s_zoom.c revision 27558a160a9fe91745728d7626995cd88f8fe339 
1/* $Id: s_zoom.c,v 1.23 2003/03/01 01:50:26 brianp Exp $ */
2
3/*
4 * Mesa 3-D graphics library
5 * Version:  5.1
6 *
7 * Copyright (C) 1999-2003  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 "imports.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, GLint skipPixels )
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   zoomed.z = span->z;
65   zoomed.zStep = span->zStep;  /* span->zStep == 0 */
66   zoomed.fog = span->fog;
67   zoomed.fogStep = span->fogStep;
68   if (format == GL_RGBA || format == GL_RGB) {
69      zoomed.interpMask = span->interpMask & ~SPAN_RGBA;
70      zoomed.arrayMask |= SPAN_RGBA;
71   }
72   else if (format == GL_COLOR_INDEX) {
73      zoomed.interpMask = span->interpMask & ~SPAN_INDEX;
74      zoomed.arrayMask |= SPAN_INDEX;
75   }
76
77   /*
78    * Compute which columns to draw: [c0, c1)
79    */
80#if 0
81   c0 = (GLint) span->x;
82   c1 = (GLint) (span->x + span->end * ctx->Pixel.ZoomX);
83#else
84   c0 = (GLint) (span->x + skipPixels * ctx->Pixel.ZoomX);
85   c1 = (GLint) (span->x + (skipPixels + span->end) * ctx->Pixel.ZoomX);
86#endif
87   if (c0 == c1) {
88      return;
89   }
90   else if (c1 < c0) {
91      /* swap */
92      GLint ctmp = c1;
93      c1 = c0;
94      c0 = ctmp;
95   }
96   if (c0 < 0) {
97      zoomed.x = 0;
98      zoomed.start = 0;
99      zoomed.end = c1;
100      skipCol = -c0;
101   }
102   else {
103      zoomed.x = c0;
104      zoomed.start = 0;
105      zoomed.end = c1 - c0;
106      skipCol = 0;
107   }
108   if (zoomed.end > maxWidth)
109      zoomed.end = maxWidth;
110
111   /*
112    * Compute which rows to draw: [r0, r1)
113    */
114   row = span->y - y0;
115   r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
116   r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
117   if (r0 == r1) {
118      return;
119   }
120   else if (r1 < r0) {
121      /* swap */
122      GLint rtmp = r1;
123      r1 = r0;
124      r0 = rtmp;
125   }
126
127   ASSERT(r0 < r1);
128   ASSERT(c0 < c1);
129
130   /*
131    * Trivial clip rejection testing.
132    */
133   if (r1 < 0) /* below window */
134      return;
135   if (r0 >= (GLint) ctx->DrawBuffer->Height) /* above window */
136      return;
137   if (c1 < 0) /* left of window */
138      return;
139   if (c0 >= (GLint) ctx->DrawBuffer->Width) /* right of window */
140      return;
141
142   /* zoom the span horizontally */
143   if (format == GL_RGBA) {
144      if (ctx->Pixel.ZoomX == -1.0F) {
145         /* common case */
146         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
147            i = span->end - (j + skipCol) - 1;
148            COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
149         }
150      }
151      else {
152         /* general solution */
153         const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
154         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
155            i = (GLint) ((j + skipCol) * xscale);
156            if (ctx->Pixel.ZoomX < 0.0) {
157               ASSERT(i <= 0);
158               i = span->end + i - 1;
159            }
160            ASSERT(i >= 0);
161            ASSERT(i < (GLint)  span->end);
162            COPY_CHAN4(zoomed.array->rgba[j], rgba[i]);
163         }
164      }
165   }
166   else if (format == GL_RGB) {
167      if (ctx->Pixel.ZoomX == -1.0F) {
168         /* common case */
169         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
170            i = span->end - (j + skipCol) - 1;
171            zoomed.array->rgba[j][0] = rgb[i][0];
172            zoomed.array->rgba[j][1] = rgb[i][1];
173            zoomed.array->rgba[j][2] = rgb[i][2];
174            zoomed.array->rgba[j][3] = CHAN_MAX;
175         }
176      }
177      else {
178         /* general solution */
179         const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
180         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
181            i = (GLint) ((j + skipCol) * xscale);
182            if (ctx->Pixel.ZoomX < 0.0) {
183               ASSERT(i <= 0);
184               i = span->end + i - 1;
185            }
186            ASSERT(i >= 0);
187            ASSERT(i < (GLint) span->end);
188            zoomed.array->rgba[j][0] = rgb[i][0];
189            zoomed.array->rgba[j][1] = rgb[i][1];
190            zoomed.array->rgba[j][2] = rgb[i][2];
191            zoomed.array->rgba[j][3] = CHAN_MAX;
192         }
193      }
194   }
195   else if (format == GL_COLOR_INDEX) {
196      if (ctx->Pixel.ZoomX == -1.0F) {
197         /* common case */
198         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
199            i = span->end - (j + skipCol) - 1;
200            zoomed.array->index[j] = indexes[i];
201         }
202      }
203      else {
204         /* general solution */
205         const GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
206         for (j = (GLint) zoomed.start; j < (GLint) zoomed.end; j++) {
207            i = (GLint) ((j + skipCol) * xscale);
208            if (ctx->Pixel.ZoomX < 0.0) {
209               ASSERT(i <= 0);
210               i = span->end + i - 1;
211            }
212            ASSERT(i >= 0);
213            ASSERT(i < (GLint) span->end);
214            zoomed.array->index[j] = indexes[i];
215         }
216      }
217   }
218
219   /* write the span in rows [r0, r1) */
220   if (format == GL_RGBA || format == GL_RGB) {
221      /* Writing the span may modify the colors, so make a backup now if we're
222       * going to call _mesa_write_zoomed_span() more than once.
223       * Also, clipping may change the span end value, so store it as well.
224       */
225      const GLint end = zoomed.end; /* save */
226      if (r1 - r0 > 1) {
227         MEMCPY(rgbaSave, zoomed.array->rgba, zoomed.end * 4 * sizeof(GLchan));
228      }
229      for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
230         _mesa_write_rgba_span(ctx, &zoomed);
231         zoomed.end = end;  /* restore */
232         if (r1 - r0 > 1) {
233            /* restore the colors */
234            MEMCPY(zoomed.array->rgba, rgbaSave, zoomed.end*4 * sizeof(GLchan));
235         }
236      }
237   }
238   else if (format == GL_COLOR_INDEX) {
239      const GLint end = zoomed.end; /* save */
240      if (r1 - r0 > 1) {
241         MEMCPY(indexSave, zoomed.array->index, zoomed.end * sizeof(GLuint));
242      }
243      for (zoomed.y = r0; zoomed.y < r1; zoomed.y++) {
244         _mesa_write_index_span(ctx, &zoomed);
245         zoomed.end = end;  /* restore */
246         if (r1 - r0 > 1) {
247            /* restore the colors */
248            MEMCPY(zoomed.array->index, indexSave, zoomed.end * sizeof(GLuint));
249         }
250      }
251   }
252}
253
254
255void
256_mesa_write_zoomed_rgba_span( GLcontext *ctx, const struct sw_span *span,
257                              CONST GLchan rgba[][4], GLint y0,
258                              GLint skipPixels )
259{
260   zoom_span(ctx, span, (const GLvoid *) rgba, y0, GL_RGBA, skipPixels);
261}
262
263
264void
265_mesa_write_zoomed_rgb_span( GLcontext *ctx, const struct sw_span *span,
266                             CONST GLchan rgb[][3], GLint y0,
267                             GLint skipPixels )
268{
269   zoom_span(ctx, span, (const GLvoid *) rgb, y0, GL_RGB, skipPixels);
270}
271
272
273void
274_mesa_write_zoomed_index_span( GLcontext *ctx, const struct sw_span *span,
275                               GLint y0, GLint skipPixels )
276{
277  zoom_span(ctx, span, (const GLvoid *) span->array->index, y0,
278            GL_COLOR_INDEX, skipPixels);
279}
280
281
282/*
283 * As above, but write stencil values.
284 */
285void
286_mesa_write_zoomed_stencil_span( GLcontext *ctx,
287                                 GLuint n, GLint x, GLint y,
288                                 const GLstencil stencil[], GLint y0,
289                                 GLint skipPixels )
290{
291   GLint m;
292   GLint r0, r1, row, r;
293   GLint i, j, skipcol;
294   GLstencil zstencil[MAX_WIDTH];  /* zoomed stencil values */
295   GLint maxwidth = MIN2( ctx->DrawBuffer->Width, MAX_WIDTH );
296
297   (void) skipPixels;  /* XXX this shouldn't be ignored */
298
299   /* compute width of output row */
300   m = (GLint) FABSF( n * ctx->Pixel.ZoomX );
301   if (m==0) {
302      return;
303   }
304   if (ctx->Pixel.ZoomX<0.0) {
305      /* adjust x coordinate for left/right mirroring */
306      x = x - m;
307   }
308
309   /* compute which rows to draw */
310   row = y - y0;
311   r0 = y0 + (GLint) (row * ctx->Pixel.ZoomY);
312   r1 = y0 + (GLint) ((row+1) * ctx->Pixel.ZoomY);
313   if (r0==r1) {
314      return;
315   }
316   else if (r1<r0) {
317      GLint rtmp = r1;
318      r1 = r0;
319      r0 = rtmp;
320   }
321
322   /* return early if r0...r1 is above or below window */
323   if (r0<0 && r1<0) {
324      /* below window */
325      return;
326   }
327   if (r0 >= (GLint) ctx->DrawBuffer->Height &&
328       r1 >= (GLint) ctx->DrawBuffer->Height) {
329      /* above window */
330      return;
331   }
332
333   /* check if left edge is outside window */
334   skipcol = 0;
335   if (x<0) {
336      skipcol = -x;
337      m += x;
338   }
339   /* make sure span isn't too long or short */
340   if (m>maxwidth) {
341      m = maxwidth;
342   }
343   else if (m<=0) {
344      return;
345   }
346
347   ASSERT( m <= MAX_WIDTH );
348
349   /* zoom the span horizontally */
350   if (ctx->Pixel.ZoomX==-1.0F) {
351      /* n==m */
352      for (j=0;j<m;j++) {
353         i = n - (j+skipcol) - 1;
354         zstencil[j] = stencil[i];
355      }
356   }
357   else {
358      GLfloat xscale = 1.0F / ctx->Pixel.ZoomX;
359      for (j=0;j<m;j++) {
360         i = (GLint) ((j+skipcol) * xscale);
361         if (i<0)  i = n + i - 1;
362         zstencil[j] = stencil[i];
363      }
364   }
365
366   /* write the span */
367   for (r=r0; r<r1; r++) {
368      _mesa_write_stencil_span( ctx, m, x+skipcol, r, zstencil );
369   }
370}
371