While convenient as a std::array, it's also quite a large set of data as
well (32KB). It being an array also means data cannot be std::moved. Any
situation where the code is being set or relocated means that a full
copy of that 32KB data must be done.
If we use a std::vector we do need to allocate on the heap, however, it
does allow us to std::move the data we have within the std::vector into
another std::vector instance, eliminating the need to always copy the
program data (as std::move in this case would just transfer the pointers
and bare necessities over to the new vector instance).
Namespaces all OpenGL code under the OpenGL namespace.
Prevents polluting the global namespace and allows clear distinction
between other renderers' code in the future.
LOG_TRACE is only enabled on debug builds which can be quite slow when
trying to debug graphics issues. Instead we can log the messages to the
debug log, which is available on both release and debug builds.
This is an OpenGL renderer-specific data type. Given that, this type
shouldn't be used within the base interface for the rasterizer. Instead,
we can pass this information to the rasterizer via reference.
Given we use a base-class type within the renderer for the rasterizer
(RasterizerInterface), we want to allow renderers to perform more
complex initialization if they need to do such a thing. This makes it
important to reserve type information.
Given the OpenGL renderer is quite simple settings-wise, this is just a
simple shuffling of the initialization code. For something like Vulkan
however this might involve doing something like:
// Initialize and call rasterizer-specific function that requires
// the full type of the instance created.
auto raster = std::make_unique<VulkanRasterizer>(some, params);
raster->CallSomeVulkanRasterizerSpecificFunction();
// Assign to base class variable
rasterizer = std::move(raster)
We were only writing to the first render target before.
Note that this is only the GLSL side of the implementation, supporting multiple render targets requires more changes in the OpenGL renderer.
Dual Source blending is not implemented and stuff that uses it might not work at all.
Before each draw call, for every enabled vertex array configured as instanced, we take the current instance id and divide it by its configured divisor, then we multiply that by the corresponding stride and increment the start address by the resulting amount. This way we can simulate the vertex array being incremented once per instance without actually using OpenGL's instancing functions.
