1 /*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 2009 VMware, Inc. All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
23 */
24
25
26 /**
27 * \file viewport.c
28 * glViewport and glDepthRange functions.
29 */
30
31
32 #include "context.h"
33 #include "enums.h"
34 #include "macros.h"
35 #include "mtypes.h"
36 #include "viewport.h"
37
38 static void
clamp_viewport(struct gl_context * ctx,GLfloat * x,GLfloat * y,GLfloat * width,GLfloat * height)39 clamp_viewport(struct gl_context *ctx, GLfloat *x, GLfloat *y,
40 GLfloat *width, GLfloat *height)
41 {
42 /* clamp width and height to the implementation dependent range */
43 *width = MIN2(*width, (GLfloat) ctx->Const.MaxViewportWidth);
44 *height = MIN2(*height, (GLfloat) ctx->Const.MaxViewportHeight);
45
46 /* The GL_ARB_viewport_array spec says:
47 *
48 * "The location of the viewport's bottom-left corner, given by (x,y),
49 * are clamped to be within the implementation-dependent viewport
50 * bounds range. The viewport bounds range [min, max] tuple may be
51 * determined by calling GetFloatv with the symbolic constant
52 * VIEWPORT_BOUNDS_RANGE (see section 6.1)."
53 */
54 if (_mesa_has_ARB_viewport_array(ctx) ||
55 _mesa_has_OES_viewport_array(ctx)) {
56 *x = CLAMP(*x,
57 ctx->Const.ViewportBounds.Min, ctx->Const.ViewportBounds.Max);
58 *y = CLAMP(*y,
59 ctx->Const.ViewportBounds.Min, ctx->Const.ViewportBounds.Max);
60 }
61 }
62
63 static void
set_viewport_no_notify(struct gl_context * ctx,unsigned idx,GLfloat x,GLfloat y,GLfloat width,GLfloat height)64 set_viewport_no_notify(struct gl_context *ctx, unsigned idx,
65 GLfloat x, GLfloat y,
66 GLfloat width, GLfloat height)
67 {
68 if (ctx->ViewportArray[idx].X == x &&
69 ctx->ViewportArray[idx].Width == width &&
70 ctx->ViewportArray[idx].Y == y &&
71 ctx->ViewportArray[idx].Height == height)
72 return;
73
74 FLUSH_VERTICES(ctx, ctx->DriverFlags.NewViewport ? 0 : _NEW_VIEWPORT);
75 ctx->NewDriverState |= ctx->DriverFlags.NewViewport;
76
77 ctx->ViewportArray[idx].X = x;
78 ctx->ViewportArray[idx].Width = width;
79 ctx->ViewportArray[idx].Y = y;
80 ctx->ViewportArray[idx].Height = height;
81 }
82
83 struct gl_viewport_inputs {
84 GLfloat X, Y; /**< position */
85 GLfloat Width, Height; /**< size */
86 };
87
88 struct gl_depthrange_inputs {
89 GLdouble Near, Far; /**< Depth buffer range */
90 };
91
92 static void
viewport(struct gl_context * ctx,GLint x,GLint y,GLsizei width,GLsizei height)93 viewport(struct gl_context *ctx, GLint x, GLint y, GLsizei width,
94 GLsizei height)
95 {
96 struct gl_viewport_inputs input = { x, y, width, height };
97
98 /* Clamp the viewport to the implementation dependent values. */
99 clamp_viewport(ctx, &input.X, &input.Y, &input.Width, &input.Height);
100
101 /* The GL_ARB_viewport_array spec says:
102 *
103 * "Viewport sets the parameters for all viewports to the same values
104 * and is equivalent (assuming no errors are generated) to:
105 *
106 * for (uint i = 0; i < MAX_VIEWPORTS; i++)
107 * ViewportIndexedf(i, 1, (float)x, (float)y, (float)w, (float)h);"
108 *
109 * Set all of the viewports supported by the implementation, but only
110 * signal the driver once at the end.
111 */
112 for (unsigned i = 0; i < ctx->Const.MaxViewports; i++)
113 set_viewport_no_notify(ctx, i, input.X, input.Y, input.Width, input.Height);
114
115 if (ctx->Driver.Viewport)
116 ctx->Driver.Viewport(ctx);
117 }
118
119 /**
120 * Set the viewport.
121 * \sa Called via glViewport() or display list execution.
122 *
123 * Flushes the vertices and calls _mesa_set_viewport() with the given
124 * parameters.
125 */
126 void GLAPIENTRY
_mesa_Viewport_no_error(GLint x,GLint y,GLsizei width,GLsizei height)127 _mesa_Viewport_no_error(GLint x, GLint y, GLsizei width, GLsizei height)
128 {
129 GET_CURRENT_CONTEXT(ctx);
130 viewport(ctx, x, y, width, height);
131 }
132
133 void GLAPIENTRY
_mesa_Viewport(GLint x,GLint y,GLsizei width,GLsizei height)134 _mesa_Viewport(GLint x, GLint y, GLsizei width, GLsizei height)
135 {
136 GET_CURRENT_CONTEXT(ctx);
137
138 if (MESA_VERBOSE & VERBOSE_API)
139 _mesa_debug(ctx, "glViewport %d %d %d %d\n", x, y, width, height);
140
141 if (width < 0 || height < 0) {
142 _mesa_error(ctx, GL_INVALID_VALUE,
143 "glViewport(%d, %d, %d, %d)", x, y, width, height);
144 return;
145 }
146
147 viewport(ctx, x, y, width, height);
148 }
149
150
151 /**
152 * Set new viewport parameters and update derived state.
153 * Usually called from _mesa_Viewport().
154 *
155 * \param ctx GL context.
156 * \param idx Index of the viewport to be updated.
157 * \param x, y coordinates of the lower left corner of the viewport rectangle.
158 * \param width width of the viewport rectangle.
159 * \param height height of the viewport rectangle.
160 */
161 void
_mesa_set_viewport(struct gl_context * ctx,unsigned idx,GLfloat x,GLfloat y,GLfloat width,GLfloat height)162 _mesa_set_viewport(struct gl_context *ctx, unsigned idx, GLfloat x, GLfloat y,
163 GLfloat width, GLfloat height)
164 {
165 clamp_viewport(ctx, &x, &y, &width, &height);
166 set_viewport_no_notify(ctx, idx, x, y, width, height);
167
168 if (ctx->Driver.Viewport)
169 ctx->Driver.Viewport(ctx);
170 }
171
172 static void
viewport_array(struct gl_context * ctx,GLuint first,GLsizei count,struct gl_viewport_inputs * inputs)173 viewport_array(struct gl_context *ctx, GLuint first, GLsizei count,
174 struct gl_viewport_inputs *inputs)
175 {
176 for (GLsizei i = 0; i < count; i++) {
177 clamp_viewport(ctx, &inputs[i].X, &inputs[i].Y,
178 &inputs[i].Width, &inputs[i].Height);
179
180 set_viewport_no_notify(ctx, i + first, inputs[i].X, inputs[i].Y,
181 inputs[i].Width, inputs[i].Height);
182 }
183
184 if (ctx->Driver.Viewport)
185 ctx->Driver.Viewport(ctx);
186 }
187
188 void GLAPIENTRY
_mesa_ViewportArrayv_no_error(GLuint first,GLsizei count,const GLfloat * v)189 _mesa_ViewportArrayv_no_error(GLuint first, GLsizei count, const GLfloat *v)
190 {
191 GET_CURRENT_CONTEXT(ctx);
192
193 struct gl_viewport_inputs *p = (struct gl_viewport_inputs *)v;
194 viewport_array(ctx, first, count, p);
195 }
196
197 void GLAPIENTRY
_mesa_ViewportArrayv(GLuint first,GLsizei count,const GLfloat * v)198 _mesa_ViewportArrayv(GLuint first, GLsizei count, const GLfloat *v)
199 {
200 int i;
201 struct gl_viewport_inputs *p = (struct gl_viewport_inputs *)v;
202 GET_CURRENT_CONTEXT(ctx);
203
204 if (MESA_VERBOSE & VERBOSE_API)
205 _mesa_debug(ctx, "glViewportArrayv %d %d\n", first, count);
206
207 if ((first + count) > ctx->Const.MaxViewports) {
208 _mesa_error(ctx, GL_INVALID_VALUE,
209 "glViewportArrayv: first (%d) + count (%d) > MaxViewports "
210 "(%d)",
211 first, count, ctx->Const.MaxViewports);
212 return;
213 }
214
215 /* Verify width & height */
216 for (i = 0; i < count; i++) {
217 if (p[i].Width < 0 || p[i].Height < 0) {
218 _mesa_error(ctx, GL_INVALID_VALUE,
219 "glViewportArrayv: index (%d) width or height < 0 "
220 "(%f, %f)",
221 i + first, p[i].Width, p[i].Height);
222 return;
223 }
224 }
225
226 viewport_array(ctx, first, count, p);
227 }
228
229 static void
viewport_indexed_err(struct gl_context * ctx,GLuint index,GLfloat x,GLfloat y,GLfloat w,GLfloat h,const char * function)230 viewport_indexed_err(struct gl_context *ctx, GLuint index, GLfloat x, GLfloat y,
231 GLfloat w, GLfloat h, const char *function)
232 {
233 if (MESA_VERBOSE & VERBOSE_API)
234 _mesa_debug(ctx, "%s(%d, %f, %f, %f, %f)\n",
235 function, index, x, y, w, h);
236
237 if (index >= ctx->Const.MaxViewports) {
238 _mesa_error(ctx, GL_INVALID_VALUE,
239 "%s: index (%d) >= MaxViewports (%d)",
240 function, index, ctx->Const.MaxViewports);
241 return;
242 }
243
244 /* Verify width & height */
245 if (w < 0 || h < 0) {
246 _mesa_error(ctx, GL_INVALID_VALUE,
247 "%s: index (%d) width or height < 0 (%f, %f)",
248 function, index, w, h);
249 return;
250 }
251
252 _mesa_set_viewport(ctx, index, x, y, w, h);
253 }
254
255 void GLAPIENTRY
_mesa_ViewportIndexedf_no_error(GLuint index,GLfloat x,GLfloat y,GLfloat w,GLfloat h)256 _mesa_ViewportIndexedf_no_error(GLuint index, GLfloat x, GLfloat y,
257 GLfloat w, GLfloat h)
258 {
259 GET_CURRENT_CONTEXT(ctx);
260 _mesa_set_viewport(ctx, index, x, y, w, h);
261 }
262
263 void GLAPIENTRY
_mesa_ViewportIndexedf(GLuint index,GLfloat x,GLfloat y,GLfloat w,GLfloat h)264 _mesa_ViewportIndexedf(GLuint index, GLfloat x, GLfloat y,
265 GLfloat w, GLfloat h)
266 {
267 GET_CURRENT_CONTEXT(ctx);
268 viewport_indexed_err(ctx, index, x, y, w, h, "glViewportIndexedf");
269 }
270
271 void GLAPIENTRY
_mesa_ViewportIndexedfv_no_error(GLuint index,const GLfloat * v)272 _mesa_ViewportIndexedfv_no_error(GLuint index, const GLfloat *v)
273 {
274 GET_CURRENT_CONTEXT(ctx);
275 _mesa_set_viewport(ctx, index, v[0], v[1], v[2], v[3]);
276 }
277
278 void GLAPIENTRY
_mesa_ViewportIndexedfv(GLuint index,const GLfloat * v)279 _mesa_ViewportIndexedfv(GLuint index, const GLfloat *v)
280 {
281 GET_CURRENT_CONTEXT(ctx);
282 viewport_indexed_err(ctx, index, v[0], v[1], v[2], v[3],
283 "glViewportIndexedfv");
284 }
285
286 static void
set_depth_range_no_notify(struct gl_context * ctx,unsigned idx,GLclampd nearval,GLclampd farval)287 set_depth_range_no_notify(struct gl_context *ctx, unsigned idx,
288 GLclampd nearval, GLclampd farval)
289 {
290 if (ctx->ViewportArray[idx].Near == nearval &&
291 ctx->ViewportArray[idx].Far == farval)
292 return;
293
294 /* The depth range is needed by program state constants. */
295 FLUSH_VERTICES(ctx, _NEW_VIEWPORT);
296 ctx->NewDriverState |= ctx->DriverFlags.NewViewport;
297
298 ctx->ViewportArray[idx].Near = CLAMP(nearval, 0.0, 1.0);
299 ctx->ViewportArray[idx].Far = CLAMP(farval, 0.0, 1.0);
300 }
301
302 void
_mesa_set_depth_range(struct gl_context * ctx,unsigned idx,GLclampd nearval,GLclampd farval)303 _mesa_set_depth_range(struct gl_context *ctx, unsigned idx,
304 GLclampd nearval, GLclampd farval)
305 {
306 set_depth_range_no_notify(ctx, idx, nearval, farval);
307
308 if (ctx->Driver.DepthRange)
309 ctx->Driver.DepthRange(ctx);
310 }
311
312 /**
313 * Called by glDepthRange
314 *
315 * \param nearval specifies the Z buffer value which should correspond to
316 * the near clip plane
317 * \param farval specifies the Z buffer value which should correspond to
318 * the far clip plane
319 */
320 void GLAPIENTRY
_mesa_DepthRange(GLclampd nearval,GLclampd farval)321 _mesa_DepthRange(GLclampd nearval, GLclampd farval)
322 {
323 unsigned i;
324 GET_CURRENT_CONTEXT(ctx);
325
326 if (MESA_VERBOSE&VERBOSE_API)
327 _mesa_debug(ctx, "glDepthRange %f %f\n", nearval, farval);
328
329 /* The GL_ARB_viewport_array spec says:
330 *
331 * "DepthRange sets the depth range for all viewports to the same
332 * values and is equivalent (assuming no errors are generated) to:
333 *
334 * for (uint i = 0; i < MAX_VIEWPORTS; i++)
335 * DepthRangeIndexed(i, n, f);"
336 *
337 * Set the depth range for all of the viewports supported by the
338 * implementation, but only signal the driver once at the end.
339 */
340 for (i = 0; i < ctx->Const.MaxViewports; i++)
341 set_depth_range_no_notify(ctx, i, nearval, farval);
342
343 if (ctx->Driver.DepthRange) {
344 ctx->Driver.DepthRange(ctx);
345 }
346 }
347
348 void GLAPIENTRY
_mesa_DepthRangef(GLclampf nearval,GLclampf farval)349 _mesa_DepthRangef(GLclampf nearval, GLclampf farval)
350 {
351 _mesa_DepthRange(nearval, farval);
352 }
353
354 /**
355 * Update a range DepthRange values
356 *
357 * \param first starting array index
358 * \param count count of DepthRange items to update
359 * \param v pointer to memory containing
360 * GLclampd near and far clip-plane values
361 */
362 static ALWAYS_INLINE void
depth_range_arrayv(struct gl_context * ctx,GLuint first,GLsizei count,const struct gl_depthrange_inputs * const inputs)363 depth_range_arrayv(struct gl_context *ctx, GLuint first, GLsizei count,
364 const struct gl_depthrange_inputs *const inputs)
365 {
366 for (GLsizei i = 0; i < count; i++)
367 set_depth_range_no_notify(ctx, i + first, inputs[i].Near, inputs[i].Far);
368
369 if (ctx->Driver.DepthRange)
370 ctx->Driver.DepthRange(ctx);
371 }
372
373 void GLAPIENTRY
_mesa_DepthRangeArrayv_no_error(GLuint first,GLsizei count,const GLclampd * v)374 _mesa_DepthRangeArrayv_no_error(GLuint first, GLsizei count, const GLclampd *v)
375 {
376 GET_CURRENT_CONTEXT(ctx);
377
378 const struct gl_depthrange_inputs *const p =
379 (struct gl_depthrange_inputs *)v;
380 depth_range_arrayv(ctx, first, count, p);
381 }
382
383 void GLAPIENTRY
_mesa_DepthRangeArrayv(GLuint first,GLsizei count,const GLclampd * v)384 _mesa_DepthRangeArrayv(GLuint first, GLsizei count, const GLclampd *v)
385 {
386 const struct gl_depthrange_inputs *const p =
387 (struct gl_depthrange_inputs *) v;
388 GET_CURRENT_CONTEXT(ctx);
389
390 if (MESA_VERBOSE & VERBOSE_API)
391 _mesa_debug(ctx, "glDepthRangeArrayv %d %d\n", first, count);
392
393 if ((first + count) > ctx->Const.MaxViewports) {
394 _mesa_error(ctx, GL_INVALID_VALUE,
395 "glDepthRangev: first (%d) + count (%d) >= MaxViewports (%d)",
396 first, count, ctx->Const.MaxViewports);
397 return;
398 }
399
400 depth_range_arrayv(ctx, first, count, p);
401 }
402
403 void GLAPIENTRY
_mesa_DepthRangeArrayfvOES(GLuint first,GLsizei count,const GLfloat * v)404 _mesa_DepthRangeArrayfvOES(GLuint first, GLsizei count, const GLfloat *v)
405 {
406 int i;
407 GET_CURRENT_CONTEXT(ctx);
408
409 if (MESA_VERBOSE & VERBOSE_API)
410 _mesa_debug(ctx, "glDepthRangeArrayfv %d %d\n", first, count);
411
412 if ((first + count) > ctx->Const.MaxViewports) {
413 _mesa_error(ctx, GL_INVALID_VALUE,
414 "glDepthRangeArrayfv: first (%d) + count (%d) >= MaxViewports (%d)",
415 first, count, ctx->Const.MaxViewports);
416 return;
417 }
418
419 for (i = 0; i < count; i++)
420 set_depth_range_no_notify(ctx, i + first, v[i * 2], v[i * 2 + 1]);
421
422 if (ctx->Driver.DepthRange)
423 ctx->Driver.DepthRange(ctx);
424 }
425
426 /**
427 * Update a single DepthRange
428 *
429 * \param index array index to update
430 * \param nearval specifies the Z buffer value which should correspond to
431 * the near clip plane
432 * \param farval specifies the Z buffer value which should correspond to
433 * the far clip plane
434 */
435 void GLAPIENTRY
_mesa_DepthRangeIndexed_no_error(GLuint index,GLclampd nearval,GLclampd farval)436 _mesa_DepthRangeIndexed_no_error(GLuint index, GLclampd nearval,
437 GLclampd farval)
438 {
439 GET_CURRENT_CONTEXT(ctx);
440 _mesa_set_depth_range(ctx, index, nearval, farval);
441 }
442
443
444 void GLAPIENTRY
_mesa_DepthRangeIndexed(GLuint index,GLclampd nearval,GLclampd farval)445 _mesa_DepthRangeIndexed(GLuint index, GLclampd nearval, GLclampd farval)
446 {
447 GET_CURRENT_CONTEXT(ctx);
448
449 if (MESA_VERBOSE & VERBOSE_API)
450 _mesa_debug(ctx, "glDepthRangeIndexed(%d, %f, %f)\n",
451 index, nearval, farval);
452
453 if (index >= ctx->Const.MaxViewports) {
454 _mesa_error(ctx, GL_INVALID_VALUE,
455 "glDepthRangeIndexed: index (%d) >= MaxViewports (%d)",
456 index, ctx->Const.MaxViewports);
457 return;
458 }
459
460 _mesa_set_depth_range(ctx, index, nearval, farval);
461 }
462
463 void GLAPIENTRY
_mesa_DepthRangeIndexedfOES(GLuint index,GLfloat nearval,GLfloat farval)464 _mesa_DepthRangeIndexedfOES(GLuint index, GLfloat nearval, GLfloat farval)
465 {
466 _mesa_DepthRangeIndexed(index, nearval, farval);
467 }
468
469 /**
470 * Initialize the context viewport attribute group.
471 * \param ctx the GL context.
472 */
_mesa_init_viewport(struct gl_context * ctx)473 void _mesa_init_viewport(struct gl_context *ctx)
474 {
475 unsigned i;
476
477 ctx->Transform.ClipOrigin = GL_LOWER_LEFT;
478 ctx->Transform.ClipDepthMode = GL_NEGATIVE_ONE_TO_ONE;
479
480 /* Note: ctx->Const.MaxViewports may not have been set by the driver yet,
481 * so just initialize all of them.
482 */
483 for (i = 0; i < MAX_VIEWPORTS; i++) {
484 /* Viewport group */
485 ctx->ViewportArray[i].X = 0;
486 ctx->ViewportArray[i].Y = 0;
487 ctx->ViewportArray[i].Width = 0;
488 ctx->ViewportArray[i].Height = 0;
489 ctx->ViewportArray[i].Near = 0.0;
490 ctx->ViewportArray[i].Far = 1.0;
491 }
492 }
493
494
495 static ALWAYS_INLINE void
clip_control(struct gl_context * ctx,GLenum origin,GLenum depth,bool no_error)496 clip_control(struct gl_context *ctx, GLenum origin, GLenum depth, bool no_error)
497 {
498 if (ctx->Transform.ClipOrigin == origin &&
499 ctx->Transform.ClipDepthMode == depth)
500 return;
501
502 if (!no_error &&
503 origin != GL_LOWER_LEFT && origin != GL_UPPER_LEFT) {
504 _mesa_error(ctx, GL_INVALID_ENUM, "glClipControl");
505 return;
506 }
507
508 if (!no_error &&
509 depth != GL_NEGATIVE_ONE_TO_ONE && depth != GL_ZERO_TO_ONE) {
510 _mesa_error(ctx, GL_INVALID_ENUM, "glClipControl");
511 return;
512 }
513
514 /* Affects transform state and the viewport transform */
515 FLUSH_VERTICES(ctx, ctx->DriverFlags.NewClipControl ? 0 :
516 _NEW_TRANSFORM | _NEW_VIEWPORT);
517 ctx->NewDriverState |= ctx->DriverFlags.NewClipControl;
518
519 if (ctx->Transform.ClipOrigin != origin) {
520 ctx->Transform.ClipOrigin = origin;
521
522 /* Affects the winding order of the front face. */
523 if (ctx->DriverFlags.NewPolygonState)
524 ctx->NewDriverState |= ctx->DriverFlags.NewPolygonState;
525 else
526 ctx->NewState |= _NEW_POLYGON;
527
528 if (ctx->Driver.FrontFace)
529 ctx->Driver.FrontFace(ctx, ctx->Polygon.FrontFace);
530 }
531
532 if (ctx->Transform.ClipDepthMode != depth) {
533 ctx->Transform.ClipDepthMode = depth;
534
535 if (ctx->Driver.DepthRange)
536 ctx->Driver.DepthRange(ctx);
537 }
538 }
539
540
541 void GLAPIENTRY
_mesa_ClipControl_no_error(GLenum origin,GLenum depth)542 _mesa_ClipControl_no_error(GLenum origin, GLenum depth)
543 {
544 GET_CURRENT_CONTEXT(ctx);
545 clip_control(ctx, origin, depth, true);
546 }
547
548
549 void GLAPIENTRY
_mesa_ClipControl(GLenum origin,GLenum depth)550 _mesa_ClipControl(GLenum origin, GLenum depth)
551 {
552 GET_CURRENT_CONTEXT(ctx);
553
554 if (MESA_VERBOSE & VERBOSE_API)
555 _mesa_debug(ctx, "glClipControl(%s, %s)\n",
556 _mesa_enum_to_string(origin),
557 _mesa_enum_to_string(depth));
558
559 ASSERT_OUTSIDE_BEGIN_END(ctx);
560
561 if (!ctx->Extensions.ARB_clip_control) {
562 _mesa_error(ctx, GL_INVALID_OPERATION, "glClipControl");
563 return;
564 }
565
566 clip_control(ctx, origin, depth, false);
567 }
568
569 /**
570 * Computes the scaling and the translation part of the
571 * viewport transform matrix of the \param i-th viewport
572 * and writes that into \param scale and \param translate.
573 */
574 void
_mesa_get_viewport_xform(struct gl_context * ctx,unsigned i,float scale[3],float translate[3])575 _mesa_get_viewport_xform(struct gl_context *ctx, unsigned i,
576 float scale[3], float translate[3])
577 {
578 float x = ctx->ViewportArray[i].X;
579 float y = ctx->ViewportArray[i].Y;
580 float half_width = 0.5f * ctx->ViewportArray[i].Width;
581 float half_height = 0.5f * ctx->ViewportArray[i].Height;
582 double n = ctx->ViewportArray[i].Near;
583 double f = ctx->ViewportArray[i].Far;
584
585 scale[0] = half_width;
586 translate[0] = half_width + x;
587 if (ctx->Transform.ClipOrigin == GL_UPPER_LEFT) {
588 scale[1] = -half_height;
589 } else {
590 scale[1] = half_height;
591 }
592 translate[1] = half_height + y;
593
594 if (ctx->Transform.ClipDepthMode == GL_NEGATIVE_ONE_TO_ONE) {
595 scale[2] = 0.5 * (f - n);
596 translate[2] = 0.5 * (n + f);
597 } else {
598 scale[2] = f - n;
599 translate[2] = n;
600 }
601 }
602