aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/libraries/irrlicht-1.8/source/Irrlicht/CTRTextureGouraud.cpp
blob: fd3a0200fc4efc3a5c38185f7e4360f57f48c52e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CTRTextureGouraud.h"

#ifdef _IRR_COMPILE_WITH_SOFTWARE_

namespace irr
{
namespace video
{

//! constructor
CTRTextureGouraud::CTRTextureGouraud(IZBuffer* zbuffer)
	: RenderTarget(0), ZBuffer(zbuffer), SurfaceWidth(0), SurfaceHeight(0),
		BackFaceCullingEnabled(true), lockedZBuffer(0),
		lockedSurface(0), lockedTexture(0), lockedTextureWidth(0),
		textureXMask(0), textureYMask(0), Texture(0)
{
	#ifdef _DEBUG
	setDebugName("CTRTextureGouraud");
	#endif

	if (ZBuffer)
		zbuffer->grab();
}



//! destructor
CTRTextureGouraud::~CTRTextureGouraud()
{
	if (RenderTarget)
		RenderTarget->drop();

	if (ZBuffer)
		ZBuffer->drop();

	if (Texture)
		Texture->drop();
}



//! sets the Texture
void CTRTextureGouraud::setTexture(video::IImage* texture)
{
	if (Texture)
		Texture->drop();

	Texture = texture;

	if (Texture)
	{
		Texture->grab();
		lockedTextureWidth = Texture->getDimension().Width;

		textureXMask = lockedTextureWidth-1;
		textureYMask = Texture->getDimension().Height-1;
	}
}




//! en or disables the backface culling
void CTRTextureGouraud::setBackfaceCulling(bool enabled)
{
	BackFaceCullingEnabled = enabled;
}



//! sets a render target
void CTRTextureGouraud::setRenderTarget(video::IImage* surface, const core::rect<s32>& viewPort)
{
	if (RenderTarget)
		RenderTarget->drop();

	RenderTarget = surface;

	if (RenderTarget)
	{
		SurfaceWidth = RenderTarget->getDimension().Width;
		SurfaceHeight = RenderTarget->getDimension().Height;
		RenderTarget->grab();
		ViewPortRect = viewPort;
	}		
}



//! draws an indexed triangle list
void CTRTextureGouraud::drawIndexedTriangleList(S2DVertex* vertices, s32 vertexCount, const u16* indexList, s32 triangleCount)
{
	const S2DVertex *v1, *v2, *v3;

	f32 tmpDiv; // temporary division factor
	f32 longest; // saves the longest span
	s32 height; // saves height of triangle
	u16* targetSurface; // target pointer where to plot pixels
	s32 spanEnd; // saves end of spans
	f32 leftdeltaxf; // amount of pixels to increase on left side of triangle
	f32 rightdeltaxf; // amount of pixels to increase on right side of triangle
	s32 leftx, rightx; // position where we are 
	f32 leftxf, rightxf; // same as above, but as f32 values
	s32 span; // current span
	u16 *hSpanBegin, *hSpanEnd; // pointer used when plotting pixels
	s32 leftR, leftG, leftB, rightR, rightG, rightB; // color values
	s32 leftStepR, leftStepG, leftStepB,
		rightStepR, rightStepG, rightStepB; // color steps
	s32 spanR, spanG, spanB, spanStepR, spanStepG, spanStepB; // color interpolating values while drawing a span.
	s32 leftTx, rightTx, leftTy, rightTy; // texture interpolating values
	s32 leftTxStep, rightTxStep, leftTyStep, rightTyStep; // texture interpolating values
	s32 spanTx, spanTy, spanTxStep, spanTyStep; // values of Texturecoords when drawing a span
	core::rect<s32> TriangleRect;

	s32 leftZValue, rightZValue;
	s32 leftZStep, rightZStep;
	s32 spanZValue, spanZStep; // ZValues when drawing a span
	TZBufferType* zTarget, *spanZTarget; // target of ZBuffer;

	lockedSurface = (u16*)RenderTarget->lock();
	lockedZBuffer = ZBuffer->lock();
	lockedTexture = (u16*)Texture->lock();
	
	for (s32 i=0; i<triangleCount; ++i)
	{
		v1 = &vertices[*indexList];
		++indexList;
		v2 = &vertices[*indexList];
		++indexList;
		v3 = &vertices[*indexList];
		++indexList;

		// back face culling

		if (BackFaceCullingEnabled)
		{
			s32 z = ((v3->Pos.X - v1->Pos.X) * (v3->Pos.Y - v2->Pos.Y)) -
				((v3->Pos.Y - v1->Pos.Y) * (v3->Pos.X - v2->Pos.X));

			if (z < 0)
				continue;
		}

		//near plane clipping

		if (v1->ZValue<0 && v2->ZValue<0 && v3->ZValue<0)
			continue;

		// sort for width for inscreen clipping

		if (v1->Pos.X > v2->Pos.X)	swapVertices(&v1, &v2);
		if (v1->Pos.X > v3->Pos.X)	swapVertices(&v1, &v3);
		if (v2->Pos.X > v3->Pos.X)	swapVertices(&v2, &v3);

		if ((v1->Pos.X - v3->Pos.X) == 0)
			continue;

		TriangleRect.UpperLeftCorner.X = v1->Pos.X;
		TriangleRect.LowerRightCorner.X = v3->Pos.X;

		// sort for height for faster drawing.

		if (v1->Pos.Y > v2->Pos.Y)	swapVertices(&v1, &v2);
		if (v1->Pos.Y > v3->Pos.Y)	swapVertices(&v1, &v3);
		if (v2->Pos.Y > v3->Pos.Y)	swapVertices(&v2, &v3);

		TriangleRect.UpperLeftCorner.Y = v1->Pos.Y;
		TriangleRect.LowerRightCorner.Y = v3->Pos.Y;

		if (!TriangleRect.isRectCollided(ViewPortRect))
			continue;

		// calculate height of triangle
		height = v3->Pos.Y - v1->Pos.Y;
		if (!height)
			continue;

		// calculate longest span

		longest = (v2->Pos.Y - v1->Pos.Y) / (f32)height * (v3->Pos.X - v1->Pos.X) + (v1->Pos.X - v2->Pos.X);

		spanEnd = v2->Pos.Y;
		span = v1->Pos.Y;
		leftxf = (f32)v1->Pos.X;
		rightxf = (f32)v1->Pos.X;

		leftZValue = v1->ZValue;
		rightZValue = v1->ZValue;

		leftR = rightR = video::getRed(v1->Color)<<8;
		leftG = rightG = video::getGreen(v1->Color)<<8;
		leftB = rightB = video::getBlue(v1->Color)<<8;
		leftTx = rightTx = v1->TCoords.X;
		leftTy = rightTy = v1->TCoords.Y;

		targetSurface = lockedSurface + span * SurfaceWidth;
		zTarget = lockedZBuffer + span * SurfaceWidth;

		if (longest < 0.0f)
		{
			tmpDiv = 1.0f / (f32)(v2->Pos.Y - v1->Pos.Y);
			rightdeltaxf = (v2->Pos.X - v1->Pos.X) * tmpDiv;
			rightZStep = (s32)((v2->ZValue - v1->ZValue) * tmpDiv);
			rightStepR = (s32)(((s32)(video::getRed(v2->Color)<<8) - rightR) * tmpDiv);
			rightStepG = (s32)(((s32)(video::getGreen(v2->Color)<<8) - rightG) * tmpDiv);
			rightStepB = (s32)(((s32)(video::getBlue(v2->Color)<<8) - rightB) * tmpDiv);
			rightTxStep = (s32)((v2->TCoords.X - rightTx) * tmpDiv);
			rightTyStep = (s32)((v2->TCoords.Y - rightTy) * tmpDiv);

			tmpDiv = 1.0f / (f32)height;
			leftdeltaxf = (v3->Pos.X - v1->Pos.X) * tmpDiv;
			leftZStep = (s32)((v3->ZValue - v1->ZValue) * tmpDiv);
			leftStepR = (s32)(((s32)(video::getRed(v3->Color)<<8) - leftR) * tmpDiv);
			leftStepG = (s32)(((s32)(video::getGreen(v3->Color)<<8) - leftG) * tmpDiv);
			leftStepB = (s32)(((s32)(video::getBlue(v3->Color)<<8) - leftB) * tmpDiv);
			leftTxStep = (s32)((v3->TCoords.X - leftTx) * tmpDiv);
			leftTyStep = (s32)((v3->TCoords.Y - leftTy) * tmpDiv);
		}
		else
		{
			tmpDiv = 1.0f / (f32)height;
			rightdeltaxf = (v3->Pos.X - v1->Pos.X) * tmpDiv;
			rightZStep = (s32)((v3->ZValue - v1->ZValue) * tmpDiv);
			rightStepR = (s32)(((s32)(video::getRed(v3->Color)<<8) - rightR) * tmpDiv);
			rightStepG = (s32)(((s32)(video::getGreen(v3->Color)<<8) - rightG) * tmpDiv);
			rightStepB = (s32)(((s32)(video::getBlue(v3->Color)<<8) - rightB) * tmpDiv);
			rightTxStep = (s32)((v3->TCoords.X - rightTx) * tmpDiv);
			rightTyStep = (s32)((v3->TCoords.Y - rightTy) * tmpDiv);

			tmpDiv = 1.0f / (f32)(v2->Pos.Y - v1->Pos.Y);
			leftdeltaxf = (v2->Pos.X - v1->Pos.X) * tmpDiv;
			leftZStep = (s32)((v2->ZValue - v1->ZValue) * tmpDiv);
			leftStepR = (s32)(((s32)(video::getRed(v2->Color)<<8) - leftR) * tmpDiv);
			leftStepG = (s32)(((s32)(video::getGreen(v2->Color)<<8) - leftG) * tmpDiv);
			leftStepB = (s32)(((s32)(video::getBlue(v2->Color)<<8) - leftB) * tmpDiv);
			leftTxStep = (s32)((v2->TCoords.X - leftTx) * tmpDiv);
			leftTyStep = (s32)((v2->TCoords.Y - leftTy) * tmpDiv);
		}


		// do it twice, once for the first half of the triangle,
		// end then for the second half.

		for (s32 triangleHalf=0; triangleHalf<2; ++triangleHalf)
		{
			if (spanEnd > ViewPortRect.LowerRightCorner.Y)
				spanEnd = ViewPortRect.LowerRightCorner.Y;

			// if the span <0, than we can skip these spans, 
			// and proceed to the next spans which are really on the screen.
			if (span < ViewPortRect.UpperLeftCorner.Y)
			{
				// we'll use leftx as temp variable
				if (spanEnd < ViewPortRect.UpperLeftCorner.Y)
				{
					leftx = spanEnd - span;
					span = spanEnd;
				}
				else
				{
					leftx = ViewPortRect.UpperLeftCorner.Y - span; 
					span = ViewPortRect.UpperLeftCorner.Y;
				}

				leftxf += leftdeltaxf*leftx;
				rightxf += rightdeltaxf*leftx;
				targetSurface += SurfaceWidth*leftx;
				zTarget += SurfaceWidth*leftx;
				leftZValue += leftZStep*leftx;
				rightZValue += rightZStep*leftx;

				leftR += leftStepR*leftx;
				leftG += leftStepG*leftx;
				leftB += leftStepB*leftx;
				rightR += rightStepR*leftx;
				rightG += rightStepG*leftx;
				rightB += rightStepB*leftx;

				leftTx += leftTxStep*leftx;
				leftTy += leftTyStep*leftx;
				rightTx += rightTxStep*leftx;
				rightTy += rightTyStep*leftx;
			}


			// the main loop. Go through every span and draw it.

			while (span < spanEnd)
			{
				leftx = (s32)(leftxf);
				rightx = (s32)(rightxf + 0.5f);

				// perform some clipping
				// thanks to a correction by hybrid
                // calculations delayed to correctly propagate to textures etc.
				s32 tDiffLeft=0, tDiffRight=0;
				if (leftx<ViewPortRect.UpperLeftCorner.X)
					tDiffLeft=ViewPortRect.UpperLeftCorner.X-leftx;
				else
				if (leftx>ViewPortRect.LowerRightCorner.X)
					tDiffLeft=ViewPortRect.LowerRightCorner.X-leftx;

				if (rightx<ViewPortRect.UpperLeftCorner.X)
					tDiffRight=ViewPortRect.UpperLeftCorner.X-rightx;
				else
				if (rightx>ViewPortRect.LowerRightCorner.X)
					tDiffRight=ViewPortRect.LowerRightCorner.X-rightx;

				// draw the span
				if (rightx + tDiffRight - leftx - tDiffLeft)
				{
					tmpDiv = 1.0f / (f32)(rightx - leftx);
					spanZStep = (s32)((rightZValue - leftZValue) * tmpDiv);
					spanZValue = leftZValue+tDiffLeft*spanZStep;

					spanStepR = (s32)((rightR - leftR) * tmpDiv);
					spanR = leftR+tDiffLeft*spanStepR;
					spanStepG = (s32)((rightG - leftG) * tmpDiv);
					spanG = leftG+tDiffLeft*spanStepG;
					spanStepB = (s32)((rightB - leftB) * tmpDiv);
					spanB = leftB+tDiffLeft*spanStepB;

					spanTxStep = (s32)((rightTx - leftTx) * tmpDiv);
					spanTx = leftTx + tDiffLeft*spanTxStep;
					spanTyStep = (s32)((rightTy - leftTy) * tmpDiv);
					spanTy = leftTy+tDiffLeft*spanTyStep;

					hSpanBegin = targetSurface + leftx+tDiffLeft;
					spanZTarget = zTarget + leftx+tDiffLeft;
					hSpanEnd = targetSurface + rightx+tDiffRight;

					while (hSpanBegin < hSpanEnd) 
					{
						if (spanZValue > *spanZTarget)
						{
							*spanZTarget = spanZValue;
							u16 color = lockedTexture[((spanTy>>8)&textureYMask) * lockedTextureWidth + ((spanTx>>8)&textureXMask)];
							*hSpanBegin = video::RGB16(video::getRed(color) * (spanR>>8) >>2,
									video::getGreen(color) * (spanG>>8) >>2,
									video::getBlue(color) * (spanB>>8) >>2);
						}

						spanR += spanStepR;
						spanG += spanStepG;
						spanB += spanStepB;

						spanTx += spanTxStep;
						spanTy += spanTyStep;
						
						spanZValue += spanZStep;
						++hSpanBegin;
						++spanZTarget;
					}
				}

				leftxf += leftdeltaxf;
				rightxf += rightdeltaxf;
				++span;
				targetSurface += SurfaceWidth;
				zTarget += SurfaceWidth;
				leftZValue += leftZStep;
				rightZValue += rightZStep;

				leftR += leftStepR;
				leftG += leftStepG;
				leftB += leftStepB;
				rightR += rightStepR;
				rightG += rightStepG;
				rightB += rightStepB;

				leftTx += leftTxStep;
				leftTy += leftTyStep;
				rightTx += rightTxStep;
				rightTy += rightTyStep;
			}

			if (triangleHalf>0) // break, we've gout only two halves
				break;


			// setup variables for second half of the triangle.

			if (longest < 0.0f)
			{
				tmpDiv = 1.0f / (v3->Pos.Y - v2->Pos.Y);

				rightdeltaxf = (v3->Pos.X - v2->Pos.X) * tmpDiv;
				rightxf = (f32)v2->Pos.X;

				rightZValue = v2->ZValue;
				rightZStep = (s32)((v3->ZValue - v2->ZValue) * tmpDiv);

				rightR = video::getRed(v2->Color)<<8;
				rightG = video::getGreen(v2->Color)<<8;
				rightB = video::getBlue(v2->Color)<<8;
				rightStepR = (s32)(((s32)(video::getRed(v3->Color)<<8) - rightR) * tmpDiv);
				rightStepG = (s32)(((s32)(video::getGreen(v3->Color)<<8) - rightG) * tmpDiv);
				rightStepB = (s32)(((s32)(video::getBlue(v3->Color)<<8) - rightB) * tmpDiv);

				rightTx = v2->TCoords.X;
				rightTy = v2->TCoords.Y;
				rightTxStep = (s32)((v3->TCoords.X - rightTx) * tmpDiv);
				rightTyStep = (s32)((v3->TCoords.Y - rightTy) * tmpDiv);
			}
			else
			{
				tmpDiv = 1.0f / (v3->Pos.Y - v2->Pos.Y);

				leftdeltaxf = (v3->Pos.X - v2->Pos.X) * tmpDiv;
				leftxf = (f32)v2->Pos.X;

				leftZValue = v2->ZValue;
				leftZStep = (s32)((v3->ZValue - v2->ZValue) * tmpDiv);

				leftR = video::getRed(v2->Color)<<8;
				leftG = video::getGreen(v2->Color)<<8;
				leftB = video::getBlue(v2->Color)<<8;
				leftStepR = (s32)(((s32)(video::getRed(v3->Color)<<8) - leftR) * tmpDiv);
				leftStepG = (s32)(((s32)(video::getGreen(v3->Color)<<8) - leftG) * tmpDiv);
				leftStepB = (s32)(((s32)(video::getBlue(v3->Color)<<8) - leftB) * tmpDiv);

				leftTx = v2->TCoords.X;
				leftTy = v2->TCoords.Y;
				leftTxStep = (s32)((v3->TCoords.X - leftTx) * tmpDiv);
				leftTyStep = (s32)((v3->TCoords.Y - leftTy) * tmpDiv);
			}


			spanEnd = v3->Pos.Y;
		}

	}

	RenderTarget->unlock();
	ZBuffer->unlock();
	Texture->unlock();
}


} // end namespace video
} // end namespace irr

#endif // _IRR_COMPILE_WITH_SOFTWARE_

namespace irr
{
namespace video
{

//! creates a flat triangle renderer
ITriangleRenderer* createTriangleRendererTextureGouraud(IZBuffer* zbuffer)
{
	#ifdef _IRR_COMPILE_WITH_SOFTWARE_
	return new CTRTextureGouraud(zbuffer);
	#else
	return 0;
	#endif // _IRR_COMPILE_WITH_SOFTWARE_
}


} // end namespace video
} // end namespace irr