Incorrect rotations using openGL GLM and shaders -

the goal of program display simple colored triangle rotating on y axis without translation. i'm using glm library. problem transformations of triangle not correct : has strange , not logical behaviour. here's c++ code plus vertex shader , fragment shader code :

c++ code :

float angle = 0.0f;  struct vertex {     float x, y, z; };  static vertex vertices[9] = {     -1.000000f, 0.000000f, 0.000000f,     0.000000f, 1.000000f, 0.000000f,     1.000000f, 0.000000f, 0.000000f };  static vertex colors[9] = {     1.000000f, 0.000000f, 0.000000f,     0.000000f, 1.000000f, 0.000000f,     0.000000f, 0.000000f, 1.000000f };  [...]  int                  main(int ac, char **av) {     bool            continuer = true;     sdl_event       event;     gluint          vboid[2];     gluint          programid = 0;      //sdl window initialization      sdl_init(sdl_init_video);     sdl_wm_setcaption("vbo tests",null);     sdl_setvideomode(width, height, 32, sdl_opengl);      //viewport initialization      glviewport(0, 0, width, height);      //projection initialization      glm::mat4 projection = glm::mat4(1.0f);     projection = glm::perspective<glfloat>(60.0f, (float)(width/height), 1.0f, 1000.0f);      //view initialization      glm::mat4 view = glm::lookat<glfloat>(glm::vec3(0.0f, 0.0f, 8.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));      glewinit();      //shaders initialization      programid = initshaders("triangle.vert", "triangle.frag");      //main loop      while (continuer)     {         eventlistener(&event, &continuer);          glcleardepth(1.0f);         glclearcolor(0.13f, 0.12f, 0.13f, 1.0f);         glclear(gl_color_buffer_bit | gl_depth_buffer_bit);          gluseprogram(programid);          //model transformations          glm::mat4 model = glm::mat4(1.0f);         model *= glm::translate(model, glm::vec3(0.0f, 0.0f, 0.0f));         model *= glm::rotate(model, angle, glm::vec3(0.0f, 1.0f, 0.0f));          glm::mat4 modelviewmatrix = model * view;         glm::mat4 modelviewprojectionmatrix = projection * modelviewmatrix;          glvertexattribpointer(0, 3, gl_float, gl_false, 0, vertices);         glvertexattribpointer(1, 3, gl_float, gl_false, 0, colors);          glenablevertexattribarray(0);         glenablevertexattribarray(1);          gluniformmatrix4fv(glgetuniformlocation(programid, "modelview"), 1, gl_true, glm::value_ptr(modelviewmatrix));         gluniformmatrix4fv(glgetuniformlocation(programid, "mvp"), 1, gl_true, glm::value_ptr(modelviewprojectionmatrix));          gldrawarrays(gl_triangles, 0, 3);          gldisablevertexattribarray(1);         gldisablevertexattribarray(0);          gluseprogram(0);          angle += 0.020f;          glflush();         sdl_gl_swapbuffers();     }      sdl_quit();     return (0); } 

vertex shader code :

#version 330  in vec3 vertexposition; in vec3 vertexcolor;  uniform mat4 modelviewmatrix; uniform mat4 mvp;  out vec3 color;  void main() {     color = vertexcolor;      gl_position = mvp * vec4(vertexposition, 1.0f); } 

fragment shader code :

#version 330  in vec3 color; out vec4 fragcolor;  void main() {     fragcolor = vec4(color, 1.0); } 

when declare simple matrix rotation model, send vertex shader , use mvp , works. when add projection matrix + view matrix not work correctly. here's picture :

normally, triangle should @ center of screen.

does can me?

this line:

glm::mat4 modelviewmatrix = model * view; 

should read:

glm::mat4 modelviewmatrix = view * model; 

matrix calculations done in reverse, , want first multiply vertex model matrix, not view.

you can take @ my other answer, explaining these concepts bit.