opengl_es_examples/TrainingCourse/FastTnL/OGLES2/OGLES2FastTnL.cpp

/******************************************************************************

 @File         OGLES2FastTnL.cpp

 @Title        Fast Transformation and Lighting

 @Version      

 @Copyright    Copyright (C)  Imagination Technologies Limited.

 @Platform     Independent

 @Description  Demonstrates fast transform and lighting in the vertex shader.

******************************************************************************/
#include <math.h>

#include "PVRShell.h"
#include "OGLES2Tools.h"



/******************************************************************************
 Constants
******************************************************************************/

// Camera constants. Used for making the projection matrix
const float CAM_FOV  = PVRT_PI / 6;
const float CAM_NEAR = 4.0f;

// Index to bind the attributes to vertex shaders
const int VERTEX_ARRAY   = 0;
const int NORMAL_ARRAY   = 1;
const int TEXCOORD_ARRAY = 2;

/******************************************************************************
 Content file names
******************************************************************************/

// Source and binary shaders
const char c_szFragShaderSrcFile[]	= "FragShader.fsh";
const char c_szFragShaderBinFile[]	= "FragShader.fsc";
const char c_szVertShaderSrcFile[]	= "VertShader.vsh";
const char c_szVertShaderBinFile[]	= "VertShader.vsc";

// PVR texture files
const char c_szTextureFile[]		= "Basetex.pvr";

// POD scene files
const char c_szSceneFile[]			= "Mask.pod";


/*!****************************************************************************
 Class implementing the PVRShell functions.
******************************************************************************/
class OGLES2FastTnL : public PVRShell
{
	// Print3D class used to display text
	CPVRTPrint3D	m_Print3D;

	// 3D Model
	CPVRTModelPOD	m_Scene;

	// Projection and view matrices
	PVRTMat4 m_mViewProj;

	// OpenGL handles for shaders, textures and VBOs
	GLuint m_uiVertShader;
	GLuint m_uiFragShader;
	GLuint m_uiTexture;
	GLuint* m_puiVbo;
	GLuint* m_puiIndexVbo;

	// Group shader programs and their uniform locations together
	struct
	{
		GLuint uiId;
		GLuint uiMVPMatrixLoc;
		GLuint uiLightDirLoc;
		GLuint uiMaterialBiasLoc;
		GLuint uiMaterialScaleLoc;
	}
	m_ShaderProgram;

	// View Angle for animation
	float			m_fAngleY;

public:
	virtual bool InitApplication();
	virtual bool InitView();
	virtual bool ReleaseView();
	virtual bool QuitApplication();
	virtual bool RenderScene();

	bool LoadTextures(CPVRTString* pErrorStr);
	bool LoadShaders(CPVRTString* pErrorStr);
	void LoadVbos();

	void DrawMesh(int i32NodeIndex);
};

/*!****************************************************************************
 @Function		LoadTextures
 @Output		pErrorStr		A string describing the error on failure
 @Return		bool			true if no error occured
 @Description	Loads the textures required for this training course
******************************************************************************/
bool OGLES2FastTnL::LoadTextures(CPVRTString* const pErrorStr)
{
	if(PVRTTextureLoadFromPVR(c_szTextureFile, &m_uiTexture) != PVR_SUCCESS)
	{
		*pErrorStr = "ERROR: Failed to load texture.";
		return false;
	}

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

	return true;
}

/*!****************************************************************************
 @Function		LoadShaders
 @Output		pErrorStr		A string describing the error on failure
 @Return		bool			true if no error occured
 @Description	Loads and compiles the shaders and links the shader programs
				required for this training course
******************************************************************************/
bool OGLES2FastTnL::LoadShaders(CPVRTString* pErrorStr)
{
	/*
		Load and compile the shaders from files.
		Binary shaders are tried first, source shaders
		are used as fallback.
	*/
	if (PVRTShaderLoadFromFile(
			c_szVertShaderBinFile, c_szVertShaderSrcFile, GL_VERTEX_SHADER, GL_SGX_BINARY_IMG, &m_uiVertShader, pErrorStr) != PVR_SUCCESS)
	{
		return false;
	}

	if (PVRTShaderLoadFromFile(
			c_szFragShaderBinFile, c_szFragShaderSrcFile, GL_FRAGMENT_SHADER, GL_SGX_BINARY_IMG, &m_uiFragShader, pErrorStr) != PVR_SUCCESS)
	{
		return false;
	}

	/*
		Set up and link the shader program
	*/
	const char* aszAttribs[] = { "inVertex", "inNormal", "inTexCoord" };
	if (PVRTCreateProgram(&m_ShaderProgram.uiId, m_uiVertShader, m_uiFragShader, aszAttribs, 3, pErrorStr) != PVR_SUCCESS)
	{
		PVRShellSet(prefExitMessage, pErrorStr->c_str());
		return false;
	}
	// Set the sampler2D variable to the first texture unit
	glUniform1i(glGetUniformLocation(m_ShaderProgram.uiId, "sTexture"), 0);

	// Store the location of uniforms for later use
	m_ShaderProgram.uiMVPMatrixLoc		= glGetUniformLocation(m_ShaderProgram.uiId, "MVPMatrix");
	m_ShaderProgram.uiLightDirLoc		= glGetUniformLocation(m_ShaderProgram.uiId, "LightDirection");
	m_ShaderProgram.uiMaterialBiasLoc	= glGetUniformLocation(m_ShaderProgram.uiId, "MaterialBias");
	m_ShaderProgram.uiMaterialScaleLoc	= glGetUniformLocation(m_ShaderProgram.uiId, "MaterialScale");

	return true;
}

/*!****************************************************************************
 @Function		LoadVbos
 @Description	Loads the mesh data required for this training course into
				vertex buffer objects
******************************************************************************/
void OGLES2FastTnL::LoadVbos()
{
	if (!m_puiVbo)      m_puiVbo = new GLuint[m_Scene.nNumMesh];
	if (!m_puiIndexVbo) m_puiIndexVbo = new GLuint[m_Scene.nNumMesh];

	/*
		Load vertex data of all meshes in the scene into VBOs

		The meshes have been exported with the "Interleave Vectors" option,
		so all data is interleaved in the buffer at pMesh->pInterleaved.
		Interleaving data improves the memory access pattern and cache efficiency,
		thus it can be read faster by the hardware.
	*/
	glGenBuffers(m_Scene.nNumMesh, m_puiVbo);
	for (unsigned int i = 0; i < m_Scene.nNumMesh; ++i)
	{
		// Load vertex data into buffer object
		SPODMesh& Mesh = m_Scene.pMesh[i];
		unsigned int uiSize = Mesh.nNumVertex * Mesh.sVertex.nStride;
		glBindBuffer(GL_ARRAY_BUFFER, m_puiVbo[i]);
		glBufferData(GL_ARRAY_BUFFER, uiSize, Mesh.pInterleaved, GL_STATIC_DRAW);

		// Load index data into buffer object if available
		m_puiIndexVbo[i] = 0;
		if (Mesh.sFaces.pData)
		{
			glGenBuffers(1, &m_puiIndexVbo[i]);
			uiSize = PVRTModelPODCountIndices(Mesh) * sizeof(GLshort);
			glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_puiIndexVbo[i]);
			glBufferData(GL_ELEMENT_ARRAY_BUFFER, uiSize, Mesh.sFaces.pData, GL_STATIC_DRAW);
		}
	}
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}

/*!****************************************************************************
 @Function		InitApplication
 @Return		bool		true if no error occured
 @Description	Code in InitApplication() will be called by PVRShell once per
				run, before the rendering context is created.
				Used to initialize variables that are not dependant on it
				(e.g. external modules, loading meshes, etc.)
				If the rendering context is lost, InitApplication() will
				not be called again.
******************************************************************************/
bool OGLES2FastTnL::InitApplication()
{
	m_puiVbo = 0;
	m_puiIndexVbo = 0;

	// Get and set the read path for content files
	CPVRTResourceFile::SetReadPath((char*)PVRShellGet(prefReadPath));

	// Load the scene
	if (m_Scene.ReadFromFile(c_szSceneFile) != PVR_SUCCESS)
	{
		PVRShellSet(prefExitMessage, "ERROR: Couldn't load the .pod file\n");
		return false;
	}

	m_fAngleY = 0.0;

	return true;
}

/*!****************************************************************************
 @Function		QuitApplication
 @Return		bool		true if no error occured
 @Description	Code in QuitApplication() will be called by PVRShell once per
				run, just before exiting the program.
				If the rendering context is lost, QuitApplication() will
				not be called.x
******************************************************************************/
bool OGLES2FastTnL::QuitApplication()
{
	// Free the memory allocated for the scene
	m_Scene.Destroy();

	delete [] m_puiVbo;
	delete [] m_puiIndexVbo;

    return true;
}

/*!****************************************************************************
 @Function		InitView
 @Return		bool		true if no error occured
 @Description	Code in InitView() will be called by PVRShell upon
				initialization or after a change in the rendering context.
				Used to initialize variables that are dependant on the rendering
				context (e.g. textures, vertex buffers, etc.)
******************************************************************************/
bool OGLES2FastTnL::InitView()
{
	CPVRTString ErrorStr;

	/*
		Initialize VBO data
	*/
	LoadVbos();

	/*
		Load textures
	*/
	if (!LoadTextures(&ErrorStr))
	{
		PVRShellSet(prefExitMessage, ErrorStr.c_str());
		return false;
	}

	/*
		Load and compile the shaders & link programs
	*/
	if (!LoadShaders(&ErrorStr))
	{
		PVRShellSet(prefExitMessage, ErrorStr.c_str());
		return false;
	}

	// Is the screen rotated?
	bool bRotate = PVRShellGet(prefIsRotated) && PVRShellGet(prefFullScreen);
	/*
		Initialize Print3D
	*/
	if(m_Print3D.SetTextures(0,PVRShellGet(prefWidth),PVRShellGet(prefHeight), bRotate) != PVR_SUCCESS)
	{
		PVRShellSet(prefExitMessage, "ERROR: Cannot initialise Print3D\n");
		return false;
	}

	/*
		Calculate the projection and view matrices
	*/
	float fAspect = PVRShellGet(prefWidth) / (float)PVRShellGet(prefHeight);
	m_mViewProj = PVRTMat4::PerspectiveFovFloatDepthRH(CAM_FOV, fAspect, CAM_NEAR, PVRTMat4::OGL, bRotate);
	m_mViewProj *= PVRTMat4::LookAtRH(PVRTVec3(0.f, 0.f, 150.f), PVRTVec3(0.f), PVRTVec3(0.f, 1.f, 0.f));

	/*
		Set default shader material uniforms
	*/
	float fSpecularConcentration = 0.8f;	// a value from 0 to 1 (wider, concetrated)
	float fSpecularIntensity = 0.5f;		// a value from 0 to 1

	// Specular bias
	glUniform1f(m_ShaderProgram.uiMaterialBiasLoc, fSpecularConcentration);
	// Specular intensity scale
	glUniform1f(m_ShaderProgram.uiMaterialScaleLoc, fSpecularIntensity / (1.0f - fSpecularConcentration));

	/*
		Set OpenGL ES render states needed for this training course
	*/
	// Enable backface culling and depth test
	glCullFace(GL_BACK);
	glEnable(GL_CULL_FACE);

	// Enable z-buffer test
	// We are using a projection matrix optimized for a floating point depth buffer,
	// so the depth test and clear value need to be inverted (1 becomes near, 0 becomes far).
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_GEQUAL);
	glClearDepthf(0.0f);

	// Use a nice bright blue as clear colour
	glClearColor(0.6f, 0.8f, 1.0f, 1.0f);

	return true;
}

/*!****************************************************************************
 @Function		ReleaseView
 @Return		bool		true if no error occured
 @Description	Code in ReleaseView() will be called by PVRShell when the
				application quits or before a change in the rendering context.
******************************************************************************/
bool OGLES2FastTnL::ReleaseView()
{
	// Delete textures
	glDeleteTextures(1, &m_uiTexture);

	// Delete program and shader objects
	glDeleteProgram(m_ShaderProgram.uiId);

	glDeleteShader(m_uiVertShader);
	glDeleteShader(m_uiFragShader);

	// Delete buffer objects
	glDeleteBuffers(m_Scene.nNumMesh, m_puiVbo);
	glDeleteBuffers(m_Scene.nNumMesh, m_puiIndexVbo);

	// Release Print3D Textures
	m_Print3D.ReleaseTextures();

	return true;
}

/*!****************************************************************************
 @Function		RenderScene
 @Return		bool		true if no error occured
 @Description	Main rendering loop function of the program. The shell will
				call this function every frame.
				eglSwapBuffers() will be performed by PVRShell automatically.
				PVRShell will also manage important OS events.
				Will also manage relevent OS events. The user has access to
				these events through an abstraction layer provided by PVRShell.
******************************************************************************/
bool OGLES2FastTnL::RenderScene()
{
	// Clear the color and depth buffer
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// Use shader program
	glUseProgram(m_ShaderProgram.uiId);

	// Bind texture
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, m_uiTexture);

	/*
		Now that the uniforms are set, call another function to actually draw the mesh.
	*/
	DrawMesh(0);

	// Rotate the model matrix
	PVRTMat4 mModel = PVRTMat4::RotationY(m_fAngleY);
	m_fAngleY += 0.02f;

	// Calculate model view projection matrix
	PVRTMat4 mMVP = m_mViewProj * mModel;

	// Feeds Projection Model View matrix to the shaders
	glUniformMatrix4fv(m_ShaderProgram.uiMVPMatrixLoc, 1, GL_FALSE, mMVP.ptr());

	/*
		The inverse of a rotation matrix is the transposed matrix
		Because of v * M = transpose(M) * v, this means:
		v * R == inverse(R) * v
		So we don't have to actually invert or transpose the matrix
		to transform back from world space to model space
	*/
	PVRTVec3 vMsLightDir = (PVRTVec3(1, 1, 1) * PVRTMat3(mModel)).normalized();
	glUniform3fv(m_ShaderProgram.uiLightDirLoc, 1, vMsLightDir.ptr());

	// Displays the demo name using the tools. For a detailed explanation, see the training course IntroducingPVRTools
	m_Print3D.DisplayDefaultTitle("FastTnL", "", ePVRTPrint3DLogoIMG);
	m_Print3D.Flush();

	return true;
}

/*!****************************************************************************
 @Function		DrawMesh
 @Input			i32NodeIndex		Node index of the mesh to draw
 @Description	Draws a SPODMesh after the model view matrix has been set and
				the meterial prepared.
******************************************************************************/
void OGLES2FastTnL::DrawMesh(int i32NodeIndex)
{
	int i32MeshIndex = m_Scene.pNode[i32NodeIndex].nIdx;
	SPODMesh* pMesh = &m_Scene.pMesh[i32MeshIndex];

	// bind the VBO for the mesh
	glBindBuffer(GL_ARRAY_BUFFER, m_puiVbo[i32MeshIndex]);
	// bind the index buffer, won't hurt if the handle is 0
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_puiIndexVbo[i32MeshIndex]);

	// Enable the vertex attribute arrays
	glEnableVertexAttribArray(VERTEX_ARRAY);
	glEnableVertexAttribArray(NORMAL_ARRAY);
	glEnableVertexAttribArray(TEXCOORD_ARRAY);

	// Set the vertex attribute offsets
	glVertexAttribPointer(VERTEX_ARRAY, 3, GL_FLOAT, GL_FALSE, pMesh->sVertex.nStride, pMesh->sVertex.pData);
	glVertexAttribPointer(NORMAL_ARRAY, 3, GL_FLOAT, GL_FALSE, pMesh->sNormals.nStride, pMesh->sNormals.pData);
	glVertexAttribPointer(TEXCOORD_ARRAY, 2, GL_FLOAT, GL_FALSE, pMesh->psUVW[0].nStride, pMesh->psUVW[0].pData);

	/*
		The geometry can be exported in 4 ways:
		- Indexed Triangle list
		- Non-Indexed Triangle list
		- Indexed Triangle strips
		- Non-Indexed Triangle strips
	*/
	if(pMesh->nNumStrips == 0)
	{
		if(m_puiIndexVbo[i32MeshIndex])
		{
			// Indexed Triangle list
			glDrawElements(GL_TRIANGLES, pMesh->nNumFaces*3, GL_UNSIGNED_SHORT, 0);
		}
		else
		{
			// Non-Indexed Triangle list
			glDrawArrays(GL_TRIANGLES, 0, pMesh->nNumFaces*3);
		}
	}
	else
	{
		for(int i = 0; i < (int)pMesh->nNumStrips; ++i)
		{
			int offset = 0;
			if(m_puiIndexVbo[i32MeshIndex])
			{
				// Indexed Triangle strips
				glDrawElements(GL_TRIANGLE_STRIP, pMesh->pnStripLength[i]+2, GL_UNSIGNED_SHORT, (GLshort*)(offset*2));
			}
			else
			{
				// Non-Indexed Triangle strips
				glDrawArrays(GL_TRIANGLE_STRIP, offset, pMesh->pnStripLength[i]+2);
			}
			offset += pMesh->pnStripLength[i]+2;
		}
	}

	// Safely disable the vertex attribute arrays
	glDisableVertexAttribArray(VERTEX_ARRAY);
	glDisableVertexAttribArray(NORMAL_ARRAY);
	glDisableVertexAttribArray(TEXCOORD_ARRAY);

	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}

/*!****************************************************************************
 @Function		NewDemo
 @Return		PVRShell*		The demo supplied by the user
 @Description	This function must be implemented by the user of the shell.
				The user should return its PVRShell object defining the
				behaviour of the application.
******************************************************************************/
PVRShell* NewDemo()
{
	return new OGLES2FastTnL();
}

/******************************************************************************
 End of file (OGLES2FastTnL.cpp)
******************************************************************************/