The GTK and OS X platforms already ignored the requested bit depth and
always used 32 bit. Windows and SDL would set a 16 bit color depth for
the screen, but still did all of the rendering short of the final
present in 32 bit.
Basically add another layer of indirection around accessing VAOs. The problem
is that VAOs are not shared between OpenGL contexts. This mechanism allows to
treat them mostly as if they were shared if they are only accessed through
the API defined in CStdGL.
This is accomplished by caching all existing VAOs per context. If a VAO is
being accessed, it is checked whether that VAO exists in the currently
selected context. If yes, return it, otherwise create a new VAO and return it,
together with a flag that indicates that the VAO needs to be initialized.
I don't expect much of a performance benefit from this, but it works toward
removal of legacy OpenGL usage. Note that we are already using VBOs for
meshes, so this does not require any functionality that we don't require
already.
Replace the hardcoded VAI_ constants with that. The VAI constants are now
moved to C4DrawGL as C4SSA_ constants, similar to the C4SSU ones. This allows
to introduce other attributes to replace vertex positions, normals, colors
and texture coordinates with attributes in later commits. This, in turn, is
needed because the built-in attributes are no longer available in the OpenGL
core profile.
Also, while at it, cleanup C4Shader a bit. Use std::vector<> instead of
maintaining an own array of uniform names. Delete the vertex and fragment
objects after the full shader program has been linked. Make sure that
C4Shader::Init keeps the old program in place if the new one cannot be
compiled or linked.
Code outside of C4FoWRegion should not care about the internals of the
class. Therefore, we remove direct access to the backing surface (and
secondary buffer surface) and replace it instead with accessors that
return those few values that are required by outside code.
There are only a couple of error values worth considering, so we can just
write out own function for it. Disable error checking in C4FoWRegion.cpp as
well, since we have the --debug-opengl flag now.
This should allow us to get rid of the GLU dependency soon.
Instead, compute the projection, modelview and normal matrices explictly
and upload them as shader uniforms. This is one step towards using the
OpenGL 3 core profile.
It looks like sometimes graphics drivers don't report the correct number for
maximum uniforms, since the workaround was enabled even though Newton
confirmed disabling the workaround worked just fine on his GPU. Therefore,
don't listen to what the graphics driver is saying but just try to compile the
shader, and fall back to the workaround if the compilation fails.
This implements the proposal made in the forum for "shiny" materials -
material can now determine the angle at which the most light is reflected.
Shiny materials might set this lower to approximate a "reflection" effect,
and increase the "spottiness" at the same time. To compensate for the
lack of brightness without light, "emittance" can be used.
Not sure this is the most elegant way to model this - the "proper" way
here would be to have emittance, shading and specular as three separate
light parameters instead of molding one into the other and using the third
to compensate.
Furthermore, this reorganises shaders in a major way: We reduce the
number of shader files down to three, pushing a number of possible
configurations into preprocessor. I believe this should be easier to
understand, which for the moment trumps theoretical extensibility
benefits.
Add a C4ShaderCall parameter to tho most important drawing functions, and
make C4DrawGL's CreateSpriteShader public with additional parameters to
specify additional defines and shader slices. C4Sky uses this to compile its
own shader with OC_SKY defined.
In comparison to the old system, this is a downgrade - instead of being
able to set a full color mapping by gamma ramp, we now get just a value
per colour channel.
Upside is that we do not need to play around with the global gamma ramps
any more, which was arguably the wrong way to do it.
This commit will likely break everything that has been using gamma so far.
The GLEW headers of Ubuntu 12.04 LTS don't know about GL_KHR_debug yet,
so we have to test for it before using its enum. Additionally, drivers
without support for GL_KHR_debug would emit INVALID_ENUM, so we test for
driver support too.
When an error's log output is represented graphically the graphics
operation can lead to another error (or the same error again), which
will be logged graphically again and so forth, until stack overflow.
So log to the log file only.
4x3 matrices use the same number of uniform components as 4x4 ones.
If we're short on uniform components, don't transpose the transformation
matrix before sending it to the shader, and transpose it in the shader
itself instead, saving 4 components per bone.
Instead of transforming all vertices on the CPU every time an animation
progresses, we now only recalculate the skeleton, leaving the heavy
lifting for the GPU. This also means we no longer have to push all
vertices onto the bus every frame, because the mesh isn't changing and
can therefore be stored in a GL_STATIC_DRAW VBO when it's first loaded.
The downside of this approach is that there's only a limited number of
uniforms and vertex attributes we can pass to the shader. At the moment
these limits are a maximum of 128 bones per skeleton, and no vertex can
be influenced by more than 8 bones at once. So far this is no problem,
as the most complex skeleton in the base game uses less than 64 bones
and no more than 6 bone weights per vertex.
glGetString(GL_EXTENSIONS) is deprecated starting with OpenGL 3.0.
Instead, you're now supposed to retrieve the list of extensions one by
one with glGetStringi.
Nicolas Hake