s_copypix.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

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

   /* Determine if copy should be bottom-to-top or top-to-bottom */
   if (!overlapping && 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 (overlapping) {
      GLint ssy = sy;
      tmpImage = (GLfloat *) _mesa_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) {
         _mesa_memcpy(depth, p, width * sizeof(GLfloat));
         p += width;
      }
      else {
         _swrast_read_depth_span_float(ctx, readRb, width, srcx, sy, depth);
      }

      /* apply scale and bias */
      scale_and_bias_z(ctx, width, depth, span.array->z);

      /* write depth values */
      span.x = destx;
      span.y = dy;
      span.end = width;
      if (fb->Visual.rgbMode) {
         if (zoom)
            _swrast_write_zoomed_depth_span(ctx, destx, desty, &span);
         else
            _swrast_write_rgba_span(ctx, &span);
      }
      else {
         if (zoom)
            _swrast_write_zoomed_depth_span(ctx, destx, desty, &span);
         else
            _swrast_write_index_span(ctx, &span);
      }
   }

   if (overlapping)
      _mesa_free(tmpImage);
}



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

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

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

   /* Determine if copy should be bottom-to-top or top-to-bottom */
   if (!overlapping && 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 (overlapping) {
      GLint ssy = sy;
      tmpImage = (GLstencil *) _mesa_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) {
         _mesa_memcpy(stencil, p, width * sizeof(GLstencil));
         p += width;
      }
      else {
         _swrast_read_stencil_span( ctx, rb, width, srcx, sy, stencil );
      }

      _mesa_apply_stencil_transfer_ops(ctx, width, stencil);

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

   if (overlapping)
      _mesa_free(tmpImage);
}


/**
 * This isn't terribly efficient.  If a driver really has combined
 * depth/stencil buffers the driver should implement an optimized
 * CopyPixels function.
 */
static void
copy_depth_stencil_pixels(GLcontext *ctx,
                          const GLint srcX, const GLint srcY,
                          const GLint width, const GLint height,
                          const GLint destX, const GLint destY)
{
   struct gl_renderbuffer *stencilReadRb, *depthReadRb, *depthDrawRb;
   GLint sy, dy, stepy;
   GLint j;
   GLstencil *tempStencilImage = NULL, *stencilPtr = NULL;
   GLfloat *tempDepthImage = NULL, *depthPtr = NULL;
   const GLfloat depthScale = ctx->DrawBuffer->_DepthMaxF;
   const GLuint stencilMask = ctx->Stencil.WriteMask[0];
   const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
   const GLboolean scaleOrBias
      = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
   GLint overlapping;

   depthDrawRb = ctx->DrawBuffer->_DepthBuffer;
   depthReadRb = ctx->ReadBuffer->_DepthBuffer;
   stencilReadRb = ctx->ReadBuffer->_StencilBuffer;

   ASSERT(depthDrawRb);
   ASSERT(depthReadRb);
   ASSERT(stencilReadRb);

   if (ctx->DrawBuffer == ctx->ReadBuffer) {
      overlapping = regions_overlap(srcX, srcY, destX, destY, width, height,
                                    ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
   }
   else {
      overlapping = GL_FALSE;
   }

   /* Determine if copy should be bottom-to-top or top-to-bottom */
   if (!overlapping && 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 (overlapping) {
      GLint ssy = sy;

      if (stencilMask != 0x0) {
         tempStencilImage
            = (GLstencil *) _mesa_malloc(width * height * sizeof(GLstencil));
         if (!tempStencilImage) {
            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
            return;
         }

         /* get copy of stencil pixels */
         stencilPtr = tempStencilImage;
         for (j = 0; j < height; j++, ssy += stepy) {
            _swrast_read_stencil_span(ctx, stencilReadRb,
                                      width, srcX, ssy, stencilPtr);
            stencilPtr += width;
         }
         stencilPtr = tempStencilImage;
      }

      if (ctx->Depth.Mask) {
         tempDepthImage
            = (GLfloat *) _mesa_malloc(width * height * sizeof(GLfloat));
         if (!tempDepthImage) {
            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
            _mesa_free(tempStencilImage);
            return;
         }

         /* get copy of depth pixels */
         depthPtr = tempDepthImage;
         for (j = 0; j < height; j++, ssy += stepy) {
            _swrast_read_depth_span_float(ctx, depthReadRb,
                                          width, srcX, ssy, depthPtr);
            depthPtr += width;
         }
         depthPtr = tempDepthImage;
      }
   }

   for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
      if (stencilMask != 0x0) {
         GLstencil stencil[MAX_WIDTH];

         /* Get stencil values */
         if (overlapping) {
            _mesa_memcpy(stencil, stencilPtr, width * sizeof(GLstencil));
            stencilPtr += width;
         }
         else {
            _swrast_read_stencil_span(ctx, stencilReadRb,
                                      width, srcX, sy, stencil);
         }

         _mesa_apply_stencil_transfer_ops(ctx, width, stencil);

         /* Write values */
         if (zoom) {
            _swrast_write_zoomed_stencil_span(ctx, destX, destY, width,
                                              destX, dy, stencil);
         }
         else {
            _swrast_write_stencil_span( ctx, width, destX, dy, stencil );
         }
      }

      if (ctx->Depth.Mask) {
         GLfloat depth[MAX_WIDTH];
         GLuint zVals32[MAX_WIDTH];
         GLushort zVals16[MAX_WIDTH];
         GLvoid *zVals;
         GLuint zBytes;

         /* get depth values */
         if (overlapping) {
            _mesa_memcpy(depth, depthPtr, width * sizeof(GLfloat));
            depthPtr += width;
         }
         else {
            _swrast_read_depth_span_float(ctx, depthReadRb,
                                          width, srcX, sy, depth);
         }

         /* scale & bias */
         if (scaleOrBias) {
            _mesa_scale_and_bias_depth(ctx, width, depth);
         }
         /* convert to integer Z values */
         if (depthDrawRb->DataType == GL_UNSIGNED_SHORT) {
            GLint k;
            for (k = 0; k < width; k++)
               zVals16[k] = (GLushort) (depth[k] * depthScale);
            zVals = zVals16;
            zBytes = 2;
         }
         else {
            GLint k;
            for (k = 0; k < width; k++)
               zVals32[k] = (GLuint) (depth[k] * depthScale);
            zVals = zVals32;
            zBytes = 4;
         }

         /* Write values */
         if (zoom) {
            _swrast_write_zoomed_z_span(ctx, destX, destY, width,
                                        destX, dy, zVals);
         }
         else {
            _swrast_put_row(ctx, depthDrawRb, width, destX, dy, zVals, zBytes);
         }
      }
   }

   if (tempStencilImage)
      _mesa_free(tempStencilImage);

   if (tempDepthImage)
      _mesa_free(tempDepthImage);
}



/**
 * Try to do a fast copy pixels.
 */
static GLboolean
fast_copy_pixels(GLcontext *ctx,
                 GLint srcX, GLint srcY, GLsizei width, GLsizei height,
                 GLint dstX, GLint dstY, GLenum type)
{
   struct gl_framebuffer *srcFb = ctx->ReadBuffer;
   struct gl_framebuffer *dstFb = ctx->DrawBuffer;
   struct gl_renderbuffer *srcRb, *dstRb;
   GLint row, yStep;

   if (SWRAST_CONTEXT(ctx)->_RasterMask != 0x0 ||
       ctx->Pixel.ZoomX != 1.0F ||
       ctx->Pixel.ZoomY != 1.0F ||
       ctx->_ImageTransferState) {
      /* can't handle these */
      return GL_FALSE;
   }

   if (type == GL_COLOR) {
      if (dstFb->_NumColorDrawBuffers != 1)
         return GL_FALSE;
      srcRb = srcFb->_ColorReadBuffer;
      dstRb = dstFb->_ColorDrawBuffers[0];
   }
   else if (type == GL_STENCIL) {
      srcRb = srcFb->_StencilBuffer;
      dstRb = dstFb->_StencilBuffer;
   }
   else if (type == GL_DEPTH) {
      srcRb = srcFb->_DepthBuffer;
      dstRb = dstFb->_DepthBuffer;
   }
   else {
      ASSERT(type == GL_DEPTH_STENCIL_EXT);
      /* XXX correct? */
      srcRb = srcFb->Attachment[BUFFER_DEPTH].Renderbuffer;
      dstRb = dstFb->Attachment[BUFFER_DEPTH].Renderbuffer;
   }

   /* src and dst renderbuffers must be same format and type */
   if (!srcRb || !dstRb ||
       srcRb->DataType != dstRb->DataType ||
       srcRb->_BaseFormat != dstRb->_BaseFormat) {
      return GL_FALSE;
   }

   /* clipping not supported */
   if (srcX < 0 || srcX + width > (GLint) srcFb->Width ||
       srcY < 0 || srcY + height > (GLint) srcFb->Height ||
       dstX < dstFb->_Xmin || dstX + width > dstFb->_Xmax ||
       dstY < dstFb->_Ymin || dstY + height > dstFb->_Ymax) {
      return GL_FALSE;
   }

   /* overlapping src/dst doesn't matter, just determine Y direction */
   if (srcY < dstY) {
      /* top-down  max-to-min */
      srcY = srcY + height - 1;
      dstY = dstY + height - 1;
      yStep = -1;
   }
   else {
      /* bottom-up  min-to-max */
      yStep = 1;
   }

   for (row = 0; row < height; row++) {
      GLuint temp[MAX_WIDTH][4];
      srcRb->GetRow(ctx, srcRb, width, srcX, srcY, temp);
      dstRb->PutRow(ctx, dstRb, width, dstX, dstY, temp, NULL);
      srcY += yStep;
      dstY += yStep;
   }

   return GL_TRUE;
}


/**
 * Do software-based glCopyPixels.
 * By time we get here, all parameters will have been error-checked.
 */
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 (!fast_copy_pixels(ctx, srcx, srcy, width, height, destx, desty, type)) {
      switch (type) {
      case GL_COLOR:
         if (ctx->Visual.rgbMode) {
            copy_rgba_pixels( ctx, srcx, srcy, width, height, destx, desty );
         }
         else {
            copy_ci_pixels( ctx, srcx, srcy, width, height, destx, desty );
         }
         break;
      case GL_DEPTH:
         copy_depth_pixels( ctx, srcx, srcy, width, height, destx, desty );
         break;
      case GL_STENCIL:
         copy_stencil_pixels( ctx, srcx, srcy, width, height, destx, desty );
         break;
      case GL_DEPTH_STENCIL_EXT:
         copy_depth_stencil_pixels(ctx, srcx, srcy, width, height, destx, desty);
         break;
      default:
         _mesa_problem(ctx, "unexpected type in _swrast_CopyPixels");
      }
   }

   RENDER_FINISH(swrast,ctx);
}