Before this commit, updates to the bitmap font in the graphics window
cause missing characters in the text window and vice versa. This is
because BitmapFont contains a texture that's mutated, and sharing it
would also require sharing display lists between GL contexts, which
is not done (and overly complicated for this case anyway).
Before this commit, when an entity is clicked at or dragged, and it
shares a place with other entities, which of them is selected is
decided more or less at random. This is particularly annoying when
dragging.
After this commit, when clicking, an entity from the current group
is given preference, and when dragging, an entity from a request
is given preference. This allows e.g. dragging points of a sketch
even when an extrusion of that sketch is active.
Before this commit, tooltips in the text window are drawn under
the red "X" indicating a disabled button. After this commit, they
are moved on top of that.
This commit also alters the OpenGL renderers' SetCamera() method
to clear the depth buffer, as that would interfere with drawing
the UI; the toolbar would get occluded by geometry.
To actually achieve improved performance with the OpenGL 2 renderer,
we have to cache geometry that doesn't change when the viewport does
(note that the rendered pixels can change quite dramatically because
we can reconfigure shaders; e.g. stippling can be drawn in screen
coordinates).
This commit adds a BatchCanvas interface that can be implemented
by renderers, and uses it for drawing entities such as lines and
points.
There are two main reasons to desire an OpenGL 2 renderer:
1. Compatibility. The compatibility profile, ironically, does not
offer a lot of compatibility, and our OpenGL 1 renderer will not
run on Android, iOS, or WebGL.
2. Performance. The immediate mode does not scale, and in fact
becomes very slow with only a moderate amount of lines on screen,
and only a somewhat large amount of triangles.
This commit implements a basic OpenGL 2 renderer that uses only
features from the (OpenGL 3.2) core profile. It is not yet faster
than the OpenGL 1 renderer, primarily because it uses a lot of small
draw calls.
This commit uses OpenGL 2 on Linux and Mac OS X directly (i.e. links
to the GL symbols from version 2+); on Windows this is impossible
with the default drivers, so for now OpenGL 1 is still used there.
OpenGL 2 and newer do not have the glPolygonMode(..., GL_LINES) API,
so produce the wireframe on our side. It's somewhat slow, and draws
every line three times, but it is cached when the OpenGL 2 renderer
is used, and this should do for a debugging feature.
SurfaceRenderer is a new renderer implementing the Canvas interface
running entirely on the CPU; it projects strokes and triangles
in the exact same way as OpenGL would, and it can be used for
rendering into raster or vector 2d surfaces.
This has the following benefits:
* Less geometry to generate; we can do both in one pass;
* Less geometry to draw;
* Eliminate overdraw of outlines on top of emphasized edges;
* In future, being able to seamlessly stitch stippled lines.
The contour edges are now also drawn before emphasized edges;
this makes intersections of contour and emphasized edges look better
as the thinner emphasized edge doesn't clobber the depth buffer.
This has several desirable consequences:
* It is now possible to port SolveSpace to a later version of
OpenGL, such as OpenGLES 2, so that it runs on platforms that
only have that OpenGL version;
* The majority of geometry is now rendered without references to
the camera in C++ code, so a renderer can now submit it to
the video card once and re-rasterize with a different projection
matrix every time the projection is changed, avoiding expensive
reuploads;
* The DOGD (draw or get distance) interface is now
a straightforward Canvas implementation;
* There are no more direct references to SS.GW.(projection)
in sketch rendering code, which allows rendering to multiple
viewports;
* There are no more unnecessary framebuffer flips on CPU on Cocoa
and GTK;
* The platform-dependent GL code is now confined to rendergl1.cpp.
* The Microsoft and Apple headers required by it that are prone to
identifier conflicts are no longer included globally;
* The rendergl1.cpp implementation can now be omitted from
compilation to run SolveSpace headless or with a different
OpenGL version.
Note these implementation details of Canvas:
* GetCamera currently always returns a reference to the field
`Camera camera;`. This is so that a future renderer that caches
geometry in the video memory can define it as asserting, which
would provide assurance against code that could accidentally
put something projection-dependent in the cache;
* Line and triangle rendering is specified through a level of
indirection, hStroke and hFill. This is so that a future renderer
that batches geometry could cheaply group identical styles.
* DrawPixmap and DrawVectorText accept a (o,u,v) and not a matrix.
This is so that a future renderer into an output format that
uses 2d transforms (e.g. SVG) could easily derive those.
Some additional internal changes were required to enable this:
* Pixmap is now always passed as std::shared_ptr<{const ,}Pixmap>.
This is so that the renderer could cache uploaded textures
between API calls, which requires it to capture a (weak)
reference.
* The PlatformPathEqual function was properly extracted into
platform-specific code. This is so that the <windows.h> header
could be included only where needed (in platform/w32* as well
as rendergl1.cpp).
* The SBsp{2,3}::DebugDraw functions were removed. They can be
rewritten using the Canvas API if they are ever needed.
While no visual changes were originally intended, some minor fixes
happened anyway:
* The "emphasis" yellow line from top-left corner is now correctly
rendered much wider.
* The marquee rectangle is now pixel grid aligned.
* The hidden entities now do not clobber the depth buffer, removing
some minor artifacts.
* The workplane "tab" now scales with the font used to render
the workplane name.
* The workplane name font is now taken from the normals style.
* Workplane and constraint line stipple is insignificantly
different. This is so that it can reuse the existing stipple
codepaths; rendering of workplanes and constraints predates
those.
Some debug functionality was added:
* In graphics window, an fps counter that becomes red when
rendering under 60fps is drawn.
