s_copypix.c

winNT技术操作系统,国外开放的原代码和LIUX一样

      if (ctx->Pixel.PixelTextureEnabled && ctx->Texture._EnabledUnits) {
         span.end = width;
         _swrast_pixel_texture(ctx, &span);
      }

      /* Write color span */
      if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
         drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
      }
      else if (zoom) {
         span.x = destx;
         span.y = dy;
         span.end = width;
         _swrast_write_zoomed_rgba_span(ctx, &span,
                                     (CONST GLchan (*)[4]) span.array->rgba,
                                     desty, 0);
      }
      else {
         span.x = destx;
         span.y = dy;
         span.end = width;
         _swrast_write_rgba_span(ctx, &span);
      }
   }

   if (overlapping)
      FREE(tmpImage);
}


static void
copy_ci_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
                GLint width, GLint height,
                GLint destx, GLint desty )
{
   GLuint *tmpImage,*p;
   GLint sy, dy, stepy;
   GLint j;
   GLboolean changeBuffer;
   const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
   const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
   GLint overlapping;
   struct sw_span span;

   if (!ctx->ReadBuffer->_ColorReadBuffer) {
      /* no readbuffer - OK */
      return;
   }

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

   /* Determine if copy should be bottom-to-top or top-to-bottom */
   if (srcy<desty) {
      /* top-down  max-to-min */
      sy = srcy + height - 1;
      dy = desty + height - 1;
      stepy = -1;
   }
   else {
      /* bottom-up  min-to-max */
      sy = srcy;
      dy = desty;
      stepy = 1;
   }

   if (ctx->DrawBuffer == ctx->ReadBuffer) {
      overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
                                    ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
   }
   else {
      overlapping = GL_FALSE;
   }

   if (ctx->Depth.Test)
      _swrast_span_default_z(ctx, &span);
   if (ctx->Fog.Enabled)
      _swrast_span_default_fog(ctx, &span);

   /* If read and draw buffer are different we must do buffer switching */
   changeBuffer = ctx->Pixel.ReadBuffer != ctx->Color.DrawBuffer[0]
               || ctx->DrawBuffer != ctx->ReadBuffer;

   if (overlapping) {
      GLint ssy = sy;
      tmpImage = (GLuint *) MALLOC(width * height * sizeof(GLuint));
      if (!tmpImage) {
         _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
         return;
      }
      /* setup source */
      if (changeBuffer)
         _swrast_use_read_buffer(ctx);
      /* read the image */
      p = tmpImage;
      for (j = 0; j < height; j++, ssy += stepy) {
         _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
                                  width, srcx, ssy, p );
         p += width;
      }
      p = tmpImage;
      /* restore to draw buffer */
      if (changeBuffer) {
         _swrast_use_draw_buffer(ctx);
         changeBuffer = GL_FALSE;
      }
   }
   else {
      tmpImage = NULL;  /* silence compiler warning */
      p = NULL;
   }

   for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
      /* Get color indexes */
      if (overlapping) {
         MEMCPY(span.array->index, p, width * sizeof(GLuint));
         p += width;
      }
      else {
         if (changeBuffer)
            _swrast_use_read_buffer(ctx);
         _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
                                  width, srcx, sy, span.array->index );
         if (changeBuffer)
            _swrast_use_draw_buffer(ctx);
      }

      /* Apply shift, offset, look-up table */
      if (shift_or_offset) {
         _mesa_shift_and_offset_ci( ctx, width, span.array->index );
      }
      if (ctx->Pixel.MapColorFlag) {
         _mesa_map_ci( ctx, width, span.array->index );
      }

      /* write color indexes */
      span.x = destx;
      span.y = dy;
      span.end = width;
      if (zoom)
         _swrast_write_zoomed_index_span(ctx, &span, desty, 0);
      else
         _swrast_write_index_span(ctx, &span);
   }

   if (overlapping)
      FREE(tmpImage);
}



/*
 * TODO: Optimize!!!!
 */
static void
copy_depth_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
                   GLint width, GLint height,
                   GLint destx, GLint desty )
{
   const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
   struct gl_renderbuffer *readRb
      = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
   GLfloat *p, *tmpImage;
   GLint sy, dy, stepy;
   GLint i, j;
   const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
   GLint overlapping;
   struct sw_span span;

   if (!readRb) {
      /* no readbuffer - OK */
      return;
   }

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

   if (!ctx->Visual.depthBits) {
      _mesa_error( ctx, GL_INVALID_OPERATION, "glCopyPixels" );
      return;
   }

   /* Determine if copy should be bottom-to-top or top-to-bottom */
   if (srcy<desty) {
      /* top-down  max-to-min */
      sy = srcy + height - 1;
      dy = desty + height - 1;
      stepy = -1;
   }
   else {
      /* bottom-up  min-to-max */
      sy = srcy;
      dy = desty;
      stepy = 1;
   }

   if (ctx->DrawBuffer == ctx->ReadBuffer) {
      overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
                                    ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
   }
   else {
      overlapping = GL_FALSE;
   }

   _swrast_span_default_color(ctx, &span);
   if (ctx->Fog.Enabled)
      _swrast_span_default_fog(ctx, &span);

   if (overlapping) {
      GLint ssy = sy;
      tmpImage = (GLfloat *) MALLOC(width * height * sizeof(GLfloat));
      if (!tmpImage) {
         _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
         return;
      }
      p = tmpImage;
      for (j = 0; j < height; j++, ssy += stepy) {
         _swrast_read_depth_span_float(ctx, readRb, width, srcx, ssy, p);
         p += width;
      }
      p = tmpImage;
   }
   else {
      tmpImage = NULL;  /* silence compiler warning */
      p = NULL;
   }

   for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
      GLfloat depth[MAX_WIDTH];
      /* get depth values */
      if (overlapping) {
         MEMCPY(depth, p, width * sizeof(GLfloat));
         p += width;
      }
      else {
         _swrast_read_depth_span_float(ctx, readRb, width, srcx, sy, depth);
      }

      /* apply scale and bias */
      for (i = 0; i < width; i++) {
         GLfloat d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
         span.array->z[i] = (GLdepth) (CLAMP(d, 0.0F, 1.0F) * depthMax);
      }

      /* write depth values */
      span.x = destx;
      span.y = dy;
      span.end = width;
      if (ctx->Visual.rgbMode) {
         if (zoom)
            _swrast_write_zoomed_rgba_span( ctx, &span, 
                            (const GLchan (*)[4])span.array->rgba, desty, 0 );
         else
            _swrast_write_rgba_span(ctx, &span);
      }
      else {
         if (zoom)
            _swrast_write_zoomed_index_span( ctx, &span, desty, 0 );
         else
            _swrast_write_index_span(ctx, &span);
      }
   }

   if (overlapping)
      FREE(tmpImage);
}



static void
copy_stencil_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
                     GLint width, GLint height,
                     GLint destx, GLint desty )
{
   struct gl_renderbuffer *rb
      = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
   GLint sy, dy, stepy;
   GLint j;
   GLstencil *p, *tmpImage;
   const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
   const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
   GLint overlapping;

   if (!ctx->Visual.stencilBits) {
      _mesa_error( ctx, GL_INVALID_OPERATION, "glCopyPixels" );
      return;
   }

   if (!rb) {
      /* no readbuffer - OK */
      return;
   }

   /* Determine if copy should be bottom-to-top or top-to-bottom */
   if (srcy < desty) {
      /* top-down  max-to-min */
      sy = srcy + height - 1;
      dy = desty + height - 1;
      stepy = -1;
   }
   else {
      /* bottom-up  min-to-max */
      sy = srcy;
      dy = desty;
      stepy = 1;
   }

   if (ctx->DrawBuffer == ctx->ReadBuffer) {
      overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
                                    ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
   }
   else {
      overlapping = GL_FALSE;
   }

   if (overlapping) {
      GLint ssy = sy;
      tmpImage = (GLstencil *) MALLOC(width * height * sizeof(GLstencil));
      if (!tmpImage) {
         _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
         return;
      }
      p = tmpImage;
      for (j = 0; j < height; j++, ssy += stepy) {
         _swrast_read_stencil_span( ctx, rb, width, srcx, ssy, p );
         p += width;
      }
      p = tmpImage;
   }
   else {
      tmpImage = NULL;  /* silence compiler warning */
      p = NULL;
   }

   for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
      GLstencil stencil[MAX_WIDTH];

      /* Get stencil values */
      if (overlapping) {
         MEMCPY(stencil, p, width * sizeof(GLstencil));
         p += width;
      }
      else {
         _swrast_read_stencil_span( ctx, rb, width, srcx, sy, stencil );
      }

      /* Apply shift, offset, look-up table */
      if (shift_or_offset) {
         _mesa_shift_and_offset_stencil( ctx, width, stencil );
      }
      if (ctx->Pixel.MapStencilFlag) {
         _mesa_map_stencil( ctx, width, stencil );
      }

      /* Write stencil values */
      if (zoom) {
         _swrast_write_zoomed_stencil_span( ctx, width, destx, dy,
                                          stencil, desty, 0 );
      }
      else {
         _swrast_write_stencil_span( ctx, width, destx, dy, stencil );
      }
   }

   if (overlapping)
      FREE(tmpImage);
}



void
_swrast_CopyPixels( GLcontext *ctx,
		    GLint srcx, GLint srcy, GLsizei width, GLsizei height,
		    GLint destx, GLint desty,
		    GLenum type )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   RENDER_START(swrast,ctx);
      
   if (swrast->NewState)
      _swrast_validate_derived( ctx );

   if (type == GL_COLOR && ctx->Visual.rgbMode) {
      copy_rgba_pixels( ctx, srcx, srcy, width, height, destx, desty );
   }
   else if (type == GL_COLOR && !ctx->Visual.rgbMode) {
      copy_ci_pixels( ctx, srcx, srcy, width, height, destx, desty );
   }
   else if (type == GL_DEPTH) {
      copy_depth_pixels( ctx, srcx, srcy, width, height, destx, desty );
   }
   else if (type == GL_STENCIL) {
      copy_stencil_pixels( ctx, srcx, srcy, width, height, destx, desty );
   }
   else {
      _mesa_error( ctx, GL_INVALID_ENUM, "glCopyPixels" );
   }

   RENDER_FINISH(swrast,ctx);
}