s_drawpix.c

mesa-6.5-minigui源码

            /* convert CI data to RGBA */
            if (ctx->Pixel.ZoomX==1.0F && ctx->Pixel.ZoomY==1.0F) {
               /* no zooming */
               GLint row;
               for (row=0; row<drawHeight; row++) {
                  ASSERT(drawWidth <= MAX_WIDTH);
                  _mesa_map_ci8_to_rgba(ctx, drawWidth, src, span.array->rgba);
                  rb->PutRow(ctx, rb, drawWidth, destX, destY,
                             span.array->rgba, NULL);
                  src += rowLength;
                  destY++;
               }
               return GL_TRUE;
            }
            else if (ctx->Pixel.ZoomX==1.0F && ctx->Pixel.ZoomY==-1.0F) {
               /* upside-down */
               GLint row;
               for (row=0; row<drawHeight; row++) {
                  ASSERT(drawWidth <= MAX_WIDTH);
                  _mesa_map_ci8_to_rgba(ctx, drawWidth, src, span.array->rgba);
                  destY--;
                  rb->PutRow(ctx, rb, drawWidth, destX, destY,
                             span.array->rgba, NULL);
                  src += rowLength;
               }
               return GL_TRUE;
            }
            else {
               /* with zooming */
               GLint row;
               for (row=0; row<drawHeight; row++) {
                  ASSERT(drawWidth <= MAX_WIDTH);
                  _mesa_map_ci8_to_rgba(ctx, drawWidth, src, span.array->rgba);
                  span.x = destX;
                  span.y = destY;
                  span.end = drawWidth;
                  _swrast_write_zoomed_rgba_span(ctx, imgX, imgY, &span,
                            (CONST GLchan (*)[4]) span.array->rgba);
                  src += rowLength;
                  destY++;
               }
               return GL_TRUE;
            }
         }
         else if (ctx->_ImageTransferState==0) {
            /* write CI data to CI frame buffer */
            GLint row;
            if (ctx->Pixel.ZoomX==1.0F && ctx->Pixel.ZoomY==1.0F) {
               /* no zooming */
               for (row=0; row<drawHeight; row++) {
                  GLuint index32[MAX_WIDTH];
                  GLint col;
                  for (col = 0; col < drawWidth; col++)
                     index32[col] = src[col];
                  rb->PutRow(ctx, rb, drawWidth, destX, destY, index32, NULL);
                  src += rowLength;
                  destY++;
               }
               return GL_TRUE;
            }
            else {
               /* with zooming */
               return GL_FALSE;
            }
         }
      }
      else {
         /* can't handle this pixel format and/or data type here */
         return GL_FALSE;
      }
   }

   /* can't do a simple draw, have to use slow path */
   return GL_FALSE;
}



/*
 * Draw color index image.
 */
static void
draw_index_pixels( GLcontext *ctx, GLint x, GLint y,
                   GLsizei width, GLsizei height,
                   GLenum type,
                   const struct gl_pixelstore_attrib *unpack,
                   const GLvoid *pixels )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   const GLint imgX = x, imgY = y;
   const GLboolean zoom = ctx->Pixel.ZoomX!=1.0 || ctx->Pixel.ZoomY!=1.0;
   GLint row, skipPixels;
   struct sw_span span;

   INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_INDEX);

   if (ctx->Depth.Test)
      _swrast_span_default_z(ctx, &span);
   if (swrast->_FogEnabled)
      _swrast_span_default_fog(ctx, &span);

   /*
    * General solution
    */
   skipPixels = 0;
   while (skipPixels < width) {
      const GLint spanWidth = MIN2(width - skipPixels, MAX_WIDTH);
      ASSERT(spanWidth <= MAX_WIDTH);
      for (row = 0; row < height; row++) {
         const GLvoid *source = _mesa_image_address2d(unpack, pixels,
                                                      width, height,
                                                      GL_COLOR_INDEX, type,
                                                      row, skipPixels);
         _mesa_unpack_index_span(ctx, spanWidth, GL_UNSIGNED_INT,
                                 span.array->index, type, source, unpack,
                                 ctx->_ImageTransferState);

         /* These may get changed during writing/clipping */
         span.x = x + skipPixels;
         span.y = y + row;
         span.end = spanWidth;
         
         if (zoom)
            _swrast_write_zoomed_index_span(ctx, imgX, imgY, &span);
         else
            _swrast_write_index_span(ctx, &span);
      }
      skipPixels += spanWidth;
   }
}



/*
 * Draw stencil image.
 */
static void
draw_stencil_pixels( GLcontext *ctx, GLint x, GLint y,
                     GLsizei width, GLsizei height,
                     GLenum type,
                     const struct gl_pixelstore_attrib *unpack,
                     const GLvoid *pixels )
{
   const GLboolean zoom = ctx->Pixel.ZoomX != 1.0 || ctx->Pixel.ZoomY != 1.0;
   GLint skipPixels;

   /* if width > MAX_WIDTH, have to process image in chunks */
   skipPixels = 0;
   while (skipPixels < width) {
      const GLint spanX = x + skipPixels;
      const GLint spanWidth = MIN2(width - skipPixels, MAX_WIDTH);
      GLint row;
      for (row = 0; row < height; row++) {
         const GLint spanY = y + row;
         GLstencil values[MAX_WIDTH];
         GLenum destType = (sizeof(GLstencil) == sizeof(GLubyte))
                         ? GL_UNSIGNED_BYTE : GL_UNSIGNED_SHORT;
         const GLvoid *source = _mesa_image_address2d(unpack, pixels,
                                                      width, height,
                                                      GL_COLOR_INDEX, type,
                                                      row, skipPixels);
         _mesa_unpack_index_span(ctx, spanWidth, destType, values,
                                 type, source, unpack,
                                 ctx->_ImageTransferState);
         if (ctx->_ImageTransferState & IMAGE_SHIFT_OFFSET_BIT) {
            _mesa_shift_and_offset_stencil(ctx, spanWidth, values);
         }
         if (ctx->Pixel.MapStencilFlag) {
            _mesa_map_stencil(ctx, spanWidth, values);
         }

         if (zoom) {
            _swrast_write_zoomed_stencil_span(ctx, x, y, spanWidth,
                                              spanX, spanY, values);
         }
         else {
            _swrast_write_stencil_span(ctx, spanWidth, spanX, spanY, values);
         }
      }
      skipPixels += spanWidth;
   }
}


/*
 * Draw depth image.
 */
static void
draw_depth_pixels( GLcontext *ctx, GLint x, GLint y,
                   GLsizei width, GLsizei height,
                   GLenum type,
                   const struct gl_pixelstore_attrib *unpack,
                   const GLvoid *pixels )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   const GLboolean scaleOrBias
      = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
   const GLboolean zoom = ctx->Pixel.ZoomX != 1.0 || ctx->Pixel.ZoomY != 1.0;
   struct sw_span span;

   INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_Z);

   _swrast_span_default_color(ctx, &span);

   if (swrast->_FogEnabled)
      _swrast_span_default_fog(ctx, &span);
   if (ctx->Texture._EnabledCoordUnits)
      _swrast_span_default_texcoords(ctx, &span);

   if (type == GL_UNSIGNED_SHORT
       && ctx->DrawBuffer->Visual.depthBits == 16
       && !scaleOrBias
       && !zoom
       && ctx->Visual.rgbMode
       && width <= MAX_WIDTH) {
      /* Special case: directly write 16-bit depth values */
      GLint row;
      for (row = 0; row < height; row++) {
         const GLushort *zSrc = (const GLushort *)
            _mesa_image_address2d(unpack, pixels, width, height,
                                  GL_DEPTH_COMPONENT, type, row, 0);
         GLint i;
         for (i = 0; i < width; i++)
            span.array->z[i] = zSrc[i];
         span.x = x;
         span.y = y + row;
         span.end = width;
         _swrast_write_rgba_span(ctx, &span);
      }
   }
   else if (type == GL_UNSIGNED_INT
            && !scaleOrBias
            && !zoom
            && ctx->Visual.rgbMode
            && width <= MAX_WIDTH) {
      /* Special case: shift 32-bit values down to Visual.depthBits */
      const GLint shift = 32 - ctx->DrawBuffer->Visual.depthBits;
      GLint row;
      for (row = 0; row < height; row++) {
         const GLuint *zSrc = (const GLuint *)
            _mesa_image_address2d(unpack, pixels, width, height,
                                  GL_DEPTH_COMPONENT, type, row, 0);
         if (shift == 0) {
            _mesa_memcpy(span.array->z, zSrc, width * sizeof(GLuint));
         }
         else {
            GLint col;
            for (col = 0; col < width; col++)
               span.array->z[col] = zSrc[col] >> shift;
         }
         span.x = x;
         span.y = y + row;
         span.end = width;
         _swrast_write_rgba_span(ctx, &span);
      }
   }
   else {
      /* General case */
      const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
      GLint skipPixels = 0;

      /* in case width > MAX_WIDTH do the copy in chunks */
      while (skipPixels < width) {
         const GLint spanWidth = MIN2(width - skipPixels, MAX_WIDTH);
         GLint row;
         ASSERT(span.end <= MAX_WIDTH);
         for (row = 0; row < height; row++) {
            const GLvoid *zSrc = _mesa_image_address2d(unpack,
                                                      pixels, width, height,
                                                      GL_DEPTH_COMPONENT, type,
                                                      row, skipPixels);

            /* Set these for each row since the _swrast_write_* function may
             * change them while clipping.
             */
            span.x = x + skipPixels;
            span.y = y + row;
            span.end = spanWidth;

            _mesa_unpack_depth_span(ctx, spanWidth,
                                    GL_UNSIGNED_INT, span.array->z, depthMax,
                                    type, zSrc, unpack);
            if (zoom) {
               _swrast_write_zoomed_depth_span(ctx, x, y, &span);
            }
            else if (ctx->Visual.rgbMode) {
               _swrast_write_rgba_span(ctx, &span);
            }
            else {
               _swrast_write_index_span(ctx, &span);
            }
         }
         skipPixels += spanWidth;
      }
   }
}



/*
 * Draw RGBA image.
 */
static void
draw_rgba_pixels( GLcontext *ctx, GLint x, GLint y,
                  GLsizei width, GLsizei height,
                  GLenum format, GLenum type,
                  const struct gl_pixelstore_attrib *unpack,
                  const GLvoid *pixels )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   const GLint imgX = x, imgY = y;
   struct gl_renderbuffer *rb = NULL; /* only used for quickDraw path */
   const GLboolean zoom = ctx->Pixel.ZoomX!=1.0 || ctx->Pixel.ZoomY!=1.0;
   GLboolean quickDraw;
   GLfloat *convImage = NULL;
   GLuint transferOps = ctx->_ImageTransferState;
   struct sw_span span;

   INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);

   /* Try an optimized glDrawPixels first */
   if (fast_draw_pixels(ctx, x, y, width, height, format, type, unpack, pixels))
      return;

   if (ctx->Depth.Test)
      _swrast_span_default_z(ctx, &span);
   if (swrast->_FogEnabled)
      _swrast_span_default_fog(ctx, &span);
   if (ctx->Texture._EnabledCoordUnits)
      _swrast_span_default_texcoords(ctx, &span);

   if (swrast->_RasterMask == 0 && !zoom && x >= 0 && y >= 0
       && x + width <= (GLint) ctx->DrawBuffer->Width
       && y + height <= (GLint) ctx->DrawBuffer->Height
       && ctx->DrawBuffer->_NumColorDrawBuffers[0] == 1) {
      quickDraw = GL_TRUE;
      rb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
   }
   else {
      quickDraw = GL_FALSE;
      rb = NULL;
   }

   if (ctx->Pixel.Convolution2DEnabled || ctx->Pixel.Separable2DEnabled) {
      /* Convolution has to be handled specially.  We'll create an
       * intermediate image, applying all pixel transfer operations
       * up to convolution.  Then we'll convolve the image.  Then
       * we'll proceed with the rest of the transfer operations and
       * rasterize the image.
       */
      GLint row;
      GLfloat *dest, *tmpImage;

      tmpImage = (GLfloat *) _mesa_malloc(width * height * 4 * sizeof(GLfloat));
      if (!tmpImage) {
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glDrawPixels");
         return;
      }
      convImage = (GLfloat *) _mesa_malloc(width * height * 4 * sizeof(GLfloat));
      if (!convImage) {
         _mesa_free(tmpImage);
         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glDrawPixels");
         return;
      }

      /* Unpack the image and apply transfer ops up to convolution */