image.c revision 1614de4045c36ab6ec060e3bd0d1f3394d05b91e 
1/*
2 * Mesa 3-D graphics library
3 * Version:  7.5
4 *
5 * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
6 * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the "Software"),
10 * to deal in the Software without restriction, including without limitation
11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12 * and/or sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included
16 * in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
21 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 */
25
26
27/**
28 * \file image.c
29 * Image handling.
30 */
31
32
33#include "glheader.h"
34#include "colormac.h"
35#include "image.h"
36#include "imports.h"
37#include "macros.h"
38#include "mfeatures.h"
39#include "mtypes.h"
40
41
42
43/**
44 * \return GL_TRUE if type is packed pixel type, GL_FALSE otherwise.
45 */
46GLboolean
47_mesa_type_is_packed(GLenum type)
48{
49   switch (type) {
50   case GL_UNSIGNED_BYTE_3_3_2:
51   case GL_UNSIGNED_BYTE_2_3_3_REV:
52   case MESA_UNSIGNED_BYTE_4_4:
53   case GL_UNSIGNED_SHORT_5_6_5:
54   case GL_UNSIGNED_SHORT_5_6_5_REV:
55   case GL_UNSIGNED_SHORT_4_4_4_4:
56   case GL_UNSIGNED_SHORT_4_4_4_4_REV:
57   case GL_UNSIGNED_SHORT_5_5_5_1:
58   case GL_UNSIGNED_SHORT_1_5_5_5_REV:
59   case GL_UNSIGNED_INT_8_8_8_8:
60   case GL_UNSIGNED_INT_8_8_8_8_REV:
61   case GL_UNSIGNED_INT_10_10_10_2:
62   case GL_UNSIGNED_INT_2_10_10_10_REV:
63   case GL_UNSIGNED_SHORT_8_8_MESA:
64   case GL_UNSIGNED_SHORT_8_8_REV_MESA:
65   case GL_UNSIGNED_INT_24_8_EXT:
66   case GL_UNSIGNED_INT_5_9_9_9_REV:
67   case GL_UNSIGNED_INT_10F_11F_11F_REV:
68   case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
69      return GL_TRUE;
70   }
71
72   return GL_FALSE;
73}
74
75
76
77/**
78 * Flip the order of the 2 bytes in each word in the given array.
79 *
80 * \param p array.
81 * \param n number of words.
82 */
83void
84_mesa_swap2( GLushort *p, GLuint n )
85{
86   GLuint i;
87   for (i = 0; i < n; i++) {
88      p[i] = (p[i] >> 8) | ((p[i] << 8) & 0xff00);
89   }
90}
91
92
93
94/*
95 * Flip the order of the 4 bytes in each word in the given array.
96 */
97void
98_mesa_swap4( GLuint *p, GLuint n )
99{
100   GLuint i, a, b;
101   for (i = 0; i < n; i++) {
102      b = p[i];
103      a =  (b >> 24)
104	| ((b >> 8) & 0xff00)
105	| ((b << 8) & 0xff0000)
106	| ((b << 24) & 0xff000000);
107      p[i] = a;
108   }
109}
110
111
112/**
113 * Get the size of a GL data type.
114 *
115 * \param type GL data type.
116 *
117 * \return the size, in bytes, of the given data type, 0 if a GL_BITMAP, or -1
118 * if an invalid type enum.
119 */
120GLint
121_mesa_sizeof_type( GLenum type )
122{
123   switch (type) {
124      case GL_BITMAP:
125	 return 0;
126      case GL_UNSIGNED_BYTE:
127         return sizeof(GLubyte);
128      case GL_BYTE:
129	 return sizeof(GLbyte);
130      case GL_UNSIGNED_SHORT:
131	 return sizeof(GLushort);
132      case GL_SHORT:
133	 return sizeof(GLshort);
134      case GL_UNSIGNED_INT:
135	 return sizeof(GLuint);
136      case GL_INT:
137	 return sizeof(GLint);
138      case GL_FLOAT:
139	 return sizeof(GLfloat);
140      case GL_DOUBLE:
141	 return sizeof(GLdouble);
142      case GL_HALF_FLOAT_ARB:
143	 return sizeof(GLhalfARB);
144      case GL_FIXED:
145	 return sizeof(GLfixed);
146      default:
147         return -1;
148   }
149}
150
151
152/**
153 * Same as _mesa_sizeof_type() but also accepting the packed pixel
154 * format data types.
155 */
156GLint
157_mesa_sizeof_packed_type( GLenum type )
158{
159   switch (type) {
160      case GL_BITMAP:
161	 return 0;
162      case GL_UNSIGNED_BYTE:
163         return sizeof(GLubyte);
164      case GL_BYTE:
165	 return sizeof(GLbyte);
166      case GL_UNSIGNED_SHORT:
167	 return sizeof(GLushort);
168      case GL_SHORT:
169	 return sizeof(GLshort);
170      case GL_UNSIGNED_INT:
171	 return sizeof(GLuint);
172      case GL_INT:
173	 return sizeof(GLint);
174      case GL_HALF_FLOAT_ARB:
175	 return sizeof(GLhalfARB);
176      case GL_FLOAT:
177	 return sizeof(GLfloat);
178      case GL_UNSIGNED_BYTE_3_3_2:
179      case GL_UNSIGNED_BYTE_2_3_3_REV:
180      case MESA_UNSIGNED_BYTE_4_4:
181         return sizeof(GLubyte);
182      case GL_UNSIGNED_SHORT_5_6_5:
183      case GL_UNSIGNED_SHORT_5_6_5_REV:
184      case GL_UNSIGNED_SHORT_4_4_4_4:
185      case GL_UNSIGNED_SHORT_4_4_4_4_REV:
186      case GL_UNSIGNED_SHORT_5_5_5_1:
187      case GL_UNSIGNED_SHORT_1_5_5_5_REV:
188      case GL_UNSIGNED_SHORT_8_8_MESA:
189      case GL_UNSIGNED_SHORT_8_8_REV_MESA:
190         return sizeof(GLushort);
191      case GL_UNSIGNED_INT_8_8_8_8:
192      case GL_UNSIGNED_INT_8_8_8_8_REV:
193      case GL_UNSIGNED_INT_10_10_10_2:
194      case GL_UNSIGNED_INT_2_10_10_10_REV:
195      case GL_UNSIGNED_INT_24_8_EXT:
196      case GL_UNSIGNED_INT_5_9_9_9_REV:
197      case GL_UNSIGNED_INT_10F_11F_11F_REV:
198         return sizeof(GLuint);
199      case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
200         return 8;
201      default:
202         return -1;
203   }
204}
205
206
207/**
208 * Get the number of components in a pixel format.
209 *
210 * \param format pixel format.
211 *
212 * \return the number of components in the given format, or -1 if a bad format.
213 */
214GLint
215_mesa_components_in_format( GLenum format )
216{
217   switch (format) {
218      case GL_COLOR_INDEX:
219      case GL_STENCIL_INDEX:
220      case GL_DEPTH_COMPONENT:
221      case GL_RED:
222      case GL_RED_INTEGER_EXT:
223      case GL_GREEN:
224      case GL_GREEN_INTEGER_EXT:
225      case GL_BLUE:
226      case GL_BLUE_INTEGER_EXT:
227      case GL_ALPHA:
228      case GL_ALPHA_INTEGER_EXT:
229      case GL_LUMINANCE:
230      case GL_LUMINANCE_INTEGER_EXT:
231      case GL_INTENSITY:
232         return 1;
233
234      case GL_LUMINANCE_ALPHA:
235      case GL_LUMINANCE_ALPHA_INTEGER_EXT:
236      case GL_RG:
237      case GL_YCBCR_MESA:
238      case GL_DEPTH_STENCIL_EXT:
239      case GL_DUDV_ATI:
240      case GL_DU8DV8_ATI:
241	 return 2;
242
243      case GL_RGB:
244      case GL_BGR:
245      case GL_RGB_INTEGER_EXT:
246      case GL_BGR_INTEGER_EXT:
247	 return 3;
248
249      case GL_RGBA:
250      case GL_BGRA:
251      case GL_ABGR_EXT:
252      case GL_RGBA_INTEGER_EXT:
253      case GL_BGRA_INTEGER_EXT:
254         return 4;
255
256      default:
257         return -1;
258   }
259}
260
261
262/**
263 * Get the bytes per pixel of pixel format type pair.
264 *
265 * \param format pixel format.
266 * \param type pixel type.
267 *
268 * \return bytes per pixel, or -1 if a bad format or type was given.
269 */
270GLint
271_mesa_bytes_per_pixel( GLenum format, GLenum type )
272{
273   GLint comps = _mesa_components_in_format( format );
274   if (comps < 0)
275      return -1;
276
277   switch (type) {
278      case GL_BITMAP:
279         return 0;  /* special case */
280      case GL_BYTE:
281      case GL_UNSIGNED_BYTE:
282         return comps * sizeof(GLubyte);
283      case GL_SHORT:
284      case GL_UNSIGNED_SHORT:
285         return comps * sizeof(GLshort);
286      case GL_INT:
287      case GL_UNSIGNED_INT:
288         return comps * sizeof(GLint);
289      case GL_FLOAT:
290         return comps * sizeof(GLfloat);
291      case GL_HALF_FLOAT_ARB:
292         return comps * sizeof(GLhalfARB);
293      case GL_UNSIGNED_BYTE_3_3_2:
294      case GL_UNSIGNED_BYTE_2_3_3_REV:
295         if (format == GL_RGB || format == GL_BGR ||
296             format == GL_RGB_INTEGER_EXT || format == GL_BGR_INTEGER_EXT)
297            return sizeof(GLubyte);
298         else
299            return -1;  /* error */
300      case GL_UNSIGNED_SHORT_5_6_5:
301      case GL_UNSIGNED_SHORT_5_6_5_REV:
302         if (format == GL_RGB || format == GL_BGR ||
303             format == GL_RGB_INTEGER_EXT || format == GL_BGR_INTEGER_EXT)
304            return sizeof(GLushort);
305         else
306            return -1;  /* error */
307      case GL_UNSIGNED_SHORT_4_4_4_4:
308      case GL_UNSIGNED_SHORT_4_4_4_4_REV:
309      case GL_UNSIGNED_SHORT_5_5_5_1:
310      case GL_UNSIGNED_SHORT_1_5_5_5_REV:
311         if (format == GL_RGBA || format == GL_BGRA || format == GL_ABGR_EXT ||
312             format == GL_RGBA_INTEGER_EXT || format == GL_BGRA_INTEGER_EXT)
313            return sizeof(GLushort);
314         else
315            return -1;
316      case GL_UNSIGNED_INT_8_8_8_8:
317      case GL_UNSIGNED_INT_8_8_8_8_REV:
318      case GL_UNSIGNED_INT_10_10_10_2:
319      case GL_UNSIGNED_INT_2_10_10_10_REV:
320         if (format == GL_RGBA || format == GL_BGRA || format == GL_ABGR_EXT ||
321             format == GL_RGBA_INTEGER_EXT || format == GL_BGRA_INTEGER_EXT)
322            return sizeof(GLuint);
323         else
324            return -1;
325      case GL_UNSIGNED_SHORT_8_8_MESA:
326      case GL_UNSIGNED_SHORT_8_8_REV_MESA:
327         if (format == GL_YCBCR_MESA)
328            return sizeof(GLushort);
329         else
330            return -1;
331      case GL_UNSIGNED_INT_24_8_EXT:
332         if (format == GL_DEPTH_STENCIL_EXT)
333            return sizeof(GLuint);
334         else
335            return -1;
336      case GL_UNSIGNED_INT_5_9_9_9_REV:
337         if (format == GL_RGB)
338            return sizeof(GLuint);
339         else
340            return -1;
341      case GL_UNSIGNED_INT_10F_11F_11F_REV:
342         if (format == GL_RGB)
343            return sizeof(GLuint);
344         else
345            return -1;
346      case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
347         if (format == GL_DEPTH_STENCIL)
348            return 8;
349         else
350            return -1;
351      default:
352         return -1;
353   }
354}
355
356
357/**
358 * Test for a legal pixel format and type.
359 *
360 * \param format pixel format.
361 * \param type pixel type.
362 *
363 * \return GL_TRUE if the given pixel format and type are legal, or GL_FALSE
364 * otherwise.
365 */
366GLboolean
367_mesa_is_legal_format_and_type(const struct gl_context *ctx,
368                               GLenum format, GLenum type)
369{
370   switch (format) {
371      case GL_COLOR_INDEX:
372      case GL_STENCIL_INDEX:
373         switch (type) {
374            case GL_BITMAP:
375            case GL_BYTE:
376            case GL_UNSIGNED_BYTE:
377            case GL_SHORT:
378            case GL_UNSIGNED_SHORT:
379            case GL_INT:
380            case GL_UNSIGNED_INT:
381            case GL_FLOAT:
382               return GL_TRUE;
383            case GL_HALF_FLOAT_ARB:
384               return ctx->Extensions.ARB_half_float_pixel;
385            default:
386               return GL_FALSE;
387         }
388      case GL_RED:
389      case GL_GREEN:
390      case GL_BLUE:
391      case GL_ALPHA:
392#if 0 /* not legal!  see table 3.6 of the 1.5 spec */
393      case GL_INTENSITY:
394#endif
395      case GL_LUMINANCE:
396      case GL_LUMINANCE_ALPHA:
397      case GL_DEPTH_COMPONENT:
398         switch (type) {
399            case GL_BYTE:
400            case GL_UNSIGNED_BYTE:
401            case GL_SHORT:
402            case GL_UNSIGNED_SHORT:
403            case GL_INT:
404            case GL_UNSIGNED_INT:
405            case GL_FLOAT:
406               return GL_TRUE;
407            case GL_HALF_FLOAT_ARB:
408               return ctx->Extensions.ARB_half_float_pixel;
409            default:
410               return GL_FALSE;
411         }
412      case GL_RG:
413	 if (!ctx->Extensions.ARB_texture_rg)
414	    return GL_FALSE;
415
416         switch (type) {
417            case GL_BYTE:
418            case GL_UNSIGNED_BYTE:
419            case GL_SHORT:
420            case GL_UNSIGNED_SHORT:
421            case GL_INT:
422            case GL_UNSIGNED_INT:
423            case GL_FLOAT:
424               return GL_TRUE;
425            case GL_HALF_FLOAT_ARB:
426               return ctx->Extensions.ARB_half_float_pixel;
427            default:
428               return GL_FALSE;
429         }
430      case GL_RGB:
431         switch (type) {
432            case GL_BYTE:
433            case GL_UNSIGNED_BYTE:
434            case GL_SHORT:
435            case GL_UNSIGNED_SHORT:
436            case GL_INT:
437            case GL_UNSIGNED_INT:
438            case GL_FLOAT:
439            case GL_UNSIGNED_BYTE_3_3_2:
440            case GL_UNSIGNED_BYTE_2_3_3_REV:
441            case GL_UNSIGNED_SHORT_5_6_5:
442            case GL_UNSIGNED_SHORT_5_6_5_REV:
443               return GL_TRUE;
444            case GL_HALF_FLOAT_ARB:
445               return ctx->Extensions.ARB_half_float_pixel;
446            case GL_UNSIGNED_INT_5_9_9_9_REV:
447               return ctx->Extensions.EXT_texture_shared_exponent;
448            case GL_UNSIGNED_INT_10F_11F_11F_REV:
449               return ctx->Extensions.EXT_packed_float;
450            default:
451               return GL_FALSE;
452         }
453      case GL_BGR:
454         switch (type) {
455            /* NOTE: no packed types are supported with BGR.  That's
456             * intentional, according to the GL spec.
457             */
458            case GL_BYTE:
459            case GL_UNSIGNED_BYTE:
460            case GL_SHORT:
461            case GL_UNSIGNED_SHORT:
462            case GL_INT:
463            case GL_UNSIGNED_INT:
464            case GL_FLOAT:
465               return GL_TRUE;
466            case GL_HALF_FLOAT_ARB:
467               return ctx->Extensions.ARB_half_float_pixel;
468            default:
469               return GL_FALSE;
470         }
471      case GL_RGBA:
472      case GL_BGRA:
473      case GL_ABGR_EXT:
474         switch (type) {
475            case GL_BYTE:
476            case GL_UNSIGNED_BYTE:
477            case GL_SHORT:
478            case GL_UNSIGNED_SHORT:
479            case GL_INT:
480            case GL_UNSIGNED_INT:
481            case GL_FLOAT:
482            case GL_UNSIGNED_SHORT_4_4_4_4:
483            case GL_UNSIGNED_SHORT_4_4_4_4_REV:
484            case GL_UNSIGNED_SHORT_5_5_5_1:
485            case GL_UNSIGNED_SHORT_1_5_5_5_REV:
486            case GL_UNSIGNED_INT_8_8_8_8:
487            case GL_UNSIGNED_INT_8_8_8_8_REV:
488            case GL_UNSIGNED_INT_10_10_10_2:
489            case GL_UNSIGNED_INT_2_10_10_10_REV:
490               return GL_TRUE;
491            case GL_HALF_FLOAT_ARB:
492               return ctx->Extensions.ARB_half_float_pixel;
493            default:
494               return GL_FALSE;
495         }
496      case GL_YCBCR_MESA:
497         if (type == GL_UNSIGNED_SHORT_8_8_MESA ||
498             type == GL_UNSIGNED_SHORT_8_8_REV_MESA)
499            return GL_TRUE;
500         else
501            return GL_FALSE;
502      case GL_DEPTH_STENCIL_EXT:
503         if ((ctx->Extensions.EXT_packed_depth_stencil &&
504              type == GL_UNSIGNED_INT_24_8_EXT) ||
505             (ctx->Extensions.ARB_depth_buffer_float &&
506              type == GL_FLOAT_32_UNSIGNED_INT_24_8_REV))
507            return GL_TRUE;
508         else
509            return GL_FALSE;
510      case GL_DUDV_ATI:
511      case GL_DU8DV8_ATI:
512         switch (type) {
513            case GL_BYTE:
514            case GL_UNSIGNED_BYTE:
515            case GL_SHORT:
516            case GL_UNSIGNED_SHORT:
517            case GL_INT:
518            case GL_UNSIGNED_INT:
519            case GL_FLOAT:
520               return GL_TRUE;
521            default:
522               return GL_FALSE;
523         }
524
525      /* integer-valued formats */
526      case GL_RED_INTEGER_EXT:
527      case GL_GREEN_INTEGER_EXT:
528      case GL_BLUE_INTEGER_EXT:
529      case GL_ALPHA_INTEGER_EXT:
530         switch (type) {
531            case GL_BYTE:
532            case GL_UNSIGNED_BYTE:
533            case GL_SHORT:
534            case GL_UNSIGNED_SHORT:
535            case GL_INT:
536            case GL_UNSIGNED_INT:
537               return ctx->Extensions.EXT_texture_integer;
538            default:
539               return GL_FALSE;
540         }
541
542      case GL_RGB_INTEGER_EXT:
543         switch (type) {
544            case GL_BYTE:
545            case GL_UNSIGNED_BYTE:
546            case GL_SHORT:
547            case GL_UNSIGNED_SHORT:
548            case GL_INT:
549            case GL_UNSIGNED_INT:
550               return ctx->Extensions.EXT_texture_integer;
551            case GL_UNSIGNED_BYTE_3_3_2:
552            case GL_UNSIGNED_BYTE_2_3_3_REV:
553            case GL_UNSIGNED_SHORT_5_6_5:
554            case GL_UNSIGNED_SHORT_5_6_5_REV:
555               return ctx->Extensions.ARB_texture_rgb10_a2ui;
556            default:
557               return GL_FALSE;
558         }
559
560      case GL_BGR_INTEGER_EXT:
561         switch (type) {
562            case GL_BYTE:
563            case GL_UNSIGNED_BYTE:
564            case GL_SHORT:
565            case GL_UNSIGNED_SHORT:
566            case GL_INT:
567            case GL_UNSIGNED_INT:
568            /* NOTE: no packed formats w/ BGR format */
569               return ctx->Extensions.EXT_texture_integer;
570            default:
571               return GL_FALSE;
572         }
573
574      case GL_RGBA_INTEGER_EXT:
575      case GL_BGRA_INTEGER_EXT:
576         switch (type) {
577            case GL_BYTE:
578            case GL_UNSIGNED_BYTE:
579            case GL_SHORT:
580            case GL_UNSIGNED_SHORT:
581            case GL_INT:
582            case GL_UNSIGNED_INT:
583               return ctx->Extensions.EXT_texture_integer;
584            case GL_UNSIGNED_SHORT_4_4_4_4:
585            case GL_UNSIGNED_SHORT_4_4_4_4_REV:
586            case GL_UNSIGNED_SHORT_5_5_5_1:
587            case GL_UNSIGNED_SHORT_1_5_5_5_REV:
588            case GL_UNSIGNED_INT_8_8_8_8:
589            case GL_UNSIGNED_INT_8_8_8_8_REV:
590            case GL_UNSIGNED_INT_10_10_10_2:
591            case GL_UNSIGNED_INT_2_10_10_10_REV:
592               return ctx->Extensions.ARB_texture_rgb10_a2ui;
593            default:
594               return GL_FALSE;
595         }
596
597      case GL_LUMINANCE_INTEGER_EXT:
598      case GL_LUMINANCE_ALPHA_INTEGER_EXT:
599         switch (type) {
600            case GL_BYTE:
601            case GL_UNSIGNED_BYTE:
602            case GL_SHORT:
603            case GL_UNSIGNED_SHORT:
604            case GL_INT:
605            case GL_UNSIGNED_INT:
606               return ctx->Extensions.EXT_texture_integer;
607            default:
608               return GL_FALSE;
609         }
610
611      default:
612         ; /* fall-through */
613   }
614   return GL_FALSE;
615}
616
617
618/**
619 * Test if the given image format is a color/RGBA format (i.e., not color
620 * index, depth, stencil, etc).
621 * \param format  the image format value (may by an internal texture format)
622 * \return GL_TRUE if its a color/RGBA format, GL_FALSE otherwise.
623 */
624GLboolean
625_mesa_is_color_format(GLenum format)
626{
627   switch (format) {
628      case GL_RED:
629      case GL_GREEN:
630      case GL_BLUE:
631      case GL_ALPHA:
632      case GL_ALPHA4:
633      case GL_ALPHA8:
634      case GL_ALPHA12:
635      case GL_ALPHA16:
636      case 1:
637      case GL_LUMINANCE:
638      case GL_LUMINANCE4:
639      case GL_LUMINANCE8:
640      case GL_LUMINANCE12:
641      case GL_LUMINANCE16:
642      case 2:
643      case GL_LUMINANCE_ALPHA:
644      case GL_LUMINANCE4_ALPHA4:
645      case GL_LUMINANCE6_ALPHA2:
646      case GL_LUMINANCE8_ALPHA8:
647      case GL_LUMINANCE12_ALPHA4:
648      case GL_LUMINANCE12_ALPHA12:
649      case GL_LUMINANCE16_ALPHA16:
650      case GL_INTENSITY:
651      case GL_INTENSITY4:
652      case GL_INTENSITY8:
653      case GL_INTENSITY12:
654      case GL_INTENSITY16:
655      case GL_R8:
656      case GL_R16:
657      case GL_RG:
658      case GL_RG8:
659      case GL_RG16:
660      case 3:
661      case GL_RGB:
662      case GL_BGR:
663      case GL_R3_G3_B2:
664      case GL_RGB4:
665      case GL_RGB5:
666      case GL_RGB8:
667      case GL_RGB10:
668      case GL_RGB12:
669      case GL_RGB16:
670      case 4:
671      case GL_ABGR_EXT:
672      case GL_RGBA:
673      case GL_BGRA:
674      case GL_RGBA2:
675      case GL_RGBA4:
676      case GL_RGB5_A1:
677      case GL_RGBA8:
678      case GL_RGB10_A2:
679      case GL_RGBA12:
680      case GL_RGBA16:
681      /* float texture formats */
682      case GL_ALPHA16F_ARB:
683      case GL_ALPHA32F_ARB:
684      case GL_LUMINANCE16F_ARB:
685      case GL_LUMINANCE32F_ARB:
686      case GL_LUMINANCE_ALPHA16F_ARB:
687      case GL_LUMINANCE_ALPHA32F_ARB:
688      case GL_INTENSITY16F_ARB:
689      case GL_INTENSITY32F_ARB:
690      case GL_R16F:
691      case GL_R32F:
692      case GL_RG16F:
693      case GL_RG32F:
694      case GL_RGB16F_ARB:
695      case GL_RGB32F_ARB:
696      case GL_RGBA16F_ARB:
697      case GL_RGBA32F_ARB:
698      /* compressed formats */
699      case GL_COMPRESSED_ALPHA:
700      case GL_COMPRESSED_LUMINANCE:
701      case GL_COMPRESSED_LUMINANCE_ALPHA:
702      case GL_COMPRESSED_INTENSITY:
703      case GL_COMPRESSED_RED:
704      case GL_COMPRESSED_RG:
705      case GL_COMPRESSED_RGB:
706      case GL_COMPRESSED_RGBA:
707      case GL_RGB_S3TC:
708      case GL_RGB4_S3TC:
709      case GL_RGBA_S3TC:
710      case GL_RGBA4_S3TC:
711      case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
712      case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
713      case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
714      case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
715      case GL_COMPRESSED_RGB_FXT1_3DFX:
716      case GL_COMPRESSED_RGBA_FXT1_3DFX:
717#if FEATURE_EXT_texture_sRGB
718      case GL_SRGB_EXT:
719      case GL_SRGB8_EXT:
720      case GL_SRGB_ALPHA_EXT:
721      case GL_SRGB8_ALPHA8_EXT:
722      case GL_SLUMINANCE_ALPHA_EXT:
723      case GL_SLUMINANCE8_ALPHA8_EXT:
724      case GL_SLUMINANCE_EXT:
725      case GL_SLUMINANCE8_EXT:
726      case GL_COMPRESSED_SRGB_EXT:
727      case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
728      case GL_COMPRESSED_SRGB_ALPHA_EXT:
729      case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
730      case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
731      case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
732      case GL_COMPRESSED_SLUMINANCE_EXT:
733      case GL_COMPRESSED_SLUMINANCE_ALPHA_EXT:
734#endif /* FEATURE_EXT_texture_sRGB */
735      case GL_COMPRESSED_RED_RGTC1:
736      case GL_COMPRESSED_SIGNED_RED_RGTC1:
737      case GL_COMPRESSED_RG_RGTC2:
738      case GL_COMPRESSED_SIGNED_RG_RGTC2:
739      case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
740      case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
741      case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
742      case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
743      case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
744      case GL_ETC1_RGB8_OES:
745      /* generic integer formats */
746      case GL_RED_INTEGER_EXT:
747      case GL_GREEN_INTEGER_EXT:
748      case GL_BLUE_INTEGER_EXT:
749      case GL_ALPHA_INTEGER_EXT:
750      case GL_RGB_INTEGER_EXT:
751      case GL_RGBA_INTEGER_EXT:
752      case GL_BGR_INTEGER_EXT:
753      case GL_BGRA_INTEGER_EXT:
754      case GL_LUMINANCE_INTEGER_EXT:
755      case GL_LUMINANCE_ALPHA_INTEGER_EXT:
756      /* sized integer formats */
757      case GL_RGBA32UI_EXT:
758      case GL_RGB32UI_EXT:
759      case GL_ALPHA32UI_EXT:
760      case GL_INTENSITY32UI_EXT:
761      case GL_LUMINANCE32UI_EXT:
762      case GL_LUMINANCE_ALPHA32UI_EXT:
763      case GL_RGBA16UI_EXT:
764      case GL_RGB16UI_EXT:
765      case GL_ALPHA16UI_EXT:
766      case GL_INTENSITY16UI_EXT:
767      case GL_LUMINANCE16UI_EXT:
768      case GL_LUMINANCE_ALPHA16UI_EXT:
769      case GL_RGBA8UI_EXT:
770      case GL_RGB8UI_EXT:
771      case GL_ALPHA8UI_EXT:
772      case GL_INTENSITY8UI_EXT:
773      case GL_LUMINANCE8UI_EXT:
774      case GL_LUMINANCE_ALPHA8UI_EXT:
775      case GL_RGBA32I_EXT:
776      case GL_RGB32I_EXT:
777      case GL_ALPHA32I_EXT:
778      case GL_INTENSITY32I_EXT:
779      case GL_LUMINANCE32I_EXT:
780      case GL_LUMINANCE_ALPHA32I_EXT:
781      case GL_RGBA16I_EXT:
782      case GL_RGB16I_EXT:
783      case GL_ALPHA16I_EXT:
784      case GL_INTENSITY16I_EXT:
785      case GL_LUMINANCE16I_EXT:
786      case GL_LUMINANCE_ALPHA16I_EXT:
787      case GL_RGBA8I_EXT:
788      case GL_RGB8I_EXT:
789      case GL_ALPHA8I_EXT:
790      case GL_INTENSITY8I_EXT:
791      case GL_LUMINANCE8I_EXT:
792      case GL_LUMINANCE_ALPHA8I_EXT:
793      /* signed, normalized texture formats */
794      case GL_RED_SNORM:
795      case GL_R8_SNORM:
796      case GL_R16_SNORM:
797      case GL_RG_SNORM:
798      case GL_RG8_SNORM:
799      case GL_RG16_SNORM:
800      case GL_RGB_SNORM:
801      case GL_RGB8_SNORM:
802      case GL_RGB16_SNORM:
803      case GL_RGBA_SNORM:
804      case GL_RGBA8_SNORM:
805      case GL_RGBA16_SNORM:
806      case GL_ALPHA_SNORM:
807      case GL_ALPHA8_SNORM:
808      case GL_ALPHA16_SNORM:
809      case GL_LUMINANCE_SNORM:
810      case GL_LUMINANCE8_SNORM:
811      case GL_LUMINANCE16_SNORM:
812      case GL_LUMINANCE_ALPHA_SNORM:
813      case GL_LUMINANCE8_ALPHA8_SNORM:
814      case GL_LUMINANCE16_ALPHA16_SNORM:
815      case GL_INTENSITY_SNORM:
816      case GL_INTENSITY8_SNORM:
817      case GL_INTENSITY16_SNORM:
818      case GL_RGB9_E5:
819      case GL_R11F_G11F_B10F:
820      case GL_RGB10_A2UI:
821         return GL_TRUE;
822      case GL_YCBCR_MESA:  /* not considered to be RGB */
823         /* fall-through */
824      default:
825         return GL_FALSE;
826   }
827}
828
829
830/**
831 * Test if the given image format is a depth component format.
832 */
833GLboolean
834_mesa_is_depth_format(GLenum format)
835{
836   switch (format) {
837      case GL_DEPTH_COMPONENT:
838      case GL_DEPTH_COMPONENT16:
839      case GL_DEPTH_COMPONENT24:
840      case GL_DEPTH_COMPONENT32:
841      case GL_DEPTH_COMPONENT32F:
842         return GL_TRUE;
843      default:
844         return GL_FALSE;
845   }
846}
847
848
849/**
850 * Test if the given image format is a stencil format.
851 */
852GLboolean
853_mesa_is_stencil_format(GLenum format)
854{
855   switch (format) {
856      case GL_STENCIL_INDEX:
857         return GL_TRUE;
858      default:
859         return GL_FALSE;
860   }
861}
862
863
864/**
865 * Test if the given image format is a YCbCr format.
866 */
867GLboolean
868_mesa_is_ycbcr_format(GLenum format)
869{
870   switch (format) {
871      case GL_YCBCR_MESA:
872         return GL_TRUE;
873      default:
874         return GL_FALSE;
875   }
876}
877
878
879/**
880 * Test if the given image format is a depth+stencil format.
881 */
882GLboolean
883_mesa_is_depthstencil_format(GLenum format)
884{
885   switch (format) {
886      case GL_DEPTH24_STENCIL8_EXT:
887      case GL_DEPTH_STENCIL_EXT:
888      case GL_DEPTH32F_STENCIL8:
889         return GL_TRUE;
890      default:
891         return GL_FALSE;
892   }
893}
894
895
896/**
897 * Test if the given image format is a depth or stencil format.
898 */
899GLboolean
900_mesa_is_depth_or_stencil_format(GLenum format)
901{
902   switch (format) {
903      case GL_DEPTH_COMPONENT:
904      case GL_DEPTH_COMPONENT16:
905      case GL_DEPTH_COMPONENT24:
906      case GL_DEPTH_COMPONENT32:
907      case GL_STENCIL_INDEX:
908      case GL_STENCIL_INDEX1_EXT:
909      case GL_STENCIL_INDEX4_EXT:
910      case GL_STENCIL_INDEX8_EXT:
911      case GL_STENCIL_INDEX16_EXT:
912      case GL_DEPTH_STENCIL_EXT:
913      case GL_DEPTH24_STENCIL8_EXT:
914      case GL_DEPTH_COMPONENT32F:
915      case GL_DEPTH32F_STENCIL8:
916         return GL_TRUE;
917      default:
918         return GL_FALSE;
919   }
920}
921
922
923/**
924 * Test if the given image format is a dudv format.
925 */
926GLboolean
927_mesa_is_dudv_format(GLenum format)
928{
929   switch (format) {
930      case GL_DUDV_ATI:
931      case GL_DU8DV8_ATI:
932         return GL_TRUE;
933      default:
934         return GL_FALSE;
935   }
936}
937
938
939/**
940 * Test if the given format is an integer (non-normalized) format.
941 */
942GLboolean
943_mesa_is_integer_format(GLenum format)
944{
945   switch (format) {
946   /* generic integer formats */
947   case GL_RED_INTEGER_EXT:
948   case GL_GREEN_INTEGER_EXT:
949   case GL_BLUE_INTEGER_EXT:
950   case GL_ALPHA_INTEGER_EXT:
951   case GL_RGB_INTEGER_EXT:
952   case GL_RGBA_INTEGER_EXT:
953   case GL_BGR_INTEGER_EXT:
954   case GL_BGRA_INTEGER_EXT:
955   case GL_LUMINANCE_INTEGER_EXT:
956   case GL_LUMINANCE_ALPHA_INTEGER_EXT:
957   /* specific integer formats */
958   case GL_RGBA32UI_EXT:
959   case GL_RGB32UI_EXT:
960   case GL_RG32UI:
961   case GL_R32UI:
962   case GL_ALPHA32UI_EXT:
963   case GL_INTENSITY32UI_EXT:
964   case GL_LUMINANCE32UI_EXT:
965   case GL_LUMINANCE_ALPHA32UI_EXT:
966   case GL_RGBA16UI_EXT:
967   case GL_RGB16UI_EXT:
968   case GL_RG16UI:
969   case GL_R16UI:
970   case GL_ALPHA16UI_EXT:
971   case GL_INTENSITY16UI_EXT:
972   case GL_LUMINANCE16UI_EXT:
973   case GL_LUMINANCE_ALPHA16UI_EXT:
974   case GL_RGBA8UI_EXT:
975   case GL_RGB8UI_EXT:
976   case GL_RG8UI:
977   case GL_R8UI:
978   case GL_ALPHA8UI_EXT:
979   case GL_INTENSITY8UI_EXT:
980   case GL_LUMINANCE8UI_EXT:
981   case GL_LUMINANCE_ALPHA8UI_EXT:
982   case GL_RGBA32I_EXT:
983   case GL_RGB32I_EXT:
984   case GL_RG32I:
985   case GL_R32I:
986   case GL_ALPHA32I_EXT:
987   case GL_INTENSITY32I_EXT:
988   case GL_LUMINANCE32I_EXT:
989   case GL_LUMINANCE_ALPHA32I_EXT:
990   case GL_RGBA16I_EXT:
991   case GL_RGB16I_EXT:
992   case GL_RG16I:
993   case GL_R16I:
994   case GL_ALPHA16I_EXT:
995   case GL_INTENSITY16I_EXT:
996   case GL_LUMINANCE16I_EXT:
997   case GL_LUMINANCE_ALPHA16I_EXT:
998   case GL_RGBA8I_EXT:
999   case GL_RGB8I_EXT:
1000   case GL_RG8I:
1001   case GL_R8I:
1002   case GL_ALPHA8I_EXT:
1003   case GL_INTENSITY8I_EXT:
1004   case GL_LUMINANCE8I_EXT:
1005   case GL_LUMINANCE_ALPHA8I_EXT:
1006   case GL_RGB10_A2UI:
1007      return GL_TRUE;
1008   default:
1009      return GL_FALSE;
1010   }
1011}
1012
1013
1014/**
1015 * Test if an image format is a supported compressed format.
1016 * \param format the internal format token provided by the user.
1017 * \return GL_TRUE if compressed, GL_FALSE if uncompressed
1018 */
1019GLboolean
1020_mesa_is_compressed_format(struct gl_context *ctx, GLenum format)
1021{
1022   switch (format) {
1023   case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
1024   case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
1025   case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
1026   case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
1027      return ctx->Extensions.EXT_texture_compression_s3tc;
1028   case GL_RGB_S3TC:
1029   case GL_RGB4_S3TC:
1030   case GL_RGBA_S3TC:
1031   case GL_RGBA4_S3TC:
1032      return ctx->Extensions.S3_s3tc;
1033   case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
1034   case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
1035   case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
1036   case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
1037      return ctx->Extensions.EXT_texture_sRGB
1038         && ctx->Extensions.EXT_texture_compression_s3tc;
1039   case GL_COMPRESSED_RGB_FXT1_3DFX:
1040   case GL_COMPRESSED_RGBA_FXT1_3DFX:
1041      return ctx->Extensions.TDFX_texture_compression_FXT1;
1042   case GL_COMPRESSED_RED_RGTC1:
1043   case GL_COMPRESSED_SIGNED_RED_RGTC1:
1044   case GL_COMPRESSED_RG_RGTC2:
1045   case GL_COMPRESSED_SIGNED_RG_RGTC2:
1046      return ctx->Extensions.ARB_texture_compression_rgtc;
1047   case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
1048   case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
1049   case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
1050   case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
1051      return ctx->Extensions.EXT_texture_compression_latc;
1052   case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
1053      return ctx->Extensions.ATI_texture_compression_3dc;
1054   case GL_ETC1_RGB8_OES:
1055      return ctx->Extensions.OES_compressed_ETC1_RGB8_texture;
1056#if FEATURE_ES
1057   case GL_PALETTE4_RGB8_OES:
1058   case GL_PALETTE4_RGBA8_OES:
1059   case GL_PALETTE4_R5_G6_B5_OES:
1060   case GL_PALETTE4_RGBA4_OES:
1061   case GL_PALETTE4_RGB5_A1_OES:
1062   case GL_PALETTE8_RGB8_OES:
1063   case GL_PALETTE8_RGBA8_OES:
1064   case GL_PALETTE8_R5_G6_B5_OES:
1065   case GL_PALETTE8_RGBA4_OES:
1066   case GL_PALETTE8_RGB5_A1_OES:
1067      return ctx->API == API_OPENGLES;
1068#endif
1069   default:
1070      return GL_FALSE;
1071   }
1072}
1073
1074
1075/**
1076 * Does the given base texture/renderbuffer format have the channel
1077 * named by 'pname'?
1078 */
1079GLboolean
1080_mesa_base_format_has_channel(GLenum base_format, GLenum pname)
1081{
1082   switch (pname) {
1083   case GL_TEXTURE_RED_SIZE:
1084   case GL_TEXTURE_RED_TYPE:
1085   case GL_RENDERBUFFER_RED_SIZE_EXT:
1086   case GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE:
1087      if (base_format == GL_RED ||
1088	  base_format == GL_RG ||
1089	  base_format == GL_RGB ||
1090	  base_format == GL_RGBA) {
1091	 return GL_TRUE;
1092      }
1093      return GL_FALSE;
1094   case GL_TEXTURE_GREEN_SIZE:
1095   case GL_TEXTURE_GREEN_TYPE:
1096   case GL_RENDERBUFFER_GREEN_SIZE_EXT:
1097   case GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE:
1098      if (base_format == GL_RG ||
1099	  base_format == GL_RGB ||
1100	  base_format == GL_RGBA) {
1101	 return GL_TRUE;
1102      }
1103      return GL_FALSE;
1104   case GL_TEXTURE_BLUE_SIZE:
1105   case GL_TEXTURE_BLUE_TYPE:
1106   case GL_RENDERBUFFER_BLUE_SIZE_EXT:
1107   case GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE:
1108      if (base_format == GL_RGB ||
1109	  base_format == GL_RGBA) {
1110	 return GL_TRUE;
1111      }
1112      return GL_FALSE;
1113   case GL_TEXTURE_ALPHA_SIZE:
1114   case GL_TEXTURE_ALPHA_TYPE:
1115   case GL_RENDERBUFFER_ALPHA_SIZE_EXT:
1116   case GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE:
1117      if (base_format == GL_RGBA ||
1118	  base_format == GL_ALPHA ||
1119	  base_format == GL_LUMINANCE_ALPHA) {
1120	 return GL_TRUE;
1121      }
1122      return GL_FALSE;
1123   case GL_TEXTURE_LUMINANCE_SIZE:
1124   case GL_TEXTURE_LUMINANCE_TYPE:
1125      if (base_format == GL_LUMINANCE ||
1126	  base_format == GL_LUMINANCE_ALPHA) {
1127	 return GL_TRUE;
1128      }
1129      return GL_FALSE;
1130   case GL_TEXTURE_INTENSITY_SIZE:
1131   case GL_TEXTURE_INTENSITY_TYPE:
1132      if (base_format == GL_INTENSITY) {
1133	 return GL_TRUE;
1134      }
1135      return GL_FALSE;
1136   case GL_TEXTURE_DEPTH_SIZE:
1137   case GL_TEXTURE_DEPTH_TYPE:
1138   case GL_RENDERBUFFER_DEPTH_SIZE_EXT:
1139   case GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE:
1140      if (base_format == GL_DEPTH_STENCIL ||
1141	  base_format == GL_DEPTH_COMPONENT) {
1142	 return GL_TRUE;
1143      }
1144      return GL_FALSE;
1145   case GL_RENDERBUFFER_STENCIL_SIZE_EXT:
1146   case GL_FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE:
1147      if (base_format == GL_DEPTH_STENCIL ||
1148	  base_format == GL_STENCIL_INDEX) {
1149	 return GL_TRUE;
1150      }
1151      return GL_FALSE;
1152   default:
1153      _mesa_warning(NULL, "%s: Unexpected channel token 0x%x\n",
1154		    __FUNCTION__, pname);
1155      return GL_FALSE;
1156   }
1157
1158   return GL_FALSE;
1159}
1160
1161
1162/**
1163 * Return the address of a specific pixel in an image (1D, 2D or 3D).
1164 *
1165 * Pixel unpacking/packing parameters are observed according to \p packing.
1166 *
1167 * \param dimensions either 1, 2 or 3 to indicate dimensionality of image
1168 * \param image  starting address of image data
1169 * \param width  the image width
1170 * \param height  theimage height
1171 * \param format  the pixel format
1172 * \param type  the pixel data type
1173 * \param packing  the pixelstore attributes
1174 * \param img  which image in the volume (0 for 1D or 2D images)
1175 * \param row  row of pixel in the image (0 for 1D images)
1176 * \param column column of pixel in the image
1177 *
1178 * \return address of pixel on success, or NULL on error.
1179 *
1180 * \sa gl_pixelstore_attrib.
1181 */
1182GLvoid *
1183_mesa_image_address( GLuint dimensions,
1184                     const struct gl_pixelstore_attrib *packing,
1185                     const GLvoid *image,
1186                     GLsizei width, GLsizei height,
1187                     GLenum format, GLenum type,
1188                     GLint img, GLint row, GLint column )
1189{
1190   GLint alignment;        /* 1, 2 or 4 */
1191   GLint pixels_per_row;
1192   GLint rows_per_image;
1193   GLint skiprows;
1194   GLint skippixels;
1195   GLint skipimages;       /* for 3-D volume images */
1196   GLubyte *pixel_addr;
1197
1198   ASSERT(dimensions >= 1 && dimensions <= 3);
1199
1200   alignment = packing->Alignment;
1201   if (packing->RowLength > 0) {
1202      pixels_per_row = packing->RowLength;
1203   }
1204   else {
1205      pixels_per_row = width;
1206   }
1207   if (packing->ImageHeight > 0) {
1208      rows_per_image = packing->ImageHeight;
1209   }
1210   else {
1211      rows_per_image = height;
1212   }
1213
1214   skippixels = packing->SkipPixels;
1215   /* Note: SKIP_ROWS _is_ used for 1D images */
1216   skiprows = packing->SkipRows;
1217   /* Note: SKIP_IMAGES is only used for 3D images */
1218   skipimages = (dimensions == 3) ? packing->SkipImages : 0;
1219
1220   if (type == GL_BITMAP) {
1221      /* BITMAP data */
1222      GLint comp_per_pixel;   /* components per pixel */
1223      GLint bytes_per_comp;   /* bytes per component */
1224      GLint bytes_per_row;
1225      GLint bytes_per_image;
1226
1227      /* Compute bytes per component */
1228      bytes_per_comp = _mesa_sizeof_packed_type( type );
1229      if (bytes_per_comp < 0) {
1230         return NULL;
1231      }
1232
1233      /* Compute number of components per pixel */
1234      comp_per_pixel = _mesa_components_in_format( format );
1235      if (comp_per_pixel < 0) {
1236         return NULL;
1237      }
1238
1239      bytes_per_row = alignment
1240                    * CEILING( comp_per_pixel*pixels_per_row, 8*alignment );
1241
1242      bytes_per_image = bytes_per_row * rows_per_image;
1243
1244      pixel_addr = (GLubyte *) image
1245                 + (skipimages + img) * bytes_per_image
1246                 + (skiprows + row) * bytes_per_row
1247                 + (skippixels + column) / 8;
1248   }
1249   else {
1250      /* Non-BITMAP data */
1251      GLint bytes_per_pixel, bytes_per_row, remainder, bytes_per_image;
1252      GLint topOfImage;
1253
1254      bytes_per_pixel = _mesa_bytes_per_pixel( format, type );
1255
1256      /* The pixel type and format should have been error checked earlier */
1257      assert(bytes_per_pixel > 0);
1258
1259      bytes_per_row = pixels_per_row * bytes_per_pixel;
1260      remainder = bytes_per_row % alignment;
1261      if (remainder > 0)
1262         bytes_per_row += (alignment - remainder);
1263
1264      ASSERT(bytes_per_row % alignment == 0);
1265
1266      bytes_per_image = bytes_per_row * rows_per_image;
1267
1268      if (packing->Invert) {
1269         /* set pixel_addr to the last row */
1270         topOfImage = bytes_per_row * (height - 1);
1271         bytes_per_row = -bytes_per_row;
1272      }
1273      else {
1274         topOfImage = 0;
1275      }
1276
1277      /* compute final pixel address */
1278      pixel_addr = (GLubyte *) image
1279                 + (skipimages + img) * bytes_per_image
1280                 + topOfImage
1281                 + (skiprows + row) * bytes_per_row
1282                 + (skippixels + column) * bytes_per_pixel;
1283   }
1284
1285   return (GLvoid *) pixel_addr;
1286}
1287
1288
1289GLvoid *
1290_mesa_image_address1d( const struct gl_pixelstore_attrib *packing,
1291                       const GLvoid *image,
1292                       GLsizei width,
1293                       GLenum format, GLenum type,
1294                       GLint column )
1295{
1296   return _mesa_image_address(1, packing, image, width, 1,
1297                              format, type, 0, 0, column);
1298}
1299
1300
1301GLvoid *
1302_mesa_image_address2d( const struct gl_pixelstore_attrib *packing,
1303                       const GLvoid *image,
1304                       GLsizei width, GLsizei height,
1305                       GLenum format, GLenum type,
1306                       GLint row, GLint column )
1307{
1308   return _mesa_image_address(2, packing, image, width, height,
1309                              format, type, 0, row, column);
1310}
1311
1312
1313GLvoid *
1314_mesa_image_address3d( const struct gl_pixelstore_attrib *packing,
1315                       const GLvoid *image,
1316                       GLsizei width, GLsizei height,
1317                       GLenum format, GLenum type,
1318                       GLint img, GLint row, GLint column )
1319{
1320   return _mesa_image_address(3, packing, image, width, height,
1321                              format, type, img, row, column);
1322}
1323
1324
1325
1326/**
1327 * Compute the stride (in bytes) between image rows.
1328 *
1329 * \param packing the pixelstore attributes
1330 * \param width image width.
1331 * \param format pixel format.
1332 * \param type pixel data type.
1333 *
1334 * \return the stride in bytes for the given parameters, or -1 if error
1335 */
1336GLint
1337_mesa_image_row_stride( const struct gl_pixelstore_attrib *packing,
1338                        GLint width, GLenum format, GLenum type )
1339{
1340   GLint bytesPerRow, remainder;
1341
1342   ASSERT(packing);
1343
1344   if (type == GL_BITMAP) {
1345      if (packing->RowLength == 0) {
1346         bytesPerRow = (width + 7) / 8;
1347      }
1348      else {
1349         bytesPerRow = (packing->RowLength + 7) / 8;
1350      }
1351   }
1352   else {
1353      /* Non-BITMAP data */
1354      const GLint bytesPerPixel = _mesa_bytes_per_pixel(format, type);
1355      if (bytesPerPixel <= 0)
1356         return -1;  /* error */
1357      if (packing->RowLength == 0) {
1358         bytesPerRow = bytesPerPixel * width;
1359      }
1360      else {
1361         bytesPerRow = bytesPerPixel * packing->RowLength;
1362      }
1363   }
1364
1365   remainder = bytesPerRow % packing->Alignment;
1366   if (remainder > 0) {
1367      bytesPerRow += (packing->Alignment - remainder);
1368   }
1369
1370   if (packing->Invert) {
1371      /* negate the bytes per row (negative row stride) */
1372      bytesPerRow = -bytesPerRow;
1373   }
1374
1375   return bytesPerRow;
1376}
1377
1378
1379/*
1380 * Compute the stride between images in a 3D texture (in bytes) for the given
1381 * pixel packing parameters and image width, format and type.
1382 */
1383GLint
1384_mesa_image_image_stride( const struct gl_pixelstore_attrib *packing,
1385                          GLint width, GLint height,
1386                          GLenum format, GLenum type )
1387{
1388   GLint bytesPerRow, bytesPerImage, remainder;
1389
1390   ASSERT(packing);
1391
1392   if (type == GL_BITMAP) {
1393      if (packing->RowLength == 0) {
1394         bytesPerRow = (width + 7) / 8;
1395      }
1396      else {
1397         bytesPerRow = (packing->RowLength + 7) / 8;
1398      }
1399   }
1400   else {
1401      const GLint bytesPerPixel = _mesa_bytes_per_pixel(format, type);
1402
1403      if (bytesPerPixel <= 0)
1404         return -1;  /* error */
1405      if (packing->RowLength == 0) {
1406         bytesPerRow = bytesPerPixel * width;
1407      }
1408      else {
1409         bytesPerRow = bytesPerPixel * packing->RowLength;
1410      }
1411   }
1412
1413   remainder = bytesPerRow % packing->Alignment;
1414   if (remainder > 0)
1415      bytesPerRow += (packing->Alignment - remainder);
1416
1417   if (packing->ImageHeight == 0)
1418      bytesPerImage = bytesPerRow * height;
1419   else
1420      bytesPerImage = bytesPerRow * packing->ImageHeight;
1421
1422   return bytesPerImage;
1423}
1424
1425
1426
1427/**
1428 * "Expand" a bitmap from 1-bit per pixel to 8-bits per pixel.
1429 * This is typically used to convert a bitmap into a GLubyte/pixel texture.
1430 * "On" bits will set texels to \p onValue.
1431 * "Off" bits will not modify texels.
1432 * \param width  src bitmap width in pixels
1433 * \param height  src bitmap height in pixels
1434 * \param unpack  bitmap unpacking state
1435 * \param bitmap  the src bitmap data
1436 * \param destBuffer  start of dest buffer
1437 * \param destStride  row stride in dest buffer
1438 * \param onValue  if bit is 1, set destBuffer pixel to this value
1439 */
1440void
1441_mesa_expand_bitmap(GLsizei width, GLsizei height,
1442                    const struct gl_pixelstore_attrib *unpack,
1443                    const GLubyte *bitmap,
1444                    GLubyte *destBuffer, GLint destStride,
1445                    GLubyte onValue)
1446{
1447   const GLubyte *srcRow = (const GLubyte *)
1448      _mesa_image_address2d(unpack, bitmap, width, height,
1449                            GL_COLOR_INDEX, GL_BITMAP, 0, 0);
1450   const GLint srcStride = _mesa_image_row_stride(unpack, width,
1451                                                  GL_COLOR_INDEX, GL_BITMAP);
1452   GLint row, col;
1453
1454#define SET_PIXEL(COL, ROW) \
1455   destBuffer[(ROW) * destStride + (COL)] = onValue;
1456
1457   for (row = 0; row < height; row++) {
1458      const GLubyte *src = srcRow;
1459
1460      if (unpack->LsbFirst) {
1461         /* Lsb first */
1462         GLubyte mask = 1U << (unpack->SkipPixels & 0x7);
1463         for (col = 0; col < width; col++) {
1464
1465            if (*src & mask) {
1466               SET_PIXEL(col, row);
1467            }
1468
1469            if (mask == 128U) {
1470               src++;
1471               mask = 1U;
1472            }
1473            else {
1474               mask = mask << 1;
1475            }
1476         }
1477
1478         /* get ready for next row */
1479         if (mask != 1)
1480            src++;
1481      }
1482      else {
1483         /* Msb first */
1484         GLubyte mask = 128U >> (unpack->SkipPixels & 0x7);
1485         for (col = 0; col < width; col++) {
1486
1487            if (*src & mask) {
1488               SET_PIXEL(col, row);
1489            }
1490
1491            if (mask == 1U) {
1492               src++;
1493               mask = 128U;
1494            }
1495            else {
1496               mask = mask >> 1;
1497            }
1498         }
1499
1500         /* get ready for next row */
1501         if (mask != 128)
1502            src++;
1503      }
1504
1505      srcRow += srcStride;
1506   } /* row */
1507
1508#undef SET_PIXEL
1509}
1510
1511
1512
1513
1514/**
1515 * Convert an array of RGBA colors from one datatype to another.
1516 * NOTE: src may equal dst.  In that case, we use a temporary buffer.
1517 */
1518void
1519_mesa_convert_colors(GLenum srcType, const GLvoid *src,
1520                     GLenum dstType, GLvoid *dst,
1521                     GLuint count, const GLubyte mask[])
1522{
1523   GLuint *tempBuffer;
1524   const GLboolean useTemp = (src == dst);
1525
1526   tempBuffer = malloc(count * MAX_PIXEL_BYTES);
1527   if (!tempBuffer)
1528      return;
1529
1530   ASSERT(srcType != dstType);
1531
1532   switch (srcType) {
1533   case GL_UNSIGNED_BYTE:
1534      if (dstType == GL_UNSIGNED_SHORT) {
1535         const GLubyte (*src1)[4] = (const GLubyte (*)[4]) src;
1536         GLushort (*dst2)[4] = (GLushort (*)[4]) (useTemp ? tempBuffer : dst);
1537         GLuint i;
1538         for (i = 0; i < count; i++) {
1539            if (!mask || mask[i]) {
1540               dst2[i][RCOMP] = UBYTE_TO_USHORT(src1[i][RCOMP]);
1541               dst2[i][GCOMP] = UBYTE_TO_USHORT(src1[i][GCOMP]);
1542               dst2[i][BCOMP] = UBYTE_TO_USHORT(src1[i][BCOMP]);
1543               dst2[i][ACOMP] = UBYTE_TO_USHORT(src1[i][ACOMP]);
1544            }
1545         }
1546         if (useTemp)
1547            memcpy(dst, tempBuffer, count * 4 * sizeof(GLushort));
1548      }
1549      else {
1550         const GLubyte (*src1)[4] = (const GLubyte (*)[4]) src;
1551         GLfloat (*dst4)[4] = (GLfloat (*)[4]) (useTemp ? tempBuffer : dst);
1552         GLuint i;
1553         ASSERT(dstType == GL_FLOAT);
1554         for (i = 0; i < count; i++) {
1555            if (!mask || mask[i]) {
1556               dst4[i][RCOMP] = UBYTE_TO_FLOAT(src1[i][RCOMP]);
1557               dst4[i][GCOMP] = UBYTE_TO_FLOAT(src1[i][GCOMP]);
1558               dst4[i][BCOMP] = UBYTE_TO_FLOAT(src1[i][BCOMP]);
1559               dst4[i][ACOMP] = UBYTE_TO_FLOAT(src1[i][ACOMP]);
1560            }
1561         }
1562         if (useTemp)
1563            memcpy(dst, tempBuffer, count * 4 * sizeof(GLfloat));
1564      }
1565      break;
1566   case GL_UNSIGNED_SHORT:
1567      if (dstType == GL_UNSIGNED_BYTE) {
1568         const GLushort (*src2)[4] = (const GLushort (*)[4]) src;
1569         GLubyte (*dst1)[4] = (GLubyte (*)[4]) (useTemp ? tempBuffer : dst);
1570         GLuint i;
1571         for (i = 0; i < count; i++) {
1572            if (!mask || mask[i]) {
1573               dst1[i][RCOMP] = USHORT_TO_UBYTE(src2[i][RCOMP]);
1574               dst1[i][GCOMP] = USHORT_TO_UBYTE(src2[i][GCOMP]);
1575               dst1[i][BCOMP] = USHORT_TO_UBYTE(src2[i][BCOMP]);
1576               dst1[i][ACOMP] = USHORT_TO_UBYTE(src2[i][ACOMP]);
1577            }
1578         }
1579         if (useTemp)
1580            memcpy(dst, tempBuffer, count * 4 * sizeof(GLubyte));
1581      }
1582      else {
1583         const GLushort (*src2)[4] = (const GLushort (*)[4]) src;
1584         GLfloat (*dst4)[4] = (GLfloat (*)[4]) (useTemp ? tempBuffer : dst);
1585         GLuint i;
1586         ASSERT(dstType == GL_FLOAT);
1587         for (i = 0; i < count; i++) {
1588            if (!mask || mask[i]) {
1589               dst4[i][RCOMP] = USHORT_TO_FLOAT(src2[i][RCOMP]);
1590               dst4[i][GCOMP] = USHORT_TO_FLOAT(src2[i][GCOMP]);
1591               dst4[i][BCOMP] = USHORT_TO_FLOAT(src2[i][BCOMP]);
1592               dst4[i][ACOMP] = USHORT_TO_FLOAT(src2[i][ACOMP]);
1593            }
1594         }
1595         if (useTemp)
1596            memcpy(dst, tempBuffer, count * 4 * sizeof(GLfloat));
1597      }
1598      break;
1599   case GL_FLOAT:
1600      if (dstType == GL_UNSIGNED_BYTE) {
1601         const GLfloat (*src4)[4] = (const GLfloat (*)[4]) src;
1602         GLubyte (*dst1)[4] = (GLubyte (*)[4]) (useTemp ? tempBuffer : dst);
1603         GLuint i;
1604         for (i = 0; i < count; i++) {
1605            if (!mask || mask[i])
1606               _mesa_unclamped_float_rgba_to_ubyte(dst1[i], src4[i]);
1607         }
1608         if (useTemp)
1609            memcpy(dst, tempBuffer, count * 4 * sizeof(GLubyte));
1610      }
1611      else {
1612         const GLfloat (*src4)[4] = (const GLfloat (*)[4]) src;
1613         GLushort (*dst2)[4] = (GLushort (*)[4]) (useTemp ? tempBuffer : dst);
1614         GLuint i;
1615         ASSERT(dstType == GL_UNSIGNED_SHORT);
1616         for (i = 0; i < count; i++) {
1617            if (!mask || mask[i]) {
1618               UNCLAMPED_FLOAT_TO_USHORT(dst2[i][RCOMP], src4[i][RCOMP]);
1619               UNCLAMPED_FLOAT_TO_USHORT(dst2[i][GCOMP], src4[i][GCOMP]);
1620               UNCLAMPED_FLOAT_TO_USHORT(dst2[i][BCOMP], src4[i][BCOMP]);
1621               UNCLAMPED_FLOAT_TO_USHORT(dst2[i][ACOMP], src4[i][ACOMP]);
1622            }
1623         }
1624         if (useTemp)
1625            memcpy(dst, tempBuffer, count * 4 * sizeof(GLushort));
1626      }
1627      break;
1628   default:
1629      _mesa_problem(NULL, "Invalid datatype in _mesa_convert_colors");
1630   }
1631
1632   free(tempBuffer);
1633}
1634
1635
1636
1637
1638/**
1639 * Perform basic clipping for glDrawPixels.  The image's position and size
1640 * and the unpack SkipPixels and SkipRows are adjusted so that the image
1641 * region is entirely within the window and scissor bounds.
1642 * NOTE: this will only work when glPixelZoom is (1, 1) or (1, -1).
1643 * If Pixel.ZoomY is -1, *destY will be changed to be the first row which
1644 * we'll actually write.  Beforehand, *destY-1 is the first drawing row.
1645 *
1646 * \return  GL_TRUE if image is ready for drawing or
1647 *          GL_FALSE if image was completely clipped away (draw nothing)
1648 */
1649GLboolean
1650_mesa_clip_drawpixels(const struct gl_context *ctx,
1651                      GLint *destX, GLint *destY,
1652                      GLsizei *width, GLsizei *height,
1653                      struct gl_pixelstore_attrib *unpack)
1654{
1655   const struct gl_framebuffer *buffer = ctx->DrawBuffer;
1656
1657   if (unpack->RowLength == 0) {
1658      unpack->RowLength = *width;
1659   }
1660
1661   ASSERT(ctx->Pixel.ZoomX == 1.0F);
1662   ASSERT(ctx->Pixel.ZoomY == 1.0F || ctx->Pixel.ZoomY == -1.0F);
1663
1664   /* left clipping */
1665   if (*destX < buffer->_Xmin) {
1666      unpack->SkipPixels += (buffer->_Xmin - *destX);
1667      *width -= (buffer->_Xmin - *destX);
1668      *destX = buffer->_Xmin;
1669   }
1670   /* right clipping */
1671   if (*destX + *width > buffer->_Xmax)
1672      *width -= (*destX + *width - buffer->_Xmax);
1673
1674   if (*width <= 0)
1675      return GL_FALSE;
1676
1677   if (ctx->Pixel.ZoomY == 1.0F) {
1678      /* bottom clipping */
1679      if (*destY < buffer->_Ymin) {
1680         unpack->SkipRows += (buffer->_Ymin - *destY);
1681         *height -= (buffer->_Ymin - *destY);
1682         *destY = buffer->_Ymin;
1683      }
1684      /* top clipping */
1685      if (*destY + *height > buffer->_Ymax)
1686         *height -= (*destY + *height - buffer->_Ymax);
1687   }
1688   else { /* upside down */
1689      /* top clipping */
1690      if (*destY > buffer->_Ymax) {
1691         unpack->SkipRows += (*destY - buffer->_Ymax);
1692         *height -= (*destY - buffer->_Ymax);
1693         *destY = buffer->_Ymax;
1694      }
1695      /* bottom clipping */
1696      if (*destY - *height < buffer->_Ymin)
1697         *height -= (buffer->_Ymin - (*destY - *height));
1698      /* adjust destY so it's the first row to write to */
1699      (*destY)--;
1700   }
1701
1702   if (*height <= 0)
1703      return GL_FALSE;
1704
1705   return GL_TRUE;
1706}
1707
1708
1709/**
1710 * Perform clipping for glReadPixels.  The image's window position
1711 * and size, and the pack skipPixels, skipRows and rowLength are adjusted
1712 * so that the image region is entirely within the window bounds.
1713 * Note: this is different from _mesa_clip_drawpixels() in that the
1714 * scissor box is ignored, and we use the bounds of the current readbuffer
1715 * surface.
1716 *
1717 * \return  GL_TRUE if region to read is in bounds
1718 *          GL_FALSE if region is completely out of bounds (nothing to read)
1719 */
1720GLboolean
1721_mesa_clip_readpixels(const struct gl_context *ctx,
1722                      GLint *srcX, GLint *srcY,
1723                      GLsizei *width, GLsizei *height,
1724                      struct gl_pixelstore_attrib *pack)
1725{
1726   const struct gl_framebuffer *buffer = ctx->ReadBuffer;
1727
1728   if (pack->RowLength == 0) {
1729      pack->RowLength = *width;
1730   }
1731
1732   /* left clipping */
1733   if (*srcX < 0) {
1734      pack->SkipPixels += (0 - *srcX);
1735      *width -= (0 - *srcX);
1736      *srcX = 0;
1737   }
1738   /* right clipping */
1739   if (*srcX + *width > (GLsizei) buffer->Width)
1740      *width -= (*srcX + *width - buffer->Width);
1741
1742   if (*width <= 0)
1743      return GL_FALSE;
1744
1745   /* bottom clipping */
1746   if (*srcY < 0) {
1747      pack->SkipRows += (0 - *srcY);
1748      *height -= (0 - *srcY);
1749      *srcY = 0;
1750   }
1751   /* top clipping */
1752   if (*srcY + *height > (GLsizei) buffer->Height)
1753      *height -= (*srcY + *height - buffer->Height);
1754
1755   if (*height <= 0)
1756      return GL_FALSE;
1757
1758   return GL_TRUE;
1759}
1760
1761
1762/**
1763 * Do clipping for a glCopyTexSubImage call.
1764 * The framebuffer source region might extend outside the framebuffer
1765 * bounds.  Clip the source region against the framebuffer bounds and
1766 * adjust the texture/dest position and size accordingly.
1767 *
1768 * \return GL_FALSE if region is totally clipped, GL_TRUE otherwise.
1769 */
1770GLboolean
1771_mesa_clip_copytexsubimage(const struct gl_context *ctx,
1772                           GLint *destX, GLint *destY,
1773                           GLint *srcX, GLint *srcY,
1774                           GLsizei *width, GLsizei *height)
1775{
1776   const struct gl_framebuffer *fb = ctx->ReadBuffer;
1777   const GLint srcX0 = *srcX, srcY0 = *srcY;
1778
1779   if (_mesa_clip_to_region(0, 0, fb->Width, fb->Height,
1780                            srcX, srcY, width, height)) {
1781      *destX = *destX + *srcX - srcX0;
1782      *destY = *destY + *srcY - srcY0;
1783
1784      return GL_TRUE;
1785   }
1786   else {
1787      return GL_FALSE;
1788   }
1789}
1790
1791
1792
1793/**
1794 * Clip the rectangle defined by (x, y, width, height) against the bounds
1795 * specified by [xmin, xmax) and [ymin, ymax).
1796 * \return GL_FALSE if rect is totally clipped, GL_TRUE otherwise.
1797 */
1798GLboolean
1799_mesa_clip_to_region(GLint xmin, GLint ymin,
1800                     GLint xmax, GLint ymax,
1801                     GLint *x, GLint *y,
1802                     GLsizei *width, GLsizei *height )
1803{
1804   /* left clipping */
1805   if (*x < xmin) {
1806      *width -= (xmin - *x);
1807      *x = xmin;
1808   }
1809
1810   /* right clipping */
1811   if (*x + *width > xmax)
1812      *width -= (*x + *width - xmax);
1813
1814   if (*width <= 0)
1815      return GL_FALSE;
1816
1817   /* bottom (or top) clipping */
1818   if (*y < ymin) {
1819      *height -= (ymin - *y);
1820      *y = ymin;
1821   }
1822
1823   /* top (or bottom) clipping */
1824   if (*y + *height > ymax)
1825      *height -= (*y + *height - ymax);
1826
1827   if (*height <= 0)
1828      return GL_FALSE;
1829
1830   return GL_TRUE;
1831}
1832
1833
1834/**
1835 * Clip dst coords against Xmax (or Ymax).
1836 */
1837static inline void
1838clip_right_or_top(GLint *srcX0, GLint *srcX1,
1839                  GLint *dstX0, GLint *dstX1,
1840                  GLint maxValue)
1841{
1842   GLfloat t, bias;
1843
1844   if (*dstX1 > maxValue) {
1845      /* X1 outside right edge */
1846      ASSERT(*dstX0 < maxValue); /* X0 should be inside right edge */
1847      t = (GLfloat) (maxValue - *dstX0) / (GLfloat) (*dstX1 - *dstX0);
1848      /* chop off [t, 1] part */
1849      ASSERT(t >= 0.0 && t <= 1.0);
1850      *dstX1 = maxValue;
1851      bias = (*srcX0 < *srcX1) ? 0.5F : -0.5F;
1852      *srcX1 = *srcX0 + (GLint) (t * (*srcX1 - *srcX0) + bias);
1853   }
1854   else if (*dstX0 > maxValue) {
1855      /* X0 outside right edge */
1856      ASSERT(*dstX1 < maxValue); /* X1 should be inside right edge */
1857      t = (GLfloat) (maxValue - *dstX1) / (GLfloat) (*dstX0 - *dstX1);
1858      /* chop off [t, 1] part */
1859      ASSERT(t >= 0.0 && t <= 1.0);
1860      *dstX0 = maxValue;
1861      bias = (*srcX0 < *srcX1) ? -0.5F : 0.5F;
1862      *srcX0 = *srcX1 + (GLint) (t * (*srcX0 - *srcX1) + bias);
1863   }
1864}
1865
1866
1867/**
1868 * Clip dst coords against Xmin (or Ymin).
1869 */
1870static inline void
1871clip_left_or_bottom(GLint *srcX0, GLint *srcX1,
1872                    GLint *dstX0, GLint *dstX1,
1873                    GLint minValue)
1874{
1875   GLfloat t, bias;
1876
1877   if (*dstX0 < minValue) {
1878      /* X0 outside left edge */
1879      ASSERT(*dstX1 > minValue); /* X1 should be inside left edge */
1880      t = (GLfloat) (minValue - *dstX0) / (GLfloat) (*dstX1 - *dstX0);
1881      /* chop off [0, t] part */
1882      ASSERT(t >= 0.0 && t <= 1.0);
1883      *dstX0 = minValue;
1884      bias = (*srcX0 < *srcX1) ? 0.5F : -0.5F; /* flipped??? */
1885      *srcX0 = *srcX0 + (GLint) (t * (*srcX1 - *srcX0) + bias);
1886   }
1887   else if (*dstX1 < minValue) {
1888      /* X1 outside left edge */
1889      ASSERT(*dstX0 > minValue); /* X0 should be inside left edge */
1890      t = (GLfloat) (minValue - *dstX1) / (GLfloat) (*dstX0 - *dstX1);
1891      /* chop off [0, t] part */
1892      ASSERT(t >= 0.0 && t <= 1.0);
1893      *dstX1 = minValue;
1894      bias = (*srcX0 < *srcX1) ? 0.5F : -0.5F;
1895      *srcX1 = *srcX1 + (GLint) (t * (*srcX0 - *srcX1) + bias);
1896   }
1897}
1898
1899
1900/**
1901 * Do clipping of blit src/dest rectangles.
1902 * The dest rect is clipped against both the buffer bounds and scissor bounds.
1903 * The src rect is just clipped against the buffer bounds.
1904 *
1905 * When either the src or dest rect is clipped, the other is also clipped
1906 * proportionately!
1907 *
1908 * Note that X0 need not be less than X1 (same for Y) for either the source
1909 * and dest rects.  That makes the clipping a little trickier.
1910 *
1911 * \return GL_TRUE if anything is left to draw, GL_FALSE if totally clipped
1912 */
1913GLboolean
1914_mesa_clip_blit(struct gl_context *ctx,
1915                GLint *srcX0, GLint *srcY0, GLint *srcX1, GLint *srcY1,
1916                GLint *dstX0, GLint *dstY0, GLint *dstX1, GLint *dstY1)
1917{
1918   const GLint srcXmin = 0;
1919   const GLint srcXmax = ctx->ReadBuffer->Width;
1920   const GLint srcYmin = 0;
1921   const GLint srcYmax = ctx->ReadBuffer->Height;
1922
1923   /* these include scissor bounds */
1924   const GLint dstXmin = ctx->DrawBuffer->_Xmin;
1925   const GLint dstXmax = ctx->DrawBuffer->_Xmax;
1926   const GLint dstYmin = ctx->DrawBuffer->_Ymin;
1927   const GLint dstYmax = ctx->DrawBuffer->_Ymax;
1928
1929   /*
1930   printf("PreClipX:  src: %d .. %d  dst: %d .. %d\n",
1931          *srcX0, *srcX1, *dstX0, *dstX1);
1932   printf("PreClipY:  src: %d .. %d  dst: %d .. %d\n",
1933          *srcY0, *srcY1, *dstY0, *dstY1);
1934   */
1935
1936   /* trivial rejection tests */
1937   if (*dstX0 == *dstX1)
1938      return GL_FALSE; /* no width */
1939   if (*dstX0 <= dstXmin && *dstX1 <= dstXmin)
1940      return GL_FALSE; /* totally out (left) of bounds */
1941   if (*dstX0 >= dstXmax && *dstX1 >= dstXmax)
1942      return GL_FALSE; /* totally out (right) of bounds */
1943
1944   if (*dstY0 == *dstY1)
1945      return GL_FALSE;
1946   if (*dstY0 <= dstYmin && *dstY1 <= dstYmin)
1947      return GL_FALSE;
1948   if (*dstY0 >= dstYmax && *dstY1 >= dstYmax)
1949      return GL_FALSE;
1950
1951   if (*srcX0 == *srcX1)
1952      return GL_FALSE;
1953   if (*srcX0 <= srcXmin && *srcX1 <= srcXmin)
1954      return GL_FALSE;
1955   if (*srcX0 >= srcXmax && *srcX1 >= srcXmax)
1956      return GL_FALSE;
1957
1958   if (*srcY0 == *srcY1)
1959      return GL_FALSE;
1960   if (*srcY0 <= srcYmin && *srcY1 <= srcYmin)
1961      return GL_FALSE;
1962   if (*srcY0 >= srcYmax && *srcY1 >= srcYmax)
1963      return GL_FALSE;
1964
1965   /*
1966    * dest clip
1967    */
1968   clip_right_or_top(srcX0, srcX1, dstX0, dstX1, dstXmax);
1969   clip_right_or_top(srcY0, srcY1, dstY0, dstY1, dstYmax);
1970   clip_left_or_bottom(srcX0, srcX1, dstX0, dstX1, dstXmin);
1971   clip_left_or_bottom(srcY0, srcY1, dstY0, dstY1, dstYmin);
1972
1973   /*
1974    * src clip (just swap src/dst values from above)
1975    */
1976   clip_right_or_top(dstX0, dstX1, srcX0, srcX1, srcXmax);
1977   clip_right_or_top(dstY0, dstY1, srcY0, srcY1, srcYmax);
1978   clip_left_or_bottom(dstX0, dstX1, srcX0, srcX1, srcXmin);
1979   clip_left_or_bottom(dstY0, dstY1, srcY0, srcY1, srcYmin);
1980
1981   /*
1982   printf("PostClipX: src: %d .. %d  dst: %d .. %d\n",
1983          *srcX0, *srcX1, *dstX0, *dstX1);
1984   printf("PostClipY: src: %d .. %d  dst: %d .. %d\n",
1985          *srcY0, *srcY1, *dstY0, *dstY1);
1986   */
1987
1988   ASSERT(*dstX0 >= dstXmin);
1989   ASSERT(*dstX0 <= dstXmax);
1990   ASSERT(*dstX1 >= dstXmin);
1991   ASSERT(*dstX1 <= dstXmax);
1992
1993   ASSERT(*dstY0 >= dstYmin);
1994   ASSERT(*dstY0 <= dstYmax);
1995   ASSERT(*dstY1 >= dstYmin);
1996   ASSERT(*dstY1 <= dstYmax);
1997
1998   ASSERT(*srcX0 >= srcXmin);
1999   ASSERT(*srcX0 <= srcXmax);
2000   ASSERT(*srcX1 >= srcXmin);
2001   ASSERT(*srcX1 <= srcXmax);
2002
2003   ASSERT(*srcY0 >= srcYmin);
2004   ASSERT(*srcY0 <= srcYmax);
2005   ASSERT(*srcY1 >= srcYmin);
2006   ASSERT(*srcY1 <= srcYmax);
2007
2008   return GL_TRUE;
2009}
2010