Hello Triangle: An OpenGL ES 3.0 Example - Praise for OpenGL ES 30 Programming Guide - page 32

Example 2-1 Hello_Triangle.c Example (continued)

esLogMessage ( "Error linking program:\n%s\n", infoLog );
free ( infoLog );
}

glDeleteProgram ( programObject );
return FALSE;

}

// Store the program object
userData->programObject = programObject;

glClearColor ( 0.0f, 0.0f, 0.0f, 0.0f );
return TRUE;
}

///
// Draw a triangle using the shader pair created in Init()
//
void Draw ( ESContext *esContext )
{
UserData *userData = esContext->userData;
GLfloat vVertices[] = { 0.0f, 0.5f, 0.0f,
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f };

// Set the viewport
glViewport ( 0, 0, esContext->width, esContext->height );

// Clear the color buffer
glClear ( GL_COLOR_BUFFER_BIT );

// Use the program object
glUseProgram ( userData->programObject );

// Load the vertex data
glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE, 0, vVertices );
glEnableVertexAttribArray ( 0 );

glDrawArrays ( GL_TRIANGLES, 0, 3 );
}

void Shutdown ( ESContext *esContext )
{
UserData *userData = esContext->userData;

glDeleteProgram( userData->programObject );
}