src/mesa/state_tracker/st_cb_clear.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   * Authors:
  30   *   Keith Whitwell <keith@tungstengraphics.com>
  31   *   Brian Paul
  32   */
  33
  34 #include "glheader.h"
  35 #include "macros.h"
  36 #include "enums.h"
  37 #include "st_atom.h"
  38 #include "st_context.h"
  39 #include "st_cb_clear.h"
  40 #include "st_public.h"
  41 #include "pipe/p_context.h"
  42 #include "pipe/p_defines.h"
  43 #include "vf/vf.h"
  44
  45
  46 /**
  47  * Draw a screen-aligned quadrilateral.
  48  * Coords are window coords.
  49  */
  50 static void
  51 draw_quad(GLcontext *ctx,
  52           float x0, float y0, float x1, float y1, GLfloat z,
  53           const GLfloat color[4])
  54 {
  55    static const GLuint attribs[2] = {
  56       VF_ATTRIB_POS,
  57       VF_ATTRIB_COLOR0
  58    };
  59    GLfloat verts[4][2][4]; /* four verts, two attribs, XYZW */
  60    GLuint i;
  61
  62    /* positions */
  63    verts[0][0][0] = x0;
  64    verts[0][0][1] = y0;
  65
  66    verts[1][0][0] = x1;
  67    verts[1][0][1] = y0;
  68
  69    verts[2][0][0] = x1;
  70    verts[2][0][1] = y1;
  71
  72    verts[3][0][0] = x0;
  73    verts[3][0][1] = y1;
  74
  75    /* same for all verts: */
  76    for (i = 0; i < 4; i++) {
  77       verts[i][0][2] = z;
  78       verts[i][0][3] = 1.0;
  79       verts[i][1][0] = color[0];
  80       verts[i][1][1] = color[1];
  81       verts[i][1][2] = color[2];
  82       verts[i][1][3] = color[3];
  83    }
  84
  85    ctx->st->pipe->draw_vertices(ctx->st->pipe, GL_QUADS,
  86                                 4, (GLfloat *) verts, 2, attribs);
  87 }
  88
  89
  90
  91 /**
  92  * Do glClear by drawing a quadrilateral.
  93  */
  94 static void
  95 clear_with_quad(GLcontext *ctx,
  96                 GLboolean color, GLboolean depth, GLboolean stencil)
  97 {
  98    struct st_context *st = ctx->st;
  99    struct pipe_blend_state blend;
 100    struct pipe_depth_state depth_test;
 101    struct pipe_stencil_state stencil_test;
 102
 103    /* depth state: always pass */
 104    memset(&depth_test, 0, sizeof(depth));
 105    if (depth) {
 106       depth_test.enabled = 1;
 107       depth_test.writemask = 1;
 108       depth_test.func = PIPE_FUNC_ALWAYS;
 109    }
 110    st->pipe->set_depth_state(st->pipe, &depth_test);
 111
 112    /* stencil state: always set to ref value */
 113    memset(&stencil_test, 0, sizeof(stencil));
 114    if (stencil) {
 115       stencil_test.front_enabled = 1;
 116       stencil_test.front_func = PIPE_FUNC_ALWAYS;
 117       stencil_test.front_fail_op = PIPE_STENCIL_OP_REPLACE;
 118       stencil_test.front_zpass_op = PIPE_STENCIL_OP_REPLACE;
 119       stencil_test.front_zfail_op = PIPE_STENCIL_OP_REPLACE;
 120       stencil_test.ref_value[0] = ctx->Stencil.Clear;
 121       stencil_test.value_mask[0] = 0xff;
 122       stencil_test.write_mask[0] = ctx->Stencil.WriteMask[0];
 123    }
 124    st->pipe->set_stencil_state(st->pipe, &stencil_test);
 125
 126    /* blend state: RGBA masking */
 127    memset(&blend, 0, sizeof(blend));
 128    if (color) {
 129       if (ctx->Color.ColorMask[0])
 130          blend.colormask |= PIPE_MASK_R;
 131       if (ctx->Color.ColorMask[1])
 132          blend.colormask |= PIPE_MASK_G;
 133       if (ctx->Color.ColorMask[2])
 134          blend.colormask |= PIPE_MASK_B;
 135       if (ctx->Color.ColorMask[3])
 136          blend.colormask |= PIPE_MASK_A;
 137       if (st->ctx->Color.DitherFlag)
 138          blend.dither = 1;
 139    }
 140    st->pipe->set_blend_state(st->pipe, &blend);
 141
 142    draw_quad(ctx,
 143              ctx->Scissor.X, ctx->Scissor.Y,
 144              ctx->Scissor.X + ctx->Scissor.Width,
 145              ctx->Scissor.Y + ctx->Scissor.Height,
 146              ctx->Depth.Clear, ctx->Color.ClearColor);
 147
 148    /* Restore GL state */
 149    st->pipe->set_blend_state(st->pipe, &st->state.blend);
 150    st->pipe->set_depth_state(st->pipe, &st->state.depth);
 151    st->pipe->set_stencil_state(st->pipe, &st->state.stencil);
 152    /* OR:
 153    st_invalidate_state(ctx, _NEW_COLOR | _NEW_DEPTH | _NEW_STENCIL);
 154    */
 155 }
 156
 157
 158
 159 /**
 160  * Called via ctx->Driver.Clear()
 161  * XXX: doesn't pick up the differences between front/back/left/right
 162  * clears.  Need to sort that out...
 163  */
 164 static void st_clear(GLcontext *ctx, GLbitfield mask)
 165 {
 166    struct st_context *st = ctx->st;
 167    GLboolean color = (mask & BUFFER_BITS_COLOR) ? GL_TRUE : GL_FALSE;
 168    GLboolean depth = (mask & BUFFER_BIT_DEPTH) ? GL_TRUE : GL_FALSE;
 169    GLboolean stencil = (mask & BUFFER_BIT_STENCIL) ? GL_TRUE : GL_FALSE;
 170    GLboolean accum = (mask & BUFFER_BIT_ACCUM) ? GL_TRUE : GL_FALSE;
 171
 172    GLboolean maskColor, maskStencil;
 173    GLboolean fullscreen = !ctx->Scissor.Enabled;
 174    GLuint stencilMax = stencil ? (1 << ctx->DrawBuffer->_StencilBuffer->StencilBits) : 0;
 175
 176    /* This makes sure the softpipe has the latest scissor, etc values */
 177    st_validate_state( st );
 178
 179    maskColor = color && st->state.blend.colormask != PIPE_MASK_RGBA;
 180    maskStencil = stencil && ctx->Stencil.WriteMask[0] != stencilMax;
 181
 182    if (fullscreen && !maskColor && !maskStencil) {
 183       /* pipe->clear() should clear a particular surface, so that we
 184        * can iterate over render buffers at this level and clear the
 185        * ones GL is asking for.
 186        *
 187        * Will probably need something like pipe->clear_z_stencil() to
 188        * cope with the special case of paired and unpaired z/stencil
 189        * buffers, though could perhaps deal with them explicitly at
 190        * this level.
 191        */
 192       st->pipe->clear(st->pipe, color, depth, stencil);
 193
 194       /* And here we would do a clear on whatever surface we are using
 195        * to implement accum buffers:
 196        */
 197       assert(!accum);
 198    }
 199    else {
 200       clear_with_quad(ctx, color, depth, stencil);
 201    }
 202 }
 203
 204
 205 void st_init_cb_clear( struct st_context *st )
 206 {
 207    struct dd_function_table *functions = &st->ctx->Driver;
 208
 209    functions->Clear = st_clear;
 210 }
 211
 212
 213 void st_destroy_cb_clear( struct st_context *st )
 214 {
 215 }
 216