Add support for per-vertex point sizes

Desktop / GNOME / COGL - Neil Roberts [linux.intel.com] - 7 June 2013 10:22 UTC

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.

8495d9c Add support for per-vertex point sizes
cogl/cogl-attribute-private.h | 1 +
cogl/cogl-attribute.c | 10 ++
cogl/cogl-attribute.h | 5 +
cogl/cogl-context.c | 7 +-
cogl/cogl-context.h | 3 +
cogl/cogl-glsl-shader-boilerplate.h | 3 +-
cogl/cogl-pipeline-private.h | 6 +
cogl/cogl-pipeline-state-private.h | 7 +
cogl/cogl-pipeline-state.c | 75 +++++++++
cogl/cogl-pipeline-state.h | 44 ++++++
cogl/cogl-pipeline.c | 13 +-
cogl/cogl-private.h | 3 +-
cogl/cogl-snippet.h | 48 ++++++
cogl/driver/gl/cogl-pipeline-opengl.c | 19 ++-
cogl/driver/gl/cogl-pipeline-progend-fixed.c | 5 +
cogl/driver/gl/cogl-pipeline-vertend-glsl.c | 53 ++++++-
cogl/driver/gl/gl/cogl-driver-gl.c | 12 ++
.../gl/gl/cogl-pipeline-progend-fixed-arbfp.c | 5 +
cogl/driver/gl/gles/cogl-driver-gles.c | 2 +
doc/reference/cogl2/cogl2-sections.txt | 2 +
examples/cogl-info.c | 6 +
test-fixtures/test-utils.c | 6 +
test-fixtures/test-utils.h | 3 +-
tests/conform/Makefile.am | 1 +
tests/conform/test-conform-main.c | 5 +
tests/conform/test-point-size-attribute.c | 166 ++++++++++++++++++++
26 files changed, 496 insertions(+), 14 deletions(-)

Upstream: developer.gnome.org

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