/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors:
* Keith Whitwell <keith@tungstengraphics.com>
*/
#include "main/api_arrayelt.h"
#include "main/glheader.h"
#include "main/mtypes.h"
#include "main/vtxfmt.h"
#include "vbo_context.h"
void vbo_exec_init( struct gl_context *ctx )
{
struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
exec->ctx = ctx;
/* Initialize the arrayelt helper
*/
if (!ctx->aelt_context &&
!_ae_create_context( ctx ))
return;
vbo_exec_vtx_init( exec );
ctx->Driver.NeedFlush = 0;
ctx->Driver.CurrentExecPrimitive = PRIM_OUTSIDE_BEGIN_END;
ctx->Driver.BeginVertices = vbo_exec_BeginVertices;
ctx->Driver.FlushVertices = vbo_exec_FlushVertices;
vbo_exec_invalidate_state( ctx, ~0 );
}
void vbo_exec_destroy( struct gl_context *ctx )
{
struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
if (ctx->aelt_context) {
_ae_destroy_context( ctx );
ctx->aelt_context = NULL;
}
vbo_exec_vtx_destroy( exec );
}
/**
* Really want to install these callbacks to a central facility to be
* invoked according to the state flags. That will have to wait for a
* mesa rework:
*/
void vbo_exec_invalidate_state( struct gl_context *ctx, GLuint new_state )
{
struct vbo_context *vbo = vbo_context(ctx);
struct vbo_exec_context *exec = &vbo->exec;
if (!exec->validating && new_state & (_NEW_PROGRAM|_NEW_ARRAY)) {
exec->array.recalculate_inputs = GL_TRUE;
/* If we ended up here because a VAO was deleted, the _DrawArrays
* pointer which pointed to the VAO might be invalid now, so set it
* to NULL. This prevents crashes in driver functions like Clear
* where driver state validation might occur, but the vbo module is
* still in an invalid state.
*
* Drivers should skip vertex array state validation if _DrawArrays
* is NULL. It also has no effect on performance, because attrib
* bindings will be recalculated anyway.
*/
if (vbo->last_draw_method == DRAW_ARRAYS) {
ctx->Array._DrawArrays = NULL;
vbo->last_draw_method = DRAW_NONE;
}
}
if (new_state & _NEW_EVAL)
exec->eval.recalculate_maps = 1;
_ae_invalidate_state(ctx, new_state);
}
/**
* Figure out the number of transform feedback primitives that will be output
* considering the drawing mode, number of vertices, and instance count,
* assuming that no geometry shading is done and primitive restart is not
* used.
*
* This is used by driver back-ends in implementing the PRIMITIVES_GENERATED
* and TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN queries. It is also used to
* pre-validate draw calls in GLES3 (where draw calls only succeed if there is
* enough room in the transform feedback buffer for the result).
*/
size_t
vbo_count_tessellated_primitives(GLenum mode, GLuint count,
GLuint num_instances)
{
size_t num_primitives;
switch (mode) {
case GL_POINTS:
num_primitives = count;
break;
case GL_LINE_STRIP:
num_primitives = count >= 2 ? count - 1 : 0;
break;
case GL_LINE_LOOP:
num_primitives = count >= 2 ? count : 0;
break;
case GL_LINES:
num_primitives = count / 2;
break;
case GL_TRIANGLE_STRIP:
case GL_TRIANGLE_FAN:
case GL_POLYGON:
num_primitives = count >= 3 ? count - 2 : 0;
break;
case GL_TRIANGLES:
num_primitives = count / 3;
break;
case GL_QUAD_STRIP:
num_primitives = count >= 4 ? ((count / 2) - 1) * 2 : 0;
break;
case GL_QUADS:
num_primitives = (count / 4) * 2;
break;
default:
assert(!"Unexpected primitive type in count_tessellated_primitives"); num_primitives = 0;
break;
}
return num_primitives * num_instances;
}
/**
* In some degenarate cases we can improve our ability to merge
* consecutive primitives. For example:
* glBegin(GL_LINE_STRIP);
* glVertex(1);
* glVertex(1);
* glEnd();
* glBegin(GL_LINE_STRIP);
* glVertex(1);
* glVertex(1);
* glEnd();
* Can be merged as a GL_LINES prim with four vertices.
*
* This function converts 2-vertex line strips/loops into GL_LINES, etc.
*/
void
vbo_try_prim_conversion(struct _mesa_prim *p)
{
if (p->mode == GL_LINE_STRIP && p->count == 2) {
/* convert 2-vertex line strip to a separate line */
p->mode = GL_LINES;
}
else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
&& p->count == 3) {
/* convert 3-vertex tri strip or fan to a separate triangle */
p->mode = GL_TRIANGLES;
}
/* Note: we can't convert a 4-vertex quad strip to a separate quad
* because the vertex ordering is different. We'd have to muck
* around in the vertex data to make it work.
*/
}
/**
* Helper function for determining if two subsequent glBegin/glEnd
* primitives can be combined. This is only possible for GL_POINTS,
* GL_LINES, GL_TRIANGLES and GL_QUADS.
* If we return true, it means that we can concatenate p1 onto p0 (and
* discard p1).
*/
bool
vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
{
if (!p0->begin ||
!p1->begin ||
!p0->end ||
!p1->end)
return false;
/* The prim mode must match (ex: both GL_TRIANGLES) */
if (p0->mode != p1->mode)
return false;
/* p1's vertices must come right after p0 */
if (p0->start + p0->count != p1->start)
return false;
if (p0->basevertex != p1->basevertex ||
p0->num_instances != p1->num_instances ||
p0->base_instance != p1->base_instance)
return false;
/* can always merge subsequent GL_POINTS primitives */
if (p0->mode == GL_POINTS)
return true;
/* independent lines with no extra vertices */
if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
return true;
/* independent tris */
if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
return true;
/* independent quads */
if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
return true;
return false;
}
/**
* If we've determined that p0 and p1 can be merged, this function
* concatenates p1 onto p0.
*/
void
vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
{
assert(vbo_can_merge_prims
(p0
, p1
));
p0->count += p1->count;
p0->end = p1->end;
}