src/mesa/drivers/dri/i965/gen6_scissor_state.c

   1 /*
   2  * Copyright © 2009 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27
  28 #include "brw_context.h"
  29 #include "brw_state.h"
  30 #include "brw_defines.h"
  31 #include "intel_batchbuffer.h"
  32 #include "main/fbobject.h"
  33 #include "main/framebuffer.h"
  34
  35 static void
  36 gen6_upload_scissor_state(struct brw_context *brw)
  37 {
  38    struct gl_context *ctx = &brw->ctx;
  39    const bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
  40    struct gen6_scissor_rect *scissor;
  41    uint32_t scissor_state_offset;
  42    const unsigned int fb_width= _mesa_geometric_width(ctx->DrawBuffer);
  43    const unsigned int fb_height = _mesa_geometric_height(ctx->DrawBuffer);
  44
  45    scissor = brw_state_batch(brw, AUB_TRACE_SCISSOR_STATE,
  46                              sizeof(*scissor) * ctx->Const.MaxViewports, 32,
  47                              &scissor_state_offset);
  48
  49    /* _NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT */
  50
  51    /* The scissor only needs to handle the intersection of drawable and
  52     * scissor rect.  Clipping to the boundaries of static shared buffers
  53     * for front/back/depth is covered by looping over cliprects in brw_draw.c.
  54     *
  55     * Note that the hardware's coordinates are inclusive, while Mesa's min is
  56     * inclusive but max is exclusive.
  57     */
  58    for (unsigned i = 0; i < ctx->Const.MaxViewports; i++) {
  59       int bbox[4];
  60
  61       bbox[0] = 0;
  62       bbox[1] = fb_width;
  63       bbox[2] = 0;
  64       bbox[3] = fb_height;
  65       _mesa_intersect_scissor_bounding_box(ctx, i, bbox);
  66
  67       if (bbox[0] == bbox[1] || bbox[2] == bbox[3]) {
  68          /* If the scissor was out of bounds and got clamped to 0 width/height
  69           * at the bounds, the subtraction of 1 from maximums could produce a
  70           * negative number and thus not clip anything.  Instead, just provide
  71           * a min > max scissor inside the bounds, which produces the expected
  72           * no rendering.
  73           */
  74          scissor[i].xmin = 1;
  75          scissor[i].xmax = 0;
  76          scissor[i].ymin = 1;
  77          scissor[i].ymax = 0;
  78       } else if (render_to_fbo) {
  79          /* texmemory: Y=0=bottom */
  80          scissor[i].xmin = bbox[0];
  81          scissor[i].xmax = bbox[1] - 1;
  82          scissor[i].ymin = bbox[2];
  83          scissor[i].ymax = bbox[3] - 1;
  84       }
  85       else {
  86          /* memory: Y=0=top */
  87          scissor[i].xmin = bbox[0];
  88          scissor[i].xmax = bbox[1] - 1;
  89          scissor[i].ymin = fb_height - bbox[3];
  90          scissor[i].ymax = fb_height - bbox[2] - 1;
  91       }
  92    }
  93    BEGIN_BATCH(2);
  94    OUT_BATCH(_3DSTATE_SCISSOR_STATE_POINTERS << 16 | (2 - 2));
  95    OUT_BATCH(scissor_state_offset);
  96    ADVANCE_BATCH();
  97 }
  98
  99 const struct brw_tracked_state gen6_scissor_state = {
 100    .dirty = {
 101       .mesa = _NEW_BUFFERS |
 102               _NEW_SCISSOR |
 103               _NEW_VIEWPORT,
 104       .brw = BRW_NEW_BATCH,
 105    },
 106    .emit = gen6_upload_scissor_state,
 107 };