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authorRobert Bragg <robert@linux.intel.com>2011-07-21 12:15:05 +0100
committerChris Wilson <chris@chris-wilson.co.uk>2011-10-11 09:05:45 +0100
commit571a27b4fcfe11fec2b33c31525c353eb30c0ad7 (patch)
tree9b338440d2f1366e585a10e6da1b869ce7469772 /build
parent5783bbfc750c73a4b36ad30a054de59a7ee99f34 (diff)
backends: Adds a new Cogl based backend
This adds a new GPU accelerated backend for Cairo based on the Cogl 3D graphics API. This backend aims to support Cairo in a way that translates as naturally as possible to using a GPU, it does not strive to compete with the anti-aliasing quality of the image backend if it can't be done efficiently using the GPU - raw performance isn't the only metric of concern, so is power usage. As an overview of how the backend works: - fills are handled by tessellating paths into triangles - the backend has an extra fill_rectangle drawing operation so we have a fast-path for drawing rectangles which are so common. - strokes are also tessellated into triangles. - stroke and fill tessellations are cached to avoid the cpu overhead of tessellation and cost of upload given that its common for apps to re-draw the same path multiple times. The tessellations can survive translations and rotations increasing the probability that they can be re-used. - sources and masks are handled using multi-texturing. - clipping is handled with a scissor and the stencil buffer which we're careful to only update when they really change. - linear gradients are rendered to a 1d texture using a triangle strip + interpolating color attributes. All cairo extend modes are handled by corresponding texture sampler wrap modes without needing programmable fragment processing. - antialiasing should be handled using Cogl's multisampling API XXX: This is a work in progress!! TODO: - handle at least basic radial gradients (No need to handle full pdf semantics, since css, svg and canvas only allow radial gradients defined as one circle + a point that must lie within the first circle.) - currently we fall back to pixman for radial gradients. - support glyph rendering with a decent glyph cache design. The current plan is a per scaled-font growable cache texture + a scratch cache for one-shot/short-lived glyphs. - decide how to handle npot textures when lacking hardware support. Current plan is to add a transparent border to npot textures and use CLAMP_TO_EDGE for the default EXTEND_NONE semantics. For anything else we can allocate a shadow npot texture and scale the original to fit that so we can map extend modes to texture sampler modes.
Diffstat (limited to 'build')
-rw-r--r--build/Makefile.win32.features1
-rw-r--r--build/Makefile.win32.features-h3
-rw-r--r--build/configure.ac.features1
3 files changed, 5 insertions, 0 deletions
diff --git a/build/Makefile.win32.features b/build/Makefile.win32.features
index 650b224c..8cb155dc 100644
--- a/build/Makefile.win32.features
+++ b/build/Makefile.win32.features
@@ -19,6 +19,7 @@ CAIRO_HAS_GALLIUM_SURFACE=0
CAIRO_HAS_PNG_FUNCTIONS=1
CAIRO_HAS_GL_SURFACE=0
CAIRO_HAS_GLESV2_SURFACE=0
+CAIRO_HAS_COGL_SURFACE=0
CAIRO_HAS_DIRECTFB_SURFACE=0
CAIRO_HAS_VG_SURFACE=0
CAIRO_HAS_EGL_FUNCTIONS=0
diff --git a/build/Makefile.win32.features-h b/build/Makefile.win32.features-h
index 84d65f4f..13904cfa 100644
--- a/build/Makefile.win32.features-h
+++ b/build/Makefile.win32.features-h
@@ -62,6 +62,9 @@ endif
ifeq ($(CAIRO_HAS_GLESV2_SURFACE),1)
@echo "#define CAIRO_HAS_GLESV2_SURFACE 1" >> $(top_srcdir)/src/cairo-features.h
endif
+ifeq ($(CAIRO_HAS_COGL_SURFACE),1)
+ @echo "#define CAIRO_HAS_COGL_SURFACE 1" >> $(top_srcdir)/src/cairo-features.h
+endif
ifeq ($(CAIRO_HAS_DIRECTFB_SURFACE),1)
@echo "#define CAIRO_HAS_DIRECTFB_SURFACE 1" >> $(top_srcdir)/src/cairo-features.h
endif
diff --git a/build/configure.ac.features b/build/configure.ac.features
index faa762ca..e4a2aafc 100644
--- a/build/configure.ac.features
+++ b/build/configure.ac.features
@@ -388,6 +388,7 @@ AC_DEFUN([CAIRO_REPORT],
echo " DirectFB: $use_directfb"
echo " OpenVG: $use_vg"
echo " DRM: $use_drm"
+ echo " Cogl: $use_cogl"
echo ""
echo "The following font backends:"
echo " User: yes (always builtin)"