/*
 Copyright (c) 2013 yvt

 This file is part of OpenSpades.

 OpenSpades 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 3 of the License, or
 (at your option) any later version.

 OpenSpades 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 OpenSpades.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "GLSpriteRenderer.h"
#include <Core/Debug.h>
#include "GLImage.h"
#include "GLProgram.h"
#include "GLRenderer.h"
#include "IGLDevice.h"
#include "SWFeatureLevel.h"

namespace spades {
	namespace draw {

		GLSpriteRenderer::GLSpriteRenderer(GLRenderer *renderer)
		    : renderer(renderer),
		      device(renderer->GetGLDevice()),
		      settings(renderer->GetSettings()),
		      projectionViewMatrix("projectionViewMatrix"),
		      rightVector("rightVector"),
		      upVector("upVector"),
		      texture("mainTexture"),
		      viewMatrix("viewMatrix"),
		      fogDistance("fogDistance"),
		      fogColor("fogColor"),
		      viewOriginVector("viewOriginVector"),
		      positionAttribute("positionAttribute"),
		      spritePosAttribute("spritePosAttribute"),
		      colorAttribute("colorAttribute") {
			SPADES_MARK_FUNCTION();

			program = renderer->RegisterProgram("Shaders/Sprite.program");
		}

		GLSpriteRenderer::~GLSpriteRenderer() { SPADES_MARK_FUNCTION(); }

		void GLSpriteRenderer::Add(spades::draw::GLImage *img, spades::Vector3 center, float rad,
		                           float ang, Vector4 color) {
			SPADES_MARK_FUNCTION_DEBUG();
			Sprite spr;
			spr.image = img;
			spr.center = center;
			spr.radius = rad;
			spr.angle = ang;
			if (settings.r_hdr) {
				// linearize color
				if (color.x > color.w || color.y > color.w || color.z > color.w) {
					// emissive material
					color.x *= color.x;
					color.y *= color.y;
					color.z *= color.z;
				} else {
					// scattering/absorptive material
					float rcp = fastRcp(color.w + .01);
					color.x *= color.x * rcp;
					color.y *= color.y * rcp;
					color.z *= color.z * rcp;
				}
			}
			spr.color = color;
			sprites.push_back(spr);
		}

		void GLSpriteRenderer::Clear() {
			SPADES_MARK_FUNCTION();
			sprites.clear();
		}

		void GLSpriteRenderer::Render() {
			SPADES_MARK_FUNCTION();
			lastImage = NULL;
			program->Use();

			projectionViewMatrix(program);
			rightVector(program);
			upVector(program);
			texture(program);
			viewMatrix(program);
			fogDistance(program);
			fogColor(program);
			viewOriginVector(program);

			positionAttribute(program);
			spritePosAttribute(program);
			colorAttribute(program);

			projectionViewMatrix.SetValue(renderer->GetProjectionViewMatrix());
			viewMatrix.SetValue(renderer->GetViewMatrix());

			fogDistance.SetValue(renderer->GetFogDistance());

			const auto &viewOrigin = renderer->GetSceneDef().viewOrigin;
			viewOriginVector.SetValue(viewOrigin.x, viewOrigin.y, viewOrigin.z);

			Vector3 fogCol = renderer->GetFogColor();
			fogCol *= fogCol;
			fogColor.SetValue(fogCol.x, fogCol.y, fogCol.z);

			const client::SceneDefinition &def = renderer->GetSceneDef();
			rightVector.SetValue(def.viewAxis[0].x, def.viewAxis[0].y, def.viewAxis[0].z);
			upVector.SetValue(def.viewAxis[1].x, def.viewAxis[1].y, def.viewAxis[1].z);
			texture.SetValue(0);

			device->ActiveTexture(0);

			device->EnableVertexAttribArray(positionAttribute(), true);
			device->EnableVertexAttribArray(spritePosAttribute(), true);
			device->EnableVertexAttribArray(colorAttribute(), true);

			for (size_t i = 0; i < sprites.size(); i++) {
				Sprite &spr = sprites[i];
				if (spr.image != lastImage) {
					Flush();
					lastImage = spr.image;
					SPAssert(vertices.empty());
				}

				Vertex v;
				v.x = spr.center.x;
				v.y = spr.center.y;
				v.z = spr.center.z;
				v.radius = spr.radius;
				v.angle = spr.angle;
				v.r = spr.color.x;
				v.g = spr.color.y;
				v.b = spr.color.z;
				v.a = spr.color.w;

				uint32_t idx = (uint32_t)vertices.size();
				v.sx = -1;
				v.sy = -1;
				vertices.push_back(v);
				v.sx = 1;
				v.sy = -1;
				vertices.push_back(v);
				v.sx = -1;
				v.sy = 1;
				vertices.push_back(v);
				v.sx = 1;
				v.sy = 1;
				vertices.push_back(v);

				indices.push_back(idx);
				indices.push_back(idx + 1);
				indices.push_back(idx + 2);
				indices.push_back(idx + 1);
				indices.push_back(idx + 3);
				indices.push_back(idx + 2);
			}

			Flush();

			device->EnableVertexAttribArray(positionAttribute(), false);
			device->EnableVertexAttribArray(spritePosAttribute(), false);
			device->EnableVertexAttribArray(colorAttribute(), false);
		}

		void GLSpriteRenderer::Flush() {
			SPADES_MARK_FUNCTION_DEBUG();

			if (vertices.empty())
				return;

			device->VertexAttribPointer(positionAttribute(), 4, IGLDevice::FloatType, false,
			                            sizeof(Vertex), &(vertices[0].x));
			device->VertexAttribPointer(spritePosAttribute(), 4, IGLDevice::FloatType, false,
			                            sizeof(Vertex), &(vertices[0].sx));
			device->VertexAttribPointer(colorAttribute(), 4, IGLDevice::FloatType, false,
			                            sizeof(Vertex), &(vertices[0].r));

			SPAssert(lastImage);
			lastImage->Bind(IGLDevice::Texture2D);

			device->DrawElements(IGLDevice::Triangles,
			                     static_cast<IGLDevice::Sizei>(indices.size()),
			                     IGLDevice::UnsignedInt, indices.data());

			vertices.clear();
			indices.clear();
		}
	}
}