Lesson11: Interactive Orbit or Arcball style Camera

In this post we will discuss implementation of Orbit or Arcball style Camera.

Lesson09: Interactive First Person Shooter or FPS style Camera

 

In this post we will discuss implementation of FPS style Camera.

Lesson08: Start Camera and Roll

 In this post understand cameras space and Perspective and Orthographic  projections interactively.

The cube can be rotated using x, y and z keys. The The camera space can be changed by checking LookAt checkbox and supplying  varying input for Position, Target and Up vectors. 

Similarly, Perspective Projection can be changed by checking Perspective checkbox and supplying  varying input for FOV, Near  Plane and Far Plane.  The FOV can be changed by typing page up and down keys or mouse wheel.
Orthographic Projection can be changed by checking Orthographic checkbox and supplying  varying input for X minmax, y minmax and Z minmax values. 

Lesson07: Drawing Text interactively.

Overview 

As discussed in the  previous article, we saw how Text can be drawn in multiple fonts, sizes and colors and images can be placed side by side.

Also, the implementation of the TextMesh , TextureUtil  and TextImageSketcher were covered. 

In this post we will try to draw  text and image interactively.

Details

The purpose of  Lesson07 is to draw text and image and work with them interactively by changing fonts, colors, resize height and width.

System  class diagram

The scene class does use camera. It has an pointer to TextImageSketcher called ptextutl.

Implementation

Scene

The functionality is implemented in the Scene class derived from BaseScene class.

The three methods Init, DrawScene and Cleanup are overridden as below:

The Init method calls 

1. BaseScene::Init to create hosting window and OpenGL Context. 
2. It creates an input dialog to work with text and images interactively.
3. It calls init function with texture id GL_TEXTURE0 + 4, height and width of the bitmap. on the TextImageSketcher object to populate VBO/EBO buffers and bind them. Also create texture and bitmap. 
4. It also compiles and links shader programs.

The DrawScene method draws a string and image. 

The Cleanup method releases the resources related to VBO/EBO, Texture related resources and shader programs.

The message handler for IDOK is called when Apply button is pressed after updates are made in the input dialog. It refreshes the display.

The message handler for IDCANCEL is called when in Cancel button is pressed the input dialog. It calls 

OnCloseWindow to destroy window.

Finally the WM_CLOSE  event is  handled in OnCloseWindow function and the window is destroyed and  application is shutdown when the window is closed or Escape key is pressed. 

Application

Scene class is hosted main.cpp. which creates the scene object and displays it. Message pump is added to process windows messages.

Input dialog

The input dialog as shown below can be used to change settings and understand drawing text and images.

Output

The output looks as shown in the top. 

Lesson06: Lighting a Textured Cube interactively

Overview 

In the previous posts drawing a textured cube were explained. Also, the implementation of the LightingUtil and LightedTexCube were covered. 

In this post we will try to draw a textured cube with lighting interactively. The cube looks as shown above. The cube looks elongated because aspect ratio is not applied.

Details

The purpose of  Lesson06 is to create a lighted textured cube and work with it interactively with different types of light to understand nuances of lighting.

System  class diagram

The scene class overrides camera with an instance of ThreeDCamera. It has an instance of LightedTexCube called cube derived from TexturedCube class.

Implementation

Scene

The functionality is implemented in the Scene class derived from BaseScene class.

The three methods Init, DrawScene and Cleanup are overridden as below:

The Init method calls 

1. BaseScene::Init to create hosting window and OpenGL Context. 
2. It also attaches camera to a ThreeDCamera class object. This camera  processes keyboard and mouse inputs as explained earlier.
3. It creates an input dialog to work with lighting settings interactively.
4. It calls init function on the LightedTexCube object to populate VBO/EBO buffers and bind them. 
5. Load textures from the image file
6. It also compiles and links shader programs.

The DrawScene method draws the cube with texture wrapped and rotates as per keyboard or mouse inputs. The lighting settings are taken from the light instance of LightingUtil of the cube object.

The Cleanup method releases the resources related to VBO/EBO, Texture related resources and shader programs.

The message handler for IDOK is called when Apply button is pressed after updates are made in the input dialog. It refreshes the display.

The message handler for IDCANCEL is called when in Cancel button is pressed the input dialog. It calls 

OnCloseWindow to destroy window.

Finally the WM_CLOSE  event is  handled in OnCloseWindow function and the window is destroyed and  application is shutdown when the window is closed or Escape key is pressed. 

#include "Scene\BaseScene.h"
#include "Scene\Camera\ThreeDCamera.h"
#include "Geometry\LightingUtil.h"
#include "Geometry\Cube\LightedTexCube.h"
#include "InputDlg.h"

DWORD WINAPI ThreadFunction(LPVOID lpParam);

class Scene:public BaseScene
{
public:
	//message handler
	BEGIN_MSG_MAP(Scene0)
		MESSAGE_HANDLER(WM_CLOSE, OnCloseWindow)
		COMMAND_ID_HANDLER(IDOK, OnDoRefresh)
		COMMAND_ID_HANDLER(IDCANCEL, OnClose)
		CHAIN_MSG_MAP(BaseScene)
	END_MSG_MAP()


	//override
	int Init(RECT rect, WCHAR *windowname)
	{
		//create host window and context
		BaseScene::Init(rect, windowname);

		CreateThread(NULL, 0, ThreadFunction, this, 0, NULL);

		//attach mouse keyboard input handler
		camera = new ThreeDCamera(m_hWnd);
		::Sleep(500);
		updatecube();

		return 0;
	}

	void updatecube()
	{
		if (pcube != nullptr)
		{
			auto src = pcube->light.lightsrc.src;
			pdlg->update(&pcube->light);
			if (src != pcube->light.lightsrc.src)
			{
				pcube->Cleanup();
				delete pcube;
				pcube = nullptr;
			}
		}

		if (pcube == nullptr)
		{
			pcube = new LightedTexCube();
			pdlg->update(&pcube->light);
			pcube->Init(0, R"(..\resources\textures\rocks2.bmp)");
		}
	}

	//release resources
	void Cleanup()
	{
		pcube->Cleanup();
		delete camera;
	}


	LRESULT OnDoRefresh(WORD wParam, WORD wParam2, HWND lParam, BOOL& bHandled)
	{
		bHandled = TRUE;
		updatecube();
		Invalidate();
		return 0;
	}

	LRESULT OnClose(WORD wParam, WORD wParam2, HWND lParam, BOOL& bHandled)
	{
		return OnCloseWindow(0, 0, (LPARAM)nullptr, bHandled);
	}


	//draw the scene
	void DrawScene()
	{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		SceneCamera()->augumentModelMatrix(*pcube);
		wstring wcap = L"Lighting Settings - " + pcube->getangless();
		SetWindowTextW(wcap.c_str());
		pcube->Draw();
		SceneCamera()->MM.Reset();
	}

	//Close the window
	LRESULT OnCloseWindow(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
	{
		bHandled = TRUE;
		DestroyWindow();
		PostQuitMessage(0);
		return 0;
	}

	inline ThreeDCamera*  SceneCamera()
	{
		static auto ret = dynamic_cast<ThreeDCamera*>(camera);
		return ret;
	}

	void CreateInputDlg()
	{
		pdlg = new InputDlg();
		pdlg->Create(m_hWnd);
		pdlg->ShowWindow(SW_SHOW);
		Invalidate();
	}

private:
	LightedTexCube *pcube = nullptr;
	int IDM_INPUTDLG = 1001;
	InputDlg* pdlg;

};

DWORD WINAPI ThreadFunction(LPVOID lpParam)
{
	Scene* pscene = (Scene*)lpParam;
	pscene->CreateInputDlg();

	MSG msg;
	while (GetMessage(&msg, 0, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessageA(&msg);
	}

	return 0;
}

Application

Scene class is hosted main.cpp. which creates the scene object and displays it. Message pump is added to process windows messages.

#include "Scene.h"

Scene scene;

int WINAPI WinMain(HINSTANCE inst, HINSTANCE prev, LPSTR cmd_line, int show)
{
	scene.Init(RECT{ 100, 100, 780, 500 }, L"Lesson06: Lighting");
	scene.ShowWindow(show);

	MSG msg;
	while (GetMessage(&msg, 0, 0, 0)) 
	{
		TranslateMessage(&msg);
		DispatchMessageA(&msg);
	}

	return 0;
}

Input dialog

The input dialog as shown below can be used to change settings and understand lighting.

Output

The output looks as shown in the top. 

Lesson05: Textured Cube

Overview 

In the previous posts the graphics pipeline and vertex processing were explained. Also, the implementation of the TextureUtil and TexturedCube were covered. 

In this post we will try to draw a cube with brick texture as shown above. The cube looks elongated because aspect ratio is not applied.

Details

The purpose of  Lesson04 is to create a Window initialized with OpenGL context and draw a cube wrapped with a brick texture.

System  class diagram

The scene class overrides camera with an instance of 3DCamera. It has an instance of TexturedCube called cube derived from BaseGeometry class.

cube overrides mesh with an instance of CubeMesh to generate geometry and TextureUtil object to load texture.

Implementation

Scene

The functionality is implemented in the Scene class derived from BaseScene class.

The three methods Init,DrawScene and Cleanup are overridden as below:

The Init method calls 

1. BaseScene::Init to create hosting window and OpenGL Context. 
2. It also attaches camera to a ThreeDCamera class object. This camera  processes keyboard and mouse inputs as explained earlier.
3. It calls init function on the IndexedCube object to populate VBO/EBO buffers and bind them. 
4. Load textures from the image file
5. It also compiles and links shader programs.

The DrawScene method draws the cube with texture wrapped and rotates as per keyboard or mouse inputs.

The Cleanup method releases the resources related to VBO/EBO, Texture related resoruces and shader programs.

Finally the WM_CLOSE  event is  handled in OnCloseWindow function and the window is destroyed and  application is shutdown when the window is closed or Escape key is pressed. 

#include "Scene\BaseScene.h"
#include "Scene\Camera\ThreeDCamera.h"
#include "Geometry\Cube\TexturedCube.h"

class Scene:public BaseScene
{
public:
	//message handler
	BEGIN_MSG_MAP(Scene0)
		MESSAGE_HANDLER(WM_CLOSE, OnCloseWindow)
		CHAIN_MSG_MAP(BaseScene)
	END_MSG_MAP()

	//override
	int Init(RECT rect, WCHAR *windowname)
	{
		//create host window and context
		BaseScene::Init(rect, windowname);

		//attach mouse keyboard input handler
		camera = new ThreeDCamera(m_hWnd);

		//Create cube an set texture filename
		cube.Init(0, R"(..\resources\textures\bricks2.jpg)");
		
		
		return 0;
	}

	//release resources
	void Cleanup()
	{
		cube.Cleanup();
		delete camera;
		
	}
	
	//draw the scene
	void DrawScene()
	{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		//get model view projection matrix. 
		//only model is modified
		//view and projection will be identity matrix
		SceneCamera()->augumentModelMatrix(cube);

		cube.Draw();

		SceneCamera()->MM.Reset();

	}

	//Close the window
	LRESULT OnCloseWindow(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
	{
		bHandled = TRUE;
		DestroyWindow();
		PostQuitMessage(0);
		return 0;
	}

	inline ThreeDCamera*  SceneCamera()
	{
		static auto ret = dynamic_cast<ThreeDCamera*>(camera);
		return ret;
	}

private:
	TexturedCube cube;

};

Application

Scene class is hosted main.cpp. which creates the scene object and displays it. Message pump is added to process windows messages.

#include "Scene.h"

Scene scene;

int WINAPI WinMain(HINSTANCE inst, HINSTANCE prev, LPSTR cmd_line, int show)
{
	scene.Init(RECT{ 100, 100, 780, 500 }, L"Modern OpenGL-Tutorial - Lesson04");
	scene.ShowWindow(show);

	MSG msg;
	while (GetMessage(&msg, 0, 0, 0)) 
	{
		TranslateMessage(&msg);
		DispatchMessageA(&msg);
	}

	return 0;
}

Output

The output looks as shown in the top. The cube is rotated by 20 degrees pitch and 20 degrees yaw. The camera position at the origin looking down on -Z axis or the back face of the cube.

To rotate the cube X,Y and Z keys can be used. They rotate respectively pitch, yaw and roll the cube  by 10 degrees.

In the next post we shall create a colored cube with transformation.

Lesson04: Indexed Cube with interpolated colors

 

Overview 

In the previous posts the graphics pipeline and vertex processing were explained. Also, the implementation of the CubeMesh and IndexedCube were covered. 

In this post we will try to draw a cube with interpolated colors as shown above. The cube looks elongated because aspect ratio is not applied.

Details

The purpose of  Lesson03 is to create a Window initialized with OpenGL context and draw a cube with interpolated colors.

System  class diagram

The scene class overrides camera with an instance of 3DCamera. It has an instance of IndexedCube called cube derived from BaseGeometry class.

cube overrides mesh with an instance of CubeMesh to generate geometry.

Implementation

Scene

The functionality is implemented in the Scene class derived from BaseScene class.

The three methods Init,DrawScene and Cleanup are overridden as below:

The Init method calls 

1. BaseScene::Init to create hosting window and OpenGL Context. 
2. It also attaches camera to a ThreeDCamera class object. This camera  processes keyboard and mouse inputs as explained earlier.
3. It calls init function on the IndexedCube object to populate VBO/EBO buffers and bind them. It also compiles and links shader programs.

The DrawScene method draws the cube with interpolated colors color and rotates as per keyboard or mouse inputs.

The Cleanup method releases the resources related to VBO/EBO and shader programs.

Finally the WM_CLOSE  event is  handled in OnCloseWindow function and the window is destroyed and  application is shutdown when the window is closed or Escape key is pressed. 

#include "Scene\BaseScene.h"
#include "Scene\Camera\ThreeDCamera.h"
#include "Geometry\Cube\IndexedCube.h"

class Scene:public BaseScene
{
public:
	//message handler
	BEGIN_MSG_MAP(Scene0)
		MESSAGE_HANDLER(WM_CLOSE, OnCloseWindow)
		CHAIN_MSG_MAP(BaseScene)
	END_MSG_MAP()

	//override
	int Init(RECT rect, WCHAR *windowname)
	{
		//create host window and context
		BaseScene::Init(rect, windowname);

		//attach mouse keyboard input handler
		camera = new ThreeDCamera(m_hWnd);

		//Create cube an set color
		cube.Init();
		
		return 0;
	}

	//release resources
	void Cleanup()
	{
		cube.Cleanup();
		delete camera;
		
	}
	
	//draw the scene
	void DrawScene()
	{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		//get model view projection matrix. 
		//only model is modified
		//view and projection will be identity matrix
		SceneCamera()->augumentModelMatrix(cube);

		cube.Draw();

		SceneCamera()->MM.Reset();
	}

	//Close the window
	LRESULT OnCloseWindow(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
	{
		bHandled = TRUE;

		DestroyWindow();

		PostQuitMessage(0);
		return 0;
	}

	inline ThreeDCamera*  SceneCamera()
	{
		static auto ret = dynamic_cast<ThreeDCamera*>(camera);
		return ret;
	}

private:
	IndexedCube cube;
};

Application

Scene class is hosted main.cpp. which creates the scene object and displays it. Message pump is added to process windows messages.

#include "Scene.h"

Scene scene;

int WINAPI WinMain(HINSTANCE inst, HINSTANCE prev, LPSTR cmd_line, int show)
{
	scene.Init(RECT{ 100, 100, 780, 500 }, L"Modern OpenGL-Tutorial - Lesson03");
	scene.ShowWindow(show);

	MSG msg;
	while (GetMessage(&msg, 0, 0, 0)) 
	{
		TranslateMessage(&msg);
		DispatchMessageA(&msg);
	}

	return 0;
}

Output

The output looks as shown in the top. The cube is rotated by 20 degrees pitch and 20 degrees yaw. The camera position at the origin looking down on -Z axis or the back face of the cube.

To rotate the cube X,Y and Z keys can be used. They rotate respectively pitch, yaw and roll the cube  by 10 degrees.

In the next post we shall create a textured cube.