/*
 * Copyright © 2012 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "mtypes.h"
#include "context.h"
#include "glformats.h"
#include "macros.h"
#include "enums.h"
#include "fbobject.h"
#include "formatquery.h"

/* default implementation of QuerySamplesForFormat driverfunc, for
 * non-multisample-capable drivers. */
size_t
_mesa_query_samples_for_format(struct gl_context *ctx, GLenum target,
                               GLenum internalFormat, int samples[16])
{
   (void) target;
   (void) internalFormat;
   (void) ctx;

   samples[0] = 1;
   return 1;
}


void GLAPIENTRY
_mesa_GetInternalformativ(GLenum target, GLenum internalformat, GLenum pname,
                          GLsizei bufSize, GLint *params)
{
   GLint buffer[16];
   GLsizei count = 0;
   GET_CURRENT_CONTEXT(ctx);

   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (!ctx->Extensions.ARB_internalformat_query) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glGetInternalformativ");
      return;
   }

   assert(ctx->Driver.QuerySamplesForFormat != NULL);

   /* The ARB_internalformat_query spec says:
    *
    *     "If the <target> parameter to GetInternalformativ is not one of
    *     TEXTURE_2D_MULTISAMPLE, TEXTURE_2D_MULTISAMPLE_ARRAY or RENDERBUFFER
    *     then an INVALID_ENUM error is generated."
    */
   switch (target) {
   case GL_RENDERBUFFER:
      break;

   case GL_TEXTURE_2D_MULTISAMPLE:
   case GL_TEXTURE_2D_MULTISAMPLE_ARRAY:
      /* These enums are only valid if ARB_texture_multisample is supported */
      if ((_mesa_is_desktop_gl(ctx) &&
           ctx->Extensions.ARB_texture_multisample) ||
          _mesa_is_gles31(ctx))
         break;

   default:
      _mesa_error(ctx, GL_INVALID_ENUM,
                  "glGetInternalformativ(target=%s)",
                  _mesa_enum_to_string(target));
      return;
   }

   /* The ARB_internalformat_query spec says:
    *
    *     "If the <internalformat> parameter to GetInternalformativ is not
    *     color-, depth- or stencil-renderable, then an INVALID_ENUM error is
    *     generated."
    *
    * Page 243 of the GLES 3.0.4 spec says this for GetInternalformativ:
    *
    *     "internalformat must be color-renderable, depth-renderable or
    *     stencilrenderable (as defined in section 4.4.4)."
    *
    * Section 4.4.4 on page 212 of the same spec says:
    *
    *     "An internal format is color-renderable if it is one of the
    *     formats from table 3.13 noted as color-renderable or if it
    *     is unsized format RGBA or RGB."
    *
    * Therefore, we must accept GL_RGB and GL_RGBA here.
    */
   if (internalformat != GL_RGB && internalformat != GL_RGBA &&
       _mesa_base_fbo_format(ctx, internalformat) == 0) {
      _mesa_error(ctx, GL_INVALID_ENUM,
                  "glGetInternalformativ(internalformat=%s)",
                  _mesa_enum_to_string(internalformat));
      return;
   }

   /* The ARB_internalformat_query spec says:
    *
    *     "If the <bufSize> parameter to GetInternalformativ is negative, then
    *     an INVALID_VALUE error is generated."
    */
   if (bufSize < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "glGetInternalformativ(target=%s)",
                  _mesa_enum_to_string(target));
      return;
   }

   switch (pname) {
   case GL_SAMPLES:
      count = ctx->Driver.QuerySamplesForFormat(ctx, target,
            internalformat, buffer);
      break;
   case GL_NUM_SAMPLE_COUNTS: {
      if ((ctx->API == API_OPENGLES2 && ctx->Version == 30) &&
          _mesa_is_enum_format_integer(internalformat)) {
         /* From GL ES 3.0 specification, section 6.1.15 page 236: "Since
          * multisampling is not supported for signed and unsigned integer
          * internal formats, the value of NUM_SAMPLE_COUNTS will be zero
          * for such formats.
          *
          * Such a restriction no longer exists in GL ES 3.1.
          */
         buffer[0] = 0;
         count = 1;
      } else {
         size_t num_samples;

         /* The driver can return 0, and we should pass that along to the
          * application.  The ARB decided that ARB_internalformat_query should
          * behave as ARB_internalformat_query2 in this situation.
          *
          * The ARB_internalformat_query2 spec says:
          *
          *     "- NUM_SAMPLE_COUNTS: The number of sample counts that would be
          *        returned by querying SAMPLES is returned in <params>.
          *        * If <internalformat> is not color-renderable,
          *          depth-renderable, or stencil-renderable (as defined in
          *          section 4.4.4), or if <target> does not support multiple
          *          samples (ie other than TEXTURE_2D_MULTISAMPLE,
          *          TEXTURE_2D_MULTISAMPLE_ARRAY, or RENDERBUFFER), 0 is
          *          returned."
          */
         num_samples =  ctx->Driver.QuerySamplesForFormat(ctx, target, internalformat, buffer);

         /* QuerySamplesForFormat writes some stuff to buffer, so we have to
          * separately over-write it with the requested value.
          */
         buffer[0] = (GLint) num_samples;
         count = 1;
      }
      break;
   }
   default:
      _mesa_error(ctx, GL_INVALID_ENUM,
                  "glGetInternalformativ(pname=%s)",
                  _mesa_enum_to_string(pname));
      return;
   }

   if (bufSize != 0 && params == NULL) {
      /* Emit a warning to aid application debugging, but go ahead and do the
       * memcpy (and probably crash) anyway.
       */
      _mesa_warning(ctx,
                    "glGetInternalformativ(bufSize = %d, but params = NULL)",
                    bufSize);
   }

   /* Copy the data from the temporary buffer to the buffer supplied by the
    * application.  Clamp the size of the copy to the size supplied by the
    * application.
    */
   memcpy(params, buffer, MIN2(count, bufSize) * sizeof(GLint));

   return;
}
