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      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 (at) 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 
     34 static void
     35 gen6_upload_scissor_state(struct brw_context *brw)
     36 {
     37    struct intel_context *intel = &brw->intel;
     38    struct gl_context *ctx = &intel->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 
     43    scissor = brw_state_batch(brw, AUB_TRACE_SCISSOR_STATE,
     44 			     sizeof(*scissor), 32, &scissor_state_offset);
     45 
     46    /* _NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT */
     47 
     48    /* The scissor only needs to handle the intersection of drawable and
     49     * scissor rect.  Clipping to the boundaries of static shared buffers
     50     * for front/back/depth is covered by looping over cliprects in brw_draw.c.
     51     *
     52     * Note that the hardware's coordinates are inclusive, while Mesa's min is
     53     * inclusive but max is exclusive.
     54     */
     55    if (ctx->DrawBuffer->_Xmin == ctx->DrawBuffer->_Xmax ||
     56        ctx->DrawBuffer->_Ymin == ctx->DrawBuffer->_Ymax) {
     57       /* If the scissor was out of bounds and got clamped to 0
     58        * width/height at the bounds, the subtraction of 1 from
     59        * maximums could produce a negative number and thus not clip
     60        * anything.  Instead, just provide a min > max scissor inside
     61        * the bounds, which produces the expected no rendering.
     62        */
     63       scissor->xmin = 1;
     64       scissor->xmax = 0;
     65       scissor->ymin = 1;
     66       scissor->ymax = 0;
     67    } else if (render_to_fbo) {
     68       /* texmemory: Y=0=bottom */
     69       scissor->xmin = ctx->DrawBuffer->_Xmin;
     70       scissor->xmax = ctx->DrawBuffer->_Xmax - 1;
     71       scissor->ymin = ctx->DrawBuffer->_Ymin;
     72       scissor->ymax = ctx->DrawBuffer->_Ymax - 1;
     73    }
     74    else {
     75       /* memory: Y=0=top */
     76       scissor->xmin = ctx->DrawBuffer->_Xmin;
     77       scissor->xmax = ctx->DrawBuffer->_Xmax - 1;
     78       scissor->ymin = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymax;
     79       scissor->ymax = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymin - 1;
     80    }
     81 
     82    BEGIN_BATCH(2);
     83    OUT_BATCH(_3DSTATE_SCISSOR_STATE_POINTERS << 16 | (2 - 2));
     84    OUT_BATCH(scissor_state_offset);
     85    ADVANCE_BATCH();
     86 }
     87 
     88 const struct brw_tracked_state gen6_scissor_state = {
     89    .dirty = {
     90       .mesa = _NEW_SCISSOR | _NEW_BUFFERS | _NEW_VIEWPORT,
     91       .brw = BRW_NEW_BATCH,
     92       .cache = 0,
     93    },
     94    .emit = gen6_upload_scissor_state,
     95 };
     96