Oto umowa. Jeśli zostawiam kod z glGenBuffers (1, vertexBuffers), kod się kompiluje. Ale pomyślałem, że powinno być 2, ponieważ vertexBuffers ma rozmiar dwa.

Czy czegoś mi brakuje?

Kod poniżej:

-(void)drawRect:(NSRect)dirtyRect
{    
    // get program ID for shader program
    GLuint programID = [self loadShaders];

    // get new dimensions
    NSSize dim = [self frame].size;

    // clear the background with color
    glClearColor(0.0, 0.0, 0.0, 0.4);
    glDepthRange(0.1, 100.0);
    glViewport(0, 0, dim.width, dim.height);
    glClear(GL_COLOR_BUFFER_BIT);

    // vertex data
    GLfloat vertexPositionData[] = {-dim.width/2, -dim.height/2, 0.0, 5.0,
        dim.width/2, -dim.height/2, 0.0, 5.0,
        0.0, dim.height/2, 0.0, 5.0};

    GLfloat vertexColorData[] = {1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.5, 0.0, 0.0, 1.0, 0.5};

    GLfloat scaleMatrixData[] = {1/(dim.width/2), 0.0, 0.0, 0.0,
        0.0, 1/(dim.height/2), 0.0, 0.0,
        0.0, 0.0, 1.0, 0.0,
        0.0, 0.0, 0.0, 1.0};

    GLint scaleMatrixUniform = glGetUniformLocation(programID, "scaleMatrix");

    // generate a buffer for our triangle
    glGenBuffers(1, vertexBuffers);

    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffers[0]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertexPositionData), vertexPositionData, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffers[1]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertexColorData), vertexColorData, GL_STATIC_DRAW);
    //glBindBuffer(GL_ARRAY_BUFFER, 0);

    glUseProgram(programID);

    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffers[0]);
    glEnableVertexAttribArray(VERTEX_POS_INDEX);
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffers[1]);
    glEnableVertexAttribArray(VERTEX_COLOR_INDEX);
    glVertexAttribPointer(VERTEX_POS_INDEX, VERTEX_POS_SIZE, GL_FLOAT, GL_FALSE, 0, vertexPositionData);
    glVertexAttribPointer(VERTEX_COLOR_INDEX, VERTEX_COLOR_SIZE, GL_FLOAT, GL_FALSE, 0, vertexColorData);

    glUniformMatrix4fv(scaleMatrixUniform, 1, GL_FALSE, scaleMatrixData);

    glDrawArrays(GL_TRIANGLES, 0, 3);

    glDisableVertexAttribArray(0);
    glDisableVertexAttribArray(1);
    glUseProgram(0);

    // flush buffer
    glFlush();
    [[self openGLContext] flushBuffer];
}