s_zoom.c revision 77df88727cb0a423dd5cb41498c2302d9df4fce7 
1/* $Id: s_zoom.c,v 1.17 2002/08/07 00:45:07 brianp Exp $ */
2
3/*
4 * Mesa 3-D graphics library
5 * Version:  4.1
6 *
7 * Copyright (C) 1999-2002  Brian Paul   All Rights Reserved.
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included
17 * in all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
22 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
23 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 */
26
27#include "glheader.h"
28#include "macros.h"
29#include "mem.h"
30#include "colormac.h"
31
32#include "s_context.h"
33#include "s_span.h"
34#include "s_stencil.h"
35#include "s_zoom.h"
36
37
38/*
39 * Helper function called from _mesa_write_zoomed_rgba/rgb/index_span().
40 */
41static void
42zoom_span( GLcontext *ctx, const struct sw_span *span,
43           const GLvoid *src, GLint y0, GLenum format )
44{
45   GLint r0, r1, row;
46   GLint c0, c1, skipCol;
47   GLint i, j;
48   const GLuint maxWidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
49   GLchan rgbaSave[MAX_WIDTH][4];
50   GLuint indexSave[MAX_WIDTH];
51   const GLchan (*rgba)[4] = (const GLchan (*)[4]) src;
52   const GLchan (*rgb)[3] = (const GLchan (*)[3]) src;
53   const GLuint *indexes = (const GLuint *) src;
54   struct sw_span zoomed;
55   struct span_arrays zoomed_arrays;  /* this is big! */
56
57   /* no pixel arrays! */
58   ASSERT((span->arrayMask & SPAN_XY) == 0);
59   ASSERT(span->primitive == GL_BITMAP);
60
61   INIT_SPAN(zoomed, GL_BITMAP, 0, 0, 0);
62   zoomed.array = &zoomed_arrays;
63
64   if (format == GL_RGBA || format == GL_RGB) {
65      zoomed.z = span->z;
66      zoomed.zStep = span->z;
67      zoomed.fog = span->fog;
68      zoomed.fogStep = span->fogStep;
69      zoomed.interpMask = span->interpMask & ~SPAN_RGBA;
70      zoomed.arrayMask |= SPAN_RGBA;
71   }
72   else if (format == GL_COLOR_INDEX) {
73      zoomed.z = span->z;
74      zoomed.zStep = span->z;
75      zoomed.fog = span->fog;
76      zoomed.fogStep = span->fogStep;
77      zoomed.interpMask = span->interpMask & ~SPAN_INDEX;
78      zoomed.arrayMask |= SPAN_INDEX;
79   }
80
81   /*
82    * Compute which columns to draw: [c0, c1)
83    */
84   c0 = (GLint) span->x;
85   c1 = (GLint) (span->x + span->end * ctx->Pixel.ZoomX);
86   if (c0 == c1) {
87      return;
88   }
89   else if (c1 < c0) {
90      /* swap */
91      GLint ctmp = c1;
92      c1 = c0;
93      c0 = ctmp;
94   }
95   if (c0 < 0) {
96      zoomed.x = 0;
97      zoomed.start = 0;
98      zoomed.end = c1;
99      skipCol = -c0;
100   }
101   else {
102      zoomed.x = c0;
103      zoomed.start = 0;
104      zoomed.end = c1 - c0;
105      skipCol = 0;
106   }
107   if (zoomed.end > maxWidth)
108      zoomed.end = maxWidth;
109
110   /*
111    * Compute which rows to draw: [r0, r1)
112    */
113   row = span->y - y0;
114   r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
115   r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
116   if (r0 == r1) {
117      return;
118   }
119   else if (r1 < r0) {
120      /* swap */
121      GLint rtmp = r1;
122      r1 = r0;
123      r0 = rtmp;
124   }
125
126   ASSERT(r0 < r1);
127   ASSERT(c0 < c1);
128
129   /*
130    * Trivial clip rejection testing.
131    */
132   if (r1 < 0) /* below window */
133      return;
134   if (r0 >= (GLint) ctx->DrawBuffer->Height) /* above window */
135      return;
136   if (c1 < 0) /* left of window */
137      return;
138   if (c0 >= (GLint) ctx->DrawBuffer->Width) /* right of window */
139      return;
140
141   /* zoom the span horizontally */
142   if (format == GL_RGBA) {
143      if (ctx->Pixel.ZoomX == -1.0F) {
144         /* common case */
145         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
146            i = span->end - (j + skipCol) - 1;
147            COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
148         }
149      }
150      else {
151         /* general solution */
152         const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
153         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
154            i = (GLint) ((j + skipCol) * xscale);
155            if (i < 0)
156               i = span->end + i - 1;
157            COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
158         }
159      }
160   }
161   else if (format == GL_RGB) {
162      if (ctx->Pixel.ZoomX == -1.0F) {
163         /* common case */
164         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
165            i = span->end - (j + skipCol) - 1;
166            zoomed.array->rgba[j][0] = rgb[i][0];
167            zoomed.array->rgba[j][1] = rgb[i][1];
168            zoomed.array->rgba[j][2] = rgb[i][2];
169            zoomed.array->rgba[j][3] = CHAN_MAX;
170         }
171      }
172      else {
173         /* general solution */
174         const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
175         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
176            i = (GLint) ((j + skipCol) * xscale);
177            if (i < 0)
178               i = span->end + i - 1;
179            zoomed.array->rgba[j][0] = rgb[i][0];
180            zoomed.array->rgba[j][1] = rgb[i][1];
181            zoomed.array->rgba[j][2] = rgb[i][2];
182            zoomed.array->rgba[j][3] = CHAN_MAX;
183         }
184      }
185   }
186   else if (format == GL_COLOR_INDEX) {
187      if (ctx->Pixel.ZoomX == -1.0F) {
188         /* common case */
189         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
190            i = span->end - (j + skipCol) - 1;
191            zoomed.array->index[j] = indexes[i];
192         }
193      }
194      else {
195         /* general solution */
196         const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
197         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
198            i = (GLint) ((j + skipCol) * xscale);
199            if (i < 0)
200               i = span->end + i - 1;
201            zoomed.array->index[j] = indexes[i];
202         }
203      }
204   }
205
206   /* write the span in rows [r0, r1) */
207   if (format == GL_RGBA || format == GL_RGB) {
208      /* Writing the span may modify the colors, so make a backup now if we're
209       * going to call _mesa_write_zoomed_span() more than once.
210       */
211      if (r1 - r0 > 1) {
212         MEMCPY(rgbaSave, zoomed.array->rgba, zoomed.end * 4 * sizeof(GLchan));
213      }
214      for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
215         _mesa_write_rgba_span(ctx, &zoomed);
216         if (r1 - r0 > 1) {
217            /* restore the colors */
218            MEMCPY(zoomed.array->rgba, rgbaSave, zoomed.end*4 * sizeof(GLchan));
219         }
220      }
221   }
222   else if (format == GL_COLOR_INDEX) {
223      if (r1 - r0 > 1) {
224         MEMCPY(indexSave, zoomed.array->index, zoomed.end * sizeof(GLuint));
225      }
226      for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
227         _mesa_write_index_span(ctx, &zoomed);
228         if (r1 - r0 > 1) {
229            /* restore the colors */
230            MEMCPY(zoomed.array->index, indexSave, zoomed.end * sizeof(GLuint));
231         }
232      }
233   }
234}
235
236
237void
238_mesa_write_zoomed_rgba_span( GLcontext *ctx, const struct sw_span *span,
239                              CONST GLchan rgba[][4], GLint y0 )
240{
241   zoom_span(ctx, span, (const GLvoid *) rgba, y0, GL_RGBA);
242}
243
244
245void
246_mesa_write_zoomed_rgb_span( GLcontext *ctx, const struct sw_span *span,
247                             CONST GLchan rgb[][3], GLint y0 )
248{
249   zoom_span(ctx, span, (const GLvoid *) rgb, y0, GL_RGB);
250}
251
252
253void
254_mesa_write_zoomed_index_span( GLcontext *ctx, const struct sw_span *span,
255                               GLint y0 )
256{
257  zoom_span(ctx, span, (const GLvoid *) span->array->index, y0, GL_COLOR_INDEX);
258}
259
260
261/*
262 * As above, but write stencil values.
263 */
264void
265_mesa_write_zoomed_stencil_span( GLcontext *ctx,
266                                 GLuint n, GLint x, GLint y,
267                                 const GLstencil stencil[], GLint y0 )
268{
269   GLint m;
270   GLint r0, r1, row, r;
271   GLint i, j, skipcol;
272   GLstencil zstencil[MAX_WIDTH];  /* zoomed stencil values */
273   GLint maxwidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
274
275   /* compute width of output row */
276   m = (GLint) ABSF( n * ctx->Pixel.ZoomX );
277   if (m==0) {
278      return;
279   }
280   if (ctx->Pixel.ZoomX<0.0) {
281      /* adjust x coordinate for left/right mirroring */
282      x = x - m;
283   }
284
285   /* compute which rows to draw */
286   row = y-y0;
287   r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
288   r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
289   if (r0==r1) {
290      return;
291   }
292   else if (r1<r0) {
293      GLint rtmp = r1;
294      r1 = r0;
295      r0 = rtmp;
296   }
297
298   /* return early if r0...r1 is above or below window */
299   if (r0<0 && r1<0) {
300      /* below window */
301      return;
302   }
303   if (r0 >= (GLint) ctx->DrawBuffer->Height &&
304       r1 >= (GLint) ctx->DrawBuffer->Height) {
305      /* above window */
306      return;
307   }
308
309   /* check if left edge is outside window */
310   skipcol = 0;
311   if (x<0) {
312      skipcol = -x;
313      m += x;
314   }
315   /* make sure span isn't too long or short */
316   if (m>maxwidth) {
317      m = maxwidth;
318   }
319   else if (m<=0) {
320      return;
321   }
322
323   ASSERT( m <= MAX_WIDTH );
324
325   /* zoom the span horizontally */
326   if (ctx->Pixel.ZoomX==-1.0F) {
327      /* n==m */
328      for (j=0;j<m;j++) {
329         i = n - (j+skipcol) - 1;
330         zstencil[j] = stencil[i];
331      }
332   }
333   else {
334      GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
335      for (j=0;j<m;j++) {
336         i = (GLint) ((j+skipcol) * xscale);
337         if (i<0)  i = n + i - 1;
338         zstencil[j] = stencil[i];
339      }
340   }
341
342   /* write the span */
343   for (r=r0; r<r1; r++) {
344      _mesa_write_stencil_span( ctx, m, x+skipcol, r, zstencil );
345   }
346}
347