/* *	Copyright (C) 2011-2014 Gregory hainaut
 *	Copyright (C) 2007-2009 Gabest
 *
 *  This Program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This Program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GNU Make; see the file COPYING.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA USA.
 *  http://www.gnu.org/copyleft/gpl.html
 *
 */

#include "stdafx.h"
#include "GLLoader.h"
#include "GSdx.h"
#include "GS.h"

#ifdef __unix__
PFNGLBLENDFUNCSEPARATEPROC             glBlendFuncSeparate                 = NULL;
#endif
PFNGLTEXTUREPAGECOMMITMENTEXTPROC      glTexturePageCommitmentEXT		   = NULL;

#include "PFN_GLLOADER_CPP.h"

namespace GLExtension {

	static std::unordered_set<std::string> s_extensions;

	bool Has(const std::string& ext)
	{
		return !!s_extensions.count(ext);
	}

	void Set(const std::string& ext, bool v)
	{
		if (v)
			s_extensions.insert(ext);
		else
			s_extensions.erase(ext);
	}
}

namespace ReplaceGL {
	void APIENTRY ScissorIndexed(GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height)
	{
		glScissor(left, bottom, width, height);
	}

	void APIENTRY ViewportIndexedf(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h)
	{
		glViewport(GLint(x), GLint(y), GLsizei(w), GLsizei(h));
	}

	void APIENTRY TextureBarrier()
	{
	}

}

#ifdef _WIN32
namespace Emulate_DSA {
	// Texture entry point
	void APIENTRY BindTextureUnit(GLuint unit, GLuint texture) {
		glActiveTexture(GL_TEXTURE0 + unit);
		glBindTexture(GL_TEXTURE_2D, texture);
	}

	void APIENTRY CreateTexture(GLenum target, GLsizei n, GLuint *textures) {
		glGenTextures(1, textures);
	}

	void APIENTRY TextureStorage(GLuint texture, GLsizei levels, GLenum internalformat, GLsizei width, GLsizei height) {
		BindTextureUnit(7, texture);
		glTexStorage2D(GL_TEXTURE_2D, levels, internalformat, width, height);
	}

	void APIENTRY TextureSubImage(GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void *pixels) {
		BindTextureUnit(7, texture);
		glTexSubImage2D(GL_TEXTURE_2D, level, xoffset, yoffset, width, height, format, type, pixels);
	}

	void APIENTRY CopyTextureSubImage(GLuint texture, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height) {
		BindTextureUnit(7, texture);
		glCopyTexSubImage2D(GL_TEXTURE_2D, level, xoffset, yoffset, x, y, width, height);
	}

	void APIENTRY GetTexureImage(GLuint texture, GLint level, GLenum format, GLenum type, GLsizei bufSize, void *pixels) {
		BindTextureUnit(7, texture);
		glGetTexImage(GL_TEXTURE_2D, level, format, type, pixels);
	}

	void APIENTRY TextureParameteri (GLuint texture, GLenum pname, GLint param) {
		BindTextureUnit(7, texture);
		glTexParameteri(GL_TEXTURE_2D, pname, param);
	}

	void APIENTRY GenerateTextureMipmap(GLuint texture) {
		BindTextureUnit(7, texture);
		glGenerateMipmap(GL_TEXTURE_2D);
	}

	// Misc entry point
	// (only purpose is to have a consistent API otherwise it is useless)
	void APIENTRY CreateProgramPipelines(GLsizei n, GLuint *pipelines) {
		glGenProgramPipelines(n, pipelines);
	}

	void APIENTRY CreateSamplers(GLsizei n, GLuint *samplers) {
		glGenSamplers(n, samplers);
	}

	// Replace function pointer to emulate DSA behavior
	void Init() {
		fprintf(stderr, "DSA is not supported. Expect slower performance\n");
		glBindTextureUnit             = BindTextureUnit;
		glCreateTextures              = CreateTexture;
		glTextureStorage2D            = TextureStorage;
		glTextureSubImage2D           = TextureSubImage;
		glCopyTextureSubImage2D       = CopyTextureSubImage;
		glGetTextureImage             = GetTexureImage;
		glTextureParameteri           = TextureParameteri;

		glCreateProgramPipelines      = CreateProgramPipelines;
		glCreateSamplers              = CreateSamplers;
	}
}
#endif

namespace GLLoader {

#define fprintf_once(out, ...) do if (s_first_load) fprintf(out, __VA_ARGS__); while(0);

	bool s_first_load = true;

	bool amd_legacy_buggy_driver = false;
	bool vendor_id_amd      = false;
	bool vendor_id_nvidia   = false;
	bool vendor_id_intel    = false;
	bool mesa_driver        = false;
	bool in_replayer        = false;
	bool buggy_sso_dual_src = false;

	bool found_geometry_shader = true; // we require GL3.3 so geometry must be supported by default
	bool found_GL_ARB_clear_texture = false;
	bool found_GL_ARB_get_texture_sub_image = false; // Not yet used
	// DX11 GPU
	bool found_GL_ARB_gpu_shader5 = false; // Require IvyBridge
	bool found_GL_ARB_shader_image_load_store = false; // Intel IB. Nvidia/AMD miss Mesa implementation.
	bool found_GL_ARB_shader_storage_buffer_object = false;
	bool found_GL_ARB_compute_shader = false;
	bool found_GL_ARB_texture_view = false; // maybe older gpu can support it ?

	// Mandatory in the future
	bool found_GL_ARB_multi_bind = false;
	bool found_GL_ARB_vertex_attrib_binding = false;

	// In case sparse2 isn't supported
	bool found_compatible_GL_ARB_sparse_texture2 = false;
	bool found_compatible_sparse_depth = false;

	static void mandatory(const std::string& ext)
	{
		if (!GLExtension::Has(ext)) {
			fprintf(stderr, "ERROR: %s is NOT SUPPORTED\n", ext.c_str());
			throw GSDXRecoverableError();
		}

		return;
	}

	static bool optional(const std::string& name)
	{
		bool found = GLExtension::Has(name);

		if (!found) {
			fprintf_once(stdout, "INFO: %s is NOT SUPPORTED\n", name.c_str());
		} else {
			fprintf_once(stdout, "INFO: %s is available\n", name.c_str());
		}

		std::string opt("override_");
		opt += name;

		if (theApp.GetConfigI(opt.c_str()) != -1) {
			found = theApp.GetConfigB(opt.c_str());
			fprintf(stderr, "Override %s detection (%s)\n", name.c_str(), found ? "Enabled" : "Disabled");
			GLExtension::Set(name, found);
		}

		return found;
	}

	void check_gl_version(int major, int minor)
	{
		const GLubyte* s = glGetString(GL_VERSION);
		if (s == NULL) {
			fprintf(stderr, "Error: GLLoader failed to get GL version\n");
			throw GSDXRecoverableError();
		}
		GLuint v = 1;
		while (s[v] != '\0' && s[v-1] != ' ') v++;

		const char* vendor = (const char*)glGetString(GL_VENDOR);
		fprintf_once(stdout, "OpenGL information. GPU: %s. Vendor: %s. Driver: %s\n", glGetString(GL_RENDERER), vendor, &s[v]);

		// Name changed but driver is still bad!
		if (strstr(vendor, "Advanced Micro Devices") || strstr(vendor, "ATI Technologies Inc.") || strstr(vendor, "ATI"))
			vendor_id_amd = true;
		/*if (vendor_id_amd && (
				strstr((const char*)&s[v], " 10.") || // Blacklist all 2010 AMD drivers.
				strstr((const char*)&s[v], " 11.") || // Blacklist all 2011 AMD drivers.
				strstr((const char*)&s[v], " 12.") || // Blacklist all 2012 AMD drivers.
				strstr((const char*)&s[v], " 13.") || // Blacklist all 2013 AMD drivers.
				strstr((const char*)&s[v], " 14.") || // Blacklist all 2014 AMD drivers.
				strstr((const char*)&s[v], " 15.") || // Blacklist all 2015 AMD drivers.
				strstr((const char*)&s[v], " 16.") || // Blacklist all 2016 AMD drivers.
				strstr((const char*)&s[v], " 17.") // Blacklist all 2017 AMD drivers for now.
				))
			amd_legacy_buggy_driver = true;
		*/
		if (strstr(vendor, "NVIDIA Corporation"))
			vendor_id_nvidia = true;

#ifdef _WIN32
		if (strstr(vendor, "Intel"))
			vendor_id_intel = true;
#else
		// On linux assumes the free driver if it isn't nvidia or amd pro driver
		mesa_driver = !vendor_id_nvidia && !vendor_id_amd;
#endif
		// As of 2019 SSO is still broken on intel (Kaby Lake confirmed).
		buggy_sso_dual_src = vendor_id_intel || vendor_id_amd /*|| amd_legacy_buggy_driver*/;

		if (theApp.GetConfigI("override_geometry_shader") != -1) {
			found_geometry_shader = theApp.GetConfigB("override_geometry_shader");
			GLExtension::Set("GL_ARB_geometry_shader4", found_geometry_shader);
			fprintf(stderr, "Overriding geometry shaders detection\n");
		}

		GLint major_gl = 0;
		GLint minor_gl = 0;
		glGetIntegerv(GL_MAJOR_VERSION, &major_gl);
		glGetIntegerv(GL_MINOR_VERSION, &minor_gl);
		if ( (major_gl < major) || ( major_gl == major && minor_gl < minor ) ) {
			fprintf(stderr, "OpenGL %d.%d is not supported. Only OpenGL %d.%d\n was found", major, minor, major_gl, minor_gl);
			throw GSDXRecoverableError();
		}
    }

	void check_gl_supported_extension()
	{
		int max_ext = 0;
		glGetIntegerv(GL_NUM_EXTENSIONS, &max_ext);
		for (GLint i = 0; i < max_ext; i++) {
			std::string ext{(const char*)glGetStringi(GL_EXTENSIONS, i)};
			GLExtension::Set(ext);
			//fprintf(stderr, "DEBUG ext: %s\n", ext.c_str());
		}

		// Mandatory for both renderer
		{
			// GL4.1
			mandatory("GL_ARB_separate_shader_objects");
			// GL4.2
			mandatory("GL_ARB_shading_language_420pack");
			mandatory("GL_ARB_texture_storage");
			// GL4.3
			mandatory("GL_KHR_debug");
			// GL4.4
			mandatory("GL_ARB_buffer_storage");
		}

		// Only for HW renderer
		if (theApp.GetCurrentRendererType() == GSRendererType::OGL_HW) {
			mandatory("GL_ARB_copy_image");
			mandatory("GL_ARB_clip_control");
		}

		// Extra
		{
			// Bonus
			optional("GL_ARB_sparse_texture");
			optional("GL_ARB_sparse_texture2");
			// GL4.0
			found_GL_ARB_gpu_shader5 = optional("GL_ARB_gpu_shader5");
			// GL4.2
			found_GL_ARB_shader_image_load_store = optional("GL_ARB_shader_image_load_store");
			// GL4.3
			found_GL_ARB_compute_shader = optional("GL_ARB_compute_shader");
			found_GL_ARB_shader_storage_buffer_object = optional("GL_ARB_shader_storage_buffer_object");
			found_GL_ARB_texture_view = optional("GL_ARB_texture_view");
			found_GL_ARB_vertex_attrib_binding = optional("GL_ARB_vertex_attrib_binding");
			// GL4.4
			found_GL_ARB_clear_texture = optional("GL_ARB_clear_texture");
			found_GL_ARB_multi_bind = optional("GL_ARB_multi_bind");
			// GL4.5
			optional("GL_ARB_direct_state_access");
			// Mandatory for the advance HW renderer effect. Unfortunately Mesa LLVMPIPE/SWR renderers doesn't support this extension.
			// Rendering might be corrupted but it could be good enough for test/virtual machine.
			optional("GL_ARB_texture_barrier");
			found_GL_ARB_get_texture_sub_image = optional("GL_ARB_get_texture_sub_image");
		}

		if (vendor_id_amd) {
			fprintf_once(stderr, "The OpenGL hardware renderer is slow on AMD GPUs due to an inefficient driver.\n"
					"Check out the link below for further information.\n"
					"https://github.com/PCSX2/pcsx2/wiki/OpenGL-and-AMD-GPUs---All-you-need-to-know\n");
		}

		if (vendor_id_intel && (!GLExtension::Has("GL_ARB_texture_barrier") || !GLExtension::Has("GL_ARB_direct_state_access"))) {
			// Assume that driver support is good when texture barrier and DSA is supported, disable the log then.
			fprintf_once(stderr, "The OpenGL renderer is inefficient on Intel GPUs due to an inefficient driver.\n"
					"Check out the link below for further information.\n"
					"https://github.com/PCSX2/pcsx2/wiki/OpenGL-and-Intel-GPUs-All-you-need-to-know\n");
		}

		if (!GLExtension::Has("GL_ARB_viewport_array")) {
			glScissorIndexed   = ReplaceGL::ScissorIndexed;
			glViewportIndexedf = ReplaceGL::ViewportIndexedf;
			fprintf_once(stderr, "GL_ARB_viewport_array is not supported! Function pointer will be replaced\n");
		}

		if (!GLExtension::Has("GL_ARB_texture_barrier")) {
			glTextureBarrier = ReplaceGL::TextureBarrier;
			fprintf_once(stderr, "GL_ARB_texture_barrier is not supported! Blending emulation will not be supported\n");
		}

#ifdef _WIN32
		// Thank you Intel for not providing support of basic features on your IGPUs.
		if (!GLExtension::Has("GL_ARB_direct_state_access")) {
			Emulate_DSA::Init();
		}
#endif
	}

	bool is_sparse2_compatible(const char* name, GLenum internal_fmt, int x_max, int y_max)
	{
		GLint index_count = 0;
		glGetInternalformativ(GL_TEXTURE_2D, internal_fmt, GL_NUM_VIRTUAL_PAGE_SIZES_ARB, 1, &index_count);
		if (!index_count) {
			fprintf_once(stdout, "%s isn't sparse compatible. No index found\n", name);
			return false;
		}

		GLint x, y;
		glGetInternalformativ(GL_TEXTURE_2D, internal_fmt, GL_VIRTUAL_PAGE_SIZE_X_ARB, 1, &x);
		glGetInternalformativ(GL_TEXTURE_2D, internal_fmt, GL_VIRTUAL_PAGE_SIZE_Y_ARB, 1, &y);
		if (x > x_max && y > y_max) {
			fprintf_once(stdout, "%s isn't sparse compatible. Page size (%d,%d) is too big (%d, %d)\n",
					name, x, y, x_max, y_max);
			return false;
		}

		return true;
	}

	static void check_sparse_compatibility()
	{
		if (!GLExtension::Has("GL_ARB_sparse_texture") || 
			!GLExtension::Has("GL_EXT_direct_state_access") ||
			theApp.GetConfigI("override_GL_ARB_sparse_texture") != 1) {
			found_compatible_GL_ARB_sparse_texture2 = false;
			found_compatible_sparse_depth = false;

			return;
		}

		found_compatible_GL_ARB_sparse_texture2 = true;
		if (!GLExtension::Has("GL_ARB_sparse_texture2")) {
			// Only check format from GSTextureOGL
			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_R8", GL_R8, 256, 256);

			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_R16UI", GL_R16UI, 256, 128);

			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_R32UI", GL_R32UI, 128, 128);
			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_R32I", GL_R32I, 128, 128);
			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_RGBA8", GL_RGBA8, 128, 128);

			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_RGBA16", GL_RGBA16, 128, 64);
			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_RGBA16I", GL_RGBA16I, 128, 64);
			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_RGBA16UI", GL_RGBA16UI, 128, 64);
			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_RGBA16F", GL_RGBA16F, 128, 64);

			found_compatible_GL_ARB_sparse_texture2 &= is_sparse2_compatible("GL_RGBA32F", GL_RGBA32F, 64, 64);
		}

		// Can fit in 128x64 but 128x128 is enough
		// Disable sparse depth for AMD. Bad driver strikes again.
		// driver reports a compatible sparse format for depth texture but it isn't attachable to a frame buffer.
		found_compatible_sparse_depth = !vendor_id_amd && is_sparse2_compatible("GL_DEPTH32F_STENCIL8", GL_DEPTH32F_STENCIL8, 128, 128);

		fprintf_once(stdout, "INFO sparse color texture is %s\n", found_compatible_GL_ARB_sparse_texture2 ? "available" : "NOT SUPPORTED");
		fprintf_once(stdout, "INFO sparse depth texture is %s\n", found_compatible_sparse_depth ? "available" : "NOT SUPPORTED");
	}

	void check_gl_requirements()
	{
		check_gl_version(3, 3);

		check_gl_supported_extension();

		// Bonus for sparse texture
		check_sparse_compatibility();

		fprintf_once(stdout, "\n");

		s_first_load = false;
	}
}