Improve shader profile extension to be more compatible with bgfx

[Andrewfeng123]

Currently, the profiles spirv and metal are abbreviated to spv and mtl, which means the compiled shaders are in the directories spv and mtl. This is different from the convention used in bgfx (see bgfx/examples/runtime), which leaves them as spirv and metal. Conforming to the bgfx has an added benefit: it is now possible to directly use the loadShader and loadProgram functions defined in bgfx_utils (in bgfx/examples/common/) just like the example programs. This was not possible before since the extensions spirv and metal were hard-coded into bgfx_utils.

Example:

In the CMakeLists.txt at the root of the project:

bgfx_compile_shaders(
    TYPE VERTEX
    SHADERS ${CMAKE_SOURCE_DIR}/shaders/vs.sc
    VARYING_DEF ${CMAKE_SOURCE_DIR}/shaders/varying.def.sc
    INCLUDE_DIRS "${CMAKE_SOURCE_DIR}/bgfx.cmake/bgfx/examples/" "${CMAKE_SOURCE_DIR}/bgfx.cmake/bgfx/src/"
    OUTPUT_DIR ${CMAKE_BINARY_DIR}/shaders
)

bgfx_compile_shaders(
    TYPE FRAGMENT
    SHADERS ${CMAKE_SOURCE_DIR}/shaders/fs.sc
    VARYING_DEF ${CMAKE_SOURCE_DIR}/shaders/varying.def.sc
    INCLUDE_DIRS "${CMAKE_SOURCE_DIR}/bgfx.cmake/bgfx/examples/" "${CMAKE_SOURCE_DIR}/bgfx.cmake/bgfx/src/"
    OUTPUT_DIR ${CMAKE_BINARY_DIR}/shaders
)

add_executable(main src/main.cpp 
    shaders/vs.sc 
    shaders/fs.sc
)

In main.cpp:

// ...
#include "bgfx_utils.h"
// ...
bgfx::ProgramHandle m_program = loadProgram("vs.sc", "fs.sc");

[bwrsandman]

Dx9 has been dropped. Can you take this opportunity to remove it?

[bwrsandman]

Unfortunately the changes break embedded shaders with BGFX_EMBEDDED_SHADER when using bgfx_compile_shaders with AS_HEADERS:

error: ‘vs_line_spv’ was not declared in this scope; did you mean ‘vs_line_spirv’?
[build]    97 |     BGFX_EMBEDDED_SHADER(vs_line), BGFX_EMBEDDED_SHADER(vs_line_instanced),        

The headers generate a variable with this naming:

static const uint8_t vs_line_spirv[924] =

but the BGFX_EMBEDDED_SHADER macro expects vs_line_spv

[Andrewfeng123]

@bwrsandman Okay I pushed a new commit, please let me know if this works. This is a bit of a hack, but I don't see another way of doing so without changing bgfx.