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sothro

Member Since 05 Jan 2014
Offline Last Active May 10 2014 02:00 AM

Topics I've Started

Trying to use gluUnProject/gluProject to check if hitting objects

05 May 2014 - 02:34 PM

Hi,

 

I'm trying to select a object in my 3D world. I looked online a bit and u found that you can use gluUnProject, but i don't understand how it works.

I Currently have this code:

double modelMatrix[16];
double projMatrix[16];
GLint viewport[4], winZ;
    
glGetDoublev(GL_MODELVIEW_MATRIX,modelMatrix);
glGetDoublev(GL_PROJECTION_MATRIX,projMatrix);
glGetIntegerv(GL_VIEWPORT,viewport);

 GLdouble posX, posY, posZ;
    

         glReadPixels( x, int(y), 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &winZ );

        gluProject(x,y,winZ,modelMatrix,projMatrix,viewport,&posX,&posY,&posZ);
        gluUnProject(x,y,winZ,modelMatrix,projMatrix,viewport,&posX,&posY,&posZ);

X, y and Z are my mouse position

And when i check after gluProject the numbers are huge, and after gluUnproject they are between -1 and 1(screen i gues).

But the x, y and z coordinates of my objects aren't near the numbers i'm getting back. Do i need to do a nother calculation?

 

Thanks for the help in forhand.

 


Drawing to different models

23 March 2014 - 07:03 AM

Hi,

 

I'm currently trying to draw two different models, but when i draw 2 models where i put two different meshes in.

I only see the last mesh for the 2 models. It's using the same mesh for both of the models, so i think i'm overwriting something.

 

i'm using following code for the creation part:

    Model_3D *mo= new Model_3D();
    (*mo).CreateVertices("C:\\..\\Debug\\cube.obj");
    Model_3D *m= new Model_3D();
    (*m).CreateVertices("C:\\..\\Debug\\strange.obj");
    models->push_back(mo);
    m->TranslateX(-3);
    models->push_back(m);

    GLuint programId= glCreateProgram();

    for(GLuint var=0;var<models->size();var++)
    {
        models->at(var)->CreateObject();
        CreateObject(models->at(var),programId);
    }
GLuint BufferIdsTemp[3] = { 0 };

    model->SetShaderIdFragment(LoadShader("C:\\Users\\Sander\\Documents\\RTS idee\\idee\\engine\\GameEngine\\Debug\\SimpleShader.fragment.glsl", GL_FRAGMENT_SHADER));
    model->SetShaderIdVertex( LoadShader("C:\\Users\\Sander\\Documents\\RTS idee\\idee\\engine\\GameEngine\\Debug\\SimpleShader.vertex.glsl", GL_VERTEX_SHADER));

    model->SetShaderIdProgram(glCreateProgram());
    //ShaderIds[0] = glCreateProgram();
    ExitOnGLError("ERROR: Could not create the shader program");


    glAttachShader(model->GetShaderIdProgram(), model->GetShaderIdFragment());
    glAttachShader(model->GetShaderIdProgram(), model->GetShaderIdVertex());



    glLinkProgram(model->GetShaderIdProgram());
    ExitOnGLError("ERROR: Could not link the shader program");

    ModelMatrixUniformLocation = glGetUniformLocation(model->GetShaderIdProgram(), "ModelMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for modelmatrix");
    ViewMatrixUniformLocation = glGetUniformLocation(model->GetShaderIdProgram(), "ViewMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for viewmatrix");
    ProjectionMatrixUniformLocation = glGetUniformLocation(model->GetShaderIdProgram(), "ProjectionMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for projectionMatrix");


    // bufferIds must be local array of gluints i think
    GLuint buffer=0;
    glGenVertexArrays(1, &BufferIdsTemp[0]);//&buffer);//
    //model->SetBufferId(BufferIdsTemp, 0);
    ExitOnGLError("ERROR: Could not generate the VAO");
    glBindVertexArray(BufferIdsTemp[0]);//model->GetBufferId(0));//
    ExitOnGLError("ERROR: Could not bind the VAO");

    //cube 1
    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);
    ExitOnGLError("ERROR: Could not enable vertex attributes");

    GLuint buffer2=0;

    glGenBuffers(2, &BufferIdsTemp[1]);//&buffer2 );//
    ExitOnGLError("ERROR: Could not generate the buffer objects");
    //model->SetBufferId(buffer, 1);

    int sizeVertex=sizeof(model->GetVertices().front());
    int vertexEllements=(model)->GetVertices().size();
    int sizeVertexes=sizeVertex*vertexEllements;
    glBindBuffer(GL_ARRAY_BUFFER,BufferIdsTemp[1]);// BufferIds[1]);//BufferIdsTemp
    //glBufferData(GL_ARRAY_BUFFER, sizeof(VERTICES), VERTICES, GL_STATIC_DRAW);
    glBufferData(GL_ARRAY_BUFFER, sizeVertexes, &model->GetVertices().front(), GL_STATIC_DRAW);

    ExitOnGLError("ERROR: Could not bind the VBO to the VAO");

    //glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(VERTICES[0]), (GLvoid*)0);
    //glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(VERTICES[0]), (GLvoid*)sizeof(VERTICES[0].Position));
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(model->GetVertices().front()), (GLvoid*)0);
    glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(model->GetVertices().front()), (GLvoid*)sizeof(model->GetVertices().front().Position));
    ExitOnGLError("ERROR: Could not set VAO attributes");


    int size=sizeof(model->GetIndices().front());
    int ellements=model->GetIndices().size();
    int sizeIndices=size*ellements;
    GLuint bufferId3=0;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,BufferIdsTemp[2] );//bufferId3);
    //glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(INDICES), INDICES, GL_STATIC_DRAW);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeIndices,&model->GetIndices().front(), GL_STATIC_DRAW);
    //model->SetBufferId(bufferId3,2);//
    ExitOnGLError("ERROR: Could not bind the IBO to the VAO");

    model->SetBufferId(BufferIdsTemp);
    
    glBindVertexArray(0);

And the drawing part is done by this code:

void DrawObject(Model_3D* model)
{
    float CubeAngle;
    clock_t Now = clock();
    if (LastTime == 0)
        LastTime = Now;

    //CubeRotation += 45.0f * ((float)(Now - LastTime) / CLOCKS_PER_SEC);
    CubeAngle = DegreesToRadians(CubeRotation);
    LastTime = Now;
 
    glUseProgram( model->GetShaderIdProgram());
    ExitOnGLError("ERROR: Could not use the shader program");

    glUniformMatrix4fv(model->GetModelMatrixUniformLocation(), 1, GL_FALSE,model->GetMatrix().m);
    glUniformMatrix4fv(model->GetViewMatrixUniformLocation(), 1, GL_FALSE, camera->GetCamera().m );
    ExitOnGLError("ERROR: Could not set the shader uniforms");

    glBindVertexArray(model->GetBufferIds(0));//BufferIds[0]);
    ExitOnGLError("ERROR: Could not bind the VAO for drawing purposes");

    glDrawElements( GL_TRIANGLES, model->GetIndices().size(), GL_UNSIGNED_INT, (GLvoid*)0);
    ExitOnGLError("ERROR: Could not draw the cube");

    glBindVertexArray(0);
    glUseProgram(0);

}

I have one other problem and that is that i'm trying to put the code of createobject to my model class but when i try to draw the objects then i don't see anything. But this is a secondary problem the first thing i want to understand is to draw 2 different objects.

 

Can it be that i need a different shader for every object?

 

If someone can tell me how to fix that would be very helpfull.

Thank you for the help in advance.


Drawing multiple objects

06 February 2014 - 03:38 PM

Hi,

 

Im' currently trying to draw multiple objects with opengl but when i'm trying to create my second model the program crashes with following errors: Error: 0:4: 'GL_ARB_explicit_attrib_location' : extension is disabled and then the same error with just 0:6 as difference.

 

I call the code below for every model in my vector of Model_3D objects, the GLuint programid variable isn't used.

 

My code is as follow:

void CreateObject(Model_3D *model,GLuint programid)
{
    //models->at(0)->SetShaderId(LoadShader("C:\\Users\\Sander\\Documents\\RTS idee\\idee\\engine\\GameEngine\\Debug\\SimpleShader.fragment.glsl", GL_FRAGMENT_SHADER));
    model->SetShaderIdFragment(LoadShader("C:\\Users\\Sander\\Documents\\RTS idee\\idee\\engine\\GameEngine\\Debug\\SimpleShader.fragment.glsl", GL_FRAGMENT_SHADER));
    model->SetShaderIdVertex( LoadShader("C:\\Users\\Sander\\Documents\\RTS idee\\idee\\engine\\GameEngine\\Debug\\SimpleShader.vertex.glsl", GL_VERTEX_SHADER));
    
        model->SetShaderIdProgram(glCreateProgram());
    //ShaderIds[0] = glCreateProgram();
    ExitOnGLError("ERROR: Could not create the shader program");

    
    glAttachShader(model->GetShaderIdProgram(), model->GetShaderIdFragment());
    glAttachShader(model->GetShaderIdProgram(), model->GetShaderIdVertex());
 


    glLinkProgram(model->GetShaderIdProgram());
    ExitOnGLError("ERROR: Could not link the shader program");

    ModelMatrixUniformLocation = glGetUniformLocation(model->GetShaderIdProgram(), "ModelMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for modelmatrix");
    ViewMatrixUniformLocation = glGetUniformLocation(model->GetShaderIdProgram(), "ViewMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for viewmatrix");
    ProjectionMatrixUniformLocation = glGetUniformLocation(model->GetShaderIdProgram(), "ProjectionMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for projectionMatrix");

    glGenVertexArrays(1, &BufferIds[0]);
    ExitOnGLError("ERROR: Could not generate the VAO");
    glBindVertexArray(BufferIds[0]);
    ExitOnGLError("ERROR: Could not bind the VAO");

    //cube 1
    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);
    ExitOnGLError("ERROR: Could not enable vertex attributes");

    glGenBuffers(2, &BufferIds[1]);
    ExitOnGLError("ERROR: Could not generate the buffer objects");
    
    int sizeVertex=sizeof(model->GetVertices().front());
    int vertexEllements=(model)->GetVertices().size();
    int sizeVertexes=sizeVertex*vertexEllements;
    glBindBuffer(GL_ARRAY_BUFFER, BufferIds[1]);
    //glBufferData(GL_ARRAY_BUFFER, sizeof(VERTICES), VERTICES, GL_STATIC_DRAW);
    glBufferData(GL_ARRAY_BUFFER, sizeVertexes, &model->GetVertices().front(), GL_STATIC_DRAW);

    ExitOnGLError("ERROR: Could not bind the VBO to the VAO");

    //glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(VERTICES[0]), (GLvoid*)0);
    //glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(VERTICES[0]), (GLvoid*)sizeof(VERTICES[0].Position));
        glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(model->GetVertices().front()), (GLvoid*)0);
    glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(model->GetVertices().front()), (GLvoid*)sizeof(model->GetVertices().front().Position));
    ExitOnGLError("ERROR: Could not set VAO attributes");

    
    int size=sizeof(model->GetIndices().front());
    int ellements=model->GetIndices().size();
    int sizeIndices=size*ellements;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, BufferIds[2]);
    //glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(INDICES), INDICES, GL_STATIC_DRAW);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeIndices,&model->GetIndices().front(), GL_STATIC_DRAW);

    ExitOnGLError("ERROR: Could not bind the IBO to the VAO");
 
    glBindVertexArray(0);
}

I'm probably understanding the use of the shaders and bufferIds wrong, i think i need to create seperate bufferIds for all my models, is this so?

And the glCreateProgram() is this unique for every model or the same?

 

Thanks for all the responses

 

 


.obj file loader

22 January 2014 - 01:42 PM

hi,

 

I'm having a problem with showing a model that i have loaded from a object file, the vertexes and indices are loaded oke in to 2 vectors in a seperate class. Below you see my creat methode i have set the lines in bold that have changed for drawing the loaded object in place of a hardcoded one. I think the problem lays with one of these lines. Also i have added my model class as a file.

Thank you for all the helpsmile.png

ShaderIds[1] = LoadShader("\\Debug\\SimpleShader.fragment.glsl", GL_FRAGMENT_SHADER);
    ShaderIds[2] = LoadShader("Debug\\SimpleShader.vertex.glsl", GL_VERTEX_SHADER);
    
    ShaderIds[0] = glCreateProgram();
    ExitOnGLError("ERROR: Could not create the shader program");
    
    glAttachShader(ShaderIds[0], ShaderIds[1]);
    glAttachShader(ShaderIds[0], ShaderIds[2]);

    glLinkProgram(ShaderIds[0]);
    ExitOnGLError("ERROR: Could not link the shader program");

    ModelMatrixUniformLocation = glGetUniformLocation(ShaderIds[0], "ModelMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for modelmatrix");
    ViewMatrixUniformLocation = glGetUniformLocation(ShaderIds[0], "ViewMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for viewmatrix");
    ProjectionMatrixUniformLocation = glGetUniformLocation(ShaderIds[0], "ProjectionMatrix");
    ExitOnGLError("ERROR: Could not get the shader uniform locations for projectionMatrix");

    glGenVertexArrays(1, &BufferIds[0]);
    ExitOnGLError("ERROR: Could not generate the VAO");
    glBindVertexArray(BufferIds[0]);
    ExitOnGLError("ERROR: Could not bind the VAO");

    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);
    ExitOnGLError("ERROR: Could not enable vertex attributes");

    glGenBuffers(2, &BufferIds[1]);
    ExitOnGLError("ERROR: Could not generate the buffer objects");


    glBindBuffer(GL_ARRAY_BUFFER, BufferIds[1]);
    //glBufferData(GL_ARRAY_BUFFER, sizeof(VERTICES), VERTICES, GL_STATIC_DRAW);
    glBufferData(GL_ARRAY_BUFFER, 256/*sizeof((*model).GetVertices().size())*/, &(*model).GetVertices(), GL_STATIC_DRAW);

    ExitOnGLError("ERROR: Could not bind the VBO to the VAO");


    //glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(VERTICES[0]), (GLvoid*)0);
    //glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof(VERTICES[0]), (GLvoid*)sizeof(VERTICES[0].Position));
        glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof((*model).GetVertices()[0]), (GLvoid*)0);
    glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, sizeof((*model).GetVertices()[0]), (GLvoid*)sizeof(&(*model).GetVertices()[0].Position));
    ExitOnGLError("ERROR: Could not set VAO attributes");

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, BufferIds[2]);
    //glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(INDICES), INDICES, GL_STATIC_DRAW);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, 144/*sizeof((*model).GetIndices().size())*/, &(*model).GetIndices(), GL_STATIC_DRAW);

    ExitOnGLError("ERROR: Could not bind the IBO to the VAO");
 
    glBindVertexArray(0);

Loading shaders from file error on glGetUniformLocation

05 January 2014 - 04:32 AM

Hi,

 

I'm just starting with opengl and i was following a tutorial on http://openglbook.com.(currently on chapter 4)

 

My problem is that when i try to do one of these lines :

 

ModelMatrixUniformLocation = glGetUniformLocation(ShaderIds[0], "ModelMatrix");
ViewMatrixUniformLocation = glGetUniformLocation(ShaderIds[0], "ViewMatrix");
ProjectionMatrixUniformLocation = glGetUniformLocation(ShaderIds[0], "ProjectionMatrix");

 

my program crashes and this error is triggered:

ExitOnGLError("ERROR: Could not get the shader uniform locations");

 

if anyone knows what it could be i would be very grateful.
 


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