those games and pcsx2 use directx, not opengl, that's why they work. directx is windows only, opengl is cross platform, that's why jpcsp uses it since it's written in java, which is also cross platform. java has limited support for directx, and as far as i know it doesn't even support shaders since directx support was dropped a while ago.
opengl is an open standard, so many manufacturers and corporations don't support it seriously, and you get broken drivers like intel's or amd's. because of that you get very low speeds and crashes, so blame intel/amd, not jpcsp devs. they work with what they have, and sometimes they have very little to go with.
if you want an emulator written in c, go for ppsspp. it's much earlier in development and has little compatibility so many games don't work yet, but maybe it'll work better for you. rewriting jpcsp into c++ would probably take months, and the devs would have to learn new programming language, not to mention it'd lose its multiplatform use.
opengl is an open standard, so many manufacturers and corporations don't support it seriously, and you get broken drivers like intel's or amd's. because of that you get very low speeds and crashes, so blame intel/amd, not jpcsp devs. they work with what they have, and sometimes they have very little to go with.
if you want an emulator written in c, go for ppsspp. it's much earlier in development and has little compatibility so many games don't work yet, but maybe it'll work better for you. rewriting jpcsp into c++ would probably take months, and the devs would have to learn new programming language, not to mention it'd lose its multiplatform use.