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/* $Id: s_alphabuf.c,v 1.1 2003-02-28 11:49:41 pj Exp $ */
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3
/*
4
 * Mesa 3-D graphics library
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 * Version:  4.1
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 *
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 * Copyright (C) 1999-2002  Brian Paul   All Rights Reserved.
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a
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 * copy of this software and associated documentation files (the "Software"),
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 * to deal in the Software without restriction, including without limitation
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 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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 * and/or sell copies of the Software, and to permit persons to whom the
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 * Software is furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included
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 * in all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
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 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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 */
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27
 
28
/*
29
 * Software alpha planes.  Many frame buffers don't have alpha bits so
30
 * we simulate them in software.
31
 */
32
 
33
 
34
#include "glheader.h"
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#include "context.h"
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#include "imports.h"
37
 
38
#include "s_context.h"
39
#include "s_alphabuf.h"
40
 
41
 
42
/*
43
 * Allocate a new front and back alpha buffer.
44
 */
45
void
46
_mesa_alloc_alpha_buffers( GLframebuffer *buffer )
47
{
48
   const GLint bytes = buffer->Width * buffer->Height * sizeof(GLchan);
49
 
50
   ASSERT(buffer->UseSoftwareAlphaBuffers);
51
 
52
   if (buffer->FrontLeftAlpha) {
53
      MESA_PBUFFER_FREE( buffer->FrontLeftAlpha );
54
   }
55
   buffer->FrontLeftAlpha = MESA_PBUFFER_ALLOC( bytes );
56
   if (!buffer->FrontLeftAlpha) {
57
      /* out of memory */
58
      _mesa_error( NULL, GL_OUT_OF_MEMORY,
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                   "Couldn't allocate front-left alpha buffer" );
60
   }
61
 
62
   if (buffer->Visual.doubleBufferMode) {
63
      if (buffer->BackLeftAlpha) {
64
         MESA_PBUFFER_FREE( buffer->BackLeftAlpha );
65
      }
66
      buffer->BackLeftAlpha = MESA_PBUFFER_ALLOC( bytes );
67
      if (!buffer->BackLeftAlpha) {
68
         /* out of memory */
69
         _mesa_error( NULL, GL_OUT_OF_MEMORY,
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                      "Couldn't allocate back-left alpha buffer" );
71
      }
72
   }
73
 
74
   if (buffer->Visual.stereoMode) {
75
      if (buffer->FrontRightAlpha) {
76
         MESA_PBUFFER_FREE( buffer->FrontRightAlpha );
77
      }
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      buffer->FrontRightAlpha = MESA_PBUFFER_ALLOC( bytes );
79
      if (!buffer->FrontRightAlpha) {
80
         /* out of memory */
81
         _mesa_error( NULL, GL_OUT_OF_MEMORY,
82
                      "Couldn't allocate front-right alpha buffer" );
83
      }
84
 
85
      if (buffer->Visual.doubleBufferMode) {
86
         if (buffer->BackRightAlpha) {
87
            MESA_PBUFFER_FREE( buffer->BackRightAlpha );
88
         }
89
         buffer->BackRightAlpha = MESA_PBUFFER_ALLOC( bytes );
90
         if (!buffer->BackRightAlpha) {
91
            /* out of memory */
92
            _mesa_error( NULL, GL_OUT_OF_MEMORY,
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                         "Couldn't allocate back-right alpha buffer" );
94
         }
95
      }
96
   }
97
}
98
 
99
 
100
/*
101
 * Clear all the alpha buffers
102
 */
103
void
104
_mesa_clear_alpha_buffers( GLcontext *ctx )
105
{
106
   const GLchan aclear = (GLchan) ctx->Color.ClearColor[3];
107
   GLuint bufferBit;
108
 
109
   ASSERT(ctx->DrawBuffer->UseSoftwareAlphaBuffers);
110
   ASSERT(ctx->Color.ColorMask[ACOMP]);
111
 
112
   /* loop over four possible alpha buffers */
113
   for (bufferBit = 1; bufferBit <= 8; bufferBit = bufferBit << 1) {
114
      if (bufferBit & ctx->Color._DrawDestMask) {
115
         GLchan *buffer;
116
         if (bufferBit == FRONT_LEFT_BIT) {
117
            buffer = (GLchan *) ctx->DrawBuffer->FrontLeftAlpha;
118
         }
119
         else if (bufferBit == FRONT_RIGHT_BIT) {
120
            buffer = (GLchan *) ctx->DrawBuffer->FrontRightAlpha;
121
         }
122
         else if (bufferBit == BACK_LEFT_BIT) {
123
            buffer = (GLchan *) ctx->DrawBuffer->BackLeftAlpha;
124
         }
125
         else {
126
            buffer = (GLchan *) ctx->DrawBuffer->BackRightAlpha;
127
         }
128
 
129
         if (ctx->Scissor.Enabled) {
130
            /* clear scissor region */
131
            GLint j;
132
            GLint rowLen = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
133
            GLint rows = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
134
            GLint width = ctx->DrawBuffer->Width;
135
            GLchan *aptr = buffer
136
                          + ctx->DrawBuffer->_Ymin * ctx->DrawBuffer->Width
137
                          + ctx->DrawBuffer->_Xmin;
138
            for (j = 0; j < rows; j++) {
139
#if CHAN_BITS == 8
140
               MEMSET( aptr, aclear, rowLen );
141
#elif CHAN_BITS == 16
142
               MEMSET16( aptr, aclear, rowLen );
143
#else
144
               GLint i;
145
               for (i = 0; i < rowLen; i++) {
146
                  aptr[i] = aclear;
147
               }
148
#endif
149
               aptr += width;
150
            }
151
         }
152
         else {
153
            /* clear whole buffer */
154
            GLuint pixels = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height;
155
#if CHAN_BITS == 8
156
            MEMSET(buffer, aclear, pixels);
157
#elif CHAN_BITS == 16
158
            MEMSET16(buffer, aclear, pixels);
159
#else
160
            GLuint i;
161
            for (i = 0; i < pixels; i++) {
162
               buffer[i] = aclear;
163
            }
164
#endif
165
         }
166
      }
167
   }
168
}
169
 
170
 
171
 
172
static INLINE
173
GLchan *get_alpha_buffer( GLcontext *ctx )
174
{
175
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
176
 
177
   switch (swrast->CurrentBuffer) {
178
   case FRONT_LEFT_BIT:
179
      return (GLchan *) ctx->DrawBuffer->FrontLeftAlpha;
180
      break;
181
   case BACK_LEFT_BIT:
182
      return (GLchan *) ctx->DrawBuffer->BackLeftAlpha;
183
      break;
184
   case FRONT_RIGHT_BIT:
185
      return (GLchan *) ctx->DrawBuffer->FrontRightAlpha;
186
      break;
187
   case BACK_RIGHT_BIT:
188
      return (GLchan *) ctx->DrawBuffer->BackRightAlpha;
189
      break;
190
   default:
191
      _mesa_problem(ctx, "Bad CurrentBuffer in get_alpha_buffer()");
192
      return (GLchan *) ctx->DrawBuffer->FrontLeftAlpha;
193
   }
194
}
195
 
196
 
197
void
198
_mesa_write_alpha_span( GLcontext *ctx, GLuint n, GLint x, GLint y,
199
                        CONST GLchan rgba[][4], const GLubyte mask[] )
200
{
201
   GLchan *buffer, *aptr;
202
   GLuint i;
203
 
204
   buffer = get_alpha_buffer(ctx);
205
   aptr = buffer + y * ctx->DrawBuffer->Width + x;
206
 
207
   if (mask) {
208
      for (i=0;i<n;i++) {
209
         if (mask[i]) {
210
            *aptr = rgba[i][ACOMP];
211
         }
212
         aptr++;
213
      }
214
   }
215
   else {
216
      for (i=0;i<n;i++) {
217
         *aptr++ = rgba[i][ACOMP];
218
      }
219
   }
220
}
221
 
222
 
223
void
224
_mesa_write_mono_alpha_span( GLcontext *ctx, GLuint n, GLint x, GLint y,
225
                             GLchan alpha, const GLubyte mask[] )
226
{
227
   GLchan *buffer, *aptr;
228
   GLuint i;
229
 
230
   buffer = get_alpha_buffer(ctx);
231
   aptr = buffer + y * ctx->DrawBuffer->Width + x;
232
 
233
   if (mask) {
234
      for (i=0;i<n;i++) {
235
         if (mask[i]) {
236
            *aptr = alpha;
237
         }
238
         aptr++;
239
      }
240
   }
241
   else {
242
      for (i=0;i<n;i++) {
243
         *aptr++ = alpha;
244
      }
245
   }
246
}
247
 
248
 
249
void
250
_mesa_write_alpha_pixels( GLcontext *ctx,
251
                          GLuint n, const GLint x[], const GLint y[],
252
                          CONST GLchan rgba[][4], const GLubyte mask[] )
253
{
254
   GLchan *buffer;
255
   GLuint i;
256
 
257
   buffer = get_alpha_buffer(ctx);
258
 
259
   if (mask) {
260
      for (i=0;i<n;i++) {
261
         if (mask[i]) {
262
            GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
263
            *aptr = rgba[i][ACOMP];
264
         }
265
      }
266
   }
267
   else {
268
      for (i=0;i<n;i++) {
269
         GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
270
         *aptr = rgba[i][ACOMP];
271
      }
272
   }
273
}
274
 
275
 
276
void
277
_mesa_write_mono_alpha_pixels( GLcontext *ctx,
278
                               GLuint n, const GLint x[], const GLint y[],
279
                               GLchan alpha, const GLubyte mask[] )
280
{
281
   GLchan *buffer;
282
   GLuint i;
283
 
284
   buffer = get_alpha_buffer(ctx);
285
 
286
   if (mask) {
287
      for (i=0;i<n;i++) {
288
         if (mask[i]) {
289
            GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
290
            *aptr = alpha;
291
         }
292
      }
293
   }
294
   else {
295
      for (i=0;i<n;i++) {
296
         GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
297
         *aptr = alpha;
298
      }
299
   }
300
}
301
 
302
 
303
 
304
void
305
_mesa_read_alpha_span( GLcontext *ctx,
306
                       GLuint n, GLint x, GLint y, GLchan rgba[][4] )
307
{
308
   const GLchan *buffer, *aptr;
309
   GLuint i;
310
 
311
   buffer = get_alpha_buffer(ctx);
312
   aptr = buffer + y * ctx->DrawBuffer->Width + x;
313
 
314
   for (i = 0; i < n; i++)
315
      rgba[i][ACOMP] = *aptr++;
316
}
317
 
318
 
319
void
320
_mesa_read_alpha_pixels( GLcontext *ctx,
321
                         GLuint n, const GLint x[], const GLint y[],
322
                         GLchan rgba[][4], const GLubyte mask[] )
323
{
324
   const GLchan *buffer;
325
   GLuint i;
326
 
327
   buffer = get_alpha_buffer(ctx);
328
 
329
   for (i = 0; i < n; i++) {
330
      if (mask[i]) {
331
         const GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i];
332
         rgba[i][ACOMP] = *aptr;
333
      }
334
   }
335
}