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
  33 static void
  34 gen6_upload_scissor_state(struct brw_context *brw)
  35 {
  36    struct intel_context *intel = &brw->intel;
  37    struct gl_context *ctx = &intel->ctx;
  38    const GLboolean render_to_fbo = (ctx->DrawBuffer->Name != 0);
  39    struct gen6_scissor_rect *scissor;
  40    uint32_t scissor_state_offset;
  41
  42    scissor = brw_state_batch(brw, sizeof(*scissor), 32, &scissor_state_offset);
  43
  44    /* _NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT */
  45
  46    /* The scissor only needs to handle the intersection of drawable and
  47     * scissor rect.  Clipping to the boundaries of static shared buffers
  48     * for front/back/depth is covered by looping over cliprects in brw_draw.c.
  49     *
  50     * Note that the hardware's coordinates are inclusive, while Mesa's min is
  51     * inclusive but max is exclusive.
  52     */
  53    if (ctx->DrawBuffer->_Xmin == ctx->DrawBuffer->_Xmax ||
  54        ctx->DrawBuffer->_Ymin == ctx->DrawBuffer->_Ymax) {
  55       /* If the scissor was out of bounds and got clamped to 0
  56        * width/height at the bounds, the subtraction of 1 from
  57        * maximums could produce a negative number and thus not clip
  58        * anything.  Instead, just provide a min > max scissor inside
  59        * the bounds, which produces the expected no rendering.
  60        */
  61       scissor->xmin = 1;
  62       scissor->xmax = 0;
  63       scissor->ymin = 1;
  64       scissor->ymax = 0;
  65    } else if (render_to_fbo) {
  66       /* texmemory: Y=0=bottom */
  67       scissor->xmin = ctx->DrawBuffer->_Xmin;
  68       scissor->xmax = ctx->DrawBuffer->_Xmax - 1;
  69       scissor->ymin = ctx->DrawBuffer->_Ymin;
  70       scissor->ymax = ctx->DrawBuffer->_Ymax - 1;
  71    }
  72    else {
  73       /* memory: Y=0=top */
  74       scissor->xmin = ctx->DrawBuffer->_Xmin;
  75       scissor->xmax = ctx->DrawBuffer->_Xmax - 1;
  76       scissor->ymin = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymax;
  77       scissor->ymax = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymin - 1;
  78    }
  79
  80    BEGIN_BATCH(2);
  81    OUT_BATCH(_3DSTATE_SCISSOR_STATE_POINTERS << 16 | (2 - 2));
  82    OUT_BATCH(scissor_state_offset);
  83    ADVANCE_BATCH();
  84 }
  85
  86 const struct brw_tracked_state gen6_scissor_state = {
  87    .dirty = {
  88       .mesa = _NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT,
  89       .brw = BRW_NEW_BATCH,
  90       .cache = 0,
  91    },
  92    .emit = gen6_upload_scissor_state,
  93 };