bool load_program(const char * asset_program, program & result)
{
auto data = assets_storage::instance().read<program_data>(asset_program);
if(!data.v_shader() || !data.f_shader())
return false;
shader v_shader(data.v_shader(), shader_type::VERTEX);
if(!v_shader.compile())
return false;
shader f_shader(data.f_shader(), shader_type::FRAGMENT);
if(!f_shader.compile())
return false;
result.attach(v_shader);
result.attach(f_shader);
if(!result.link())
return false;
for(const auto & location : data.a_locations())
result.attribute_location(location.name, location.index);
for(const auto & location : data.u_locations())
result.uniform_location(location.name, location.index);
return true;
}
example_mandelbrot(void)
: offset_x(-0.5f)
, offset_y(0.0f)
, scale(1.0f)
, aspect(1.0f)
{
shader vs(GL.vertex_shader);
vs.source(glsl_literal(
"#version 130\n"
"uniform vec2 Offset;\n"
"uniform vec2 Scale;\n"
"in vec2 Position;\n"
"in vec2 Coord;\n"
"out vec2 vertCoord;\n"
"void main(void)\n"
"{\n"
" vertCoord = Coord*Scale+Offset;\n"
" gl_Position = vec4(Position, 0.0, 1.0);\n"
"}\n"
));
vs.compile();
shader fs(GL.fragment_shader);
fs.source(glsl_literal(
"#version 130\n"
"uniform sampler1D gradient;\n"
"in vec2 vertCoord;\n"
"out vec4 fragColor;\n"
"void main(void)\n"
"{\n"
" vec2 z = vec2(0.0, 0.0);\n"
" vec2 c = vertCoord;\n"
" int i = 0, max = 256;\n"
" while((i != max) && (distance(z, c) < 2.0))\n"
" {\n"
" vec2 zn = vec2(\n"
" z.x * z.x - z.y * z.y + c.x,\n"
" 2.0 * z.x * z.y + c.y\n"
" );\n"
" z = zn;\n"
" ++i;\n"
" }\n"
" float a = float(i)/float(max);\n"
" fragColor = texture(gradient, a+sqrt(length(c))*0.1);\n"
"} \n"
));
fs.compile();
prog.attach(vs);
prog.attach(fs);
prog.link();
gl.use(prog);
gl.query_location(offset_loc, prog, "Offset");
gl.query_location(scale_loc, prog, "Scale");
gl.uniform(offset_loc, offset_x, offset_y);
gl.bind(vao);
GLfloat position_data[4*2] = {
-1.0f, -1.0f,
-1.0f, 1.0f,
1.0f, -1.0f,
1.0f, 1.0f
};
gl.bind(GL.array_buffer, positions);
gl.buffer_data(GL.array_buffer, position_data, GL.static_draw);
vertex_attrib_location va_p;
gl.query_location(va_p, prog, "Position");
gl.vertex_array_attrib_pointer(
va_p,
2, GL.float_,
false, 0, nullptr
);
gl.enable_vertex_array_attrib(va_p);
GLfloat coord_data[4*2] = {
-1.0f, -1.0f,
-1.0f, 1.0f,
1.0f, -1.0f,
1.0f, 1.0f
};
gl.bind(GL.array_buffer, coords);
gl.buffer_data(GL.array_buffer, coord_data, GL.static_draw);
vertex_attrib_location va_c;
gl.query_location(va_c, prog, "Coord");
gl.vertex_array_attrib_pointer(
va_c,
2, GL.float_,
false, 0, nullptr
);
gl.enable_vertex_array_attrib(va_c);
GLfloat gradient_data[8*3];
for(int i=0; i<8*3; ++i)
{
gradient_data[i] = (std::rand() % 10000) / 10000.f;
}
gl.bind(GL.texture_1d, gradient);
gl.texture_min_filter(GL.texture_1d, GL.linear);
gl.texture_mag_filter(GL.texture_1d, GL.linear);
gl.texture_wrap(
GL.texture_1d,
GL.texture_wrap_s,
GL.repeat
);
gl.texture_image_1d(
GL.texture_1d,
0, GL.rgb,
8,
0, GL.rgb,
GL.float_,
const_memory_block{gradient_data}
);
gl.disable(GL.depth_test);
}
