src/mesa/swrast/s_buffers.c

   1
   2 /*
   3  * Mesa 3-D graphics library
   4  * Version:  5.1
   5  *
   6  * Copyright (C) 1999-2002  Brian Paul   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 #include "glheader.h"
  28 #include "colormac.h"
  29 #include "macros.h"
  30 #include "imports.h"
  31
  32 #include "s_accum.h"
  33 #include "s_alphabuf.h"
  34 #include "s_context.h"
  35 #include "s_depth.h"
  36 #include "s_masking.h"
  37 #include "s_stencil.h"
  38
  39
  40
  41
  42 /*
  43  * Clear the color buffer when glColorMask or glIndexMask is in effect.
  44  */
  45 static void
  46 clear_color_buffer_with_masking( GLcontext *ctx )
  47 {
  48    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  49    const GLint x = ctx->DrawBuffer->_Xmin;
  50    const GLint y = ctx->DrawBuffer->_Ymin;
  51    const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
  52    const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
  53
  54    if (ctx->Visual.rgbMode) {
  55       /* RGBA mode */
  56       GLchan clearColor[4];
  57       GLint i;
  58       CLAMPED_FLOAT_TO_CHAN(clearColor[RCOMP], ctx->Color.ClearColor[0]);
  59       CLAMPED_FLOAT_TO_CHAN(clearColor[GCOMP], ctx->Color.ClearColor[1]);
  60       CLAMPED_FLOAT_TO_CHAN(clearColor[BCOMP], ctx->Color.ClearColor[2]);
  61       CLAMPED_FLOAT_TO_CHAN(clearColor[ACOMP], ctx->Color.ClearColor[3]);
  62       for (i = 0; i < height; i++) {
  63          GLchan rgba[MAX_WIDTH][4];
  64          GLint j;
  65          for (j = 0; j < width; j++) {
  66             COPY_CHAN4(rgba[j], clearColor);
  67          }
  68          _swrast_mask_rgba_array( ctx, width, x, y + i, rgba );
  69          (*swrast->Driver.WriteRGBASpan)( ctx, width, x, y + i,
  70                                           (CONST GLchan (*)[4]) rgba, NULL );
  71       }
  72    }
  73    else {
  74       /* Color index mode */
  75       GLuint span[MAX_WIDTH];
  76       GLubyte mask[MAX_WIDTH];
  77       GLint i, j;
  78       MEMSET( mask, 1, width );
  79       for (i=0;i<height;i++) {
  80          for (j=0;j<width;j++) {
  81             span[j] = ctx->Color.ClearIndex;
  82          }
  83          _swrast_mask_index_array( ctx, width, x, y + i, span );
  84          (*swrast->Driver.WriteCI32Span)( ctx, width, x, y + i, span, mask );
  85       }
  86    }
  87 }
  88
  89
  90
  91 /*
  92  * Clear a color buffer without index/channel masking.
  93  */
  94 static void
  95 clear_color_buffer(GLcontext *ctx)
  96 {
  97    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  98    const GLint x = ctx->DrawBuffer->_Xmin;
  99    const GLint y = ctx->DrawBuffer->_Ymin;
 100    const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 101    const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
 102
 103    if (ctx->Visual.rgbMode) {
 104       /* RGBA mode */
 105       GLchan clearColor[4];
 106       GLint i;
 107
 108       CLAMPED_FLOAT_TO_CHAN(clearColor[RCOMP], ctx->Color.ClearColor[0]);
 109       CLAMPED_FLOAT_TO_CHAN(clearColor[GCOMP], ctx->Color.ClearColor[1]);
 110       CLAMPED_FLOAT_TO_CHAN(clearColor[BCOMP], ctx->Color.ClearColor[2]);
 111       CLAMPED_FLOAT_TO_CHAN(clearColor[ACOMP], ctx->Color.ClearColor[3]);
 112
 113       ASSERT(*((GLuint *) &ctx->Color.ColorMask) == 0xffffffff);
 114       ASSERT(swrast->Driver.WriteRGBASpan);
 115
 116       for (i = 0; i < height; i++) {
 117          (*swrast->Driver.WriteMonoRGBASpan)( ctx, width, x, y + i,
 118                                               clearColor, NULL );
 119       }
 120    }
 121    else {
 122       /* Color index mode */
 123       GLint i;
 124       ASSERT((ctx->Color.IndexMask & ((1 << ctx->Visual.indexBits) - 1))
 125              == (GLuint) ((1 << ctx->Visual.indexBits) - 1));
 126       ASSERT(swrast->Driver.WriteMonoCISpan);
 127       for (i = 0; i < height; i++) {
 128          (*swrast->Driver.WriteMonoCISpan)( ctx, width, x, y + i,
 129                                             ctx->Color.ClearIndex, NULL);
 130       }
 131    }
 132 }
 133
 134
 135
 136 /*
 137  * Clear the front/back/left/right color buffers.
 138  * This function is usually only called if we need to clear the
 139  * buffers with masking.
 140  */
 141 static void
 142 clear_color_buffers(GLcontext *ctx)
 143 {
 144    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 145    const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
 146    GLuint bufferBit;
 147
 148    /* loop over four possible dest color buffers */
 149    for (bufferBit = 1; bufferBit <= 8; bufferBit = bufferBit << 1) {
 150       if (bufferBit & ctx->Color._DrawDestMask) {
 151          (*swrast->Driver.SetBuffer)(ctx, ctx->DrawBuffer, bufferBit);
 152
 153          if (colorMask != 0xffffffff) {
 154             clear_color_buffer_with_masking(ctx);
 155          }
 156          else {
 157             clear_color_buffer(ctx);
 158          }
 159       }
 160    }
 161
 162    /* restore default read/draw buffer */
 163    _swrast_use_draw_buffer(ctx);
 164 }
 165
 166
 167
 168 void
 169 _swrast_Clear( GLcontext *ctx, GLbitfield mask,
 170                GLboolean all,
 171                GLint x, GLint y, GLint width, GLint height )
 172 {
 173    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 174 #ifdef DEBUG
 175    {
 176       GLbitfield legalBits = DD_FRONT_LEFT_BIT |
 177          DD_FRONT_RIGHT_BIT |
 178          DD_BACK_LEFT_BIT |
 179          DD_BACK_RIGHT_BIT |
 180          DD_DEPTH_BIT |
 181          DD_STENCIL_BIT |
 182          DD_ACCUM_BIT;
 183       assert((mask & (~legalBits)) == 0);
 184    }
 185 #endif
 186
 187    RENDER_START(swrast,ctx);
 188
 189    /* do software clearing here */
 190    if (mask) {
 191       if (mask & ctx->Color._DrawDestMask)   clear_color_buffers(ctx);
 192       if (mask & GL_DEPTH_BUFFER_BIT)    _swrast_clear_depth_buffer(ctx);
 193       if (mask & GL_ACCUM_BUFFER_BIT)    _swarst_clear_accum_buffer(ctx);
 194       if (mask & GL_STENCIL_BUFFER_BIT)  _swrast_clear_stencil_buffer(ctx);
 195    }
 196
 197    /* clear software-based alpha buffer(s) */
 198    if ( (mask & GL_COLOR_BUFFER_BIT)
 199         && ctx->DrawBuffer->UseSoftwareAlphaBuffers
 200         && ctx->Color.ColorMask[ACOMP]) {
 201       _swrast_clear_alpha_buffers( ctx );
 202    }
 203
 204    RENDER_FINISH(swrast,ctx);
 205 }
 206
 207
 208 void
 209 _swrast_alloc_buffers( GLframebuffer *buffer )
 210 {
 211    /* Reallocate other buffers if needed. */
 212    if (buffer->UseSoftwareDepthBuffer) {
 213       _swrast_alloc_depth_buffer( buffer );
 214    }
 215    if (buffer->UseSoftwareStencilBuffer) {
 216       _swrast_alloc_stencil_buffer( buffer );
 217    }
 218    if (buffer->UseSoftwareAccumBuffer) {
 219       _swrast_alloc_accum_buffer( buffer );
 220    }
 221    if (buffer->UseSoftwareAlphaBuffers) {
 222       _swrast_alloc_alpha_buffers( buffer );
 223    }
 224 }
 225
 226
 227 /*
 228  * Fallback for ctx->Driver.DrawBuffer()
 229  */
 230 void
 231 _swrast_DrawBuffer( GLcontext *ctx, GLenum mode )
 232 {
 233    _swrast_use_draw_buffer(ctx);
 234 }
 235
 236
 237 /*
 238  * Setup things so that we read/write spans from the user-designated
 239  * read buffer (set via glReadPixels).  We usually just have to call
 240  * this for glReadPixels, glCopyPixels, etc.
 241  */
 242 void
 243 _swrast_use_read_buffer( GLcontext *ctx )
 244 {
 245    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 246
 247    /* Do this so the software-emulated alpha plane span functions work! */
 248    swrast->CurrentBuffer = ctx->Pixel._ReadSrcMask;
 249    /* Tell the device driver where to read/write spans */
 250    (*swrast->Driver.SetBuffer)( ctx, ctx->ReadBuffer, swrast->CurrentBuffer );
 251 }
 252
 253
 254 /*
 255  * Setup things so that we read/write spans from the default draw buffer.
 256  * This is the usual mode that Mesa's software rasterizer operates in.
 257  */
 258 void
 259 _swrast_use_draw_buffer( GLcontext *ctx )
 260 {
 261    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 262
 263    /* The user can specify rendering to zero, one, two, or four color
 264     * buffers simultaneously with glDrawBuffer()!
 265     * We don't expect the span/point/line/triangle functions to deal with
 266     * that mess so we'll iterate over the multiple buffers as needed.
 267     * But usually we only render to one color buffer at a time.
 268     * We set ctx->Color._DriverDrawBuffer to that buffer and tell the
 269     * device driver to use that buffer.
 270     * Look in s_span.c's multi_write_rgba_span() function to see how
 271     * we loop over multiple color buffers when needed.
 272     */
 273
 274    if (ctx->Color._DrawDestMask & FRONT_LEFT_BIT)
 275       swrast->CurrentBuffer = FRONT_LEFT_BIT;
 276    else if (ctx->Color._DrawDestMask & BACK_LEFT_BIT)
 277       swrast->CurrentBuffer = BACK_LEFT_BIT;
 278    else if (ctx->Color._DrawDestMask & FRONT_RIGHT_BIT)
 279       swrast->CurrentBuffer = FRONT_RIGHT_BIT;
 280    else if (ctx->Color._DrawDestMask & BACK_RIGHT_BIT)
 281       swrast->CurrentBuffer = BACK_RIGHT_BIT;
 282    else
 283       /* glDrawBuffer(GL_NONE) */
 284       swrast->CurrentBuffer = FRONT_LEFT_BIT; /* we always have this buffer */
 285
 286    (*swrast->Driver.SetBuffer)( ctx, ctx->DrawBuffer, swrast->CurrentBuffer );
 287 }