GL_ARB_sampler_objects provides a GL object which overrides the
sampler state part of a texture object with different values. The
sampler state that Cogl currently exposes is the wrap modes and
filters. Cogl exposes the state as part of the pipeline layer state
but without this extension GL only exposes it as part of the texture
object state. This means that it won't work to use a single texture
multiple times in one primitive with different sampler states. It also
makes switching between different sampler states with a single texture
not terribly efficient because it has to change the texture object
state every time.
This patch adds a cache for sampler states in a shared hash table
attached to the CoglContext. The entire set of parameters for the
sampler state is used as the key for the hash table. When a unique
state is encountered the sampler cache will create a new entry,
otherwise it will return a const pointer to an existing entry. That
means we can have a single pointer to represent any combination of
sampler state.
Pipeline layers now just store this single pointer rather than storing
all of the sampler state. The two separate state flags for wrap modes
and filters have now been combined into one. It should be faster to
compare the sampler state now because instead of comparing each value
it can just compare the pointers to the cached sampler entries. The
hash table of cached sampler states should only need to perform its
more expensive hash on the state when a property is changed on a
pipeline, not every time it is flushed.
When the sampler objects extension is available each cached sampler
state will also get a sampler object to represent it. The common code
to flush the GL state will now simply bind this object to a unit
instead of flushing the state though the CoglTexture when possible.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Instead of storing the GLenum for the target of the last used texture
for a layer it now stores the CoglTextureType instead. The state name
has been renamed to 'texture type' instead of 'texture target'.
Previously the default pipeline layer would store 0 here to represent
that there is no texture. This has been changed to store
COGL_TEXTURE_TYPE_2D instead which means that all pipeline layers
always have a valid value for the texture type. Any places that were
previously fetching the texture from a layer to determine the target
(for example when generating shaders or when enabling a particular
texture target) now use the texture type instead. This means they will
work even for layers that don't have a texture.
This also changes it so that when binding a fallback texture instead
of always using a 2D texture it will now use the default texture
corresponding to the texture type of the layer. That way when the
generated shader tries to do a texture lookup for that type of texture
it will get a valid texture object. To make this work the patch adds a
default texture for 3D textures to the context and also makes the
default rectangle texture actually be a rectangle texture instead of
using a 2D texture.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This adds a hook called COGL_SNIPPET_HOOK_TEXTURE_COORD_TRANSFORM.
This can be used to alter the application of the layer user matrix to
a texture coordinate or it can bypass it altogether.
This is the first per-layer hook that affects the vertex shader state
so the patch includes the boilerplate needed to get that to work.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This adds a per-layer snippet hook for the texure lookup. Here the
snippet can modify the texture coordinates used for the lookup or
modify the texel resulting from the lookup. This is the first
per-layer hook so this also adds the
COGL_PIPELINE_LAYER_STATE_FRAGMENT_SNIPPETS state and all of the
boilerplate needed to make that work.
Most of the functions used by the pipeline state to manage the snippet
list has been moved into cogl-pipeline-snippet.c so that it can be
shared with the layer state.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This splits out the core CoglPipelineLayer support code from
cogl-pipeline.c into cogl-pipeline-layer.c; it splits out the debugging
code for dumping a pipeline to a .dot file into cogl-pipeline-debug.c
and it splits the CoglPipelineNode support which is shared between
CoglPipeline and CoglPipelineLayer into cogl-node.c.
Note: cogl-pipeline-layer.c only contains the layer code directly
relating to CoglPipelineLayer objects; it does not contain any
_cogl_pipeline API relating to how CoglPipeline tracks and manipulates
layers.
As part of an on-going effort to get cogl-pipeline.c into a more
maintainable state this splits out all the apis relating just to
layer state. This just leaves code relating to the core CoglPipeline
and CoglPipelineLayer design left in cogl-pipeline.c.
This splits out around 2k more lines from cogl-pipeline.c although we
are still left with nearly 4k lines so we still have some way to go!
Reviewed-by: Neil Roberts <neil@linux.intel.com>
