I'm dealing with some compatibility issues on my Xperia Play phone while trying to run my game, and because of that I must find all references to OpenGL ES extensions that are used within my app. This leads us to my question: Are there ways to use extensions other than via eglGetProcAddress() function?
Best regards, Buyuk.
The answer is yes. The normal way to use extensions is to call them directly by name, which will contain one of these strings:
OES, ARB, IMG, PVR, EXT, AMD, VIV or NV
The names are defined in these header files:
#include <EGL/eglext.h>
#include <GLES2/gl2ext.h>
The names returned from a query are different. They typically look like this:
GL_AMD_compressed_3DC_texture GL_AMD_compressed_ATC_texture GL_AMD_performance_monitor GL_AMD_program_binary_Z400 GL_AMD_tiled_rendering GL_EXT_texture_filter_anisotropic GL_EXT_texture_type_2_10_10_10_REV GL_EXT_bgra GL_OES_compressed_ETC1_RGB8_texture GL_OES_compressed_paletted_texture GL_OES_depth_texture GL_OES_depth24 GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_element_index_uint GL_OES_fbo_render_mipmap GL_OES_fragment_precision_high GL_OES_get_program_binary GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_texture_3D GL_OES_texture_float GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_half_float GL_OES_vertex_type_10_10_10_2 GL_NV_fence
No, not all extensions define new api calls, so eglGetProcAddress is not used for all of them. The good example is http://www.khronos.org/registry/gles/extensions/OES/OES_texture_float.txt - see there are new tokens (enums) here, but no new functions.
However compiling without *gl*ext.h headers, tracing out eglGetProcAddress and "#extension" strings in ESSL will give you at least some info on used non-core functionalities.
