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plotter/include/plot/render/program.hpp
T

63 lines
2.2 KiB
C++

#pragma once
#include <plot/core/color.hpp>
#include <plot/core/status.hpp>
#include <plot/gl/handle.hpp>
#include <plot/math/vec2.hpp>
namespace plot::render {
/// Linked line program and its uniform surface.
///
/// It owns the `plot::gl::Program` and knows the GLSL pair (shaders.hpp), so no
/// caller spells out a uniform name that could drift from the shader. Creating
/// it propagates what the GL layer reports: `ErrorCode::Unsupported` while
/// `plot::gl::available()` is false, `GLFailure` plus the driver's log when the
/// GLSL does not compile or link.
class LineProgram {
public:
bool create(Status* st = nullptr) noexcept;
bool valid() const noexcept { return program_.id() != 0; }
void bind() const noexcept { program_.use(); }
/// `u_scale`: data space to pixels.
void set_scale(Vec2 data_to_px) const noexcept;
/// `u_offset`: pixel offset added after `set_scale`.
void set_offset(Vec2 px) const noexcept;
/// `u_viewport`: render target size in pixels.
void set_viewport(Vec2 px) const noexcept;
/// `u_width`: stroke width in pixels.
void set_width(f32 px) const noexcept;
/// `u_color`: stroke colour, alpha included.
void set_color(Color color) const noexcept;
private:
gl::Program program_;
};
/// Linked text program and its uniform surface. It fails exactly the way
/// `LineProgram::create()` does, propagating `Unsupported` and `GLFailure`.
///
/// `create()` also points the `u_atlas` sampler at texture unit 0, which is the
/// unit `plot::gl::Texture::bind()` defaults to, and leaves this program bound.
/// The atlas itself stays with the caller, who owns its lifetime.
class TextProgram {
public:
bool create(Status* st = nullptr) noexcept;
bool valid() const noexcept { return program_.id() != 0; }
void bind() const noexcept { program_.use(); }
/// `u_viewport`: render target size in pixels.
void set_viewport(Vec2 px) const noexcept;
/// `u_px_range`: pixels per glyph cell, i.e. the on-screen size of one glyph.
void set_px_range(Vec2 px) const noexcept;
/// `u_tex_size`: atlas size in texels.
void set_texture_size(Vec2 texels) const noexcept;
/// `u_color`: tint colour, alpha included.
void set_color(Color color) const noexcept;
private:
gl::Program program_;
};
} // namespace plot::render