/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 3 of the License, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef GRIM_GFX_OPENGL_SHADERS_H
#define GRIM_GFX_OPENGL_SHADERS_H

#include "engines/grim/actor.h"
#include "engines/grim/gfx_base.h"

#include "graphics/opengl/shader.h"

#include "common/stack.h"
#include "common/rect.h"

namespace Grim {

class GfxOpenGLS : public GfxBase {
public:
	GfxOpenGLS();
	virtual ~GfxOpenGLS();

	/**
	 * Creates a render-context.
	 *
	 * @param screenW        the width of the context
	 * @param screenH        the height of the context
	 */
	void setupScreen(int screenW, int screenH) override;

	/**
	 * Query whether the current context is hardware-accelerated
	 *
	 * @return true if hw-accelerated, false otherwise
	 */
	bool isHardwareAccelerated() override { return true; };
	bool supportsShaders() override { return true; }
	void setupCameraFrustum(float fov, float nclip, float fclip) override;
	void positionCamera(const Math::Vector3d &pos, const Math::Vector3d &interest, float roll) override;
	void positionCamera(const Math::Vector3d &pos, const Math::Matrix4 &rot) override;

	Math::Matrix4 getModelView() override;
	Math::Matrix4 getProjection() override;

	void clearScreen() override;
	void clearDepthBuffer() override;

	/**
	 * Swap the buffers, making the drawn screen visible
	 */
	void flipBuffer(bool opportunistic = false) override;

	void getScreenBoundingBox(const Mesh *mesh, int *x1, int *y1, int *x2, int *y2) override;
	void getScreenBoundingBox(const EMIModel *model, int *x1, int *y1, int *x2, int *y2) override;
	void getActorScreenBBox(const Actor *actor, Common::Point &p1, Common::Point &p2) override;
	void startActorDraw(const Actor *actor) override;

	void finishActorDraw() override;
	void setShadow(Shadow *shadow) override;
	void drawShadowPlanes() override;
	void setShadowMode() override;
	void clearShadowMode() override;
	bool isShadowModeActive() override;
	void setShadowColor(byte r, byte g, byte b) override;
	void getShadowColor(byte *r, byte *g, byte *b) override;
	void destroyShadow(Shadow *shadow) override;

	void set3DMode() override;

	void translateViewpointStart() override;
	void translateViewpoint(const Math::Vector3d &vec) override;
	void rotateViewpoint(const Math::Angle &angle, const Math::Vector3d &axis) override;
	void rotateViewpoint(const Math::Matrix4 &rot) override;
	void translateViewpointFinish() override;

	void drawEMIModelFace(const EMIModel* model, const EMIMeshFace* face) override;
	void drawModelFace(const Mesh *mesh, const MeshFace *face) override;
	void drawSprite(const Sprite *sprite) override;
	void drawMesh(const Mesh *mesh) override;
	void drawDimPlane() override;

	void enableLights() override;
	void disableLights() override;
	void setupLight(Light *light, int lightId) override;
	void turnOffLight(int lightId) override;

	void createTexture(Texture *texture, const uint8 *data, const CMap *cmap, bool clamp) override;
	void selectTexture(const Texture *texture) override;
	void destroyTexture(Texture *texture) override;

	/**
	 * Prepares a bitmap for drawing
	 * performs any format conversions needed for the renderer,
	 * and might create an internal representation of the bitmap
	 * external changes to the bitmap may not be visible after this
	 * is called. Must be called before drawBitmap can be used.
	 *
	 * the external bitmap might have its data changed by this function,
	 *
	 * @param bitmap       the bitmap to be prepared
	 * @see destroyBitmap
	 * @see drawBitmap
	 */
	void createBitmap(BitmapData *bitmap) override;

	/**
	 * Draws a bitmap
	 * before this is safe to use, createBitmap MUST have been called
	 *
	 * @param bitmap       the bitmap to be drawn
	 * @see createBitmap
	 * @see destroyBitmap
	 */
	void drawBitmap(const Bitmap *bitmap, int x, int y, uint32 layer = 0) override;

	/**
	 * Deletes any internal references and representations of a bitmap
	 * after this is called, it is safe to dispose of or change the external
	 * bitmapdata.
	 *
	 * @param bitmap       the bitmap to be destroyed
	 * @see createBitmap
	 * @see drawBitmap
	 */
	void destroyBitmap(BitmapData *bitmap) override;

	void createFont(Font *font) override;
	void destroyFont(Font *font) override;

	void createTextObject(TextObject *text) override;
	void drawTextObject(const TextObject *text) override;
	void destroyTextObject(TextObject *text) override;

	Bitmap *getScreenshot(int w, int h, bool useStored) override;
	void storeDisplay() override;
	void copyStoredToDisplay() override;

	/**
	 * Dims the entire screen
	 * Sets the entire screen to 10% of its current brightness,
	 * and converts it to grayscale.
	 */
	void dimScreen() override;
	void dimRegion(int x, int y, int w, int h, float level) override;

	/**
	 * Draw a completely opaque Iris around the specified rectangle.
	 * the arguments specify the distance from the screen-edge to the first
	 * non-iris pixel.
	 *
	 * @param x		the width of the Iris
	 * @param y		the height of the Iris
	 */
	void irisAroundRegion(int x1, int y1, int x2, int y2) override;

	void drawEmergString(int x, int y, const char *text, const Color &fgColor) override;
	void loadEmergFont() override;

	void drawRectangle(const PrimitiveObject *primitive) override;
	void drawLine(const PrimitiveObject *primitive) override;
	void drawPolygon(const PrimitiveObject *primitive) override;

	const Graphics::PixelFormat getMovieFormat() const override;

	/**
	 * Prepare a movie-frame for drawing
	 * performing any necessary conversion
	 *
	 * @param width         the width of the movie-frame.
	 * @param height        the height of the movie-frame.
	 * @param bitmap        a pointer to the data for the movie-frame.
	 * @see drawMovieFrame
	 * @see releaseMovieFrame
	 */
	void prepareMovieFrame(Graphics::Surface* frame) override;
	void drawMovieFrame(int offsetX, int offsetY) override;

	/**
	 * Release the currently prepared movie-frame, if one exists.
	 *
	 * @see drawMovieFrame
	 * @see prepareMovieFrame
	 */
	void releaseMovieFrame() override;

	const char *getVideoDeviceName() override;

	void renderBitmaps(bool render) override;
	void renderZBitmaps(bool render) override;

	void createMesh(Mesh *mesh) override;
	void destroyMesh(const Mesh *mesh) override;
	void createEMIModel(EMIModel *model) override;
	void updateEMIModel(const EMIModel* model) override;
	void destroyEMIModel(EMIModel *model) override;

	void setBlendMode(bool additive) override;

protected:
	void setupShaders();
	GLuint compileShader(const char *vertex, const char *fragment);
	GLuint compileShader(const char *shader) { return compileShader(shader, shader); }
	void createSpecialtyTextureFromScreen(uint id, uint8 *data, int x, int y, int width, int height) override;

private:
	const Actor *_currentActor;
	float _alpha;
	int _maxLights;
	GLuint _emergTexture;
	OpenGL::Shader* _emergProgram;

	OpenGL::Shader* _backgroundProgram;
	OpenGL::Shader* _actorProgram;
	OpenGL::Shader* _actorLightsProgram;
	OpenGL::Shader* _spriteProgram;
	OpenGL::Shader* _dimProgram;
	OpenGL::Shader* _dimPlaneProgram;
	OpenGL::Shader* _dimRegionProgram;
	OpenGL::Shader* _smushProgram;
	GLuint _smushVBO, _quadEBO;
	OpenGL::Shader* _textProgram;
	OpenGL::Shader* _primitiveProgram;
	OpenGL::Shader* _irisProgram;
	OpenGL::Shader* _shadowPlaneProgram;

	int _smushWidth;
	int _smushHeight;
	GLuint _smushTexId;
	void setupTexturedQuad();
	void setupQuadEBO();

	void setupZBuffer();
	void drawDepthBitmap(int bitmapId, int x, int y, int w, int h, char *data);

	float _fov;
	float _nclip;
	float _fclip;
	Math::Matrix4 _projMatrix;
	Math::Matrix4 _viewMatrix;
	Math::Matrix4 _mvpMatrix;
	Math::Matrix4 _overworldProjMatrix;

	void setupTexturedCenteredQuad();

	GLuint _spriteVBO;

	Common::Stack<Math::Matrix4> _matrixStack;
	Texture *_selectedTexture;

	GLuint _zBufTex;
	Math::Vector2d _zBufTexCrop;

	struct GLSLight {
		Math::Vector4d _position;
		Math::Vector4d _direction;
		Math::Vector4d _color;
		Math::Vector4d _params;
	};

	GLSLight *_lights;
	bool _hasAmbientLight;
	bool _lightsEnabled;

	void setupPrimitives();
	GLuint nextPrimitive();
	GLuint _primitiveVBOs[32];
	uint32 _currentPrimitive;
	void drawGenericPrimitive(const float *vertices, uint32 numVertices, const PrimitiveObject *primitive);
	GLuint _irisVBO;
	GLuint _dimVBO;
	GLuint _dimRegionVBO;
	GLuint _blastVBO;
	GLuint _storedDisplay;
};

}

#endif