我遇到了一个我无法解决的问题：
尝试绘制由正方形网格（即两个三角形）形成的表面。当我只使用顶点数据和绘图时，一切正常：
//m_totalVertices = m_rows*(m_cols *6) -> m_rows and m_cols are the quantity of columns and rows that build the surface
glDrawArrays(GL_TRIANGLES, 0, m_totalVertices);
例如：
//first Quad
Vertex[0] = -15,5;
Vertex[1] = -5,5;
Vertex[2] = -5,-5;
Vertex[3] = -5,-5;
Vertex[4] = -15,-5;
Vertex[5] = -15,5;
//second Quad
Vertex[0] = -5,5;
Vertex[1] = 5,5;
Vertex[2] = 5,-5;
Vertex[3] = 5,-5;
Vertex[4] = -5,-5;
Vertex[5] = -5,5;
//third Quad
Vertex[0] = 5,5;
Vertex[1] = 15,5;
Vertex[2] = 15,-5;
Vertex[3] = 15,-5;
Vertex[4] = 5,-5;
Vertex[5] = 5,5;
结果：
作为优化问题，我想使用“索引”来减少顶点数据的数量，但表面会变形：
要绘制它，我使用下一个函数：
//m_totalVertices = m_rows*(m_cols *6) -> m_rows and m_cols are the quantity of columns and rows that build the surface
glDrawElements(GL_TRIANGLES, m_totalVertices, GL_UNSIGNED_INT, 0);
例如：
//first Quad
indices[0] = 0;
indices[1] = 1;
indices[2] = 2;
indices[3] = 2;
indices[4] = 3;
indices[5] = 0;
//second Quad
indices[6] = 1;
indices[7] = 4;
indices[8] = 5;
indices[9] = 5;
indices[10] = 2;
indices[11] = 1;
//third Quad
indices[12] = 4;
indices[13] = 6;
indices[14] = 7;
indices[15] = 7;
indices[16] = 5;
indices[17] = 4;
//first Quad
Vertex[0] = -15,5;
Vertex[1] = -5,5;
Vertex[2] = -5,-5;
Vertex[3] = -15,-5;
//second Quad
Vertex[0] = -5,5;
Vertex[1] = 5,5;
Vertex[2] = 5,-5;
Vertex[3] = -5,-5;
//third Quad
Vertex[0] = 5,5;
Vertex[1] = 15,5;
Vertex[2] = 15,-5;
Vertex[3] = 5,-5;
结果：
这是仅使用顶点数据（无索引）生成曲面的类的代码 [WORKS PERFECT]：
#include "plane.h"
#include "matrix.h"
#include "glslshader.h"
#include "texture.h"
plane::plane(GLuint cols, GLuint rows,GLuint segmentSize, mixedColors color, CTexture* texture, GLshort textureMode) :
m_matrix(0),
m_shader(0),
m_cols(cols),
m_rows(rows),
m_segmentSize(segmentSize),
m_selectedColor(color),
m_texture(texture),
m_textureMode(textureMode),
m_totalVertices(rows*(cols*6))
{
//matrix handler
m_matrix = matrix::getInstance();
//check that variables are > 1
if(m_cols < 1){m_cols = 1;}
if(m_rows < 1){m_rows = 1;}
// generate a VAO
glGenVertexArrays(1, &m_uiVAO);
vbo.createVBO();
}
plane::~plane()
{
delete m_shader;
vbo.releaseVBO();
glDeleteVertexArrays(1, &m_uiVAO);
}
bool plane::init()
{
//load the shaders
if(m_texture == NULL)
{
m_shader = new GLSLProgram("data/shaders/shader-primitives.vert", "data/shaders/shader-primitives.frag");
}
else//if primitive use texture...
{
m_shader = new GLSLProgram("data/shaders/shader-texture.vert", "data/shaders/shader-texture.frag");
}
if (!m_shader->initialize())
{
cout << "Los shaders de las primitivas no pudieron ser incializados\n";
return false;
}
m_shader->linkProgram();
//number of QUAD vertex
const GLshort QUAD_ELEMENTS = 6;
GLuint r,c,q,x;
//bind VBO
vbo.bindVBO();
//set the start where you draw the first square of the plane
// so that everything is centered
GLfloat initX,initY;
initX = initY = 0.0f;
//displacement of each QUAD in X and Y axis.
const float MODULE = 0.2f;
//find the init value of X (the start value where you draw the first QUAD)
if(m_cols > 1)
{
initX = (float)((m_cols*MODULE/2.0f))-0.1f;
}
//find the init value of y (the start value where you draw the first QUAD)
if(m_rows > 1)
{
initY = (float)((m_rows*MODULE/2.0f))-0.1f;
}
//QUAD vertex data
vector3f quad[QUAD_ELEMENTS];
quad[0] = vector3f(-0.1f,0.1f,0.0f); quad[1] = vector3f(0.1f,0.1f,0.0f);
quad[2] = vector3f(0.1f,-0.1f,0.0f); quad[3] = vector3f(0.1f,-0.1f,0.0f);
quad[4] = vector3f(-0.1f,-0.1f,0.0f); quad[5] = vector3f(-0.1f,0.1f,0.0f);
x=0;
//put QUAD vertex in the "init position"
for(x=0;x<QUAD_ELEMENTS;++x)
{
quad[x].x = quad[x].x + (-initX);
quad[x].y = quad[x].y + initY;
}
//store de actual Y value of row (Y axis)
GLfloat newRow = 0.0f;
//store de actual X value of column (X axis)
GLfloat newColumn = 0.0f;
GLuint colorCounter = 0;
for(r=0;r<m_rows;++r)
{
//reset newColumn variable to 0.0f for each new column
newColumn = 0.0f;
//for each column
for(c=0;c<m_cols;++c)
{
//copy QUAD vertex data in new array
vector3f quadCopy[QUAD_ELEMENTS] = quad;
//for each column, move 0.1f to right
for(q=0;q<QUAD_ELEMENTS;++q)
{
//move right one MODULE (in x axis)
quadCopy[q].x = float(quadCopy[q].x + newColumn);
//move down one MODULE (in Y axis)
quadCopy[q].y = float(quadCopy[q].y + newRow);
//add vertex data and color to de vbo
vector3f resizedVertex = vector3f(quadCopy[q].x*m_segmentSize,quadCopy[q].y*m_segmentSize,quadCopy[q].z);
vbo.addData(&resizedVertex,sizeof(vector3f));
//every 4 laps reset colorCounter to 0;
cout << "Vertex["<< q << "] = "<< resizedVertex.x << "," << resizedVertex.y << ";\n";
if(colorCounter == 3){colorCounter = 0;}
vbo.addData(&color4f(m_selectedColor.color[colorCounter].r,m_selectedColor.color[colorCounter].g,m_selectedColor.color[colorCounter].b,m_selectedColor.color[colorCounter].a),sizeof(color4f));
++colorCounter;
}
//for each column, move right 0.1f
newColumn += MODULE;
}
newRow -= MODULE;
}
//bind VAO
glBindVertexArray(m_uiVAO);
//bind VBO
vbo.bindVBO();
vbo.uploadDataToGPU(GL_STATIC_DRAW);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(vector3f)+sizeof(color4f), (void*)sizeof(vector3f));
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(vector3f)+sizeof(color4f), 0);
return true;
}
void plane::render()
{
//bind shader
m_shader->bindShader();
//send projection matrix to shader
m_shader->sendUniform4x4("projectionMatrix", glm::value_ptr(*m_matrix->getProjectionMatrix()));
//matrix transformations
m_matrix->loadIdentity();
m_matrix->scale(vector3f(m_scale,m_scale,m_scale));
m_matrix->translate(m_pos);
m_matrix->rotateX(m_orientation.x);
m_matrix->rotateY(m_orientation.y);
m_matrix->rotateY(m_orientation.z);
//sendtransformation matrix (modelview)
m_shader->sendUniform4x4("modelViewMatrix", glm::value_ptr(m_matrix->getModelViewMatrix()));
//bind VAO
glBindVertexArray(m_uiVAO);
glDrawArrays(GL_TRIANGLES, 0, m_totalVertices);
}
这是使用顶点数据和索引生成曲面的类（修改）的代码 [DONT WORK]：
#include "plane.h"
#include "matrix.h"
#include "glslshader.h"
#include "texture.h"
plane::plane(GLuint cols, GLuint rows,GLuint segmentSize, mixedColors color, CTexture* texture, GLshort textureMode) :
m_matrix(0),
m_shader(0),
m_cols(cols),
m_rows(rows),
m_segmentSize(segmentSize),
m_selectedColor(color),
m_texture(texture),
m_textureMode(textureMode),
m_totalVertices(rows*(cols*6))
{
//matrix handler
m_matrix = matrix::getInstance();
//check that variables are > 1
if(m_cols < 1){m_cols = 1;}
if(m_rows < 1){m_rows = 1;}
// generate a VAO
glGenVertexArrays(1, &m_uiVAO);
vbo.createVBO();
vboIndices.createVBO();
}
plane::~plane()
{
delete m_shader;
vbo.releaseVBO();
vboIndices.releaseVBO();
glDeleteVertexArrays(1, &m_uiVAO);
}
bool plane::init()
{
//load the shaders
if(m_texture == NULL)
{
m_shader = new GLSLProgram("data/shaders/shader-primitives.vert", "data/shaders/shader-primitives.frag");
}
else//if primitive use texture...
{
m_shader = new GLSLProgram("data/shaders/shader-texture.vert", "data/shaders/shader-texture.frag");
}
if (!m_shader->initialize())
{
cout << "Los shaders de las primitivas no pudieron ser incializados\n";
return false;
}
m_shader->linkProgram();
//number of QUAD vertex
const GLshort QUAD_ELEMENTS = 4;
GLuint r,c,q,x;
//---------------------------------------------------------------------------
//bind VBO
vboIndices.bindVBO(GL_ELEMENT_ARRAY_BUFFER);
//base indices that are used to generate dynamic indices to all vertex data
GLuint baseIndices[6] = {0,1,2,2,3,0};
GLshort indicesCounter = 0;
cout << "indices==========================================\n";
for(x=0;x<m_totalVertices;++x)
{
if(indicesCounter == 6)
{
cout << "new pack of indices = " << x << "\n";
baseIndices[0] = baseIndices[1];
if(x > 6){baseIndices[1] += 2;}else{if(x == 6){baseIndices[1] += 3;}}
baseIndices[2] = (baseIndices[1]+1);
baseIndices[3] = baseIndices[2];
baseIndices[4] = baseIndices[0]+1;
baseIndices[5] = baseIndices[0];
indicesCounter = 0;
}
vboIndices.addData(&baseIndices[indicesCounter],sizeof(GLuint ));
cout << "indices["<<x<<"] = " << baseIndices[indicesCounter] << "\n";
++indicesCounter;
}
//-------------------------------------------------------------------------------
//bind VBO
vbo.bindVBO();
//set the start where you draw the first square of the plane
// so that everything is centered
GLfloat initX,initY;
initX = initY = 0.0f;
//displacement of each QUAD in X and Y axis.
const float MODULE = 0.2f;
//find the init value of X (the start value where you draw the first QUAD)
if(m_cols > 1)
{
initX = (float)((m_cols*MODULE/2.0f))-0.1f;
}
//find the init value of y (the start value where you draw the first QUAD)
if(m_rows > 1)
{
initY = (float)((m_rows*MODULE/2.0f))-0.1f;
}
//QUAD vertex data
vector3f quad[QUAD_ELEMENTS];
quad[0] = vector3f(-0.1f,0.1f,0.0f); quad[1] = vector3f(0.1f,0.1f,0.0f);
quad[2] = vector3f(0.1f,-0.1f,0.0f); quad[3] = vector3f(-0.1f,-0.1f,0.0f);
//put QUAD vertex in the "init position"
for(x=0;x<QUAD_ELEMENTS;++x)
{
quad[x].x = quad[x].x + (-initX);
quad[x].y = quad[x].y + initY;
}
//store de actual Y value of row (Y axis)
GLfloat newRow = 0.0f;
//store de actual X value of column (X axis)
GLfloat newColumn = 0.0f;
GLuint colorCounter = 0;
for(r=0;r<m_rows;++r)
{
//reset newColumn variable to 0.0f for each new column
newColumn = 0.0f;
//for each column
for(c=0;c<m_cols;++c)
{
//copy QUAD vertex data in new array
vector3f quadCopy[QUAD_ELEMENTS] = quad;
//for each column, move 0.1f to right
for(q=0;q<QUAD_ELEMENTS;++q)
{
//move right one MODULE (in x axis)
quadCopy[q].x = float(quadCopy[q].x + newColumn);
//move down one MODULE (in Y axis)
quadCopy[q].y = float(quadCopy[q].y + newRow);
//add vertex data and color to de vbo
vector3f resizedVertex = vector3f(quadCopy[q].x*m_segmentSize,quadCopy[q].y*m_segmentSize,quadCopy[q].z);
vbo.addData(&resizedVertex,sizeof(vector3f));
//every 4 laps reset colorCounter to 0;
cout << "Vertex["<< q << "] = "<< resizedVertex.x << "," << resizedVertex.y << ";\n";
if(colorCounter == 3){colorCounter = 0;}
vbo.addData(&color4f(m_selectedColor.color[colorCounter].r,m_selectedColor.color[colorCounter].g,m_selectedColor.color[colorCounter].b,m_selectedColor.color[colorCounter].a),sizeof(color4f));
++colorCounter;
}
//for each column, move right 0.1f
newColumn += MODULE;
}
newRow -= MODULE;
}
//bind VAO
glBindVertexArray(m_uiVAO);
//bind VBO
vbo.bindVBO();
vbo.uploadDataToGPU(GL_STATIC_DRAW);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(vector3f)+sizeof(color4f), (void*)sizeof(vector3f));
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(vector3f)+sizeof(color4f), 0);
//load indices data in VBO
vboIndices.bindVBO(GL_ELEMENT_ARRAY_BUFFER);
vboIndices.uploadDataToGPU(GL_STATIC_DRAW);
return true;
}
void plane::render()
{
//bind shader
m_shader->bindShader();
//send projection matrix to shader
m_shader->sendUniform4x4("projectionMatrix", glm::value_ptr(*m_matrix->getProjectionMatrix()));
//matrix transformations
m_matrix->loadIdentity();
m_matrix->scale(vector3f(m_scale,m_scale,m_scale));
m_matrix->translate(m_pos);
m_matrix->rotateX(m_orientation.x);
m_matrix->rotateY(m_orientation.y);
m_matrix->rotateY(m_orientation.z);
/sendtransformation matrix (modelview)
m_shader->sendUniform4x4("modelViewMatrix", glm::value_ptr(m_matrix->getModelViewMatrix()));
//bind VAO
glBindVertexArray(m_uiVAO);
glDrawElements(GL_TRIANGLES, m_totalVertices, GL_UNSIGNED_INT, 0);
}
这是处理VBO的类的代码[这个工作完美，只放在这里让你了解这些方法是什么]：
#include "common_header.h"
#include "vertexBufferObject.h"
CVertexBufferObject::CVertexBufferObject()
{
bDataUploaded = false;
}
/*-----------------------------------------------
Name: createVBO
Params: a_iSize - initial size of buffer
Result: Creates vertex buffer object.
/*---------------------------------------------*/
void CVertexBufferObject::createVBO(int a_iSize)
{
//obtiene el ID del VBO
glGenBuffers(1, &uiBuffer);
//reserva espacio para los datos que va a alojar
data.reserve(a_iSize);
//setea el tamaño
iSize = a_iSize;
}
/*-----------------------------------------------
Name: releaseVBO
Params: none
Result: Releases VBO and frees all memory.
/*---------------------------------------------*/
void CVertexBufferObject::releaseVBO()
{
//elimina el ID obtenido
glDeleteBuffers(1, &uiBuffer);
bDataUploaded = false;
//libera todos los datos almacenados
data.clear();
}
/*-----------------------------------------------
Name: mapBufferToMemory
Params: iUsageHint - GL_READ_ONLY, GL_WRITE_ONLY...
Result: Maps whole buffer data to memory and
returns pointer to data.
/*---------------------------------------------*/
void* CVertexBufferObject::mapBufferToMemory(int iUsageHint)
{
if(!bDataUploaded)return 0;
void* ptrRes = glMapBuffer(iBufferType, iUsageHint);
return ptrRes;
}
/*-----------------------------------------------
Name: mapSubBufferToMemory
Params: iUsageHint - GL_READ_ONLY, GL_WRITE_ONLY...
uiOffset - data offset (from where should
data be mapped).
uiLength - length of data
Result: Maps specified part of buffer to memory.
/*---------------------------------------------*/
void* CVertexBufferObject::mapSubBufferToMemory(int iUsageHint, unsigned int uiOffset, unsigned int uiLength)
{
if(!bDataUploaded)return 0;
void* ptrRes = glMapBufferRange(iBufferType, uiOffset, uiLength, iUsageHint);
return ptrRes;
}
/*-----------------------------------------------
Name: unmapBuffer
Params: none
Result: Unmaps previously mapped buffer.
/*---------------------------------------------*/
void CVertexBufferObject::unmapBuffer()
{
glUnmapBuffer(iBufferType);
}
/*-----------------------------------------------
Name: bindVBOiDrawingHint)
{
glBufferData(iBufferType, data.size(), &data[0], iDrawingHint);
bDataUploaded = true;
Params: a_iBufferType - buffer type (GL_ARRAY_BUFFER, ...)
Result: Binds this VBO.
/*---------------------------------------------*/
void CVertexBufferObject::bindVBO(int a_iBufferType)
{
iBufferType = a_iBufferType;
glBindBuffer(iBufferType, uiBuffer);
}
/*-----------------------------------------------
Name: uploadDataToGPU
Params: iUsageHint - GL_STATIC_DRAW, GL_DYNAMIC_DRAW...
Result: Sends data to GPU.
/*---------------------------------------------*/
void CVertexBufferObject::uploadDataToGPU(int iDrawingHint)
{
glBufferData(iBufferType, data.size(), &data[0], iDrawingHint);
bDataUploaded = true;
data.clear();
}
/*-----------------------------------------------
Name: addData
Params: ptrData - pointer to arbitrary data
uiDataSize - data size in chars
Result: Adds arbitrary data to VBO.
/*---------------------------------------------*/
void CVertexBufferObject::addData(void* ptrData, unsigned int uiDataSize)
{
data.insert(data.end(), (char*)ptrData, (char*)ptrData+uiDataSize);
}
/*-----------------------------------------------
Name: getDataPointer
Params: none
Result: Returns data pointer (only before uplading).
/*---------------------------------------------*/
void* CVertexBufferObject::getDataPointer()
{
if(bDataUploaded)return 0;
return (void*)data[0];
}
/*-----------------------------------------------
Name: getBuffer
Params: none
Result: Returns VBO ID.
/*---------------------------------------------*/
unsigned int CVertexBufferObject::getBuffer()
{
return uiBuffer;
}