egutierrez
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>
46 lines
1.3 KiB
Markdown
46 lines
1.3 KiB
Markdown
---
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name: fullscreen_quad
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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 quad_init(Quad& q); void quad_draw(const Quad& q); void quad_destroy(Quad& q)"
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description: "VAO/VBO para un fullscreen quad de 6 vértices. El vertex shader genera las posiciones via gl_VertexID, por lo que el VBO queda vacío. quad_draw emite glDrawArrays(GL_TRIANGLES, 0, 6)."
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tags: [opengl, quad, fullscreen, vao, vbo, gfx]
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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/fullscreen_quad.cpp"
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framework: opengl
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params:
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- name: q
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desc: "Struct Quad con campos vao, vbo (GL ids). Inicializar a {0} antes de quad_init."
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output: "Modifica q in-place. quad_draw necesita un programa GL activo con vertex shader que genere posiciones desde gl_VertexID."
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---
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# fullscreen_quad
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VAO + VBO vacío para dibujar un quad de pantalla completa. El vertex shader de `gl_shader` ya embebe las 6 posiciones via `gl_VertexID`, por lo que no se necesitan datos en el VBO.
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## Ejemplo
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```cpp
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fn::gfx::Quad quad{};
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fn::gfx::quad_init(quad);
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// En el render loop (con program activo):
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glUseProgram(program);
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fn::gfx::quad_draw(quad);
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glUseProgram(0);
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// Al destruir:
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fn::gfx::quad_destroy(quad);
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```
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