第七章：3D模型渲染

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////////////////////////////////////////////////////////////////////////////////
// Filename: modelclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _MODELCLASS_H_
#define _MODELCLASS_H_

//////////////
// INCLUDES //
//////////////
#include <fstream>
using namespace std;

///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "textureclass.h"

////////////////////////////////////////////////////////////////////////////////
// Class name: ModelClass
////////////////////////////////////////////////////////////////////////////////
class ModelClass
{
private:
 struct VertexType
 {
  float x, y, z;
  float tu, tv;
  float nx, ny, nz;
 };

 struct ModelType
 {
  float x, y, z;
  float tu, tv;
  float nx, ny, nz;
 };

public:
 ModelClass();
 ModelClass(const ModelClass&);
 ~ModelClass();

bool Initialize(OpenGLClass*, char*, char*, unsigned int, bool);
 void Shutdown(OpenGLClass*);
 void Render(OpenGLClass*);

private:
 bool InitializeBuffers(OpenGLClass*);
 void ShutdownBuffers(OpenGLClass*);
 void RenderBuffers(OpenGLClass*);

 bool LoadTexture(OpenGLClass*, char*, unsigned int, bool);
 void ReleaseTexture();

bool LoadModel(char*);
 void ReleaseModel();

private:
 int m_vertexCount, m_indexCount;
 unsigned int m_vertexArrayId, m_vertexBufferId, m_indexBufferId;
 TextureClass* m_Texture;

ModelType* m_model;
};

#endif

////////////////////////////////////////////////////////////////////////////////
// Filename: modelclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "modelclass.h"

ModelClass::ModelClass()
{
 m_Texture = 0;

 m_model = 0;
}

ModelClass::ModelClass(const ModelClass& other)
{
}

ModelClass::~ModelClass()
{
}

bool ModelClass::Initialize(OpenGLClass* OpenGL, char* modelFilename, char* textureFilename, unsigned int textureUnit, bool wrap)
{
 bool result;

// Load in the model data.
 result = LoadModel(modelFilename);
 if(!result)
 {
  return false;
 }

 // Initialize the vertex and index buffers that hold the geometry for the model.
 result = InitializeBuffers(OpenGL);
 if(!result)
 {
  return false;
 }

 // Load the texture for this model.
 result = LoadTexture(OpenGL, textureFilename, textureUnit, wrap);
 if(!result)
 {
  return false;
 }

 return true;
}

void ModelClass::Shutdown(OpenGLClass* OpenGL)
{
 // Release the texture used for this model.
 ReleaseTexture();

 // Release the vertex and index buffers.
 ShutdownBuffers(OpenGL);

 // Release the model data.
 ReleaseModel();

 return;
}

void ModelClass::Render(OpenGLClass* OpenGL)
{
 // Put the vertex and index buffers on the graphics pipeline to prepare them for drawing.
 RenderBuffers(OpenGL);

 return;
}

bool ModelClass::InitializeBuffers(OpenGLClass* OpenGL)
{
 VertexType* vertices;
 unsigned int* indices;
 int i;

 // Create the vertex array.
 vertices = new VertexType[m_vertexCount];
 if(!vertices)
 {
  return false;
 }

 // Create the index array.
 indices = new unsigned int[m_indexCount];
 if(!indices)
 {
  return false;
 }

 // Load the vertex array and index array with data.
 for(i=0; i<m_vertexCount; i++)
 {
  vertices[i].x  = m_model[i].x;
  vertices[i].y  = m_model[i].y;
  vertices[i].z  = m_model[i].z;
  vertices[i].tu = m_model[i].tu;
  vertices[i].tv = 1.0f - m_model[i].tv;
  vertices[i].nx = m_model[i].nx;
  vertices[i].ny = m_model[i].ny;
  vertices[i].nz = m_model[i].nz;

  indices[i] = i;
 }

 // Allocate an OpenGL vertex array object.
 OpenGL->glGenVertexArrays(1, &m_vertexArrayId);

 // Bind the vertex array object to store all the buffers and vertex attributes we create here.
 OpenGL->glBindVertexArray(m_vertexArrayId);

 // Generate an ID for the vertex buffer.
 OpenGL->glGenBuffers(1, &m_vertexBufferId);

 // Bind the vertex buffer and load the vertex (position, texture, and normal) data into the vertex buffer.
 OpenGL->glBindBuffer(GL_ARRAY_BUFFER, m_vertexBufferId);
 OpenGL->glBufferData(GL_ARRAY_BUFFER, m_vertexCount * sizeof(VertexType), vertices, GL_STATIC_DRAW);

 // Enable the three vertex array attributes.
 OpenGL->glEnableVertexAttribArray(0);  // Vertex position.
 OpenGL->glEnableVertexAttribArray(1);  // Texture coordinates.
 OpenGL->glEnableVertexAttribArray(2);  // Normals.

 // Specify the location and format of the position portion of the vertex buffer.
 OpenGL->glBindBuffer(GL_ARRAY_BUFFER, m_vertexBufferId);
 OpenGL->glVertexAttribPointer(0, 3, GL_FLOAT, false, sizeof(VertexType), 0);

 // Specify the location and format of the texture coordinate portion of the vertex buffer.
 OpenGL->glBindBuffer(GL_ARRAY_BUFFER, m_vertexBufferId);
 OpenGL->glVertexAttribPointer(1, 2, GL_FLOAT, false, sizeof(VertexType), (unsigned char*)NULL + (3 * sizeof(float)));

 // Specify the location and format of the normal vector portion of the vertex buffer.
 OpenGL->glBindBuffer(GL_ARRAY_BUFFER, m_vertexBufferId);
 OpenGL->glVertexAttribPointer(2, 3, GL_FLOAT, false, sizeof(VertexType), (unsigned char*)NULL + (5 * sizeof(float)));

 // Generate an ID for the index buffer.
 OpenGL->glGenBuffers(1, &m_indexBufferId);

 // Bind the index buffer and load the index data into it.
 OpenGL->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_indexBufferId);
 OpenGL->glBufferData(GL_ELEMENT_ARRAY_BUFFER, m_indexCount* sizeof(unsigned int), indices, GL_STATIC_DRAW);
 
 // Now that the buffers have been loaded we can release the array data.
 delete [] vertices;
 vertices = 0;

 delete [] indices;
 indices = 0;

 return true;
}

void ModelClass::ShutdownBuffers(OpenGLClass* OpenGL)
{
 // Disable the two vertex array attributes.
 OpenGL->glDisableVertexAttribArray(0);
 OpenGL->glDisableVertexAttribArray(1);
 
 // Release the vertex buffer.
 OpenGL->glBindBuffer(GL_ARRAY_BUFFER, 0);
 OpenGL->glDeleteBuffers(1, &m_vertexBufferId);

 // Release the index buffer.
 OpenGL->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 OpenGL->glDeleteBuffers(1, &m_indexBufferId);

 // Release the vertex array object.
 OpenGL->glBindVertexArray(0);
 OpenGL->glDeleteVertexArrays(1, &m_vertexArrayId);

 return;
}

void ModelClass::RenderBuffers(OpenGLClass* OpenGL)
{
 // Bind the vertex array object that stored all the information about the vertex and index buffers.
 OpenGL->glBindVertexArray(m_vertexArrayId);

 // Render the vertex buffer using the index buffer.
 glDrawElements(GL_TRIANGLES, m_indexCount, GL_UNSIGNED_INT, 0);

 return;
}

bool ModelClass::LoadTexture(OpenGLClass* OpenGL, char* textureFilename, unsigned int textureUnit, bool wrap)
{
 bool result;

 // Create the texture object.
 m_Texture = new TextureClass;
 if(!m_Texture)
 {
  return false;
 }

 // Initialize the texture object.
 result = m_Texture->Initialize(OpenGL, textureFilename, textureUnit, wrap);
 if(!result)
 {
  return false;
 }

 return true;
}

void ModelClass::ReleaseTexture()
{
 // Release the texture object.
 if(m_Texture)
 {
  m_Texture->Shutdown();
  delete m_Texture;
  m_Texture = 0;
 }

 return;
}

bool ModelClass::LoadModel(char* filename)
{
 ifstream fin;
 char input;
 int i;

 // Open the model file.
 fin.open(filename);
 
 // If it could not open the file then exit.
 if(fin.fail())
 {
  return false;
 }

 // Read up to the value of vertex count.
 fin.get(input);
 while(input != ':')
 {
  fin.get(input);
 }

 // Read in the vertex count.
 fin >> m_vertexCount;

 // Set the number of indices to be the same as the vertex count.
 m_indexCount = m_vertexCount;

 // Create the model using the vertex count that was read in.
 m_model = new ModelType[m_vertexCount];
 if(!m_model)
 {
  return false;
 }

 // Read up to the beginning of the data.
 fin.get(input);
 while(input != ':')
 {
  fin.get(input);
 }
 fin.get(input);
 fin.get(input);

 // Read in the vertex data.
 for(i=0; i<m_vertexCount; i++)
 {
  fin >> m_model[i].x >> m_model[i].y >> m_model[i].z;
  fin >> m_model[i].tu >> m_model[i].tv;
  fin >> m_model[i].nx >> m_model[i].ny >> m_model[i].nz;
 }

 // Close the model file.
 fin.close();

 return true;
}

void ModelClass::ReleaseModel()
{
 if(m_model)
 {
  delete [] m_model;
  m_model = 0;
 }

 return;
}

////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.h
////////////////////////////////////////////////////////////////////////////////
#ifndef _GRAPHICSCLASS_H_
#define _GRAPHICSCLASS_H_

///////////////////////
// MY CLASS INCLUDES //
///////////////////////
#include "openglclass.h"
#include "cameraclass.h"
#include "modelclass.h"
#include "lightshaderclass.h"
#include "lightclass.h"

/////////////
// GLOBALS //
/////////////
const bool FULL_SCREEN = true;
const bool VSYNC_ENABLED = true;
const float SCREEN_DEPTH = 1000.0f;
const float SCREEN_NEAR = 0.1f;

////////////////////////////////////////////////////////////////////////////////
// Class name: GraphicsClass
////////////////////////////////////////////////////////////////////////////////
class GraphicsClass
{
public:
 GraphicsClass();
 GraphicsClass(const GraphicsClass&);
 ~GraphicsClass();

 bool Initialize(OpenGLClass*, HWND);
 void Shutdown();
 bool Frame();

private:
 bool Render(float);

private:
 OpenGLClass* m_OpenGL;
 CameraClass* m_Camera;
 ModelClass* m_Model;
 LightShaderClass* m_LightShader;
 LightClass* m_Light;
};

#endif

////////////////////////////////////////////////////////////////////////////////
// Filename: graphicsclass.cpp
////////////////////////////////////////////////////////////////////////////////
#include "graphicsclass.h"

GraphicsClass::GraphicsClass()
{
 m_OpenGL = 0;
 m_Camera = 0;
 m_Model = 0;
 m_LightShader = 0;
 m_Light = 0;
}

GraphicsClass::GraphicsClass(const GraphicsClass& other)
{
}

GraphicsClass::~GraphicsClass()
{
}

bool GraphicsClass::Initialize(OpenGLClass* OpenGL, HWND hwnd)
{
 bool result;

 // Store a pointer to the OpenGL class object.
 m_OpenGL = OpenGL;

 // Create the camera object.
 m_Camera = new CameraClass;
 if(!m_Camera)
 {
  return false;
 }

 // Set the initial position of the camera.
 m_Camera->SetPosition(0.0f, 0.0f, -10.0f);

 // Create the model object.
 m_Model = new ModelClass;
 if(!m_Model)
 {
  return false;
 }

 // Initialize the model object.
 result = m_Model->Initialize(m_OpenGL,  "../Engine/data/cube.txt", "../Engine/data/opengl.tga", 0, true);
 if(!result)
 {
  MessageBox(hwnd, L"Could not initialize the model object.", L"Error", MB_OK);
  return false;
 }
 
 // Create the light shader object.
 m_LightShader = new LightShaderClass;
 if(!m_LightShader)
 {
  return false;
 }

 // Initialize the light shader object.
 result = m_LightShader->Initialize(m_OpenGL, hwnd);
 if(!result)
 {
  MessageBox(hwnd, L"Could not initialize the light shader object.", L"Error", MB_OK);
  return false;
 }

 // Create the light object.
 m_Light = new LightClass;
 if(!m_Light)
 {
  return false;
 }

 // Initialize the light object.
 m_Light->SetDiffuseColor(1.0f, 1.0f, 1.0f, 1.0f);
 m_Light->SetDirection(0.0f, 0.0f, 1.0f);

 return true;
}

void GraphicsClass::Shutdown()
{
 // Release the light object.
 if(m_Light)
 {
  delete m_Light;
  m_Light = 0;
 }

 // Release the light shader object.
 if(m_LightShader)
 {
  m_LightShader->Shutdown(m_OpenGL);
  delete m_LightShader;
  m_LightShader = 0;
 }

 // Release the model object.
 if(m_Model)
 {
  m_Model->Shutdown(m_OpenGL);
  delete m_Model;
  m_Model = 0;
 }

 // Release the camera object.
 if(m_Camera)
 {
  delete m_Camera;
  m_Camera = 0;
 }

 // Release the pointer to the OpenGL class object.
 m_OpenGL = 0;

 return;
}

bool GraphicsClass::Frame()
{
 bool result;
 static float rotation = 0.0f;

 // Update the rotation variable each frame.
 rotation += 0.0174532925f * 2.0f;
 if(rotation > 360.0f)
 {
  rotation -= 360.0f;
 }

 // Render the graphics scene.
 result = Render(rotation);
 if(!result)
 {
  return false;
 }

 return true;
}

bool GraphicsClass::Render(float rotation)
{
 float worldMatrix[16];
 float viewMatrix[16];
 float projectionMatrix[16];
 float lightDirection[3];
 float diffuseLightColor[4];

 // Clear the buffers to begin the scene.
 m_OpenGL->BeginScene(0.0f, 0.0f, 0.0f, 1.0f);

 // Generate the view matrix based on the camera's position.
 m_Camera->Render();

 // Get the world, view, and projection matrices from the opengl and camera objects.
 m_OpenGL->GetWorldMatrix(worldMatrix);
 m_Camera->GetViewMatrix(viewMatrix);
 m_OpenGL->GetProjectionMatrix(projectionMatrix);

 // Get the light properties.
 m_Light->GetDirection(lightDirection);
 m_Light->GetDiffuseColor(diffuseLightColor);

 // Rotate the world matrix by the rotation value so that the triangle will spin.
 m_OpenGL->MatrixRotationY(worldMatrix, rotation);

 // Set the light shader as the current shader program and set the matrices that it will use for rendering.
 m_LightShader->SetShader(m_OpenGL);
 m_LightShader->SetShaderParameters(m_OpenGL, worldMatrix, viewMatrix, projectionMatrix, 0, lightDirection, diffuseLightColor);

 // Render the model using the light shader.
 m_Model->Render(m_OpenGL);
 
 // Present the rendered scene to the screen.
 m_OpenGL->EndScene();

 return true;
}

第七章：3D模型渲染

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原文地址：http://blog.csdn.net/weyson/article/details/47008843