Home | History | Annotate | Download | only in tnl 
      1 /*
      2  * Mesa 3-D graphics library
      3  * Version:  7.0
      4  *
      5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining a
      8  * copy of this software and associated documentation files (the "Software"),
      9  * to deal in the Software without restriction, including without limitation
     10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     11  * and/or sell copies of the Software, and to permit persons to whom the
     12  * Software is furnished to do so, subject to the following conditions:
     13  *
     14  * The above copyright notice and this permission notice shall be included
     15  * in all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
     21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  *
     24  * Authors:
     25  *    Brian Paul
     26  */
     27 
     28 #include "main/glheader.h"
     29 #include "main/mtypes.h"
     30 #include "main/dd.h"
     31 #include "main/imports.h"
     32 #include "t_context.h"
     33 #include "t_pipeline.h"
     34 
     35 
     36 struct point_stage_data {
     37    GLvector4f PointSize;
     38 };
     39 
     40 #define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->privatePtr)
     41 
     42 
     43 /**
     44  * Compute point size for each vertex from the vertex eye-space Z
     45  * coordinate and the point size attenuation factors.
     46  * Only done when point size attenuation is enabled and vertex program is
     47  * disabled.
     48  */
     49 static GLboolean
     50 run_point_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
     51 {
     52    if (ctx->Point._Attenuated && !ctx->VertexProgram._Current) {
     53       struct point_stage_data *store = POINT_STAGE_DATA(stage);
     54       struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
     55       const GLfloat *eyeCoord = (GLfloat *) VB->EyePtr->data + 2;
     56       const GLint eyeCoordStride = VB->EyePtr->stride / sizeof(GLfloat);
     57       const GLfloat p0 = ctx->Point.Params[0];
     58       const GLfloat p1 = ctx->Point.Params[1];
     59       const GLfloat p2 = ctx->Point.Params[2];
     60       const GLfloat pointSize = ctx->Point.Size;
     61       GLfloat (*size)[4] = store->PointSize.data;
     62       GLuint i;
     63 
     64       for (i = 0; i < VB->Count; i++) {
     65          const GLfloat dist = FABSF(*eyeCoord);
     66          const GLfloat q = p0 + dist * (p1 + dist * p2);
     67          const GLfloat atten = (q != 0.0F) ? INV_SQRTF(q) : 1.0F;
     68          size[i][0] = pointSize * atten; /* clamping done in rasterization */
     69          eyeCoord += eyeCoordStride;
     70       }
     71 
     72       VB->AttribPtr[_TNL_ATTRIB_POINTSIZE] = &store->PointSize;
     73    }
     74 
     75    return GL_TRUE;
     76 }
     77 
     78 
     79 static GLboolean
     80 alloc_point_data(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
     81 {
     82    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
     83    struct point_stage_data *store;
     84    stage->privatePtr = malloc(sizeof(*store));
     85    store = POINT_STAGE_DATA(stage);
     86    if (!store)
     87       return GL_FALSE;
     88 
     89    _mesa_vector4f_alloc( &store->PointSize, 0, VB->Size, 32 );
     90    return GL_TRUE;
     91 }
     92 
     93 
     94 static void
     95 free_point_data(struct tnl_pipeline_stage *stage)
     96 {
     97    struct point_stage_data *store = POINT_STAGE_DATA(stage);
     98    if (store) {
     99       _mesa_vector4f_free( &store->PointSize );
    100       free( store );
    101       stage->privatePtr = NULL;
    102    }
    103 }
    104 
    105 
    106 const struct tnl_pipeline_stage _tnl_point_attenuation_stage =
    107 {
    108    "point size attenuation",	/* name */
    109    NULL,			/* stage private data */
    110    alloc_point_data,		/* alloc data */
    111    free_point_data,		/* destructor */
    112    NULL,
    113    run_point_stage		/* run */
    114 };
    115