st_cb_readpixels.h File Reference

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Functions
struct st_renderbuffer *	st_get_color_read_renderbuffer (GLcontext *ctx)
	Return renderbuffer to use for reading color pixels for glRead/CopyPixel commands.
void	st_read_stencil_pixels (GLcontext *ctx, GLint x, GLint y, GLsizei width, GLsizei height, GLenum type, const struct gl_pixelstore_attrib *packing, GLvoid *pixels)
	glReadPixels interface to pipe
void	st_init_readpixels_functions (struct dd_function_table *functions)

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Function Documentation

struct st_renderbuffer* st_get_color_read_renderbuffer

(

GLcontext *

ctx

)

[read]

Return renderbuffer to use for reading color pixels for glRead/CopyPixel commands.

Special care is needed for the front buffer.

Definition at line 143 of file st_cb_readpixels.c.

References FRONT_STATUS_COPY_OF_BACK, and st_renderbuffer().

{
   struct gl_framebuffer *fb = ctx->ReadBuffer;
   struct st_renderbuffer *strb =
      st_renderbuffer(fb->_ColorReadBuffer);
   struct st_renderbuffer *front = 
      st_renderbuffer(fb->Attachment[BUFFER_FRONT_LEFT].Renderbuffer);

   if (strb == front
       && ctx->st->frontbuffer_status == FRONT_STATUS_COPY_OF_BACK) {
      /* reading from front color buffer, which is a logical copy of the
       * back color buffer.
       */
      struct st_renderbuffer *back = 
         st_renderbuffer(fb->Attachment[BUFFER_BACK_LEFT].Renderbuffer);
      strb = back;
   }

   return strb;
}

void st_init_readpixels_functions

(

struct dd_function_table *

functions

)

Definition at line 461 of file st_cb_readpixels.c.

References st_readpixels().

{
   functions->ReadPixels = st_readpixels;
}

void st_read_stencil_pixels	(	GLcontext *	ctx,
		GLint	x,
		GLint	y,
		GLsizei	width,
		GLsizei	height,
		GLenum	type,
		const struct gl_pixelstore_attrib *	packing,
		GLvoid *	pixels
	)

glReadPixels interface to pipe

Author:

Brian Paul Special case for reading stencil buffer. For color/depth we use get_tile(). For stencil, map the stencil buffer.

Definition at line 58 of file st_cb_readpixels.c.

References assert, ASSERT, pipe_surface::format, pipe_screen::get_tex_surface, MAX_WIDTH, PIPE_BUFFER_USAGE_CPU_READ, PIPE_FORMAT_S8_UNORM, PIPE_FORMAT_S8Z24_UNORM, PIPE_FORMAT_Z24S8_UNORM, pipe_surface_reference(), st_fb_orientation(), st_renderbuffer(), pipe_surface::stride, pipe_screen::surface_map, pipe_screen::surface_unmap, st_renderbuffer::texture, and Y_0_TOP.

{
   struct gl_framebuffer *fb = ctx->ReadBuffer;
   struct pipe_screen *screen = ctx->st->pipe->screen;
   struct st_renderbuffer *strb = st_renderbuffer(fb->_StencilBuffer);
   struct pipe_surface *ps;
   ubyte *stmap;
   GLint j;

   /* Create a CPU-READ surface/view into the renderbuffer's texture */
   ps = screen->get_tex_surface(screen, strb->texture,  0, 0, 0,
                                PIPE_BUFFER_USAGE_CPU_READ);

   /* map the stencil buffer */
   stmap = screen->surface_map(screen, ps, PIPE_BUFFER_USAGE_CPU_READ);

   /* width should never be > MAX_WIDTH since we did clipping earlier */
   ASSERT(width <= MAX_WIDTH);

   /* process image row by row */
   for (j = 0; j < height; j++, y++) {
      GLvoid *dest;
      GLstencil values[MAX_WIDTH];
      GLint srcY;

      if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {
         srcY = ctx->DrawBuffer->Height - y - 1;
      }
      else {
         srcY = y;
      }

      /* get stencil values */
      switch (ps->format) {
      case PIPE_FORMAT_S8_UNORM:
         {
            const ubyte *src = stmap + srcY * ps->stride + x;
            memcpy(values, src, width);
         }
         break;
      case PIPE_FORMAT_S8Z24_UNORM:
         {
            const uint *src = (uint *) (stmap + srcY * ps->stride + x*4);
            GLint k;
            for (k = 0; k < width; k++) {
               values[k] = src[k] >> 24;
            }
         }
         break;
      case PIPE_FORMAT_Z24S8_UNORM:
         {
            const uint *src = (uint *) (stmap + srcY * ps->stride + x*4);
            GLint k;
            for (k = 0; k < width; k++) {
               values[k] = src[k] & 0xff;
            }
         }
         break;
      default:
         assert(0);
      }

      /* store */
      dest = _mesa_image_address2d(packing, pixels, width, height,
                                   GL_STENCIL_INDEX, type, j, 0);

      _mesa_pack_stencil_span(ctx, width, type, dest, values, packing);
   }


   /* unmap the stencil buffer */
   screen->surface_unmap(screen, ps);
   pipe_surface_reference(&ps, NULL);
}

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