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Add support for per-vertex point sizes

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This adds a new function to enable per-vertex point size on a
pipeline. This can be set with
cogl_pipeline_set_per_vertex_point_size(). Once enabled the point size
can be set either by drawing with an attribute named
'cogl_point_size_in' or by writing to the 'cogl_point_size_out'
builtin from a snippet.

There is a feature flag which must be checked for before using
per-vertex point sizes. This will only be set on GL >= 2.0 or on GLES
2.0. GL will only let you set a per-vertex point size from GLSL by
writing to gl_PointSize. This is only available in GL2 and not in the
older GLSL extensions.

The per-vertex point size has its own pipeline state flag so that it
can be part of the state that affects vertex shader generation.

Having to enable the per vertex point size with a separate function is
a bit awkward. Ideally it would work like the color attribute where
you can just set it for every vertex in your primitive with
cogl_pipeline_set_color or set it per-vertex by just using the
attribute. This is harder to get working with the point size because
we need to generate a different vertex shader depending on what
attributes are bound. I think if we wanted to make this work
transparently we would still want to internally have a pipeline
property describing whether the shader was generated with per-vertex
support so that it would work with the shader cache correctly.
Potentially we could make the per-vertex property internal and
automatically make a weak pipeline whenever the attribute is bound.
However we would then also need to automatically detect when an
application is writing to cogl_point_size_out from a snippet.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 8495d9c1c15ce389885a9356d965eabd97758115)

Conflicts:
	cogl/cogl-context.c
	cogl/cogl-pipeline-private.h
	cogl/cogl-pipeline.c
	cogl/cogl-private.h
	cogl/driver/gl/cogl-pipeline-progend-fixed.c
	cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
This commit is contained in:
Neil Roberts
2012-11-08 16:56:02 +00:00
parent 2d24248a3c
commit 6d51a18e7c
26 changed files with 493 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
cogl/driver/gl/cogl-pipeline-opengl.c
View File

@ -58,7 +58,9 @@
#ifndef GL_CLAMP_TO_BORDER
#define GL_CLAMP_TO_BORDER 0x812d
#endif
#ifndef GL_PROGRAM_POINT_SIZE
#define GL_PROGRAM_POINT_SIZE 0x8642
#endif
static void
texture_unit_init (CoglContext *ctx,
@ -684,6 +686,21 @@ _cogl_pipeline_flush_color_blend_alpha_depth_state (
}
}
#ifdef HAVE_COGL_GL
if ((ctx->private_feature_flags &
COGL_PRIVATE_FEATURE_ENABLE_PROGRAM_POINT_SIZE) &&
(pipelines_difference & COGL_PIPELINE_STATE_PER_VERTEX_POINT_SIZE))
{
unsigned long state = COGL_PIPELINE_STATE_PER_VERTEX_POINT_SIZE;
CoglPipeline *authority = _cogl_pipeline_get_authority (pipeline, state);
if (authority->big_state->per_vertex_point_size)
GE( ctx, glEnable (GL_PROGRAM_POINT_SIZE) );
else
GE( ctx, glDisable (GL_PROGRAM_POINT_SIZE) );
}
#endif
if (pipeline->real_blend_enable != ctx->gl_blend_enable_cache)
{
if (pipeline->real_blend_enable)

5
cogl/driver/gl/cogl-pipeline-progend-fixed.c
View File

@ -64,6 +64,11 @@ _cogl_pipeline_progend_fixed_start (CoglPipeline *pipeline)
if (cogl_pipeline_get_user_program (pipeline))
return FALSE;
/* The fixed progend can't handle the per-vertex point size
* attribute */
if (cogl_pipeline_get_per_vertex_point_size (pipeline))
return FALSE;
return TRUE;
}

53
cogl/driver/gl/cogl-pipeline-vertend-glsl.c
View File

@ -290,12 +290,20 @@ _cogl_pipeline_vertend_glsl_start (CoglPipeline *pipeline,
"cogl_generated_source ()\n"
"{\n");
if (!(ctx->private_feature_flags &
COGL_PRIVATE_FEATURE_BUILTIN_POINT_SIZE_UNIFORM))
/* There is no builtin uniform for the pointsize on GLES2 so we need
to copy it from the custom uniform in the vertex shader */
g_string_append (shader_state->source,
" cogl_point_size_out = cogl_point_size_in;\n");
if (cogl_pipeline_get_per_vertex_point_size (pipeline))
g_string_append (shader_state->header,
"attribute float cogl_point_size_in;\n");
else if (!(ctx->private_feature_flags &
COGL_PRIVATE_FEATURE_BUILTIN_POINT_SIZE_UNIFORM))
{
/* There is no builtin uniform for the point size on GLES2 so we
need to copy it from the custom uniform in the vertex shader if
we're not using per-vertex point sizes */
g_string_append (shader_state->header,
"uniform float cogl_point_size_in;\n");
g_string_append (shader_state->source,
" cogl_point_size_out = cogl_point_size_in;\n");
}
}
static CoglBool
@ -389,6 +397,8 @@ _cogl_pipeline_vertend_glsl_end (CoglPipeline *pipeline,
GLuint shader;
CoglPipelineSnippetData snippet_data;
CoglPipelineSnippetList *vertex_snippets;
CoglBool has_per_vertex_point_size =
cogl_pipeline_get_per_vertex_point_size (pipeline);
COGL_STATIC_COUNTER (vertend_glsl_compile_counter,
"glsl vertex compile counter",
@ -407,7 +417,21 @@ _cogl_pipeline_vertend_glsl_end (CoglPipeline *pipeline,
"}\n");
g_string_append (shader_state->source,
" cogl_vertex_transform ();\n"
" cogl_vertex_transform ();\n");
if (has_per_vertex_point_size)
{
g_string_append (shader_state->header,
"void\n"
"cogl_real_point_size_calculation ()\n"
"{\n"
" cogl_point_size_out = cogl_point_size_in;\n"
"}\n");
g_string_append (shader_state->source,
" cogl_point_size_calculation ();\n");
}
g_string_append (shader_state->source,
" cogl_color_out = cogl_color_in;\n"
"}\n");
@ -423,6 +447,19 @@ _cogl_pipeline_vertend_glsl_end (CoglPipeline *pipeline,
snippet_data.source_buf = shader_state->header;
_cogl_pipeline_snippet_generate_code (&snippet_data);
/* Add hooks for the point size calculation part */
if (has_per_vertex_point_size)
{
memset (&snippet_data, 0, sizeof (snippet_data));
snippet_data.snippets = vertex_snippets;
snippet_data.hook = COGL_SNIPPET_HOOK_POINT_SIZE;
snippet_data.chain_function = "cogl_real_point_size_calculation";
snippet_data.final_name = "cogl_point_size_calculation";
snippet_data.function_prefix = "cogl_point_size_calculation";
snippet_data.source_buf = shader_state->header;
_cogl_pipeline_snippet_generate_code (&snippet_data);
}
/* Add all of the hooks for vertex processing */
memset (&snippet_data, 0, sizeof (snippet_data));
snippet_data.snippets = vertex_snippets;
@ -487,6 +524,7 @@ _cogl_pipeline_vertend_glsl_end (CoglPipeline *pipeline,
shader_state->gl_shader = shader;
}
#ifdef HAVE_COGL_GL
if ((ctx->private_feature_flags &
COGL_PRIVATE_FEATURE_BUILTIN_POINT_SIZE_UNIFORM) &&
(pipelines_difference & COGL_PIPELINE_STATE_POINT_SIZE))
@ -496,6 +534,7 @@ _cogl_pipeline_vertend_glsl_end (CoglPipeline *pipeline,
GE( ctx, glPointSize (authority->big_state->point_size) );
}
#endif /* HAVE_COGL_GL */
return TRUE;
}

12
cogl/driver/gl/gl/cogl-driver-gl.c
View File

@ -569,11 +569,23 @@ _cogl_driver_update_features (CoglContext *ctx,
if (ctx->glGenSamplers)
private_flags |= COGL_PRIVATE_FEATURE_SAMPLER_OBJECTS;
if (COGL_CHECK_GL_VERSION (gl_major, gl_minor, 3, 3) ||
_cogl_check_extension ("GL_ARB_texture_swizzle", gl_extensions) ||
_cogl_check_extension ("GL_EXT_texture_swizzle", gl_extensions))
private_flags |= COGL_PRIVATE_FEATURE_TEXTURE_SWIZZLE;
/* The per-vertex point size is only available via GLSL with the
* gl_PointSize builtin. This is only available in GL 2.0 (not the
* GLSL extensions) */
if (COGL_CHECK_GL_VERSION (gl_major, gl_minor, 2, 0))
{
COGL_FLAGS_SET (ctx->features,
COGL_FEATURE_ID_PER_VERTEX_POINT_SIZE,
TRUE);
private_flags |= COGL_PRIVATE_FEATURE_ENABLE_PROGRAM_POINT_SIZE;
}
if (ctx->driver == COGL_DRIVER_GL)
{
int max_clip_planes = 0;

5
cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
View File

@ -73,6 +73,11 @@ _cogl_pipeline_progend_fixed_arbfp_start (CoglPipeline *pipeline)
_cogl_program_get_language (user_program) != COGL_SHADER_LANGUAGE_ARBFP)
return FALSE;
/* The ARBfp progend can't handle the per-vertex point size
* attribute */
if (cogl_pipeline_get_per_vertex_point_size (pipeline))
return FALSE;
return TRUE;
}

2
cogl/driver/gl/gles/cogl-driver-gles.c
View File

@ -256,6 +256,8 @@ _cogl_driver_update_features (CoglContext *context,
COGL_FLAGS_SET (context->features, COGL_FEATURE_ID_DEPTH_RANGE, TRUE);
COGL_FLAGS_SET (context->features,
COGL_FEATURE_ID_MIRRORED_REPEAT, TRUE);
COGL_FLAGS_SET (context->features,
COGL_FEATURE_ID_PER_VERTEX_POINT_SIZE, TRUE);
private_flags |= COGL_PRIVATE_FEATURE_BLEND_CONSTANT;
}