This is a very basic implementation of glGetfloatv. It will only give a
result when used with GL_MODELVIEW_MATRIX. In the future
we can update and extend it's functionality.
The Context and Software Rasterizer now gets the array of texture units
instead of a single texture object. _Technically_, we now support some
primitive form of multi-texturing, though I'm not entirely sure how well
it will work in its current state.
Textures are now initialized with a nullptr upon generation.
They are only actually created once they are bound to a target.
Currently only the GL_TEXTURE_2D target is supported.
The software rasterizer now allows rendering with or without
a bound TEXTURE_2D.
This commit implements glGenLists(), glNewList(), glDeleteLists(), and
glCallList().
The 'compiled' records are implemented as a vector of member function
pointers and tuples containing their arguments, and a mechanism is
implemented to allow the recorded calls to copy-capture values from the
time of the call; this is currently only used with glLoadMatrix.
This code has also been optimised to be much more memory
friendly by removing a _lot_ of extraneous copies. The result
is that, when profiled, it's around 8x faster than the previous
implementation.
Co-Authored-By: Ali Mohammad Pur <ali.mpfard@gmail.com>
This is based mostly on Fabian "ryg" Giesen's 2011 blog series
"A trip through the Graphics Pipeline" and Scratchapixel's
"Rasterization: a Practical Implementation".
The rasterizer processes triangles in grid aligned 16x16 pixel blocks,
calculates barycentric coordinates and edge derivatives and interpolates
bilinearly across each block.
This will theoretically allow for better utilization of modern processor
features such as SMT and SIMD, as opposed to a classic scanline based
triangle rasterizer.
This serves as a starting point to get something on the screen.
In the future we might look into properly pipelining the main loop to
make the rasterizer more flexible, enabling us to enable/disable
certain features at the block rather than the pixel level.
According to the OpenGL 2.x spec, some calls will set the current
global error to `GL_INVALID_OPERATION` if they are used during
a `glBegin`/`glEnd` block.
This implements `glGetError` and correctly sets the state machine's
error macro (similar to LibC `errno`) when an invalid operation is
performed. This is reset on completion of a successful operation.
This currently (obviously) doesn't support any actual 3D hardware,
hence all calls are done via software rendering.
Note that any modern constructs such as shaders are unsupported,
as this driver only implements Fixed Function Pipeline functionality.
The library is split into a base GLContext interface and a software
based renderer implementation of said interface. The global glXXX
functions serve as an OpenGL compatible c-style interface to the
currently bound context instance.
Co-authored-by: Stephan Unverwerth <s.unverwerth@gmx.de>
