c++ - OpenGL point sprites render as points and not textures -

here's code

vertex shader

#version 430  in vec3 position; uniform mat4 mvp;  void main() {     gl_position = mvp * vec4(position, 1.0); } 

fragment shader

#version 430  out vec4 outputcolor; uniform sampler2d tex;  void main() {     outputcolor = texture(tex, gl_pointcoord); } 

init

void init() {     glpointsize(20.0f);     gluint tex;     glgentextures(1, &tex);     glbindtexture(gl_texture_2d, tex);     gltexparameteri(gl_texture_2d, gl_texture_min_filter, gl_linear);     gltexparameteri(gl_texture_2d, gl_texture_mag_filter, gl_linear);      bmp.open("c:\\users\\alon\\desktop\\star.bmp");     bmp.readpixels();     unsigned char *pixels = new unsigned char[bmp.neededbuffersize()];     bmp.assignpixels(pixels);     glteximage2d(gl_texture_2d, 0, gl_rgb, bmp.getwidth(), bmp.getheight(), 0, gl_rgb, gl_unsigned_byte, pixels);     delete[] pixels;      glclearcolor(0.2f, 0.2f, 0.2f, 1.0f);     glenable(gl_depth_test);     glpolygonmode(gl_front_and_back, gl_fill);      glblendfunc(gl_src_alpha, gl_one_minus_src_alpha);      gluint vaoid;     glgenvertexarrays(1, &vaoid);     glbindvertexarray(vaoid);      position_index = glgetattriblocation(program, "position");     mvp_location = glgetuniformlocation(program, "mvp");      //                      x      y      z     s     t     glfloat vertices[] = {-0.5f, -0.5f, 0.0f,                            0.5f, -0.5f, 0.0f,                            0.5f,  0.5f, 0.0f,                            0.5f,  0.5f, 0.0f,                           -0.5f,  0.5f, 0.0f,                           -0.5f, -0.5f, 0.0f};      glgenbuffers(1, &vbo);     glbindbuffer(gl_array_buffer, vbo);      glbufferdata(gl_array_buffer, sizeof(vertices), vertices, gl_static_draw);     glvertexattribpointer(position_index, 3, gl_float, gl_false, 0, 0);      glbindbuffer(gl_array_buffer, 0); } 

render

void render() {     glclear(gl_color_buffer_bit | gl_depth_buffer_bit);      glenablevertexattribarray(position_index);     glbindbuffer(gl_array_buffer, vbo);      float c;     if(btime)         c = (float)std::clock() * 2.0f / clocks_per_sec;     else         c = 0.0f;      glm::mat4 modelview = glm::rotate(-c * 50.0f, glm::vec3(0.0f, 1.0f, 0.0f));     modelview = glm::translate(glm::vec3(0.0f + ftranslatex, 0.0f, -1.75f + ftranslatez)) * modelview;     glm::mat4 projection = glm::perspective(60.0f, 16.0f/9.0f, 0.10f, 100.0f); //perspective     glm::mat4 mvp = projection * modelview;      gluniformmatrix4fv(mvp_location, 1, gl_false, &mvp[0][0]);      gldrawarrays(gl_points, 0, 6);      glbindbuffer(gl_array_buffer, 0);     gldisablevertexattribarray(position_index);      glutswapbuffers();      if(glgeterror() != gl_no_error)         exit(1); } 

the star image is:

  

output:

  

is there i'm doing wrong?

in compatbility profiles (or version of gl before 3.1), behavior want occurs when gl_point_sprite enabled. in core profile, state removed, , gl_pointcoord behaves if gl_point_sprite enabled.

to fix problem, must call glenable (gl_point_sprite).