/*************************************************************************/
/*  rasterizer_gles3.cpp                                                 */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

#include "rasterizer_gles3.h"

#include "core/os/os.h"
#include "core/project_settings.h"

RasterizerStorage *RasterizerGLES3::get_storage() {
	return storage;
}

RasterizerCanvas *RasterizerGLES3::get_canvas() {
	return canvas;
}

RasterizerScene *RasterizerGLES3::get_scene() {
	return scene;
}

#define _EXT_DEBUG_OUTPUT_SYNCHRONOUS_ARB 0x8242
#define _EXT_DEBUG_NEXT_LOGGED_MESSAGE_LENGTH_ARB 0x8243
#define _EXT_DEBUG_CALLBACK_FUNCTION_ARB 0x8244
#define _EXT_DEBUG_CALLBACK_USER_PARAM_ARB 0x8245
#define _EXT_DEBUG_SOURCE_API_ARB 0x8246
#define _EXT_DEBUG_SOURCE_WINDOW_SYSTEM_ARB 0x8247
#define _EXT_DEBUG_SOURCE_SHADER_COMPILER_ARB 0x8248
#define _EXT_DEBUG_SOURCE_THIRD_PARTY_ARB 0x8249
#define _EXT_DEBUG_SOURCE_APPLICATION_ARB 0x824A
#define _EXT_DEBUG_SOURCE_OTHER_ARB 0x824B
#define _EXT_DEBUG_TYPE_ERROR_ARB 0x824C
#define _EXT_DEBUG_TYPE_DEPRECATED_BEHAVIOR_ARB 0x824D
#define _EXT_DEBUG_TYPE_UNDEFINED_BEHAVIOR_ARB 0x824E
#define _EXT_DEBUG_TYPE_PORTABILITY_ARB 0x824F
#define _EXT_DEBUG_TYPE_PERFORMANCE_ARB 0x8250
#define _EXT_DEBUG_TYPE_OTHER_ARB 0x8251
#define _EXT_MAX_DEBUG_MESSAGE_LENGTH_ARB 0x9143
#define _EXT_MAX_DEBUG_LOGGED_MESSAGES_ARB 0x9144
#define _EXT_DEBUG_LOGGED_MESSAGES_ARB 0x9145
#define _EXT_DEBUG_SEVERITY_HIGH_ARB 0x9146
#define _EXT_DEBUG_SEVERITY_MEDIUM_ARB 0x9147
#define _EXT_DEBUG_SEVERITY_LOW_ARB 0x9148
#define _EXT_DEBUG_OUTPUT 0x92E0

#if defined(MINGW_ENABLED) || defined(_MSC_VER)
#define strcpy strcpy_s
#endif

#ifdef GLAD_ENABLED
// Restricting to GLAD as only used in initialize() with GLAD_GL_ARB_debug_output
static void GLAPIENTRY _gl_debug_print(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const GLvoid *userParam) {
	if (type == _EXT_DEBUG_TYPE_OTHER_ARB) {
		return;
	}

	if (type == _EXT_DEBUG_TYPE_PERFORMANCE_ARB) {
		return; //these are ultimately annoying, so removing for now
	}

	char debSource[256], debType[256], debSev[256];
	if (source == _EXT_DEBUG_SOURCE_API_ARB) {
		strcpy(debSource, "OpenGL");
	} else if (source == _EXT_DEBUG_SOURCE_WINDOW_SYSTEM_ARB) {
		strcpy(debSource, "Windows");
	} else if (source == _EXT_DEBUG_SOURCE_SHADER_COMPILER_ARB) {
		strcpy(debSource, "Shader Compiler");
	} else if (source == _EXT_DEBUG_SOURCE_THIRD_PARTY_ARB) {
		strcpy(debSource, "Third Party");
	} else if (source == _EXT_DEBUG_SOURCE_APPLICATION_ARB) {
		strcpy(debSource, "Application");
	} else if (source == _EXT_DEBUG_SOURCE_OTHER_ARB) {
		strcpy(debSource, "Other");
	}

	if (type == _EXT_DEBUG_TYPE_ERROR_ARB) {
		strcpy(debType, "Error");
	} else if (type == _EXT_DEBUG_TYPE_DEPRECATED_BEHAVIOR_ARB) {
		strcpy(debType, "Deprecated behavior");
	} else if (type == _EXT_DEBUG_TYPE_UNDEFINED_BEHAVIOR_ARB) {
		strcpy(debType, "Undefined behavior");
	} else if (type == _EXT_DEBUG_TYPE_PORTABILITY_ARB) {
		strcpy(debType, "Portability");
	} else if (type == _EXT_DEBUG_TYPE_PERFORMANCE_ARB) {
		strcpy(debType, "Performance");
	}

	if (severity == _EXT_DEBUG_SEVERITY_HIGH_ARB) {
		strcpy(debSev, "High");
	} else if (severity == _EXT_DEBUG_SEVERITY_MEDIUM_ARB) {
		strcpy(debSev, "Medium");
	} else if (severity == _EXT_DEBUG_SEVERITY_LOW_ARB) {
		strcpy(debSev, "Low");
	}

	String output = String() + "GL ERROR: Source: " + debSource + "\tType: " + debType + "\tID: " + itos(id) + "\tSeverity: " + debSev + "\tMessage: " + message;

	ERR_PRINT(output);
}
#endif // GLAD_ENABLED

typedef void (*DEBUGPROCARB)(GLenum source,
		GLenum type,
		GLuint id,
		GLenum severity,
		GLsizei length,
		const char *message,
		const void *userParam);

typedef void (*DebugMessageCallbackARB)(DEBUGPROCARB callback, const void *userParam);

Error RasterizerGLES3::is_viable() {
#ifdef GLAD_ENABLED
	if (!gladLoadGL()) {
		ERR_PRINT("Error initializing GLAD");
		return ERR_UNAVAILABLE;
	}

// GLVersion seems to be used for both GL and GL ES, so we need different version checks for them
#ifdef OPENGL_ENABLED // OpenGL 3.3 Core Profile required
	if (GLVersion.major < 3 || (GLVersion.major == 3 && GLVersion.minor < 3)) {
#else // OpenGL ES 3.0
	if (GLVersion.major < 3) {
#endif
		return ERR_UNAVAILABLE;
	}

#endif // GLAD_ENABLED
	return OK;
}

void RasterizerGLES3::initialize() {
	print_verbose("Using GLES3 video driver");

#ifdef GLAD_ENABLED
	if (OS::get_singleton()->is_stdout_verbose()) {
		if (GLAD_GL_ARB_debug_output) {
			glEnable(_EXT_DEBUG_OUTPUT_SYNCHRONOUS_ARB);
			glDebugMessageCallbackARB(_gl_debug_print, nullptr);
			glEnable(_EXT_DEBUG_OUTPUT);
		} else {
			print_line("OpenGL debugging not supported!");
		}
	}
#endif // GLAD_ENABLED

	/* // For debugging
	if (GLAD_GL_ARB_debug_output) {
		glDebugMessageControlARB(GL_DEBUG_SOURCE_API_ARB,GL_DEBUG_TYPE_ERROR_ARB,GL_DEBUG_SEVERITY_HIGH_ARB,0,NULL,GL_TRUE);
		glDebugMessageControlARB(GL_DEBUG_SOURCE_API_ARB,GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR_ARB,GL_DEBUG_SEVERITY_HIGH_ARB,0,NULL,GL_TRUE);
		glDebugMessageControlARB(GL_DEBUG_SOURCE_API_ARB,GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR_ARB,GL_DEBUG_SEVERITY_HIGH_ARB,0,NULL,GL_TRUE);
		glDebugMessageControlARB(GL_DEBUG_SOURCE_API_ARB,GL_DEBUG_TYPE_PORTABILITY_ARB,GL_DEBUG_SEVERITY_HIGH_ARB,0,NULL,GL_TRUE);
		glDebugMessageControlARB(GL_DEBUG_SOURCE_API_ARB,GL_DEBUG_TYPE_PERFORMANCE_ARB,GL_DEBUG_SEVERITY_HIGH_ARB,0,NULL,GL_TRUE);
		glDebugMessageControlARB(GL_DEBUG_SOURCE_API_ARB,GL_DEBUG_TYPE_OTHER_ARB,GL_DEBUG_SEVERITY_HIGH_ARB,0,NULL,GL_TRUE);
		glDebugMessageInsertARB(
				GL_DEBUG_SOURCE_API_ARB,
				GL_DEBUG_TYPE_OTHER_ARB, 1,
				GL_DEBUG_SEVERITY_HIGH_ARB,5, "hello");
	}
	*/

	print_line("OpenGL ES 3.0 Renderer: " + VisualServer::get_singleton()->get_video_adapter_name());
	storage->initialize();
	canvas->initialize();
	scene->initialize();
}

void RasterizerGLES3::begin_frame(double frame_step) {
	time_total += frame_step * time_scale;

	if (frame_step == 0) {
		//to avoid hiccups
		frame_step = 0.001;
	}

	double time_roll_over = GLOBAL_GET("rendering/limits/time/time_rollover_secs");
	time_total = Math::fmod(time_total, time_roll_over);

	storage->frame.time[0] = time_total;
	storage->frame.time[1] = Math::fmod(time_total, 3600);
	storage->frame.time[2] = Math::fmod(time_total, 900);
	storage->frame.time[3] = Math::fmod(time_total, 60);
	storage->frame.count++;
	storage->frame.delta = frame_step;

	storage->update_dirty_resources();

	storage->info.render_final = storage->info.render;
	storage->info.render.reset();

	scene->iteration();
}

void RasterizerGLES3::set_current_render_target(RID p_render_target) {
	if (!p_render_target.is_valid() && storage->frame.current_rt && storage->frame.clear_request) {
		//handle pending clear request, if the framebuffer was not cleared
		glBindFramebuffer(GL_FRAMEBUFFER, storage->frame.current_rt->fbo);

		glClearColor(
				storage->frame.clear_request_color.r,
				storage->frame.clear_request_color.g,
				storage->frame.clear_request_color.b,
				storage->frame.clear_request_color.a);

		glClear(GL_COLOR_BUFFER_BIT);
	}

	if (p_render_target.is_valid()) {
		RasterizerStorageGLES3::RenderTarget *rt = storage->render_target_owner.getornull(p_render_target);
		storage->frame.current_rt = rt;
		ERR_FAIL_COND(!rt);
		storage->frame.clear_request = false;

		glViewport(0, 0, rt->width, rt->height);

	} else {
		storage->frame.current_rt = nullptr;
		storage->frame.clear_request = false;
		glViewport(0, 0, OS::get_singleton()->get_window_size().width, OS::get_singleton()->get_window_size().height);
		glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);
	}
}

void RasterizerGLES3::restore_render_target(bool p_3d_was_drawn) {
	ERR_FAIL_COND(storage->frame.current_rt == nullptr);
	RasterizerStorageGLES3::RenderTarget *rt = storage->frame.current_rt;
	if (p_3d_was_drawn && rt->external.fbo != 0) {
		// our external render buffer is now leading, render 2d into that.
		glBindFramebuffer(GL_FRAMEBUFFER, rt->external.fbo);
	} else {
		glBindFramebuffer(GL_FRAMEBUFFER, rt->fbo);
	}
	glViewport(0, 0, rt->width, rt->height);
}

void RasterizerGLES3::clear_render_target(const Color &p_color) {
	ERR_FAIL_COND(!storage->frame.current_rt);

	storage->frame.clear_request = true;
	storage->frame.clear_request_color = p_color;
}

void RasterizerGLES3::set_boot_image(const Ref<Image> &p_image, const Color &p_color, bool p_scale, bool p_use_filter) {
	if (p_image.is_null() || p_image->empty()) {
		return;
	}

	begin_frame(0.0);

	int window_w = OS::get_singleton()->get_video_mode(0).width;
	int window_h = OS::get_singleton()->get_video_mode(0).height;

	glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);
	glViewport(0, 0, window_w, window_h);
	glDisable(GL_BLEND);
	glDepthMask(GL_FALSE);
	if (OS::get_singleton()->get_window_per_pixel_transparency_enabled()) {
		glClearColor(0.0, 0.0, 0.0, 0.0);
	} else {
		glClearColor(p_color.r, p_color.g, p_color.b, 1.0);
	}
	glClear(GL_COLOR_BUFFER_BIT);
	canvas->canvas_begin();

	RID texture = storage->texture_create();
	storage->texture_allocate(texture, p_image->get_width(), p_image->get_height(), 0, p_image->get_format(), VS::TEXTURE_TYPE_2D, p_use_filter ? VS::TEXTURE_FLAG_FILTER : 0);
	storage->texture_set_data(texture, p_image);

	Rect2 imgrect(0, 0, p_image->get_width(), p_image->get_height());
	Rect2 screenrect;
	if (p_scale) {
		if (window_w > window_h) {
			//scale horizontally
			screenrect.size.y = window_h;
			screenrect.size.x = imgrect.size.x * window_h / imgrect.size.y;
			screenrect.position.x = (window_w - screenrect.size.x) / 2;

		} else {
			//scale vertically
			screenrect.size.x = window_w;
			screenrect.size.y = imgrect.size.y * window_w / imgrect.size.x;
			screenrect.position.y = (window_h - screenrect.size.y) / 2;
		}
	} else {
		screenrect = imgrect;
		screenrect.position += ((Size2(window_w, window_h) - screenrect.size) / 2.0).floor();
	}

	RasterizerStorageGLES3::Texture *t = storage->texture_owner.get(texture);
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, t->tex_id);
	canvas->draw_generic_textured_rect(screenrect, Rect2(0, 0, 1, 1));
	glBindTexture(GL_TEXTURE_2D, 0);
	canvas->canvas_end();

	storage->free(texture); // free since it's only one frame that stays there

	end_frame(true);
}

void RasterizerGLES3::set_shader_time_scale(float p_scale) {
	time_scale = p_scale;
}

void RasterizerGLES3::blit_render_target_to_screen(RID p_render_target, const Rect2 &p_screen_rect, int p_screen) {
	ERR_FAIL_COND(storage->frame.current_rt);

	RasterizerStorageGLES3::RenderTarget *rt = storage->render_target_owner.getornull(p_render_target);
	ERR_FAIL_COND(!rt);

	if (rt->flags[RasterizerStorage::RENDER_TARGET_KEEP_3D_LINEAR]) {
		// We need to add an sRGB conversion here as we kept our buffer linear (+ a little tone mapping).

		canvas->_set_texture_rect_mode(true);

		canvas->state.canvas_shader.set_custom_shader(0);
		canvas->state.canvas_shader.set_conditional(CanvasShaderGLES3::LINEAR_TO_SRGB, true);
		canvas->state.canvas_shader.bind();

		canvas->canvas_begin();

		glDisable(GL_BLEND);

		// render to our framebuffer
		glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);

		// output our texture
		glActiveTexture(GL_TEXTURE0);
		if (rt->external.fbo != 0) {
			glBindTexture(GL_TEXTURE_2D, rt->external.color);
		} else {
			glBindTexture(GL_TEXTURE_2D, rt->color);
		}

		canvas->draw_generic_textured_rect(p_screen_rect, Rect2(0, 0, 1, -1));

		glBindTexture(GL_TEXTURE_2D, 0);
		canvas->canvas_end();

		canvas->state.canvas_shader.set_conditional(CanvasShaderGLES3::LINEAR_TO_SRGB, false);
	} else {
		// No conversion needed, take the faster approach

		Size2 win_size = OS::get_singleton()->get_window_size();
		if (rt->external.fbo != 0) {
			glBindFramebuffer(GL_READ_FRAMEBUFFER, rt->external.fbo);
		} else {
			glBindFramebuffer(GL_READ_FRAMEBUFFER, rt->fbo);
		}
		glReadBuffer(GL_COLOR_ATTACHMENT0);
		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);
		glBlitFramebuffer(0, 0, rt->width, rt->height, p_screen_rect.position.x, win_size.height - p_screen_rect.position.y - p_screen_rect.size.height, p_screen_rect.position.x + p_screen_rect.size.width, win_size.height - p_screen_rect.position.y, GL_COLOR_BUFFER_BIT, GL_NEAREST);
	}
}

void RasterizerGLES3::output_lens_distorted_to_screen(RID p_render_target, const Rect2 &p_screen_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample) {
	ERR_FAIL_COND(storage->frame.current_rt);

	RasterizerStorageGLES3::RenderTarget *rt = storage->render_target_owner.getornull(p_render_target);
	ERR_FAIL_COND(!rt);

	glDisable(GL_BLEND);

	// render to our framebuffer
	glBindFramebuffer(GL_FRAMEBUFFER, RasterizerStorageGLES3::system_fbo);

	// output our texture
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, rt->color);

	canvas->draw_lens_distortion_rect(p_screen_rect, p_k1, p_k2, p_eye_center, p_oversample);

	glBindTexture(GL_TEXTURE_2D, 0);
}

void RasterizerGLES3::end_frame(bool p_swap_buffers) {
	if (OS::get_singleton()->is_layered_allowed()) {
		if (!OS::get_singleton()->get_window_per_pixel_transparency_enabled()) {
			//clear alpha
			glColorMask(false, false, false, true);
			glClearColor(0, 0, 0, 1);
			glClear(GL_COLOR_BUFFER_BIT);
			glColorMask(true, true, true, true);
		}
	}

	if (p_swap_buffers) {
		OS::get_singleton()->swap_buffers();
	} else {
		glFinish();
	}
}

void RasterizerGLES3::finalize() {
	storage->finalize();
	canvas->finalize();
}

Rasterizer *RasterizerGLES3::_create_current() {
	return memnew(RasterizerGLES3);
}

void RasterizerGLES3::make_current() {
	_create_func = _create_current;
}

void RasterizerGLES3::register_config() {
}

bool RasterizerGLES3::gl_check_errors() {
	bool error_found = false;
	GLenum error = glGetError();
	while (error != GL_NO_ERROR) {
		switch (error) {
#ifdef DEBUG_ENABLED
			case GL_INVALID_ENUM: {
				WARN_PRINT("GL_INVALID_ENUM: An unacceptable value is specified for an enumerated argument.");
			} break;
			case GL_INVALID_VALUE: {
				WARN_PRINT("GL_INVALID_VALUE: A numeric argument is out of range.");
			} break;
			case GL_INVALID_OPERATION: {
				WARN_PRINT("GL_INVALID_OPERATION: The specified operation is not allowed in the current state.");
			} break;
			case GL_INVALID_FRAMEBUFFER_OPERATION: {
				WARN_PRINT("GL_INVALID_FRAMEBUFFER_OPERATION: The framebuffer object is not complete.");
			} break;
#endif // DEBUG_ENABLED
			case GL_OUT_OF_MEMORY: {
				ERR_PRINT("GL_OUT_OF_MEMORY: There is not enough memory left to execute the command. The state of the GL is undefined.");
			} break;
			// GL_STACK_UNDERFLOW and GL_STACK_OVERFLOW are undefined in GLES2/gl2.h, which is used when not using GLAD.
			//case GL_STACK_UNDERFLOW: {
			//	ERR_PRINT("GL_STACK_UNDERFLOW: An attempt has been made to perform an operation that would cause an internal stack to underflow.");
			//} break;
			//case GL_STACK_OVERFLOW: {
			//	ERR_PRINT("GL_STACK_OVERFLOW: An attempt has been made to perform an operation that would cause an internal stack to overflow.");
			//} break;
			default: {
#ifdef DEBUG_ENABLED
				ERR_PRINT("Unrecognized GLError");
#endif // DEBUG_ENABLED
			} break;
		}
		error_found = true;
		error = glGetError();
	}

	return error_found;
}

RasterizerGLES3::RasterizerGLES3() {
	storage = memnew(RasterizerStorageGLES3);
	canvas = memnew(RasterizerCanvasGLES3);
	scene = memnew(RasterizerSceneGLES3);
	canvas->storage = storage;
	canvas->scene_render = scene;
	storage->canvas = canvas;
	scene->storage = storage;
	storage->scene = scene;

	time_total = 0;
	time_scale = 1;
}

RasterizerGLES3::~RasterizerGLES3() {
	memdelete(storage);
	memdelete(canvas);
	memdelete(scene);
}