OpenGL ignores Quads and makes them Triangles

Question

This is the second time I\'m making a game engine, but I\'m a little stuck right now, since I cannot figure out why this is happening, no matter what object I send, OpenGL o

Answer 1

You'r shader doesn't even compile. When you declare the matrix uniforms, then you use the names model2D, view2D and projection2D:

uniform mat4 view2D;
uniform mat4 model2D;
uniform mat4 projection2D;

But when you use the matrices, then you use the names view, model and projection:

gl_Position = projection * view * model * vec4(vertex.xy, 0.0, 1.0);

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I recommend to check if the shader objects compiled successfully and if the program object link successfully.

If the compiling of a shader succeeded can be checked by glGetShaderiv and the parameter GL_COMPILE_STATUS.

e.g.

GLuint shaderObj = .... ;
glCompileShader( shaderObj );

GLint status = GL_TRUE;
glGetShaderiv( shaderObj, GL_COMPILE_STATUS, &status );
if ( status == GL_FALSE )
{
    GLint logLen;
    glGetShaderiv( shaderObj, GL_INFO_LOG_LENGTH, &logLen );
    std::vector< char >log( logLen );
    GLsizei written;
    glGetShaderInfoLog( shaderObj, logLen, &written, log.data() );
    std::cout << "compile error:" << std::endl << log.data() << std::endl;
}

If the linking of a program was successful can be checked by glGetProgramiv and the parameter GL_LINK_STATUS.

e.g.

GLuint progObj = ....;
glLinkProgram( progObj );

GLint status = GL_TRUE;
glGetProgramiv( progObj, GL_LINK_STATUS, &status );
if ( status == GL_FALSE )
{
    GLint logLen;
    glGetProgramiv( progObj, GL_INFO_LOG_LENGTH, &logLen );
    std::vector< char >log( logLen );
    GLsizei written;
    glGetProgramInfoLog( progObj, logLen, &written, log.data() );
    std::cout  << "link error:" << std::endl << log.data() << std::endl;
}