c# - Simple Example of How to Draw a Square With Texture Using Tao.Framework -

i'm trying build simple test of opengl using tao.framework. need draw square texture. far came this:

private void simpleopenglcontrol1_paint(object sender, painteventargs e) {     simpleopenglcontrol1.initializecontexts();      gl.glclearcolor(0f, 0f, 0f, 0f);     gl.glclear(gl.gl_color_buffer_bit);     gl.glortho(-1, 2, -1, 2, 1, -1);      // open image     var filename = @"c:\mypath\image.bmp";     var bmp = new bitmap(filename);     var bmpdata = bmp.lockbits(         new rectangle(0, 0, bmp.width, bmp.height),         imagelockmode.readonly,         pixelformat.format24bpprgb);      // texture     gl.glteximage2d(gl.gl_texture_2d, 0, (int)gl.gl_rgb8,         bmp.width, bmp.height, 0, gl.gl_bgr_ext,         gl.gl_unsigned_byte, bmpdata.scan0);      gl.glbindtexture(gl.gl_texture_2d, 0);      // draw square.     gl.glbegin(gl.gl_polygon);         gl.glvertex2f(0, 0);         gl.glvertex2f(0, 1);         gl.glvertex2f(1, 1);         gl.glvertex2f(1, 0);     gl.glend(); } 

the square rendered in expected shape, without texture. i'm new in opengl, more in tao.framework. how can fix it? or how correct way add texture?

edited
of @j-p i'm try this:

    //...     gl.glenable(gl.gl_texture_2d);      // draw square.     gl.glbegin(gl.gl_polygon);      gl.gltexcoord2f(0, 0); gl.glvertex2f(0, 0);     gl.gltexcoord2f(0, 1); gl.glvertex2f(0, 1);     gl.gltexcoord2f(1, 1); gl.glvertex2f(1, 1);     gl.gltexcoord2f(1, 0); gl.glvertex2f(1, 0);      gl.glend(); 

but square keep without texture.

you miss @ least

gl.enable(gl.texture2d); 

which not enabled default.

also have generate new texture slot calling:

int texid; gl.glgentextures(1, texid); //where 1 count, , texid new texture slot in gpu 

then have bind texture slot further operation applied.

gl.glbindtexture(gl.gl_texture_2d, texid); 

note calling gl.glbindtexture(gl.gl_texture_2d, 0); disable current texture.

now further operation directed texture so, can pass bitmap data texture slot calling:

gl.glteximage2d(gl.gl_texture_2d, 0, (int)gl.gl_rgb8,     bmp.width, bmp.height, 0, gl.gl_bgr_ext,     gl.gl_unsigned_byte, bmpdata.scan0); 

if want set texture parameters texgen , clamping, , many other things, here, example:

gl.gltexparameteri(gl.gl_texture_2d, gl.gl_texture_min_filter, gl.gl_linear); gl.gltexparameteri(gl.gl_texture_2d, gl.gl_texture_mag_filter, gl.gl_linear); 

your vertex declaration should include texture coordinate or have set texture coordinate generation active.

    gl.texcoord(0,1); gl.glvertex2f(0, 0);     gl.texcoord(0,0); gl.glvertex2f(0, 1);     gl.texcoord(1,0); gl.glvertex2f(1, 1);     gl.texcoord(1,1); gl.glvertex2f(1, 0); 

if want coordinate automaticaly generated can omit gl.texcoord call , enable via:

gl.glenable(gl.gl_texture_gen_s); //enable texture coordinate generation gl.glenable(gl.gl_texture_gen_t);  gl.gltexparameteri(gl.gl_texture_2d, gl.gl_texture_wrap_s, gl.gl_clamp); gl.gltexparameteri(gl.gl_texture_2d, gl.gl_texture_wrap_t, gl.gl_clamp); 

don't forget unlock bitmap data (even if garbage collector must):

bmp.unlock(bmpdata);