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    /* BRW_NEW_VIEWPORT_COUNT */
  46    const unsigned viewport_count = brw->clip.viewport_count;
  47
  48    scissor = brw_state_batch(brw, AUB_TRACE_SCISSOR_STATE,
  49                              sizeof(*scissor) * viewport_count, 32,
  50                              &scissor_state_offset);
  51
  52    /* _NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT */
  53
  54    /* The scissor only needs to handle the intersection of drawable and
  55     * scissor rect.  Clipping to the boundaries of static shared buffers
  56     * for front/back/depth is covered by looping over cliprects in brw_draw.c.
  57     *
  58     * Note that the hardware's coordinates are inclusive, while Mesa's min is
  59     * inclusive but max is exclusive.
  60     */
  61    for (unsigned i = 0; i < viewport_count; i++) {
  62       int bbox[4];
  63
  64       bbox[0] = MAX2(ctx->ViewportArray[i].X, 0);
  65       bbox[1] = MIN2(bbox[0] + ctx->ViewportArray[i].Width, fb_width);
  66       bbox[2] = MAX2(ctx->ViewportArray[i].Y, 0);
  67       bbox[3] = MIN2(bbox[2] + ctx->ViewportArray[i].Height, fb_height);
  68       _mesa_intersect_scissor_bounding_box(ctx, i, bbox);
  69
  70       if (bbox[0] == bbox[1] || bbox[2] == bbox[3]) {
  71          /* If the scissor was out of bounds and got clamped to 0 width/height
  72           * at the bounds, the subtraction of 1 from maximums could produce a
  73           * negative number and thus not clip anything.  Instead, just provide
  74           * a min > max scissor inside the bounds, which produces the expected
  75           * no rendering.
  76           */
  77          scissor[i].xmin = 1;
  78          scissor[i].xmax = 0;
  79          scissor[i].ymin = 1;
  80          scissor[i].ymax = 0;
  81       } else if (render_to_fbo) {
  82          /* texmemory: Y=0=bottom */
  83          scissor[i].xmin = bbox[0];
  84          scissor[i].xmax = bbox[1] - 1;
  85          scissor[i].ymin = bbox[2];
  86          scissor[i].ymax = bbox[3] - 1;
  87       }
  88       else {
  89          /* memory: Y=0=top */
  90          scissor[i].xmin = bbox[0];
  91          scissor[i].xmax = bbox[1] - 1;
  92          scissor[i].ymin = fb_height - bbox[3];
  93          scissor[i].ymax = fb_height - bbox[2] - 1;
  94       }
  95    }
  96    BEGIN_BATCH(2);
  97    OUT_BATCH(_3DSTATE_SCISSOR_STATE_POINTERS << 16 | (2 - 2));
  98    OUT_BATCH(scissor_state_offset);
  99    ADVANCE_BATCH();
 100 }
 101
 102 const struct brw_tracked_state gen6_scissor_state = {
 103    .dirty = {
 104       .mesa = _NEW_BUFFERS |
 105               _NEW_SCISSOR |
 106               _NEW_VIEWPORT,
 107       .brw = BRW_NEW_BATCH |
 108              BRW_NEW_BLORP |
 109              BRW_NEW_VIEWPORT_COUNT,
 110    },
 111    .emit = gen6_upload_scissor_state,
 112 };