state_trackers/vega/renderer.c

/**************************************************************************
 *
 * Copyright 2009 VMware, Inc.  All Rights Reserved.
 * Copyright 2010 LunarG, 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, 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 VMWARE 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.
 *
 **************************************************************************/

#include "renderer.h"

#include "vg_context.h"

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

#include "util/u_draw_quad.h"
#include "util/u_simple_shaders.h"
#include "util/u_memory.h"
#include "util/u_sampler.h"

#include "cso_cache/cso_context.h"
#include "tgsi/tgsi_ureg.h"

typedef enum {
   RENDERER_STATE_INIT,
   RENDERER_STATE_COPY,
   RENDERER_STATE_DRAWTEX,
   NUM_RENDERER_STATES
} RendererState;

typedef enum {
   RENDERER_VS_PLAIN,
   RENDERER_VS_COLOR,
   RENDERER_VS_TEXTURE,
   NUM_RENDERER_VS
} RendererVs;

typedef enum {
   RENDERER_FS_COLOR,
   RENDERER_FS_TEXTURE,
   NUM_RENDERER_FS
} RendererFs;

struct renderer {
   struct pipe_context *pipe;
   struct vg_context *owner;

   struct cso_context *cso;

   void *fs;

   VGfloat vertices[4][2][4];

   void *cached_vs[NUM_RENDERER_VS];
   void *cached_fs[NUM_RENDERER_FS];

   RendererState state;

   /* state data */
   union {
      struct {
         VGint tex_width;
         VGint tex_height;
      } copy;

      struct {
         VGint tex_width;
         VGint tex_height;
      } drawtex;
   } u;
};

/**
 * Return VG_TRUE if the renderer can use the resource as the asked bindings.
 */
static VGboolean renderer_can_support(struct renderer *renderer,
                                      struct pipe_resource *res,
                                      unsigned bindings)
{
   struct pipe_screen *screen = renderer->pipe->screen;

   return screen->is_format_supported(screen,
         res->format, res->target, 0, bindings, 0);
}

/**
 * Create a simple vertex shader that passes through position and the given
 * attribute.
 */
static void *create_passthrough_vs(struct pipe_context *pipe, int semantic_name)
{
   struct ureg_program *ureg;
   struct ureg_src src[2], constants[2];
   struct ureg_dst dst[2], tmp;
   int i;

   ureg = ureg_create(TGSI_PROCESSOR_VERTEX);
   if (!ureg)
      return NULL;

   /* position in surface coordinates */
   src[0] = ureg_DECL_vs_input(ureg, 0);
   dst[0] = ureg_DECL_output(ureg, TGSI_SEMANTIC_POSITION, 0);
   tmp = ureg_DECL_temporary(ureg);
   for (i = 0; i < 2; i++)
      constants[i] = ureg_DECL_constant(ureg, i);

   /* transform to clipped coordinates */
   ureg_MUL(ureg, tmp, src[0], constants[0]);
   ureg_ADD(ureg, tmp, ureg_src(tmp), constants[1]);
   ureg_MOV(ureg, dst[0], ureg_src(tmp));

   if (semantic_name >= 0) {
      src[1] = ureg_DECL_vs_input(ureg, 1);
      dst[1] = ureg_DECL_output(ureg, semantic_name, 0);
      ureg_MOV(ureg, dst[1], src[1]);
   }

   ureg_END(ureg);

   return ureg_create_shader_and_destroy(ureg, pipe);
}

/**
 * Set renderer vertex shader.
 *
 * This function modifies vertex_shader state.
 */
static void renderer_set_vs(struct renderer *r, RendererVs id)
{
   /* create as needed */
   if (!r->cached_vs[id]) {
      int semantic_name = -1;

      switch (id) {
      case RENDERER_VS_PLAIN:
         break;
      case RENDERER_VS_COLOR:
         semantic_name = TGSI_SEMANTIC_COLOR;
         break;
      case RENDERER_VS_TEXTURE:
         semantic_name = TGSI_SEMANTIC_GENERIC;
         break;
      default:
         assert(!"Unknown renderer vs id");
         break;
      }

      r->cached_vs[id] = create_passthrough_vs(r->pipe, semantic_name);
   }

   cso_set_vertex_shader_handle(r->cso, r->cached_vs[id]);
}

/**
 * Set renderer fragment shader.
 *
 * This function modifies fragment_shader state.
 */
static void renderer_set_fs(struct renderer *r, RendererFs id)
{
   /* create as needed */
   if (!r->cached_fs[id]) {
      void *fs = NULL;

      switch (id) {
      case RENDERER_FS_COLOR:
         fs = util_make_fragment_passthrough_shader(r->pipe);
         break;
      case RENDERER_FS_TEXTURE:
         fs = util_make_fragment_tex_shader(r->pipe,
               TGSI_TEXTURE_2D, TGSI_INTERPOLATE_LINEAR);
         break;
      default:
         assert(!"Unknown renderer fs id");
         break;
      }

      r->cached_fs[id] = fs;
   }

   cso_set_fragment_shader_handle(r->cso, r->cached_fs[id]);
}

/**
 * Set renderer target.
 *
 * This function modifies framebuffer and viewport states.
 */
static void renderer_set_target(struct renderer *r,
                                struct pipe_surface *cbuf,
                                struct pipe_surface *zsbuf,
                                VGboolean y0_top)
{
   struct pipe_framebuffer_state fb;

   memset(&fb, 0, sizeof(fb));
   fb.width = cbuf->width;
   fb.height = cbuf->height;
   fb.cbufs[0] = cbuf;
   fb.nr_cbufs = 1;
   fb.zsbuf = zsbuf;
   cso_set_framebuffer(r->cso, &fb);

   vg_set_viewport(r->owner, (y0_top) ? VEGA_Y0_TOP : VEGA_Y0_BOTTOM);
}

/**
 * Set renderer blend state.  Blending is disabled.
 *
 * This function modifies blend state.
 */
static void renderer_set_blend(struct renderer *r,
                               VGbitfield channel_mask)
{
   struct pipe_blend_state blend;

   memset(&blend, 0, sizeof(blend));

   blend.rt[0].rgb_src_factor = PIPE_BLENDFACTOR_ONE;
   blend.rt[0].alpha_src_factor = PIPE_BLENDFACTOR_ONE;
   blend.rt[0].rgb_dst_factor = PIPE_BLENDFACTOR_ZERO;
   blend.rt[0].alpha_dst_factor = PIPE_BLENDFACTOR_ZERO;

   if (channel_mask & VG_RED)
      blend.rt[0].colormask |= PIPE_MASK_R;
   if (channel_mask & VG_GREEN)
      blend.rt[0].colormask |= PIPE_MASK_G;
   if (channel_mask & VG_BLUE)
      blend.rt[0].colormask |= PIPE_MASK_B;
   if (channel_mask & VG_ALPHA)
      blend.rt[0].colormask |= PIPE_MASK_A;

   cso_set_blend(r->cso, &blend);
}

/**
 * Set renderer sampler and view states.
 *
 * This function modifies samplers and fragment_sampler_views states.
 */
static void renderer_set_samplers(struct renderer *r,
                                  uint num_views,
                                  struct pipe_sampler_view **views)
{
   struct pipe_sampler_state sampler;
   unsigned tex_filter = PIPE_TEX_FILTER_NEAREST;
   unsigned tex_wrap = PIPE_TEX_WRAP_CLAMP_TO_EDGE;
   uint i;

   memset(&sampler, 0, sizeof(sampler));

   sampler.min_img_filter = tex_filter;
   sampler.mag_img_filter = tex_filter;
   sampler.min_mip_filter = PIPE_TEX_MIPFILTER_NONE;

   sampler.wrap_s = tex_wrap;
   sampler.wrap_t = tex_wrap;
   sampler.wrap_r = PIPE_TEX_WRAP_CLAMP_TO_EDGE;

   sampler.normalized_coords = 1;

   /* set samplers */
   for (i = 0; i < num_views; i++)
      cso_single_sampler(r->cso, i, &sampler);
   cso_single_sampler_done(r->cso);

   /* set views */
   cso_set_fragment_sampler_views(r->cso, num_views, views);
}

/**
 * Setup renderer quad position.
 */
static void renderer_quad_pos(struct renderer *r,
                              VGfloat x0, VGfloat y0,
                              VGfloat x1, VGfloat y1,
                              VGboolean scissor)
{
   VGfloat z;

   /* the depth test is used for scissoring */
   z = (scissor) ? 0.0f : 1.0f;

   /* positions */
   r->vertices[0][0][0] = x0;
   r->vertices[0][0][1] = y0;
   r->vertices[0][0][2] = z;

   r->vertices[1][0][0] = x1;
   r->vertices[1][0][1] = y0;
   r->vertices[1][0][2] = z;

   r->vertices[2][0][0] = x1;
   r->vertices[2][0][1] = y1;
   r->vertices[2][0][2] = z;

   r->vertices[3][0][0] = x0;
   r->vertices[3][0][1] = y1;
   r->vertices[3][0][2] = z;
}

/**
 * Setup renderer quad texture coordinates.
 */
static void renderer_quad_texcoord(struct renderer *r,
                                   VGfloat x0, VGfloat y0,
                                   VGfloat x1, VGfloat y1,
                                   VGint tex_width, VGint tex_height)
{
   VGfloat s0, t0, s1, t1, r0, q0;
   VGint i;

   s0 = x0 / tex_width;
   s1 = x1 / tex_width;
   t0 = y0 / tex_height;
   t1 = y1 / tex_height;
   r0 = 0.0f;
   q0 = 1.0f;

   /* texcoords */
   r->vertices[0][1][0] = s0;
   r->vertices[0][1][1] = t0;

   r->vertices[1][1][0] = s1;
   r->vertices[1][1][1] = t0;

   r->vertices[2][1][0] = s1;
   r->vertices[2][1][1] = t1;

   r->vertices[3][1][0] = s0;
   r->vertices[3][1][1] = t1;

   for (i = 0; i < 4; i++) {
      r->vertices[i][1][2] = r0;
      r->vertices[i][1][3] = q0;
   }
}

/**
 * Draw renderer quad.
 */
static void renderer_quad_draw(struct renderer *r)
{
   struct pipe_resource *buf;

   buf = pipe_user_buffer_create(r->pipe->screen,
                                 r->vertices,
                                 sizeof(r->vertices),
                                 PIPE_BIND_VERTEX_BUFFER);
   if (buf) {
      cso_set_vertex_elements(r->cso, 2, r->owner->velems);
      util_draw_vertex_buffer(r->pipe, buf, 0,
                              PIPE_PRIM_TRIANGLE_FAN,
                              Elements(r->vertices),     /* verts */
                              Elements(r->vertices[0])); /* attribs/vert */

      pipe_resource_reference(&buf, NULL);
   }
}

/**
 * Prepare the renderer for copying.
 */
VGboolean renderer_copy_begin(struct renderer *renderer,
                              struct pipe_surface *dst,
                              VGboolean y0_top,
                              struct pipe_sampler_view *src)
{
   assert(renderer->state == RENDERER_STATE_INIT);

   /* sanity check */
   if (!renderer_can_support(renderer,
            dst->texture, PIPE_BIND_RENDER_TARGET) ||
       !renderer_can_support(renderer,
          src->texture, PIPE_BIND_SAMPLER_VIEW))
      return VG_FALSE;

   cso_save_framebuffer(renderer->cso);
   cso_save_viewport(renderer->cso);
   cso_save_blend(renderer->cso);
   cso_save_samplers(renderer->cso);
   cso_save_fragment_sampler_views(renderer->cso);
   cso_save_fragment_shader(renderer->cso);
   cso_save_vertex_shader(renderer->cso);

   renderer_set_target(renderer, dst, NULL, y0_top);

   renderer_set_blend(renderer, ~0);
   renderer_set_samplers(renderer, 1, &src);

   renderer_set_fs(renderer, RENDERER_FS_TEXTURE);
   renderer_set_vs(renderer, RENDERER_VS_TEXTURE);

   /* remember the texture size */
   renderer->u.copy.tex_width = src->texture->width0;
   renderer->u.copy.tex_height = src->texture->height0;
   renderer->state = RENDERER_STATE_COPY;

   return VG_TRUE;
}

/**
 * Draw into the destination rectangle given by (x, y, w, h).  The texture is
 * sampled from within the rectangle given by (sx, sy, sw, sh).
 *
 * The coordinates are in surface coordinates.
 */
void renderer_copy(struct renderer *renderer,
                   VGint x, VGint y, VGint w, VGint h,
                   VGint sx, VGint sy, VGint sw, VGint sh)
{
   assert(renderer->state == RENDERER_STATE_COPY);

   /* there is no depth buffer for scissoring anyway */
   renderer_quad_pos(renderer, x, y, x + w, y + h, VG_FALSE);
   renderer_quad_texcoord(renderer, sx, sy, sx + sw, sy + sh,
         renderer->u.copy.tex_width,
         renderer->u.copy.tex_height);

   renderer_quad_draw(renderer);
}

/**
 * End copying and restore the states.
 */
void renderer_copy_end(struct renderer *renderer)
{
   assert(renderer->state == RENDERER_STATE_COPY);

   cso_restore_framebuffer(renderer->cso);
   cso_restore_viewport(renderer->cso);
   cso_restore_blend(renderer->cso);
   cso_restore_samplers(renderer->cso);
   cso_restore_fragment_sampler_views(renderer->cso);
   cso_restore_fragment_shader(renderer->cso);
   cso_restore_vertex_shader(renderer->cso);

   renderer->state = RENDERER_STATE_INIT;
}

/**
 * Prepare the renderer for textured drawing.
 */
VGboolean renderer_drawtex_begin(struct renderer *renderer,
                                 struct pipe_sampler_view *src)
{
   assert(renderer->state == RENDERER_STATE_INIT);

   if (!renderer_can_support(renderer, src->texture, PIPE_BIND_SAMPLER_VIEW))
      return VG_FALSE;

   cso_save_blend(renderer->cso);
   cso_save_samplers(renderer->cso);
   cso_save_fragment_sampler_views(renderer->cso);
   cso_save_fragment_shader(renderer->cso);
   cso_save_vertex_shader(renderer->cso);

   renderer_set_blend(renderer, ~0);

   renderer_set_samplers(renderer, 1, &src);

   renderer_set_fs(renderer, RENDERER_FS_TEXTURE);
   renderer_set_vs(renderer, RENDERER_VS_TEXTURE);

   /* remember the texture size */
   renderer->u.drawtex.tex_width = src->texture->width0;
   renderer->u.drawtex.tex_height = src->texture->height0;
   renderer->state = RENDERER_STATE_DRAWTEX;

   return VG_TRUE;
}

/**
 * Draw into the destination rectangle given by (x, y, w, h).  The texture is
 * sampled from within the rectangle given by (sx, sy, sw, sh).
 *
 * The coordinates are in surface coordinates.
 */
void renderer_drawtex(struct renderer *renderer,
                      VGint x, VGint y, VGint w, VGint h,
                      VGint sx, VGint sy, VGint sw, VGint sh)
{
   assert(renderer->state == RENDERER_STATE_DRAWTEX);

   /* with scissoring */
   renderer_quad_pos(renderer, x, y, x + w, y + h, VG_TRUE);
   renderer_quad_texcoord(renderer, sx, sy, sx + sw, sy + sh,
         renderer->u.drawtex.tex_width,
         renderer->u.drawtex.tex_height);

   renderer_quad_draw(renderer);
}

/**
 * End textured drawing and restore the states.
 */
void renderer_drawtex_end(struct renderer *renderer)
{
   assert(renderer->state == RENDERER_STATE_DRAWTEX);

   cso_restore_blend(renderer->cso);
   cso_restore_samplers(renderer->cso);
   cso_restore_fragment_sampler_views(renderer->cso);
   cso_restore_fragment_shader(renderer->cso);
   cso_restore_vertex_shader(renderer->cso);

   renderer->state = RENDERER_STATE_INIT;
}

static void setup_shaders(struct renderer *ctx)
{
   struct pipe_context *pipe = ctx->pipe;
   /* fragment shader */
   ctx->fs = util_make_fragment_tex_shader(pipe, TGSI_TEXTURE_2D,
                                           TGSI_INTERPOLATE_LINEAR);
}

struct renderer * renderer_create(struct vg_context *owner)
{
   VGint i;
   struct renderer *renderer = CALLOC_STRUCT(renderer);

   if (!renderer)
      return NULL;

   renderer->owner = owner;
   renderer->pipe = owner->pipe;
   renderer->cso = owner->cso_context;

   setup_shaders(renderer);

   /* init vertex data that doesn't change */
   for (i = 0; i < 4; i++)
      renderer->vertices[i][0][3] = 1.0f; /* w */

   renderer->state = RENDERER_STATE_INIT;

   return renderer;
}

void renderer_destroy(struct renderer *ctx)
{
   int i;

   for (i = 0; i < NUM_RENDERER_VS; i++) {
      if (ctx->cached_vs[i])
         cso_delete_vertex_shader(ctx->cso, ctx->cached_vs[i]);
   }
   for (i = 0; i < NUM_RENDERER_FS; i++) {
      if (ctx->cached_fs[i])
         cso_delete_fragment_shader(ctx->cso, ctx->cached_fs[i]);
   }

#if 0
   if (ctx->fs) {
      cso_delete_fragment_shader(ctx->cso, ctx->fs);
      ctx->fs = NULL;
   }
#endif
   FREE(ctx);
}

void renderer_draw_quad(struct renderer *r,
                        VGfloat x1, VGfloat y1,
                        VGfloat x2, VGfloat y2,
                        VGfloat depth)
{
   assert(r->state == RENDERER_STATE_INIT);
   assert(floatsEqual(depth, 0.0f));

   renderer_quad_pos(r, x1, y1, x2, y2, VG_TRUE);
   renderer_quad_draw(r);
}

void renderer_draw_texture(struct renderer *r,
                           struct pipe_resource *tex,
                           VGfloat x1offset, VGfloat y1offset,
                           VGfloat x2offset, VGfloat y2offset,
                           VGfloat x1, VGfloat y1,
                           VGfloat x2, VGfloat y2)
{
   assert(r->state == RENDERER_STATE_INIT);
   assert(tex->width0 != 0);
   assert(tex->height0 != 0);

   cso_save_vertex_shader(r->cso);

   renderer_set_vs(r, RENDERER_VS_TEXTURE);

   renderer_quad_pos(r, x1, y1, x2, y2, VG_TRUE);
   renderer_quad_texcoord(r, x1offset, y1offset,
         x2offset, y2offset, tex->width0, tex->height0);
   renderer_quad_draw(r);

   cso_restore_vertex_shader(r->cso);
}

void renderer_copy_texture(struct renderer *ctx,
                           struct pipe_sampler_view *src,
                           VGfloat sx1, VGfloat sy1,
                           VGfloat sx2, VGfloat sy2,
                           struct pipe_resource *dst,
                           VGfloat dx1, VGfloat dy1,
                           VGfloat dx2, VGfloat dy2)
{
   struct pipe_surface *surf;
   VGint x, y, w, h, sx, sy, sw, sh;

   /* get the destination surface */
   surf = ctx->pipe->screen->get_tex_surface(ctx->pipe->screen,
         dst, 0, 0, 0, PIPE_BIND_RENDER_TARGET);
   if (!surf)
      return;

   assert(ctx->state == RENDERER_STATE_INIT);
   assert(src->texture->width0 != 0);
   assert(src->texture->height0 != 0);
   assert(dst->width0 != 0);
   assert(dst->height0 != 0);

   x = (VGint) dx1;
   y = (VGint) dy1;
   w = (VGint) (dx2 - dx1);
   h = (VGint) (dy2 - dy1);
   assert(floatsEqual(x, dx1) &&
          floatsEqual(y, dy1) &&
          floatsEqual(w, (dx2 - dx1)) &&
          floatsEqual(h, (dy2 - dy1)));

   sx = (VGint) sx1;
   sy = (VGint) sy1;
   sw = (VGint) (sx2 - sx1);
   sh = (VGint) (sy2 - sy1);
   assert(floatsEqual(sx, sx1) &&
          floatsEqual(sy, sy1) &&
          floatsEqual(sw, (sx2 - sx1)) &&
          floatsEqual(sh, (sy2 - sy1)));

   if (renderer_copy_begin(ctx, surf, VG_TRUE, src)) {
      renderer_copy(ctx, x, y, w, h, sx, sy, sw, sh);
      renderer_copy_end(ctx);
   }

   pipe_surface_reference(&surf, NULL);
}

void renderer_copy_surface(struct renderer *ctx,
                           struct pipe_surface *src,
                           int srcX0, int srcY0,
                           int srcX1, int srcY1,
                           struct pipe_surface *dst,
                           int dstX0, int dstY0,
                           int dstX1, int dstY1,
                           float z, unsigned filter)
{
   struct pipe_context *pipe = ctx->pipe;
   struct pipe_screen *screen = pipe->screen;
   struct pipe_sampler_view view_templ;
   struct pipe_sampler_view *view;
   struct pipe_resource texTemp, *tex;
   struct pipe_subresource subsrc, subdst;
   struct st_framebuffer *stfb = ctx->owner->draw_buffer;
   const int srcW = abs(srcX1 - srcX0);
   const int srcH = abs(srcY1 - srcY0);
   const int srcLeft = MIN2(srcX0, srcX1);
   const int srcTop = MIN2(srcY0, srcY1);

   assert(filter == PIPE_TEX_MIPFILTER_NEAREST ||
          filter == PIPE_TEX_MIPFILTER_LINEAR);

   if (srcLeft != srcX0) {
      /* left-right flip */
      int tmp = dstX0;
      dstX0 = dstX1;
      dstX1 = tmp;
   }

   if (srcTop != srcY0) {
      /* up-down flip */
      int tmp = dstY0;
      dstY0 = dstY1;
      dstY1 = tmp;
   }

   assert(screen->is_format_supported(screen, src->format, PIPE_TEXTURE_2D,
                                      0, PIPE_BIND_SAMPLER_VIEW, 0));
   assert(screen->is_format_supported(screen, dst->format, PIPE_TEXTURE_2D,
                                      0, PIPE_BIND_SAMPLER_VIEW, 0));
   assert(screen->is_format_supported(screen, dst->format, PIPE_TEXTURE_2D,
                                      0, PIPE_BIND_RENDER_TARGET, 0));

   /*
    * XXX for now we're always creating a temporary texture.
    * Strictly speaking that's not always needed.
    */

   /* create temp texture */
   memset(&texTemp, 0, sizeof(texTemp));
   texTemp.target = PIPE_TEXTURE_2D;
   texTemp.format = src->format;
   texTemp.last_level = 0;
   texTemp.width0 = srcW;
   texTemp.height0 = srcH;
   texTemp.depth0 = 1;
   texTemp.bind = PIPE_BIND_SAMPLER_VIEW;

   tex = screen->resource_create(screen, &texTemp);
   if (!tex)
      return;

   u_sampler_view_default_template(&view_templ, tex, tex->format);
   view = pipe->create_sampler_view(pipe, tex, &view_templ);

   if (!view)
      return;

   subdst.face = 0;
   subdst.level = 0;
   subsrc.face = src->face;
   subsrc.level = src->level;

   pipe->resource_copy_region(pipe,
                              tex, subdst, 0, 0, 0,  /* dest */
                              src->texture, subsrc, srcLeft, srcTop, src->zslice, /* src */
                              srcW, srcH);     /* size */

   assert(floatsEqual(z, 0.0f));

   /* draw */
   if (stfb->strb->surface == dst) {
      /* transform back to surface coordinates */
      dstY0 = dst->height - dstY0;
      dstY1 = dst->height - dstY1;

      if (renderer_drawtex_begin(ctx, view)) {
         renderer_drawtex(ctx,
               dstX0, dstY0, dstX1 - dstX0, dstY1 - dstY0,
               0, 0, view->texture->width0, view->texture->height0);
         renderer_drawtex_end(ctx);
      }
   }
   else {
      if (renderer_copy_begin(ctx, dst, VG_TRUE, view)) {
         renderer_copy(ctx,
               dstX0, dstY0, dstX1 - dstX0, dstY1 - dstY0,
               0, 0, view->texture->width0, view->texture->height0);
         renderer_copy_end(ctx);
      }
   }
}

void renderer_texture_quad(struct renderer *r,
                           struct pipe_resource *tex,
                           VGfloat x1offset, VGfloat y1offset,
                           VGfloat x2offset, VGfloat y2offset,
                           VGfloat x1, VGfloat y1,
                           VGfloat x2, VGfloat y2,
                           VGfloat x3, VGfloat y3,
                           VGfloat x4, VGfloat y4)
{
   const VGfloat z = 0.0f;

   assert(r->state == RENDERER_STATE_INIT);
   assert(tex->width0 != 0);
   assert(tex->height0 != 0);

   cso_save_vertex_shader(r->cso);

   renderer_set_vs(r, RENDERER_VS_TEXTURE);

   /* manually set up positions */
   r->vertices[0][0][0] = x1;
   r->vertices[0][0][1] = y1;
   r->vertices[0][0][2] = z;

   r->vertices[1][0][0] = x2;
   r->vertices[1][0][1] = y2;
   r->vertices[1][0][2] = z;

   r->vertices[2][0][0] = x3;
   r->vertices[2][0][1] = y3;
   r->vertices[2][0][2] = z;

   r->vertices[3][0][0] = x4;
   r->vertices[3][0][1] = y4;
   r->vertices[3][0][2] = z;

   /* texcoords */
   renderer_quad_texcoord(r, x1offset, y1offset,
         x2offset, y2offset, tex->width0, tex->height0);

   renderer_quad_draw(r);

   cso_restore_vertex_shader(r->cso);
}