src/mesa/swrast/s_bitmap.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 /**
  26  * \file swrast/s_bitmap.c
  27  * \brief glBitmap rendering.
  28  * \author Brian Paul
  29  */
  30
  31 #include "main/glheader.h"
  32 #include "main/bufferobj.h"
  33 #include "main/condrender.h"
  34 #include "main/image.h"
  35 #include "main/macros.h"
  36 #include "main/pbo.h"
  37
  38 #include "s_context.h"
  39 #include "s_span.h"
  40
  41
  42
  43 /**
  44  * Render a bitmap.
  45  * Called via ctx->Driver.Bitmap()
  46  * All parameter error checking will have been done before this is called.
  47  */
  48 void
  49 _swrast_Bitmap( struct gl_context *ctx, GLint px, GLint py,
  50                 GLsizei width, GLsizei height,
  51                 const struct gl_pixelstore_attrib *unpack,
  52                 const GLubyte *bitmap )
  53 {
  54    GLint row, col;
  55    GLuint count = 0;
  56    SWspan span;
  57
  58    assert(ctx->RenderMode == GL_RENDER);
  59
  60    if (!_mesa_check_conditional_render(ctx))
  61       return; /* don't draw */
  62
  63    bitmap = (const GLubyte *) _mesa_map_pbo_source(ctx, unpack, bitmap);
  64    if (!bitmap)
  65       return;
  66
  67    swrast_render_start(ctx);
  68
  69    if (SWRAST_CONTEXT(ctx)->NewState)
  70       _swrast_validate_derived( ctx );
  71
  72    INIT_SPAN(span, GL_BITMAP);
  73    span.end = width;
  74    span.arrayMask = SPAN_XY;
  75    _swrast_span_default_attribs(ctx, &span);
  76
  77    for (row = 0; row < height; row++) {
  78       const GLubyte *src = (const GLubyte *) _mesa_image_address2d(unpack,
  79                  bitmap, width, height, GL_COLOR_INDEX, GL_BITMAP, row, 0);
  80
  81       if (unpack->LsbFirst) {
  82          /* Lsb first */
  83          GLubyte mask = 1U << (unpack->SkipPixels & 0x7);
  84          for (col = 0; col < width; col++) {
  85             if (*src & mask) {
  86                span.array->x[count] = px + col;
  87                span.array->y[count] = py + row;
  88                count++;
  89             }
  90             if (mask == 128U) {
  91                src++;
  92                mask = 1U;
  93             }
  94             else {
  95                mask = mask << 1;
  96             }
  97          }
  98
  99          /* get ready for next row */
 100          if (mask != 1)
 101             src++;
 102       }
 103       else {
 104          /* Msb first */
 105          GLubyte mask = 128U >> (unpack->SkipPixels & 0x7);
 106          for (col = 0; col < width; col++) {
 107             if (*src & mask) {
 108                span.array->x[count] = px + col;
 109                span.array->y[count] = py + row;
 110                count++;
 111             }
 112             if (mask == 1U) {
 113                src++;
 114                mask = 128U;
 115             }
 116             else {
 117                mask = mask >> 1;
 118             }
 119          }
 120
 121          /* get ready for next row */
 122          if (mask != 128)
 123             src++;
 124       }
 125
 126       if (count + width >= SWRAST_MAX_WIDTH || row + 1 == height) {
 127          /* flush the span */
 128          span.end = count;
 129          _swrast_write_rgba_span(ctx, &span);
 130          span.end = 0;
 131          count = 0;
 132       }
 133    }
 134
 135    swrast_render_finish(ctx);
 136
 137    _mesa_unmap_pbo_source(ctx, unpack);
 138 }
 139
 140
 141 #if 0
 142 /*
 143  * XXX this is another way to implement Bitmap.  Use horizontal runs of
 144  * fragments, initializing the mask array to indicate which fragments to
 145  * draw or skip.
 146  */
 147 void
 148 _swrast_Bitmap( struct gl_context *ctx, GLint px, GLint py,
 149                 GLsizei width, GLsizei height,
 150                 const struct gl_pixelstore_attrib *unpack,
 151                 const GLubyte *bitmap )
 152 {
 153    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 154    GLint row, col;
 155    SWspan span;
 156
 157    assert(ctx->RenderMode == GL_RENDER);
 158    assert(bitmap);
 159
 160    swrast_render_start(ctx);
 161
 162    if (SWRAST_CONTEXT(ctx)->NewState)
 163       _swrast_validate_derived( ctx );
 164
 165    INIT_SPAN(span, GL_BITMAP);
 166    span.end = width;
 167    span.arrayMask = SPAN_MASK;
 168    _swrast_span_default_attribs(ctx, &span);
 169
 170    /*span.arrayMask |= SPAN_MASK;*/  /* we'll init span.mask[] */
 171    span.x = px;
 172    span.y = py;
 173    /*span.end = width;*/
 174
 175    for (row=0; row<height; row++, span.y++) {
 176       const GLubyte *src = (const GLubyte *) _mesa_image_address2d(unpack,
 177                  bitmap, width, height, GL_COLOR_INDEX, GL_BITMAP, row, 0);
 178
 179       if (unpack->LsbFirst) {
 180          /* Lsb first */
 181          GLubyte mask = 1U << (unpack->SkipPixels & 0x7);
 182          for (col=0; col<width; col++) {
 183             span.array->mask[col] = (*src & mask) ? GL_TRUE : GL_FALSE;
 184             if (mask == 128U) {
 185                src++;
 186                mask = 1U;
 187             }
 188             else {
 189                mask = mask << 1;
 190             }
 191          }
 192
 193          _swrast_write_rgba_span(ctx, &span);
 194
 195          /* get ready for next row */
 196          if (mask != 1)
 197             src++;
 198       }
 199       else {
 200          /* Msb first */
 201          GLubyte mask = 128U >> (unpack->SkipPixels & 0x7);
 202          for (col=0; col<width; col++) {
 203             span.array->mask[col] = (*src & mask) ? GL_TRUE : GL_FALSE;
 204             if (mask == 1U) {
 205                src++;
 206                mask = 128U;
 207             }
 208             else {
 209                mask = mask >> 1;
 210             }
 211          }
 212
 213          _swrast_write_rgba_span(ctx, &span);
 214
 215          /* get ready for next row */
 216          if (mask != 128)
 217             src++;
 218       }
 219    }
 220
 221    swrast_render_finish(ctx);
 222 }
 223 #endif