src/mesa/state_tracker/st_atom_viewport.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28
  29 #include "main/context.h"
  30 #include "st_context.h"
  31 #include "st_atom.h"
  32 #include "pipe/p_context.h"
  33 #include "cso_cache/cso_context.h"
  34
  35 /**
  36  * Update the viewport transformation matrix.  Depends on:
  37  *  - viewport pos/size
  38  *  - depthrange
  39  *  - window pos/size or FBO size
  40  */
  41 static void
  42 update_viewport( struct st_context *st )
  43 {
  44    struct gl_context *ctx = st->ctx;
  45    GLfloat yScale, yBias;
  46
  47    /* _NEW_BUFFERS
  48     */
  49    if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {
  50       /* Drawing to a window.  The corresponding gallium surface uses
  51        * Y=0=TOP but OpenGL is Y=0=BOTTOM.  So we need to invert the viewport.
  52        */
  53       yScale = -1;
  54       yBias = (GLfloat)ctx->DrawBuffer->Height;
  55    }
  56    else {
  57       /* Drawing to an FBO where Y=0=BOTTOM, like OpenGL - don't invert */
  58       yScale = 1.0;
  59       yBias = 0.0;
  60    }
  61
  62    /* _NEW_VIEWPORT
  63     */
  64    {
  65       GLfloat x = (GLfloat)ctx->Viewport.X;
  66       GLfloat y = (GLfloat)ctx->Viewport.Y;
  67       GLfloat z = ctx->Viewport.Near;
  68       GLfloat half_width = (GLfloat)ctx->Viewport.Width * 0.5f;
  69       GLfloat half_height = (GLfloat)ctx->Viewport.Height * 0.5f;
  70       GLfloat half_depth = (GLfloat)(ctx->Viewport.Far - ctx->Viewport.Near) * 0.5f;
  71
  72       st->state.viewport.scale[0] = half_width;
  73       st->state.viewport.scale[1] = half_height * yScale;
  74       st->state.viewport.scale[2] = half_depth;
  75       st->state.viewport.scale[3] = 1.0;
  76
  77       st->state.viewport.translate[0] = half_width + x;
  78       st->state.viewport.translate[1] = (half_height + y) * yScale + yBias;
  79       st->state.viewport.translate[2] = half_depth + z;
  80       st->state.viewport.translate[3] = 0.0;
  81
  82       cso_set_viewport(st->cso_context, &st->state.viewport);
  83    }
  84 }
  85
  86
  87 const struct st_tracked_state st_update_viewport = {
  88    "st_update_viewport",                                /* name */
  89    {                                                    /* dirty */
  90       _NEW_BUFFERS | _NEW_VIEWPORT,                     /* mesa */
  91       0,                                                /* st */
  92    },
  93    update_viewport                                      /* update */
  94 };