/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
 *
 * 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 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.
 */

/**
 * Meta operations.  Some GL operations can be expressed in terms of
 * other GL operations.  For example, glBlitFramebuffer() can be done
 * with texture mapping and glClear() can be done with polygon rendering.
 *
 * \author Brian Paul
 */

#include "main/arrayobj.h"
#include "main/buffers.h"
#include "main/enums.h"
#include "main/enable.h"
#include "main/fbobject.h"
#include "main/macros.h"
#include "main/mipmap.h"
#include "main/teximage.h"
#include "main/texobj.h"
#include "main/texparam.h"
#include "main/varray.h"
#include "main/viewport.h"
#include "drivers/common/meta.h"


/**
 * Check if the call to _mesa_meta_GenerateMipmap() will require a
 * software fallback.  The fallback path will require that the texture
 * images are mapped.
 * \return GL_TRUE if a fallback is needed, GL_FALSE otherwise
 */
static bool
fallback_required(struct gl_context *ctx, GLenum target,
                  struct gl_texture_object *texObj)
{
   const GLuint fboSave = ctx->DrawBuffer->Name;
   struct gen_mipmap_state *mipmap = &ctx->Meta->Mipmap;
   struct gl_texture_image *baseImage;
   GLuint srcLevel;
   GLenum status;

   /* check for fallbacks */
   if (target == GL_TEXTURE_3D) {
      _mesa_perf_debug(ctx, MESA_DEBUG_SEVERITY_HIGH,
                       "glGenerateMipmap() to %s target\n",
                       _mesa_lookup_enum_by_nr(target));
      return true;
   }

   srcLevel = texObj->BaseLevel;
   baseImage = _mesa_select_tex_image(ctx, texObj, target, srcLevel);
   if (!baseImage) {
      _mesa_perf_debug(ctx, MESA_DEBUG_SEVERITY_HIGH,
                       "glGenerateMipmap() couldn't find base teximage\n");
      return true;
   }

   if (_mesa_is_format_compressed(baseImage->TexFormat)) {
      _mesa_perf_debug(ctx, MESA_DEBUG_SEVERITY_HIGH,
                       "glGenerateMipmap() with %s format\n",
                       _mesa_get_format_name(baseImage->TexFormat));
      return true;
   }

   if (_mesa_get_format_color_encoding(baseImage->TexFormat) == GL_SRGB &&
       !ctx->Extensions.EXT_texture_sRGB_decode) {
      /* The texture format is sRGB but we can't turn off sRGB->linear
       * texture sample conversion.  So we won't be able to generate the
       * right colors when rendering.  Need to use a fallback.
       */
      _mesa_perf_debug(ctx, MESA_DEBUG_SEVERITY_HIGH,
                       "glGenerateMipmap() of sRGB texture without "
                       "sRGB decode\n");
      return true;
   }

   /*
    * Test that we can actually render in the texture's format.
    */
   if (!mipmap->FBO)
      _mesa_GenFramebuffers(1, &mipmap->FBO);
   _mesa_BindFramebuffer(GL_FRAMEBUFFER_EXT, mipmap->FBO);

   _mesa_meta_bind_fbo_image(GL_COLOR_ATTACHMENT0, baseImage, 0);

   status = _mesa_CheckFramebufferStatus(GL_FRAMEBUFFER_EXT);

   _mesa_BindFramebuffer(GL_FRAMEBUFFER_EXT, fboSave);

   if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      _mesa_perf_debug(ctx, MESA_DEBUG_SEVERITY_HIGH,
                       "glGenerateMipmap() got incomplete FBO\n");
      return true;
   }

   return false;
}

void
_mesa_meta_glsl_generate_mipmap_cleanup(struct gen_mipmap_state *mipmap)
{
   if (mipmap->VAO == 0)
      return;
   _mesa_DeleteVertexArrays(1, &mipmap->VAO);
   mipmap->VAO = 0;
   _mesa_DeleteBuffers(1, &mipmap->VBO);
   mipmap->VBO = 0;

   _mesa_meta_blit_shader_table_cleanup(&mipmap->shaders);
}

static GLboolean
prepare_mipmap_level(struct gl_context *ctx,
                     struct gl_texture_object *texObj, GLuint level,
                     GLsizei width, GLsizei height, GLsizei depth,
                     GLenum intFormat, mesa_format format)
{
   if (texObj->Target == GL_TEXTURE_1D_ARRAY) {
      /* Work around Mesa expecting the number of array slices in "height". */
      height = depth;
      depth = 1;
   }

   return _mesa_prepare_mipmap_level(ctx, texObj, level, width, height, depth,
                                     0, intFormat, format);
}

/**
 * Called via ctx->Driver.GenerateMipmap()
 * Note: We don't yet support 3D textures, 1D/2D array textures or texture
 * borders.
 */
void
_mesa_meta_GenerateMipmap(struct gl_context *ctx, GLenum target,
                          struct gl_texture_object *texObj)
{
   struct gen_mipmap_state *mipmap = &ctx->Meta->Mipmap;
   struct vertex verts[4];
   const GLuint baseLevel = texObj->BaseLevel;
   const GLuint maxLevel = texObj->MaxLevel;
   const GLint maxLevelSave = texObj->MaxLevel;
   const GLboolean genMipmapSave = texObj->GenerateMipmap;
   const GLuint currentTexUnitSave = ctx->Texture.CurrentUnit;
   const GLboolean use_glsl_version = ctx->Extensions.ARB_vertex_shader &&
                                      ctx->Extensions.ARB_fragment_shader;
   GLenum faceTarget;
   GLuint dstLevel;
   GLuint samplerSave;

   if (fallback_required(ctx, target, texObj)) {
      _mesa_generate_mipmap(ctx, target, texObj);
      return;
   }

   if (target >= GL_TEXTURE_CUBE_MAP_POSITIVE_X &&
       target <= GL_TEXTURE_CUBE_MAP_NEGATIVE_Z) {
      faceTarget = target;
      target = GL_TEXTURE_CUBE_MAP;
   } else {
      faceTarget = target;
   }

   _mesa_meta_begin(ctx, MESA_META_ALL & ~MESA_META_DRAW_BUFFERS);

   /* Choose between glsl version and fixed function version of
    * GenerateMipmap function.
    */
   if (use_glsl_version) {
      _mesa_meta_setup_vertex_objects(&mipmap->VAO, &mipmap->VBO, true,
                                      2, 4, 0);
      _mesa_meta_setup_blit_shader(ctx, target, &mipmap->shaders);
   } else {
      _mesa_meta_setup_ff_tnl_for_blit(&mipmap->VAO, &mipmap->VBO, 3);
      _mesa_set_enable(ctx, target, GL_TRUE);
   }

   samplerSave = ctx->Texture.Unit[ctx->Texture.CurrentUnit].Sampler ?
      ctx->Texture.Unit[ctx->Texture.CurrentUnit].Sampler->Name : 0;

   if (currentTexUnitSave != 0)
      _mesa_BindTexture(target, texObj->Name);

   if (!mipmap->Sampler) {
      _mesa_GenSamplers(1, &mipmap->Sampler);
      _mesa_BindSampler(ctx->Texture.CurrentUnit, mipmap->Sampler);

      _mesa_SamplerParameteri(mipmap->Sampler,
                              GL_TEXTURE_MIN_FILTER,
                              GL_LINEAR_MIPMAP_LINEAR);
      _mesa_SamplerParameteri(mipmap->Sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      _mesa_SamplerParameteri(mipmap->Sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
      _mesa_SamplerParameteri(mipmap->Sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
      _mesa_SamplerParameteri(mipmap->Sampler, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

      /* We don't want to encode or decode sRGB values; treat them as linear.
       * This is not technically correct for GLES3 but we don't get any API
       * error at the moment.
       */
      if (ctx->Extensions.EXT_texture_sRGB_decode) {
         _mesa_SamplerParameteri(mipmap->Sampler, GL_TEXTURE_SRGB_DECODE_EXT,
               GL_SKIP_DECODE_EXT);
      }
   } else {
      _mesa_BindSampler(ctx->Texture.CurrentUnit, mipmap->Sampler);
   }

   assert(mipmap->FBO != 0);
   _mesa_BindFramebuffer(GL_FRAMEBUFFER_EXT, mipmap->FBO);

   _mesa_TexParameteri(target, GL_GENERATE_MIPMAP, GL_FALSE);

   /* Silence valgrind warnings about reading uninitialized stack. */
   memset(verts, 0, sizeof(verts));

   /* setup vertex positions */
   verts[0].x = -1.0F;
   verts[0].y = -1.0F;
   verts[1].x =  1.0F;
   verts[1].y = -1.0F;
   verts[2].x =  1.0F;
   verts[2].y =  1.0F;
   verts[3].x = -1.0F;
   verts[3].y =  1.0F;

   /* texture is already locked, unlock now */
   _mesa_unlock_texture(ctx, texObj);

   for (dstLevel = baseLevel + 1; dstLevel <= maxLevel; dstLevel++) {
      const struct gl_texture_image *srcImage;
      struct gl_texture_image *dstImage;
      const GLuint srcLevel = dstLevel - 1;
      GLuint layer;
      GLsizei srcWidth, srcHeight, srcDepth;
      GLsizei dstWidth, dstHeight, dstDepth;

      srcImage = _mesa_select_tex_image(ctx, texObj, faceTarget, srcLevel);
      assert(srcImage->Border == 0);

      /* src size */
      srcWidth = srcImage->Width;
      if (target == GL_TEXTURE_1D_ARRAY) {
         srcHeight = 1;
         srcDepth = srcImage->Height;
      } else {
         srcHeight = srcImage->Height;
         srcDepth = srcImage->Depth;
      }

      /* new dst size */
      dstWidth = minify(srcWidth, 1);
      dstHeight = minify(srcHeight, 1);
      dstDepth = target == GL_TEXTURE_3D ? minify(srcDepth, 1) : srcDepth;

      if (dstWidth == srcWidth &&
          dstHeight == srcHeight &&
          dstDepth == srcDepth) {
         /* all done */
         break;
      }

      /* Allocate storage for the destination mipmap image(s) */

      /* Set MaxLevel large enough to hold the new level when we allocate it */
      _mesa_TexParameteri(target, GL_TEXTURE_MAX_LEVEL, dstLevel);

      if (!prepare_mipmap_level(ctx, texObj, dstLevel,
                                dstWidth, dstHeight, dstDepth,
                                srcImage->InternalFormat,
                                srcImage->TexFormat)) {
         /* All done.  We either ran out of memory or we would go beyond the
          * last valid level of an immutable texture if we continued.
          */
         break;
      }
      dstImage = _mesa_select_tex_image(ctx, texObj, faceTarget, dstLevel);

      /* limit minification to src level */
      _mesa_TexParameteri(target, GL_TEXTURE_MAX_LEVEL, srcLevel);

      /* setup viewport */
      _mesa_set_viewport(ctx, 0, 0, 0, dstWidth, dstHeight);
      _mesa_DrawBuffer(GL_COLOR_ATTACHMENT0);

      for (layer = 0; layer < dstDepth; ++layer) {
         /* Setup texture coordinates */
         _mesa_meta_setup_texture_coords(faceTarget,
                                         layer,
                                         0, 0, 1, /* width, height never used here */
                                         verts[0].tex,
                                         verts[1].tex,
                                         verts[2].tex,
                                         verts[3].tex);

         /* upload vertex data */
         _mesa_BufferData(GL_ARRAY_BUFFER_ARB, sizeof(verts),
                          verts, GL_DYNAMIC_DRAW_ARB);

         _mesa_meta_bind_fbo_image(GL_COLOR_ATTACHMENT0, dstImage, layer);

         /* sanity check */
         if (_mesa_CheckFramebufferStatus(GL_FRAMEBUFFER) !=
             GL_FRAMEBUFFER_COMPLETE) {
            _mesa_problem(ctx, "Unexpected incomplete framebuffer in "
                          "_mesa_meta_GenerateMipmap()");
            break;
         }

         assert(dstWidth == ctx->DrawBuffer->Width);
         if (target == GL_TEXTURE_1D_ARRAY) {
            assert(dstHeight == 1);
         } else {
            assert(dstHeight == ctx->DrawBuffer->Height);
         }

         _mesa_DrawArrays(GL_TRIANGLE_FAN, 0, 4);
      }
   }

   _mesa_lock_texture(ctx, texObj); /* relock */

   _mesa_BindSampler(ctx->Texture.CurrentUnit, samplerSave);

   _mesa_meta_end(ctx);

   _mesa_TexParameteri(target, GL_TEXTURE_MAX_LEVEL, maxLevelSave);
   if (genMipmapSave)
      _mesa_TexParameteri(target, GL_GENERATE_MIPMAP, genMipmapSave);
}
