src/mesa/swrast/s_buffers.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.0.1
   4  *
   5  * Copyright (C) 1999-2004  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "glheader.h"
  27 #include "colormac.h"
  28 #include "macros.h"
  29 #include "imports.h"
  30
  31 #include "s_accum.h"
  32 #include "s_alphabuf.h"
  33 #include "s_context.h"
  34 #include "s_depth.h"
  35 #include "s_masking.h"
  36 #include "s_stencil.h"
  37
  38
  39
  40
  41 /*
  42  * Clear the color buffer when glColorMask or glIndexMask is in effect.
  43  */
  44 static void
  45 clear_color_buffer_with_masking( GLcontext *ctx )
  46 {
  47    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  48    const GLint x = ctx->DrawBuffer->_Xmin;
  49    const GLint y = ctx->DrawBuffer->_Ymin;
  50    const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
  51    const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
  52
  53    if (ctx->Visual.rgbMode) {
  54       /* RGBA mode */
  55       GLchan clearColor[4];
  56       GLint i;
  57       CLAMPED_FLOAT_TO_CHAN(clearColor[RCOMP], ctx->Color.ClearColor[0]);
  58       CLAMPED_FLOAT_TO_CHAN(clearColor[GCOMP], ctx->Color.ClearColor[1]);
  59       CLAMPED_FLOAT_TO_CHAN(clearColor[BCOMP], ctx->Color.ClearColor[2]);
  60       CLAMPED_FLOAT_TO_CHAN(clearColor[ACOMP], ctx->Color.ClearColor[3]);
  61       for (i = 0; i < height; i++) {
  62          GLchan rgba[MAX_WIDTH][4];
  63          GLint j;
  64          for (j = 0; j < width; j++) {
  65             COPY_CHAN4(rgba[j], clearColor);
  66          }
  67          _swrast_mask_rgba_array( ctx, width, x, y + i, rgba );
  68          (*swrast->Driver.WriteRGBASpan)( ctx, width, x, y + i,
  69                                           (CONST GLchan (*)[4]) rgba, NULL );
  70       }
  71    }
  72    else {
  73       /* Color index mode */
  74       GLuint span[MAX_WIDTH];
  75       GLubyte mask[MAX_WIDTH];
  76       GLint i, j;
  77       MEMSET( mask, 1, width );
  78       for (i=0;i<height;i++) {
  79          for (j=0;j<width;j++) {
  80             span[j] = ctx->Color.ClearIndex;
  81          }
  82          _swrast_mask_index_array( ctx, width, x, y + i, span );
  83          (*swrast->Driver.WriteCI32Span)( ctx, width, x, y + i, span, mask );
  84       }
  85    }
  86 }
  87
  88
  89
  90 /*
  91  * Clear a color buffer without index/channel masking.
  92  */
  93 static void
  94 clear_color_buffer(GLcontext *ctx)
  95 {
  96    SWcontext *swrast = SWRAST_CONTEXT(ctx);
  97    const GLint x = ctx->DrawBuffer->_Xmin;
  98    const GLint y = ctx->DrawBuffer->_Ymin;
  99    const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 100    const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
 101
 102    if (ctx->Visual.rgbMode) {
 103       /* RGBA mode */
 104       GLchan clearColor[4];
 105       GLint i;
 106
 107       CLAMPED_FLOAT_TO_CHAN(clearColor[RCOMP], ctx->Color.ClearColor[0]);
 108       CLAMPED_FLOAT_TO_CHAN(clearColor[GCOMP], ctx->Color.ClearColor[1]);
 109       CLAMPED_FLOAT_TO_CHAN(clearColor[BCOMP], ctx->Color.ClearColor[2]);
 110       CLAMPED_FLOAT_TO_CHAN(clearColor[ACOMP], ctx->Color.ClearColor[3]);
 111
 112       ASSERT(*((GLuint *) &ctx->Color.ColorMask) == 0xffffffff);
 113       ASSERT(swrast->Driver.WriteRGBASpan);
 114
 115       for (i = 0; i < height; i++) {
 116          (*swrast->Driver.WriteMonoRGBASpan)( ctx, width, x, y + i,
 117                                               clearColor, NULL );
 118       }
 119    }
 120    else {
 121       /* Color index mode */
 122       GLint i;
 123       ASSERT((ctx->Color.IndexMask & ((1 << ctx->Visual.indexBits) - 1))
 124              == (GLuint) ((1 << ctx->Visual.indexBits) - 1));
 125       ASSERT(swrast->Driver.WriteMonoCISpan);
 126       for (i = 0; i < height; i++) {
 127          (*swrast->Driver.WriteMonoCISpan)( ctx, width, x, y + i,
 128                                             ctx->Color.ClearIndex, NULL);
 129       }
 130    }
 131 }
 132
 133
 134
 135 /*
 136  * Clear the front/back/left/right color buffers.
 137  * This function is usually only called if we need to clear the
 138  * buffers with masking.
 139  */
 140 static void
 141 clear_color_buffers(GLcontext *ctx)
 142 {
 143    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 144    const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
 145    GLuint bufferBit;
 146
 147    /* loop over four possible dest color buffers */
 148    for (bufferBit = 1; bufferBit <= 8; bufferBit = bufferBit << 1) {
 149       if (bufferBit & ctx->Color._DrawDestMask) {
 150          (*swrast->Driver.SetBuffer)(ctx, ctx->DrawBuffer, bufferBit);
 151
 152          if (colorMask != 0xffffffff) {
 153             clear_color_buffer_with_masking(ctx);
 154          }
 155          else {
 156             clear_color_buffer(ctx);
 157          }
 158       }
 159    }
 160
 161    /* restore default read/draw buffer */
 162    _swrast_use_draw_buffer(ctx);
 163 }
 164
 165
 166
 167 void
 168 _swrast_Clear( GLcontext *ctx, GLbitfield mask,
 169                GLboolean all,
 170                GLint x, GLint y, GLint width, GLint height )
 171 {
 172    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 173 #ifdef DEBUG
 174    {
 175       GLbitfield legalBits = DD_FRONT_LEFT_BIT |
 176          DD_FRONT_RIGHT_BIT |
 177          DD_BACK_LEFT_BIT |
 178          DD_BACK_RIGHT_BIT |
 179          DD_DEPTH_BIT |
 180          DD_STENCIL_BIT |
 181          DD_ACCUM_BIT;
 182       assert((mask & (~legalBits)) == 0);
 183    }
 184 #endif
 185
 186    RENDER_START(swrast,ctx);
 187
 188    /* do software clearing here */
 189    if (mask) {
 190       if (mask & ctx->Color._DrawDestMask)   clear_color_buffers(ctx);
 191       if (mask & GL_DEPTH_BUFFER_BIT)    _swrast_clear_depth_buffer(ctx);
 192       if (mask & GL_ACCUM_BUFFER_BIT)    _swrast_clear_accum_buffer(ctx);
 193       if (mask & GL_STENCIL_BUFFER_BIT)  _swrast_clear_stencil_buffer(ctx);
 194    }
 195
 196    /* clear software-based alpha buffer(s) */
 197    if ( (mask & GL_COLOR_BUFFER_BIT)
 198         && ctx->DrawBuffer->UseSoftwareAlphaBuffers
 199         && ctx->Color.ColorMask[ACOMP]) {
 200       _swrast_clear_alpha_buffers( ctx );
 201    }
 202
 203    RENDER_FINISH(swrast,ctx);
 204 }
 205
 206
 207 void
 208 _swrast_alloc_buffers( GLframebuffer *buffer )
 209 {
 210    /* Reallocate other buffers if needed. */
 211    if (buffer->UseSoftwareDepthBuffer) {
 212       _swrast_alloc_depth_buffer( buffer );
 213    }
 214    if (buffer->UseSoftwareStencilBuffer) {
 215       _swrast_alloc_stencil_buffer( buffer );
 216    }
 217    if (buffer->UseSoftwareAccumBuffer) {
 218       _swrast_alloc_accum_buffer( buffer );
 219    }
 220    if (buffer->UseSoftwareAlphaBuffers) {
 221       _swrast_alloc_alpha_buffers( buffer );
 222    }
 223 }
 224
 225
 226 /*
 227  * Fallback for ctx->Driver.DrawBuffer()
 228  */
 229 void
 230 _swrast_DrawBuffer( GLcontext *ctx, GLenum mode )
 231 {
 232    _swrast_use_draw_buffer(ctx);
 233 }
 234
 235
 236 /*
 237  * Setup things so that we read/write spans from the user-designated
 238  * read buffer (set via glReadPixels).  We usually just have to call
 239  * this for glReadPixels, glCopyPixels, etc.
 240  */
 241 void
 242 _swrast_use_read_buffer( GLcontext *ctx )
 243 {
 244    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 245
 246    /* Do this so the software-emulated alpha plane span functions work! */
 247    swrast->CurrentBuffer = ctx->Pixel._ReadSrcMask;
 248    /* Tell the device driver where to read/write spans */
 249    (*swrast->Driver.SetBuffer)( ctx, ctx->ReadBuffer, swrast->CurrentBuffer );
 250 }
 251
 252
 253 /*
 254  * Setup things so that we read/write spans from the default draw buffer.
 255  * This is the usual mode that Mesa's software rasterizer operates in.
 256  */
 257 void
 258 _swrast_use_draw_buffer( GLcontext *ctx )
 259 {
 260    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 261
 262    /* The user can specify rendering to zero, one, two, or four color
 263     * buffers simultaneously with glDrawBuffer()!
 264     * We don't expect the span/point/line/triangle functions to deal with
 265     * that mess so we'll iterate over the multiple buffers as needed.
 266     * But usually we only render to one color buffer at a time.
 267     * We set ctx->Color._DriverDrawBuffer to that buffer and tell the
 268     * device driver to use that buffer.
 269     * Look in s_span.c's multi_write_rgba_span() function to see how
 270     * we loop over multiple color buffers when needed.
 271     */
 272
 273    if (ctx->Color._DrawDestMask & FRONT_LEFT_BIT)
 274       swrast->CurrentBuffer = FRONT_LEFT_BIT;
 275    else if (ctx->Color._DrawDestMask & BACK_LEFT_BIT)
 276       swrast->CurrentBuffer = BACK_LEFT_BIT;
 277    else if (ctx->Color._DrawDestMask & FRONT_RIGHT_BIT)
 278       swrast->CurrentBuffer = FRONT_RIGHT_BIT;
 279    else if (ctx->Color._DrawDestMask & BACK_RIGHT_BIT)
 280       swrast->CurrentBuffer = BACK_RIGHT_BIT;
 281    else
 282       /* glDrawBuffer(GL_NONE) */
 283       swrast->CurrentBuffer = FRONT_LEFT_BIT; /* we always have this buffer */
 284
 285    (*swrast->Driver.SetBuffer)( ctx, ctx->DrawBuffer, swrast->CurrentBuffer );
 286 }