/**************************************************************************
 *
 * Copyright 2009 Marek Olšák <maraeo@gmail.com>
 *
 * 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, sub license, 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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.
 *
 **************************************************************************/

/**
 * @file
 * Blitter utility to facilitate acceleration of the clear, clear_render_target, clear_depth_stencil
 * resource_copy_region functions.
 *
 * @author Marek Olšák
 */

#include "pipe/p_context.h"
#include "pipe/p_defines.h"
#include "util/u_inlines.h"
#include "pipe/p_shader_tokens.h"
#include "pipe/p_state.h"

#include "util/u_format.h"
#include "util/u_memory.h"
#include "util/u_math.h"
#include "util/u_blitter.h"
#include "util/u_draw_quad.h"
#include "util/u_sampler.h"
#include "util/u_simple_shaders.h"
#include "util/u_surface.h"
#include "util/u_texture.h"

#define INVALID_PTR ((void*)~0)

struct blitter_context_priv
{
   struct blitter_context base;

   struct pipe_resource *vbuf;  /**< quad */

   float vertices[4][2][4];   /**< {pos, color} or {pos, texcoord} */

   /* Templates for various state objects. */
   struct pipe_sampler_state template_sampler_state;

   /* Constant state objects. */
   /* Vertex shaders. */
   void *vs_col; /**< Vertex shader which passes {pos, color} to the output */
   void *vs_tex; /**< Vertex shader which passes {pos, texcoord} to the output.*/

   /* Fragment shaders. */
   /* The shader at index i outputs color to color buffers 0,1,...,i-1. */
   void *fs_col[PIPE_MAX_COLOR_BUFS+1];

   /* FS which outputs a color from a texture,
      where the index is PIPE_TEXTURE_* to be sampled. */
   void *fs_texfetch_col[PIPE_MAX_TEXTURE_TYPES];

   /* FS which outputs a depth from a texture,
      where the index is PIPE_TEXTURE_* to be sampled. */
   void *fs_texfetch_depth[PIPE_MAX_TEXTURE_TYPES];

   /* Blend state. */
   void *blend_write_color;   /**< blend state with writemask of RGBA */
   void *blend_keep_color;    /**< blend state with writemask of 0 */

   /* Depth stencil alpha state. */
   void *dsa_write_depth_stencil;
   void *dsa_write_depth_keep_stencil;
   void *dsa_keep_depth_stencil;
   void *dsa_keep_depth_write_stencil;

   void *velem_state;

   /* Sampler state for clamping to a miplevel. */
   void *sampler_state[PIPE_MAX_TEXTURE_LEVELS];

   /* Rasterizer state. */
   void *rs_state;

   /* Viewport state. */
   struct pipe_viewport_state viewport;

   /* Clip state. */
   struct pipe_clip_state clip;

   /* Destination surface dimensions. */
   unsigned dst_width;
   unsigned dst_height;
};

struct blitter_context *util_blitter_create(struct pipe_context *pipe)
{
   struct blitter_context_priv *ctx;
   struct pipe_blend_state blend;
   struct pipe_depth_stencil_alpha_state dsa;
   struct pipe_rasterizer_state rs_state;
   struct pipe_sampler_state *sampler_state;
   struct pipe_vertex_element velem[2];
   unsigned i;

   ctx = CALLOC_STRUCT(blitter_context_priv);
   if (!ctx)
      return NULL;

   ctx->base.pipe = pipe;

   /* init state objects for them to be considered invalid */
   ctx->base.saved_blend_state = INVALID_PTR;
   ctx->base.saved_dsa_state = INVALID_PTR;
   ctx->base.saved_rs_state = INVALID_PTR;
   ctx->base.saved_fs = INVALID_PTR;
   ctx->base.saved_vs = INVALID_PTR;
   ctx->base.saved_velem_state = INVALID_PTR;
   ctx->base.saved_fb_state.nr_cbufs = ~0;
   ctx->base.saved_num_sampler_views = ~0;
   ctx->base.saved_num_sampler_states = ~0;
   ctx->base.saved_num_vertex_buffers = ~0;

   /* blend state objects */
   memset(&blend, 0, sizeof(blend));
   ctx->blend_keep_color = pipe->create_blend_state(pipe, &blend);

   blend.rt[0].colormask = PIPE_MASK_RGBA;
   ctx->blend_write_color = pipe->create_blend_state(pipe, &blend);

   /* depth stencil alpha state objects */
   memset(&dsa, 0, sizeof(dsa));
   ctx->dsa_keep_depth_stencil =
      pipe->create_depth_stencil_alpha_state(pipe, &dsa);

   dsa.depth.enabled = 1;
   dsa.depth.writemask = 1;
   dsa.depth.func = PIPE_FUNC_ALWAYS;
   ctx->dsa_write_depth_keep_stencil =
      pipe->create_depth_stencil_alpha_state(pipe, &dsa);

   dsa.stencil[0].enabled = 1;
   dsa.stencil[0].func = PIPE_FUNC_ALWAYS;
   dsa.stencil[0].fail_op = PIPE_STENCIL_OP_REPLACE;
   dsa.stencil[0].zpass_op = PIPE_STENCIL_OP_REPLACE;
   dsa.stencil[0].zfail_op = PIPE_STENCIL_OP_REPLACE;
   dsa.stencil[0].valuemask = 0xff;
   dsa.stencil[0].writemask = 0xff;
   ctx->dsa_write_depth_stencil =
      pipe->create_depth_stencil_alpha_state(pipe, &dsa);


   dsa.depth.enabled = 0;
   dsa.depth.writemask = 0;
   ctx->dsa_keep_depth_write_stencil =
      pipe->create_depth_stencil_alpha_state(pipe, &dsa);

   /* sampler state */
   sampler_state = &ctx->template_sampler_state;
   sampler_state->wrap_s = PIPE_TEX_WRAP_CLAMP_TO_EDGE;
   sampler_state->wrap_t = PIPE_TEX_WRAP_CLAMP_TO_EDGE;
   sampler_state->wrap_r = PIPE_TEX_WRAP_CLAMP_TO_EDGE;
   sampler_state->normalized_coords = TRUE;
   /* The sampler state objects which sample from a specified mipmap level
    * are created on-demand. */

   /* rasterizer state */
   memset(&rs_state, 0, sizeof(rs_state));
   rs_state.cull_face = PIPE_FACE_NONE;
   rs_state.gl_rasterization_rules = 1;
   rs_state.flatshade = 1;
   ctx->rs_state = pipe->create_rasterizer_state(pipe, &rs_state);

   /* vertex elements state */
   memset(&velem[0], 0, sizeof(velem[0]) * 2);
   for (i = 0; i < 2; i++) {
      velem[i].src_offset = i * 4 * sizeof(float);
      velem[i].instance_divisor = 0;
      velem[i].vertex_buffer_index = 0;
      velem[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
   }
   ctx->velem_state = pipe->create_vertex_elements_state(pipe, 2, &velem[0]);

   /* fragment shaders are created on-demand */

   /* vertex shaders */
   {
      const uint semantic_names[] = { TGSI_SEMANTIC_POSITION,
                                      TGSI_SEMANTIC_COLOR };
      const uint semantic_indices[] = { 0, 0 };
      ctx->vs_col =
         util_make_vertex_passthrough_shader(pipe, 2, semantic_names,
                                             semantic_indices);
   }
   {
      const uint semantic_names[] = { TGSI_SEMANTIC_POSITION,
                                      TGSI_SEMANTIC_GENERIC };
      const uint semantic_indices[] = { 0, 0 };
      ctx->vs_tex =
         util_make_vertex_passthrough_shader(pipe, 2, semantic_names,
                                             semantic_indices);
   }

   /* set invariant vertex coordinates */
   for (i = 0; i < 4; i++)
      ctx->vertices[i][0][3] = 1; /*v.w*/

   /* create the vertex buffer */
   ctx->vbuf = pipe_buffer_create(ctx->base.pipe->screen,
                                  PIPE_BIND_VERTEX_BUFFER,
                                  sizeof(ctx->vertices));

   return &ctx->base;
}

void util_blitter_destroy(struct blitter_context *blitter)
{
   struct blitter_context_priv *ctx = (struct blitter_context_priv*)blitter;
   struct pipe_context *pipe = blitter->pipe;
   int i;

   pipe->delete_blend_state(pipe, ctx->blend_write_color);
   pipe->delete_blend_state(pipe, ctx->blend_keep_color);
   pipe->delete_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_stencil);
   pipe->delete_depth_stencil_alpha_state(pipe,
                                          ctx->dsa_write_depth_keep_stencil);
   pipe->delete_depth_stencil_alpha_state(pipe, ctx->dsa_write_depth_stencil);
   pipe->delete_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_write_stencil);

   pipe->delete_rasterizer_state(pipe, ctx->rs_state);
   pipe->delete_vs_state(pipe, ctx->vs_col);
   pipe->delete_vs_state(pipe, ctx->vs_tex);
   pipe->delete_vertex_elements_state(pipe, ctx->velem_state);

   for (i = 0; i < PIPE_MAX_TEXTURE_TYPES; i++) {
      if (ctx->fs_texfetch_col[i])
         pipe->delete_fs_state(pipe, ctx->fs_texfetch_col[i]);
      if (ctx->fs_texfetch_depth[i])
         pipe->delete_fs_state(pipe, ctx->fs_texfetch_depth[i]);
   }

   for (i = 0; i <= PIPE_MAX_COLOR_BUFS && ctx->fs_col[i]; i++)
      if (ctx->fs_col[i])
         pipe->delete_fs_state(pipe, ctx->fs_col[i]);

   for (i = 0; i < PIPE_MAX_TEXTURE_LEVELS; i++)
      if (ctx->sampler_state[i])
         pipe->delete_sampler_state(pipe, ctx->sampler_state[i]);

   pipe_resource_reference(&ctx->vbuf, NULL);
   FREE(ctx);
}

static void blitter_check_saved_CSOs(struct blitter_context_priv *ctx)
{
   /* make sure these CSOs have been saved */
   assert(ctx->base.saved_blend_state != INVALID_PTR &&
          ctx->base.saved_dsa_state != INVALID_PTR &&
          ctx->base.saved_rs_state != INVALID_PTR &&
          ctx->base.saved_fs != INVALID_PTR &&
          ctx->base.saved_vs != INVALID_PTR &&
          ctx->base.saved_velem_state != INVALID_PTR);
}

static void blitter_restore_CSOs(struct blitter_context_priv *ctx)
{
   struct pipe_context *pipe = ctx->base.pipe;
   unsigned i;

   /* restore the state objects which are always required to be saved */
   pipe->bind_blend_state(pipe, ctx->base.saved_blend_state);
   pipe->bind_depth_stencil_alpha_state(pipe, ctx->base.saved_dsa_state);
   pipe->bind_rasterizer_state(pipe, ctx->base.saved_rs_state);
   pipe->bind_fs_state(pipe, ctx->base.saved_fs);
   pipe->bind_vs_state(pipe, ctx->base.saved_vs);
   pipe->bind_vertex_elements_state(pipe, ctx->base.saved_velem_state);

   ctx->base.saved_blend_state = INVALID_PTR;
   ctx->base.saved_dsa_state = INVALID_PTR;
   ctx->base.saved_rs_state = INVALID_PTR;
   ctx->base.saved_fs = INVALID_PTR;
   ctx->base.saved_vs = INVALID_PTR;
   ctx->base.saved_velem_state = INVALID_PTR;

   pipe->set_stencil_ref(pipe, &ctx->base.saved_stencil_ref);

   pipe->set_viewport_state(pipe, &ctx->base.saved_viewport);
   pipe->set_clip_state(pipe, &ctx->base.saved_clip);

   /* restore the state objects which are required to be saved before copy/fill
    */
   if (ctx->base.saved_fb_state.nr_cbufs != ~0) {
      pipe->set_framebuffer_state(pipe, &ctx->base.saved_fb_state);
      util_assign_framebuffer_state(&ctx->base.saved_fb_state, NULL);
      ctx->base.saved_fb_state.nr_cbufs = ~0;
   }

   if (ctx->base.saved_num_sampler_states != ~0) {
      pipe->bind_fragment_sampler_states(pipe,
                                         ctx->base.saved_num_sampler_states,
                                         ctx->base.saved_sampler_states);
      ctx->base.saved_num_sampler_states = ~0;
   }

   if (ctx->base.saved_num_sampler_views != ~0) {
      pipe->set_fragment_sampler_views(pipe,
                                       ctx->base.saved_num_sampler_views,
                                       ctx->base.saved_sampler_views);

      for (i = 0; i < ctx->base.saved_num_sampler_views; i++)
         pipe_sampler_view_reference(&ctx->base.saved_sampler_views[i],
                                     NULL);

      ctx->base.saved_num_sampler_views = ~0;
   }

   if (ctx->base.saved_num_vertex_buffers != ~0) {
      pipe->set_vertex_buffers(pipe,
                               ctx->base.saved_num_vertex_buffers,
                               ctx->base.saved_vertex_buffers);

      for (i = 0; i < ctx->base.saved_num_vertex_buffers; i++) {
         if (ctx->base.saved_vertex_buffers[i].buffer) {
            pipe_resource_reference(&ctx->base.saved_vertex_buffers[i].buffer,
                                    NULL);
         }
      }
      ctx->base.saved_num_vertex_buffers = ~0;
   }
}

static void blitter_set_rectangle(struct blitter_context_priv *ctx,
                                  unsigned x1, unsigned y1,
                                  unsigned x2, unsigned y2,
                                  float depth)
{
   int i;

   /* set vertex positions */
   ctx->vertices[0][0][0] = (float)x1 / ctx->dst_width * 2.0f - 1.0f; /*v0.x*/
   ctx->vertices[0][0][1] = (float)y1 / ctx->dst_height * 2.0f - 1.0f; /*v0.y*/

   ctx->vertices[1][0][0] = (float)x2 / ctx->dst_width * 2.0f - 1.0f; /*v1.x*/
   ctx->vertices[1][0][1] = (float)y1 / ctx->dst_height * 2.0f - 1.0f; /*v1.y*/

   ctx->vertices[2][0][0] = (float)x2 / ctx->dst_width * 2.0f - 1.0f; /*v2.x*/
   ctx->vertices[2][0][1] = (float)y2 / ctx->dst_height * 2.0f - 1.0f; /*v2.y*/

   ctx->vertices[3][0][0] = (float)x1 / ctx->dst_width * 2.0f - 1.0f; /*v3.x*/
   ctx->vertices[3][0][1] = (float)y2 / ctx->dst_height * 2.0f - 1.0f; /*v3.y*/

   for (i = 0; i < 4; i++)
      ctx->vertices[i][0][2] = depth; /*z*/

   /* viewport */
   ctx->viewport.scale[0] = 0.5f * ctx->dst_width;
   ctx->viewport.scale[1] = 0.5f * ctx->dst_height;
   ctx->viewport.scale[2] = 1.0f;
   ctx->viewport.scale[3] = 1.0f;
   ctx->viewport.translate[0] = 0.5f * ctx->dst_width;
   ctx->viewport.translate[1] = 0.5f * ctx->dst_height;
   ctx->viewport.translate[2] = 0.0f;
   ctx->viewport.translate[3] = 0.0f;
   ctx->base.pipe->set_viewport_state(ctx->base.pipe, &ctx->viewport);

   /* clip */
   ctx->base.pipe->set_clip_state(ctx->base.pipe, &ctx->clip);
}

static void blitter_set_clear_color(struct blitter_context_priv *ctx,
                                    const float *rgba)
{
   int i;

   if (rgba) {
      for (i = 0; i < 4; i++) {
         ctx->vertices[i][1][0] = rgba[0];
         ctx->vertices[i][1][1] = rgba[1];
         ctx->vertices[i][1][2] = rgba[2];
         ctx->vertices[i][1][3] = rgba[3];
      }
   } else {
      for (i = 0; i < 4; i++) {
         ctx->vertices[i][1][0] = 0;
         ctx->vertices[i][1][1] = 0;
         ctx->vertices[i][1][2] = 0;
         ctx->vertices[i][1][3] = 0;
      }
   }
}

static void blitter_set_texcoords_2d(struct blitter_context_priv *ctx,
                                     struct pipe_resource *src,
                                     struct pipe_subresource subsrc,
                                     unsigned x1, unsigned y1,
                                     unsigned x2, unsigned y2)
{
   int i;
   float s1 = x1 / (float)u_minify(src->width0,  subsrc.level);
   float t1 = y1 / (float)u_minify(src->height0, subsrc.level);
   float s2 = x2 / (float)u_minify(src->width0,  subsrc.level);
   float t2 = y2 / (float)u_minify(src->height0, subsrc.level);

   ctx->vertices[0][1][0] = s1; /*t0.s*/
   ctx->vertices[0][1][1] = t1; /*t0.t*/

   ctx->vertices[1][1][0] = s2; /*t1.s*/
   ctx->vertices[1][1][1] = t1; /*t1.t*/

   ctx->vertices[2][1][0] = s2; /*t2.s*/
   ctx->vertices[2][1][1] = t2; /*t2.t*/

   ctx->vertices[3][1][0] = s1; /*t3.s*/
   ctx->vertices[3][1][1] = t2; /*t3.t*/

   for (i = 0; i < 4; i++) {
      ctx->vertices[i][1][2] = 0; /*r*/
      ctx->vertices[i][1][3] = 1; /*q*/
   }
}

static void blitter_set_texcoords_3d(struct blitter_context_priv *ctx,
                                     struct pipe_resource *src,
                                     struct pipe_subresource subsrc,
                                     unsigned zslice,
                                     unsigned x1, unsigned y1,
                                     unsigned x2, unsigned y2)
{
   int i;
   float r = zslice / (float)u_minify(src->depth0, subsrc.level);

   blitter_set_texcoords_2d(ctx, src, subsrc, x1, y1, x2, y2);

   for (i = 0; i < 4; i++)
      ctx->vertices[i][1][2] = r; /*r*/
}

static void blitter_set_texcoords_cube(struct blitter_context_priv *ctx,
                                       struct pipe_resource *src,
                                       struct pipe_subresource subsrc,
                                       unsigned x1, unsigned y1,
                                       unsigned x2, unsigned y2)
{
   int i;
   float s1 = x1 / (float)u_minify(src->width0,  subsrc.level);
   float t1 = y1 / (float)u_minify(src->height0, subsrc.level);
   float s2 = x2 / (float)u_minify(src->width0,  subsrc.level);
   float t2 = y2 / (float)u_minify(src->height0, subsrc.level);
   float st[4][2];

   st[0][0] = s1;
   st[0][1] = t1;
   st[1][0] = s2;
   st[1][1] = t1;
   st[2][0] = s2;
   st[2][1] = t2;
   st[3][0] = s1;
   st[3][1] = t2;

   util_map_texcoords2d_onto_cubemap(subsrc.face,
                                     /* pointer, stride in floats */
                                     &st[0][0], 2,
                                     &ctx->vertices[0][1][0], 8);

   for (i = 0; i < 4; i++)
      ctx->vertices[i][1][3] = 1; /*q*/
}

static void blitter_set_dst_dimensions(struct blitter_context_priv *ctx,
                                       unsigned width, unsigned height)
{
   ctx->dst_width = width;
   ctx->dst_height = height;
}

static void blitter_draw_quad(struct blitter_context_priv *ctx)
{
   struct pipe_context *pipe = ctx->base.pipe;

   /* write vertices and draw them */
   pipe_buffer_write(pipe, ctx->vbuf,
                     0, sizeof(ctx->vertices), ctx->vertices);

   util_draw_vertex_buffer(pipe, ctx->vbuf, 0, PIPE_PRIM_TRIANGLE_FAN,
                           4,  /* verts */
                           2); /* attribs/vert */
}

static INLINE
void **blitter_get_sampler_state(struct blitter_context_priv *ctx,
                                 int miplevel)
{
   struct pipe_context *pipe = ctx->base.pipe;
   struct pipe_sampler_state *sampler_state = &ctx->template_sampler_state;

   assert(miplevel < PIPE_MAX_TEXTURE_LEVELS);

   /* Create the sampler state on-demand. */
   if (!ctx->sampler_state[miplevel]) {
      sampler_state->lod_bias = miplevel;
      sampler_state->min_lod = miplevel;
      sampler_state->max_lod = miplevel;

      ctx->sampler_state[miplevel] = pipe->create_sampler_state(pipe,
                                                                sampler_state);
   }

   /* Return void** so that it can be passed to bind_fragment_sampler_states
    * directly. */
   return &ctx->sampler_state[miplevel];
}

static INLINE
void *blitter_get_fs_col(struct blitter_context_priv *ctx, unsigned num_cbufs)
{
   struct pipe_context *pipe = ctx->base.pipe;

   assert(num_cbufs <= PIPE_MAX_COLOR_BUFS);

   if (!ctx->fs_col[num_cbufs])
      ctx->fs_col[num_cbufs] =
         util_make_fragment_clonecolor_shader(pipe, num_cbufs);

   return ctx->fs_col[num_cbufs];
}

/** Convert PIPE_TEXTURE_x to TGSI_TEXTURE_x */
static unsigned
pipe_tex_to_tgsi_tex(enum pipe_texture_target pipe_tex_target)
{
   switch (pipe_tex_target) {
   case PIPE_TEXTURE_1D:
      return TGSI_TEXTURE_1D;
   case PIPE_TEXTURE_2D:
      return TGSI_TEXTURE_2D;
   case PIPE_TEXTURE_3D:
      return TGSI_TEXTURE_3D;
   case PIPE_TEXTURE_CUBE:
      return TGSI_TEXTURE_CUBE;
   default:
      assert(0 && "unexpected texture target");
      return TGSI_TEXTURE_UNKNOWN;
   }
}


static INLINE
void *blitter_get_fs_texfetch_col(struct blitter_context_priv *ctx,
                                  unsigned tex_target)
{
   struct pipe_context *pipe = ctx->base.pipe;

   assert(tex_target < PIPE_MAX_TEXTURE_TYPES);

   /* Create the fragment shader on-demand. */
   if (!ctx->fs_texfetch_col[tex_target]) {
      unsigned tgsi_tex = pipe_tex_to_tgsi_tex(tex_target);

      ctx->fs_texfetch_col[tex_target] =
        util_make_fragment_tex_shader(pipe, tgsi_tex, TGSI_INTERPOLATE_LINEAR);
   }

   return ctx->fs_texfetch_col[tex_target];
}

static INLINE
void *blitter_get_fs_texfetch_depth(struct blitter_context_priv *ctx,
                                    unsigned tex_target)
{
   struct pipe_context *pipe = ctx->base.pipe;

   assert(tex_target < PIPE_MAX_TEXTURE_TYPES);

   /* Create the fragment shader on-demand. */
   if (!ctx->fs_texfetch_depth[tex_target]) {
      unsigned tgsi_tex = pipe_tex_to_tgsi_tex(tex_target);

      ctx->fs_texfetch_depth[tex_target] =
         util_make_fragment_tex_shader_writedepth(pipe, tgsi_tex,
                                                  TGSI_INTERPOLATE_LINEAR);
   }

   return ctx->fs_texfetch_depth[tex_target];
}

void util_blitter_clear(struct blitter_context *blitter,
                        unsigned width, unsigned height,
                        unsigned num_cbufs,
                        unsigned clear_buffers,
                        const float *rgba,
                        double depth, unsigned stencil)
{
   struct blitter_context_priv *ctx = (struct blitter_context_priv*)blitter;
   struct pipe_context *pipe = ctx->base.pipe;
   struct pipe_stencil_ref sr = { { 0 } };

   assert(num_cbufs <= PIPE_MAX_COLOR_BUFS);

   blitter_check_saved_CSOs(ctx);

   /* bind CSOs */
   if (clear_buffers & PIPE_CLEAR_COLOR)
      pipe->bind_blend_state(pipe, ctx->blend_write_color);
   else
      pipe->bind_blend_state(pipe, ctx->blend_keep_color);

   if ((clear_buffers & PIPE_CLEAR_DEPTHSTENCIL) == PIPE_CLEAR_DEPTHSTENCIL) {
      sr.ref_value[0] = stencil & 0xff;
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_write_depth_stencil);
      pipe->set_stencil_ref(pipe, &sr);
   }
   else if (clear_buffers & PIPE_CLEAR_DEPTH) {
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_write_depth_keep_stencil);
   }
   else if (clear_buffers & PIPE_CLEAR_STENCIL) {
      sr.ref_value[0] = stencil & 0xff;
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_write_stencil);
      pipe->set_stencil_ref(pipe, &sr);
   }
   else
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_stencil);

   pipe->bind_rasterizer_state(pipe, ctx->rs_state);
   pipe->bind_vertex_elements_state(pipe, ctx->velem_state);
   pipe->bind_fs_state(pipe, blitter_get_fs_col(ctx, num_cbufs));
   pipe->bind_vs_state(pipe, ctx->vs_col);

   blitter_set_dst_dimensions(ctx, width, height);
   blitter_set_clear_color(ctx, rgba);
   blitter_set_rectangle(ctx, 0, 0, width, height, depth);
   blitter_draw_quad(ctx);
   blitter_restore_CSOs(ctx);
}

static
boolean is_overlap(unsigned sx1, unsigned sx2, unsigned sy1, unsigned sy2,
                   unsigned dx1, unsigned dx2, unsigned dy1, unsigned dy2)
{
   return sx1 < dx2 && sx2 > dx1 && sy1 < dy2 && sy2 > dy1;
}

void util_blitter_copy_region(struct blitter_context *blitter,
                              struct pipe_resource *dst,
                              struct pipe_subresource subdst,
                              unsigned dstx, unsigned dsty, unsigned dstz,
                              struct pipe_resource *src,
                              struct pipe_subresource subsrc,
                              unsigned srcx, unsigned srcy, unsigned srcz,
                              unsigned width, unsigned height,
                              boolean ignore_stencil)
{
   struct blitter_context_priv *ctx = (struct blitter_context_priv*)blitter;
   struct pipe_context *pipe = ctx->base.pipe;
   struct pipe_screen *screen = pipe->screen;
   struct pipe_surface *dstsurf;
   struct pipe_framebuffer_state fb_state;
   struct pipe_sampler_view viewTempl, *view;
   unsigned bind;
   boolean is_stencil, is_depth;

   /* Give up if textures are not set. */
   assert(dst && src);
   if (!dst || !src)
      return;

   /* Sanity checks. */
   if (dst == src) {
      assert(!is_overlap(srcx, srcx + width, srcy, srcy + height,
                         dstx, dstx + width, dsty, dsty + height));
   } else {
      assert(dst->format == src->format);
   }
   assert(src->target < PIPE_MAX_TEXTURE_TYPES);

   /* Is this a ZS format? */
   is_depth = util_format_get_component_bits(src->format, UTIL_FORMAT_COLORSPACE_ZS, 0) != 0;
   is_stencil = util_format_get_component_bits(src->format, UTIL_FORMAT_COLORSPACE_ZS, 1) != 0;

   if (is_depth || is_stencil)
      bind = PIPE_BIND_DEPTH_STENCIL;
   else
      bind = PIPE_BIND_RENDER_TARGET;

   /* Check if we can sample from and render to the surfaces. */
   /* (assuming copying a stencil buffer is not possible) */
    if ((!ignore_stencil && is_stencil) ||
       !screen->is_format_supported(screen, dst->format, dst->target,
                                    dst->nr_samples, bind, 0) ||
       !screen->is_format_supported(screen, src->format, src->target,
                                    src->nr_samples, PIPE_BIND_SAMPLER_VIEW, 0)) {
      util_resource_copy_region(pipe, dst, subdst, dstx, dsty, dstz,
                                src, subsrc, srcx, srcy, srcz, width, height);
      return;
   }

   /* Get surfaces. */
   dstsurf = screen->get_tex_surface(screen, dst,
                                     subdst.face, subdst.level, dstz,
                                     bind);

   /* Check whether the states are properly saved. */
   blitter_check_saved_CSOs(ctx);
   assert(blitter->saved_fb_state.nr_cbufs != ~0);
   assert(blitter->saved_num_sampler_views != ~0);
   assert(blitter->saved_num_sampler_states != ~0);

   /* Initialize framebuffer state. */
   fb_state.width = dstsurf->width;
   fb_state.height = dstsurf->height;

   if (is_depth) {
      pipe->bind_blend_state(pipe, ctx->blend_keep_color);
      pipe->bind_depth_stencil_alpha_state(pipe,
                                           ctx->dsa_write_depth_keep_stencil);
      pipe->bind_fs_state(pipe,
                          blitter_get_fs_texfetch_depth(ctx, src->target));

      fb_state.nr_cbufs = 0;
      fb_state.zsbuf = dstsurf;
   } else {
      pipe->bind_blend_state(pipe, ctx->blend_write_color);
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_stencil);
      pipe->bind_fs_state(pipe,
                          blitter_get_fs_texfetch_col(ctx, src->target));

      fb_state.nr_cbufs = 1;
      fb_state.cbufs[0] = dstsurf;
      fb_state.zsbuf = 0;
   }

   /* Initialize sampler view. */
   u_sampler_view_default_template(&viewTempl, src, src->format);
   view = pipe->create_sampler_view(pipe, src, &viewTempl);

   /* Set rasterizer state, shaders, and textures. */
   pipe->bind_rasterizer_state(pipe, ctx->rs_state);
   pipe->bind_vs_state(pipe, ctx->vs_tex);
   pipe->bind_fragment_sampler_states(pipe, 1,
                                      blitter_get_sampler_state(ctx, subsrc.level));
   pipe->bind_vertex_elements_state(pipe, ctx->velem_state);
   pipe->set_fragment_sampler_views(pipe, 1, &view);
   pipe->set_framebuffer_state(pipe, &fb_state);

   /* Set texture coordinates. */
   switch (src->target) {
      case PIPE_TEXTURE_1D:
      case PIPE_TEXTURE_2D:
         blitter_set_texcoords_2d(ctx, src, subsrc,
                                  srcx, srcy, srcx+width, srcy+height);
         break;
      case PIPE_TEXTURE_3D:
         blitter_set_texcoords_3d(ctx, src, subsrc, srcz,
                                  srcx, srcy, srcx+width, srcy+height);
         break;
      case PIPE_TEXTURE_CUBE:
         blitter_set_texcoords_cube(ctx, src, subsrc,
                                    srcx, srcy, srcx+width, srcy+height);
         break;
      default:
         assert(0);
         return;
   }

   blitter_set_dst_dimensions(ctx, dstsurf->width, dstsurf->height);
   blitter_set_rectangle(ctx, dstx, dsty, dstx+width, dsty+height, 0);
   blitter_draw_quad(ctx);
   blitter_restore_CSOs(ctx);

   pipe_surface_reference(&dstsurf, NULL);
   pipe_sampler_view_reference(&view, NULL);
}

/* Clear a region of a color surface to a constant value. */
void util_blitter_clear_render_target(struct blitter_context *blitter,
                                      struct pipe_surface *dstsurf,
                                      const float *rgba,
                                      unsigned dstx, unsigned dsty,
                                      unsigned width, unsigned height)
{
   struct blitter_context_priv *ctx = (struct blitter_context_priv*)blitter;
   struct pipe_context *pipe = ctx->base.pipe;
   struct pipe_framebuffer_state fb_state;

   assert(dstsurf->texture);
   if (!dstsurf->texture)
      return;

   /* check the saved state */
   blitter_check_saved_CSOs(ctx);
   assert(blitter->saved_fb_state.nr_cbufs != ~0);

   /* bind CSOs */
   pipe->bind_blend_state(pipe, ctx->blend_write_color);
   pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_stencil);
   pipe->bind_rasterizer_state(pipe, ctx->rs_state);
   pipe->bind_fs_state(pipe, blitter_get_fs_col(ctx, 1));
   pipe->bind_vs_state(pipe, ctx->vs_col);
   pipe->bind_vertex_elements_state(pipe, ctx->velem_state);

   /* set a framebuffer state */
   fb_state.width = dstsurf->width;
   fb_state.height = dstsurf->height;
   fb_state.nr_cbufs = 1;
   fb_state.cbufs[0] = dstsurf;
   fb_state.zsbuf = 0;
   pipe->set_framebuffer_state(pipe, &fb_state);

   blitter_set_dst_dimensions(ctx, dstsurf->width, dstsurf->height);
   blitter_set_clear_color(ctx, rgba);
   blitter_set_rectangle(ctx, dstx, dsty, dstx+width, dsty+height, 0);
   blitter_draw_quad(ctx);
   blitter_restore_CSOs(ctx);
}

/* Clear a region of a depth stencil surface. */
void util_blitter_clear_depth_stencil(struct blitter_context *blitter,
                                      struct pipe_surface *dstsurf,
                                      unsigned clear_flags,
                                      double depth,
                                      unsigned stencil,
                                      unsigned dstx, unsigned dsty,
                                      unsigned width, unsigned height)
{
   struct blitter_context_priv *ctx = (struct blitter_context_priv*)blitter;
   struct pipe_context *pipe = ctx->base.pipe;
   struct pipe_framebuffer_state fb_state;
   struct pipe_stencil_ref sr = { { 0 } };

   assert(dstsurf->texture);
   if (!dstsurf->texture)
      return;

   /* check the saved state */
   blitter_check_saved_CSOs(ctx);
   assert(blitter->saved_fb_state.nr_cbufs != ~0);

   /* bind CSOs */
   pipe->bind_blend_state(pipe, ctx->blend_keep_color);
   if ((clear_flags & PIPE_CLEAR_DEPTHSTENCIL) == PIPE_CLEAR_DEPTHSTENCIL) {
      sr.ref_value[0] = stencil & 0xff;
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_write_depth_stencil);
      pipe->set_stencil_ref(pipe, &sr);
   }
   else if (clear_flags & PIPE_CLEAR_DEPTH) {
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_write_depth_keep_stencil);
   }
   else if (clear_flags & PIPE_CLEAR_STENCIL) {
      sr.ref_value[0] = stencil & 0xff;
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_write_stencil);
      pipe->set_stencil_ref(pipe, &sr);
   }
   else
      /* hmm that should be illegal probably, or make it a no-op somewhere */
      pipe->bind_depth_stencil_alpha_state(pipe, ctx->dsa_keep_depth_stencil);

   pipe->bind_rasterizer_state(pipe, ctx->rs_state);
   pipe->bind_fs_state(pipe, blitter_get_fs_col(ctx, 0));
   pipe->bind_vs_state(pipe, ctx->vs_col);
   pipe->bind_vertex_elements_state(pipe, ctx->velem_state);

   /* set a framebuffer state */
   fb_state.width = dstsurf->width;
   fb_state.height = dstsurf->height;
   fb_state.nr_cbufs = 0;
   fb_state.cbufs[0] = 0;
   fb_state.zsbuf = dstsurf;
   pipe->set_framebuffer_state(pipe, &fb_state);

   blitter_set_dst_dimensions(ctx, dstsurf->width, dstsurf->height);
   blitter_set_rectangle(ctx, dstx, dsty, dstx+width, dsty+height, depth);
   blitter_draw_quad(ctx);
   blitter_restore_CSOs(ctx);
}