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3008b56e76
- cpp/functions/gfx: gl_shader, gl_framebuffer, fullscreen_quad, shader_canvas - cpp/apps/shaders_lab: main + 3 seed shaders (plasma, circle, checker) - ImGui docking layout: Code | Canvas | Controls Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
63 lines
1.8 KiB
Markdown
63 lines
1.8 KiB
Markdown
---
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name: gl_framebuffer
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kind: function
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lang: cpp
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domain: gfx
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version: "1.0.0"
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purity: impure
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signature: "void fb_init(Framebuffer& f); void fb_resize(Framebuffer& f, int w, int h); void fb_destroy(Framebuffer& f)"
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description: "CRUD de un framebuffer OpenGL (FBO + textura RGBA8). fb_resize es no-op si las dimensiones no cambian. Listo para uso con ImGui::Image."
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tags: [opengl, framebuffer, fbo, texture, gfx, offscreen]
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uses_functions: []
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uses_types: []
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returns: []
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returns_optional: false
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error_type: "error_go_core"
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imports: [GL/gl.h, GL/glext.h]
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tested: false
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tests: []
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test_file_path: ""
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file_path: "cpp/functions/gfx/gl_framebuffer.cpp"
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framework: opengl
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params:
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- name: f
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desc: "Struct Framebuffer con campos fbo, tex (GL ids), width, height. Inicializar a {0} antes de fb_init."
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- name: w
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desc: "Ancho deseado en pixels (fb_resize)"
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- name: h
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desc: "Alto deseado en pixels (fb_resize)"
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output: "Modifica f in-place. Después de fb_init, f.fbo y f.tex son IDs GL válidos. fb_destroy pone todos los campos a 0."
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---
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# gl_framebuffer
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FBO con textura color RGBA8 (GL_CLAMP_TO_EDGE, GL_LINEAR). Diseñado para renderizado offscreen y posterior display via `ImGui::Image`.
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## Ciclo de vida
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```cpp
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fn::gfx::Framebuffer fb{};
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fn::gfx::fb_init(fb); // fbo + tex 1x1
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// En el render loop:
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fn::gfx::fb_resize(fb, w, h); // no-op si mismas dimensiones
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// Al destruir:
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fn::gfx::fb_destroy(fb);
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```
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## Uso con ImGui::Image
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```cpp
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// Flip Y porque OpenGL tiene origen bottom-left
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ImGui::Image(
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reinterpret_cast<ImTextureID>(static_cast<uintptr_t>(fb.tex)),
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size,
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ImVec2(0, 1), ImVec2(1, 0)
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);
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```
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## Notas
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`fb_resize` recrea solo la textura (no el FBO) cuando las dimensiones cambian, reattachando la nueva textura al FBO existente. Esto minimiza el overhead de resize.
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