BUFFER_SIZE / 4);
249 DSGXSoftwareEdgeListInit(&softwareRenderer->activeEdges, DS_GX_POLYGON_BUFFER_SIZE);
250 DSGXSoftwareSpanListInit(&softwareRenderer->activeSpans, DS_GX_POLYGON_BUFFER_SIZE / 2);
251 softwareRenderer->bucket = anonymousMemoryMap(sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
252 softwareRenderer->scanlineCache = anonymousMemoryMap(sizeof(color_t) * DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS);
253}
254
255static void DSGXSoftwareRendererReset(struct DSGXRenderer* renderer) {
256 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
257 softwareRenderer->flushPending = false;
258}
259
260static void DSGXSoftwareRendererDeinit(struct DSGXRenderer* renderer) {
261 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
262 DSGXSoftwarePolygonListDeinit(&softwareRenderer->activePolys);
263 DSGXSoftwareEdgeListDeinit(&softwareRenderer->activeEdges);
264 DSGXSoftwareSpanListDeinit(&softwareRenderer->activeSpans);
265 mappedMemoryFree(softwareRenderer->bucket, sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
266 mappedMemoryFree(softwareRenderer->scanlineCache, sizeof(color_t) * DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS);
267}
268
269static void DSGXSoftwareRendererInvalidateTex(struct DSGXRenderer* renderer, int slot) {
270 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
271 // TODO
272}
273
274static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSGXVertex* verts, struct DSGXPolygon* polys, unsigned polyCount, bool wSort) {
275 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
276
277 softwareRenderer->flushPending = true;
278 softwareRenderer->wSort = wSort;
279 softwareRenderer->verts = verts;
280 DSGXSoftwarePolygonListClear(&softwareRenderer->activePolys);
281 DSGXSoftwareEdgeListClear(&softwareRenderer->activeEdges);
282 unsigned i;
283 for (i = 0; i < polyCount; ++i) {
284 struct DSGXSoftwarePolygon* poly = DSGXSoftwarePolygonListAppend(&softwareRenderer->activePolys);
285 struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
286 poly->poly = &polys[i];
287 poly->texFormat = DSGXTexParamsGetFormat(poly->poly->texParams);
288 poly->texW = 8 << DSGXTexParamsGetSSize(poly->poly->texParams);
289 poly->texH = 8 << DSGXTexParamsGetTSize(poly->poly->texParams);
290 switch (poly->texFormat) {
291 case 0:
292 case 7:
293 poly->texBase = NULL;
294 poly->palBase = NULL;
295 break;
296 case 2:
297 poly->texBase = &renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET][(DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 2) & 0xFFFF];
298 poly->palBase = &renderer->texPal[poly->poly->palBase >> 12][(poly->poly->palBase << 2) & 0x1FFF];
299 break;
300 default:
301 poly->texBase = &renderer->tex[DSGXTexParamsGetVRAMBase(poly->poly->texParams) >> VRAM_BLOCK_OFFSET][(DSGXTexParamsGetVRAMBase(poly->poly->texParams) << 2) & 0xFFFF];
302 poly->palBase = &renderer->texPal[poly->poly->palBase >> 11][(poly->poly->palBase << 3) & 0x1FFF];
303 break;
304 }
305 edge->polyId = i;
306
307 struct DSGXVertex* v0 = &verts[poly->poly->vertIds[0]];
308 struct DSGXVertex* v1;
309
310 int v;
311 for (v = 1; v < poly->poly->verts; ++v) {
312 v1 = &verts[poly->poly->vertIds[v]];
313 if (v0->vy >= v1->vy) {
314 edge->y0 = SCREEN_SIZE - v0->vy;
315 edge->x0 = v0->vx;
316 edge->z0 = v0->vz;
317 edge->w0 = v0->vw;
318 _expandColor(v0->color, &edge->cr0, &edge->cg0, &edge->cb0);
319 edge->s0 = v0->vs;
320 edge->t0 = v0->vt;
321
322 edge->y1 = SCREEN_SIZE - v1->vy;
323 edge->x1 = v1->vx;
324 edge->z1 = v1->vz;
325 edge->w1 = v1->vw;
326 _expandColor(v1->color, &edge->cr1, &edge->cg1, &edge->cb1);
327 edge->s1 = v1->vs;
328 edge->t1 = v1->vt;
329 } else {
330 edge->y0 = SCREEN_SIZE - v1->vy;
331 edge->x0 = v1->vx;
332 edge->z0 = v1->vz;
333 edge->w0 = v1->vw;
334 _expandColor(v1->color, &edge->cr0, &edge->cg0, &edge->cb0);
335 edge->s0 = v1->vs;
336 edge->t0 = v1->vt;
337
338 edge->y1 = SCREEN_SIZE - v0->vy;
339 edge->x1 = v0->vx;
340 edge->z1 = v0->vz;
341 edge->w1 = v0->vw;
342 _expandColor(v0->color, &edge->cr1, &edge->cg1, &edge->cb1);
343 edge->s1 = v0->vs;
344 edge->t1 = v0->vt;
345 }
346
347 edge = DSGXSoftwareEdgeListAppend(&softwareRenderer->activeEdges);
348 edge->polyId = i;
349 v0 = v1;
350 }
351
352 v1 = &verts[poly->poly->vertIds[0]];
353 if (v0->vy >= v1->vy) {
354 edge->y0 = SCREEN_SIZE - v0->vy;
355 edge->x0 = v0->vx;
356 edge->z0 = v0->vz;
357 edge->w0 = v0->vw;
358 _expandColor(v0->color, &edge->cr0, &edge->cg0, &edge->cb0);
359 edge->s0 = v0->vs;
360 edge->t0 = v0->vt;
361
362 edge->y1 = SCREEN_SIZE - v1->vy;
363 edge->x1 = v1->vx;
364 edge->z1 = v1->vz;
365 edge->w1 = v1->vw;
366 _expandColor(v1->color, &edge->cr1, &edge->cg1, &edge->cb1);
367 edge->s1 = v1->vs;
368 edge->t1 = v1->vt;
369 } else {
370 edge->y0 = SCREEN_SIZE - v1->vy;
371 edge->x0 = v1->vx;
372 edge->w0 = v1->vw;
373 edge->z0 = v1->vz;
374 _expandColor(v1->color, &edge->cr0, &edge->cg0, &edge->cb0);
375 edge->s0 = v1->vs;
376 edge->t0 = v1->vt;
377
378 edge->y1 = SCREEN_SIZE - v0->vy;
379 edge->x1 = v0->vx;
380 edge->z1 = v0->vz;
381 edge->w1 = v0->vw;
382 _expandColor(v0->color, &edge->cr1, &edge->cg1, &edge->cb1);
383 edge->s1 = v0->vs;
384 edge->t1 = v0->vt;
385 }
386 }
387 qsort(DSGXSoftwareEdgeListGetPointer(&softwareRenderer->activeEdges, 0), DSGXSoftwareEdgeListSize(&softwareRenderer->activeEdges), sizeof(struct DSGXSoftwareEdge), _edgeSort);
388}
389
390static void DSGXSoftwareRendererDrawScanline(struct DSGXRenderer* renderer, int y) {
391 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
392 if (!softwareRenderer->flushPending) {
393 return;
394 }
395 DSGXSoftwareSpanListClear(&softwareRenderer->activeSpans);
396 memset(softwareRenderer->bucket, 0, sizeof(*softwareRenderer->bucket) * DS_GX_POLYGON_BUFFER_SIZE);
397 int i;
398 for (i = DSGXSoftwareEdgeListSize(&softwareRenderer->activeEdges); i; --i) {
399 size_t idx = i - 1;
400 struct DSGXSoftwareEdge* edge = DSGXSoftwareEdgeListGetPointer(&softwareRenderer->activeEdges, idx);
401 if (edge->y1 >> 12 < y) {
402 DSGXSoftwareEdgeListShift(&softwareRenderer->activeEdges, idx, 1);
403 continue;
404 } else if (edge->y0 >> 12 > y) {
405 continue;
406 }
407
408 unsigned poly = edge->polyId;
409 struct DSGXSoftwareSpan* span = softwareRenderer->bucket[poly];
410 if (span && !span->ep[1].w) {
411 _edgeToSpan(span, edge, 1, y);
412 softwareRenderer->bucket[poly] = NULL;
413 } else if (!span) {
414 span = DSGXSoftwareSpanListAppend(&softwareRenderer->activeSpans);
415 memset(&span->ep[1], 0, sizeof(span->ep[1]));
416 span->poly = DSGXSoftwarePolygonListGetPointer(&softwareRenderer->activePolys, poly);
417 if (!_edgeToSpan(span, edge, 0, y)) {
418 // Horizontal line
419 DSGXSoftwareSpanListShift(&softwareRenderer->activeSpans, DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans) - 1, 1);
420 } else {
421 softwareRenderer->bucket[poly] = span;
422 }
423 }
424 }
425 qsort(DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, 0), DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans), sizeof(struct DSGXSoftwareSpan), _spanSort);
426
427 color_t* scanline = &softwareRenderer->scanlineCache[DS_VIDEO_HORIZONTAL_PIXELS * y];
428
429 int nextSpanX = DS_VIDEO_HORIZONTAL_PIXELS;
430 if (DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans)) {
431 nextSpanX = DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans) - 1)->ep[0].x;
432 nextSpanX >>= 12;
433 }
434 for (i = 0; i < DS_VIDEO_HORIZONTAL_PIXELS; ++i) {
435 struct DSGXSoftwareSpan* span = NULL;
436 struct DSGXSoftwareEndpoint ep;
437 int32_t depth = INT32_MAX;
438 scanline[i] = FLAG_UNWRITTEN;
439 if (i >= nextSpanX) {
440 size_t nextSpanId = DSGXSoftwareSpanListSize(&softwareRenderer->activeSpans);
441 span = DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, nextSpanId - 1);
442 while (i > (span->ep[1].x >> 12) || !span->ep[1].x) {
443 DSGXSoftwareSpanListShift(&softwareRenderer->activeSpans, nextSpanId - 1, 1);
444 --nextSpanId;
445 if (!nextSpanId) {
446 nextSpanX = DS_VIDEO_HORIZONTAL_PIXELS;
447 span = NULL;
448 break;
449 }
450 span = DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, nextSpanId - 1);
451 nextSpanX = span->ep[0].x >> 12;
452 }
453 while (span && i > (span->ep[0].x >> 12)) {
454 if (i <= (span->ep[1].x >> 12)) {
455 _lerpEndpoint(span, &ep, i);
456 color_t color = _lookupColor(&ep, span->poly);
457 if (color != FLAG_UNWRITTEN) {
458 if (softwareRenderer->wSort) {
459 if (ep.w < depth) {
460 depth = ep.w;
461 scanline[i] = color;
462 }
463 } else {
464 if (ep.z < depth) {
465 depth = ep.z;
466 scanline[i] = color;
467 }
468 }
469 }
470 }
471 --nextSpanId;
472 if (!nextSpanId) {
473 break;
474 }
475 span = DSGXSoftwareSpanListGetPointer(&softwareRenderer->activeSpans, nextSpanId - 1);
476 }
477 }
478 }
479 if (y == DS_VIDEO_VERTICAL_PIXELS - 1) {
480 softwareRenderer->flushPending = false;
481 }
482}
483
484static void DSGXSoftwareRendererGetScanline(struct DSGXRenderer* renderer, int y, color_t** output) {
485 struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
486 *output = &softwareRenderer->scanlineCache[DS_VIDEO_HORIZONTAL_PIXELS * y];
487}