我试图掌握2D＆amp; amp; 3D现代OpenGL＆amp;所以以下只是我使用的代码的一部分。我不确定我做错了什么或错过了什么，但我已经把它缩小到了这个范围;我想查看X＆amp; amp;的开销。 Y＆amp;忽略z（即平面概述）。但也可以查看3D，因此对于3D z点需要有效。
在下面的示例中，点应显示垂直或水平线，但它们显示在一个角度上，即一个点的对角线或更改z值会影响顶部视图显示，而不应该这样。
非常感谢任何帮助，反馈或批评。 在此先感谢：）。
X/Y/Z points example & get sent to SetObjectData() function;
//horizontal
-70.0,20.0,50.0
25.0,20.00,0.0
70.0,20.00,-50.0
//vertical
20.0,80.0,100.0
20.0,20.0,100.0
20.0,-90.0,-100.0
m_oglWindow_OverHead.CreateGLContext(Rect, this);
m_oglWindow_OverHead.InitParm(60,0.0,0.0,0.0,1.0,1.0,1.0,0,0,-150.00);
m_oglWindow_OverHead.PrepareScene(1.0,1.0,1.0,1,2);
void OpenGLRenderer::InitParm(float fovy, float RotateX, float RotateY, float RotateZ, float ScaleX, float ScaleY, float ScaleZ, float TranslateX, float TranslateY, float TranslateZ)
{
m_fovy = fovy;
m_RotateX = RotateX;
m_RotateY = RotateY;
m_RotateZ = RotateZ;
//following currently not in use elsewhere, to be implemented.
//m_ScaleX = ScaleX;
//m_ScaleY = ScaleY;
//m_ScaleZ = ScaleZ;
//m_TranslateX = TranslateX;
//m_TranslateY = TranslateY;
//m_TranslateZ = TranslateZ;
}
void OpenGLRenderer::PrepareScene(float r, float g, float b, float alpha, int iViewType)
{
wglMakeCurrent(m_hdc, m_hrc);
glClearColor(r, b, g, alpha); //background to clear with.
if(iViewType == VIEW_2D)
{
InitShaderProgram();
glDisable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
ExitOnGLError(_T("ERROR: Could not set OpenGL depth testing options"));
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glFrontFace(GL_CCW);
ExitOnGLError(_T("ERROR: Could not set OpenGL culling options"));
if(m_RotateX !=0)
{
const float angle = m_RotateX;
m_glmModelMatrix = glm::rotate(m_glmModelMatrix,angle, glm::vec3(1,0,0)); //x,y,z
}
if(m_RotateY !=0)
{
const float angle = m_RotateY;
m_glmModelMatrix = glm::rotate(m_glmModelMatrix,angle, glm::vec3(0,1,0)); //x,y,z
}
if(m_RotateZ !=0)
{
const float angle = m_RotateZ;
m_glmModelMatrix = glm::rotate(m_glmModelMatrix,angle, glm::vec3(0,0,1)); //x,y,z
}
m_glmViewMatrix = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, -50.0f)); // Create view matrix which will translate back 50 units
m_glmProjectionMatrix = glm::ortho<float>(-250.0f,250.0f,250.0f,-250.0f,-100.0f,250.0f); //world coordinates
}
wglMakeCurrent(NULL, NULL);
}
void OpenGLRenderer::SetObjectData(const gl_vvCords vVerticesA, gl_vvCords vVerticesB)
{
wglMakeCurrent(m_hdc, m_hrc);
unsigned int TotalNumObjects = m_NumberVAOs = vVerticesA.size();
m_vGLSizeCount.clear();
m_vVaoID.clear();
m_vVaoID.resize(m_NumberVAOs+2);
m_vVboID.clear();
m_vVboID.resize(m_NumberVAOs+2);
glGenVertexArrays(TotalNumObjects, &m_vVaoID[0]);
int m_GLIntSize = 4;
for(unsigned int iObjectNum=0;iObjectNum<TotalNumObjects;iObjectNum++)
{
m_GLSizeCount = vVerticesA.at(iObjectNum).size();
m_vGLSizeCount.push_back(m_GLSizeCount);
//VAO setup
glBindVertexArray(m_vVaoID[iObjectNum]);
glGenBuffers(1, &m_vVboID[iObjectNum]);
glBindBuffer(GL_ARRAY_BUFFER, m_vVboID[iObjectNum]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vVerticesA.at(iObjectNum)), &vVerticesA.at(iObjectNum).at(0), GL_STATIC_DRAW);
glVertexAttribPointer((GLuint)0, m_GLIntSize, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(0);
GLfloat r=0.0,b=0.0,g=0.0,a=1.0;
std::vector<GLfloat> vColor;
for(int i=0;i<m_GLSizeCount;i++)
{
vColor.push_back(r);
vColor.push_back(b);
vColor.push_back(g);
vColor.push_back(a);
}
glGenBuffers(1, &m_vVboID[iObjectNum+1]);
glBindBuffer(GL_ARRAY_BUFFER, m_vVboID[iObjectNum+1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(float)*vColor.size(), &vColor[0], GL_STATIC_DRAW);
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(1);
}
wglMakeCurrent(NULL, NULL);
}
void OpenGLRenderer::DrawScene()
{
wglMakeCurrent(m_hdc, m_hrc);
switch(m_iViewType)
{
case VIEW_2D:
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(ShaderIDs[0]);
for(int i=0;i<m_NumberVAOs;i++)
{
if(m_vGLSizeCount.size() > 0 )
{
if(m_iShowObjectType1.at(i) == 1 && ((m_iShowObjectType2.at(i) == 1 || m_iShowObjectType2.at(i) == 2 )))
{
glUniformMatrix4fv(m_ProjectionMatrixUniformLocation, 1, GL_FALSE, &m_glmProjectionMatrix[0][0]); // Send our projection matrix to the shader
glUniformMatrix4fv(m_ViewMatrixUniformLocation, 1, GL_FALSE, &m_glmViewMatrix[0][0]); // Send our view matrix to the shader
glUniformMatrix4fv(m_ModelMatrixUniformLocation, 1, GL_FALSE, &m_glmModelMatrix[0][0]); // Send our model matrix to the shader
glBindVertexArray(m_vVaoID.at(i));
glDrawArrays(GL_LINE_STRIP, 0, m_GLSizeCount);
ExitOnGLError(_T("ERROR: Could not draw item"));
}
}
}
glUseProgram(0);
}
break;
default:
break;
}
//--------------------------------
SwapBuffers(m_hdc);
wglMakeCurrent(NULL, NULL);
}
const GLchar* VertexShader =
{
"#version 330\n"\
"layout(location=0) in vec4 in_Position;\n"\
"layout(location=1) in vec4 in_Color;\n"\
"out vec4 ex_Color;\n"\
"uniform mat4 vsModelMatrix;\n"\
"uniform mat4 vsViewMatrix;\n"\
"uniform mat4 vsProjectionMatrix;\n"\
"void main(void)\n"\
"{\n"\
"gl_Position = (vsProjectionMatrix * vsViewMatrix * vsModelMatrix) * in_Position;\n"\
"ex_Color = in_Color;\n"\
"}\n"
};
const GLchar* FragmentShader =
{
"#version 330\n"\
"in vec4 ex_Color;\n"\
"out vec4 out_Color;\n"\
"void main(void)\n"\
"{\n"\
" out_Color = ex_Color;\n"\
"}\n"\
};
void OpenGLRenderer::InitShaderProgram()
{
ShaderIDs[0] = glCreateProgram();
ExitOnGLError(_T("ERROR: Could not create the shader program"));
ShaderIDs[1] = glCreateShader(GL_VERTEX_SHADER);
ShaderIDs[2] = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(ShaderIDs[1], 1, &VertexShader, NULL);
glCompileShader(ShaderIDs[1]);
glShaderSource(ShaderIDs[2], 1, &FragmentShader, NULL);
glCompileShader(ShaderIDs[2]);
glAttachShader(ShaderIDs[0], ShaderIDs[1]);
glAttachShader(ShaderIDs[0], ShaderIDs[2]);
glLinkProgram(ShaderIDs[0]);
ExitOnGLError(_T("ERROR: Could not link the shader program"));
m_ModelMatrixUniformLocation = glGetUniformLocation(ShaderIDs[0], "vsModelMatrix");
m_ViewMatrixUniformLocation = glGetUniformLocation(ShaderIDs[0], "vsViewMatrix");
m_ProjectionMatrixUniformLocation = glGetUniformLocation(ShaderIDs[0], "vsProjectionMatrix");
ExitOnGLError(_T("ERROR: Could not get shader uniform locations"));
};
void OpenGLRenderer::OnSize(UINT nType, int cx, int cy)
{
if (0 >= cx || 0 >= cy || nType == SIZE_MINIMIZED)
return;
if(m_hdc != NULL)
{
wglMakeCurrent(m_hdc, m_hrc);
switch(m_iViewType)
{
case VIEW_2D:
{
CurrentWidth = GetViewPortWidth();//cx;
CurrentHeight = GetViewPortHeight();//cy;
glViewport(0, 0, CurrentWidth, CurrentHeight);
glUseProgram(ShaderIDs[0]);
glUniformMatrix4fv(m_ProjectionMatrixUniformLocation, 1, GL_FALSE, &m_glmProjectionMatrix[0][0]); // Send our projection matrix to the shader
glUniformMatrix4fv(m_ViewMatrixUniformLocation, 1, GL_FALSE, &m_glmViewMatrix[0][0]); // Send our view matrix to the shader
glUniformMatrix4fv(m_ModelMatrixUniformLocation, 1, GL_FALSE, &m_glmModelMatrix[0][0]); // Send our model matrix to the shader
glUseProgram(0);
}
break;
}
//necessary for resizing windows
GetWindowRect(m_rect);
MoveWindow(m_oldWindow.left,m_oldWindow.top,GetViewPortWidth(),GetViewPortHeight(),TRUE);
GetWindowRect(m_rect);
wglMakeCurrent(NULL, NULL);
}
}
答案 0 :(得分：1)
glVertexAttribPointer()来电的参数存在问题。这些是代码中的关键行：
int m_GLIntSize = 4;
...
glVertexAttribPointer((GLuint)0, m_GLIntSize, GL_FLOAT, GL_FALSE, 0, 0);
glVertexAttribPointer()的第二个参数是属性的组件数。因此，此调用指定应将4个float组件用于属性0。
但是问题中的示例数据每个顶点只显示3个坐标。由于该属性只有3个组件，因此调用应为：
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);