SDL_DrawGPUIndexedPrimitives(3)

💅 SDL_DrawGPUIndexedPrimitives(3) 💅

okay bestie, welcome to the SDL3 FUNCTIONS section of the manual, and today's main character is SDL_DrawGPUIndexedPrimitives — she draws stuff with an index buffer AND instancing on, like the overachiever she is ✨

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🌸 NAME 🌸

SDL_DrawGPUIndexedPrimitives — draws data using bound graphics state with an index buffer and instancing enabled. no cap, that's literally the whole job description 🎀

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✨ SYNOPSIS ✨

#include <SDL3/SDL_gpu.h>

void SDL_DrawGPUIndexedPrimitives(
    SDL_GPURenderPass *render_pass,
    Uint32 num_indices,
    Uint32 num_instances,
    Uint32 first_index,
    Sint32 vertex_offset,
    Uint32 first_instance);

she's a void, she returns nothing, she simply serves 🫶

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💖 DESCRIPTION 💖

okay so first things first, and this is important: you must NOT call this function before binding a graphics pipeline. like, pipeline first, bestie. the vibe check happens in that order, always. 🙈

now for the tea ☕ — the first_vertex and first_instance parameters are NOT compatible with the built-in vertex/instance ID variables in shaders (think SV_VertexID, that kind of thing). and it's not her fault! GPU APIs and shader languages simply do not define these built-in variables consistently, so they're all out here doing their own thing 😭

so if your shader depends on those built-ins, the only way to keep behavior consistent and portable is to always pass 0 for the correlating parameter in the draw calls. that's it. that's the rule. periodt 💅

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🌈 FUNCTION PARAMETERS 🌈

• render_pass — a render pass handle. your backstage pass, your VIP wristband, the whole vibe 🎟️
• num_indices — the number of indices to draw per instance.
• num_instances — the number of instances to draw. how many copies we're serving today 👑
• first_index — the starting index within the index buffer. where we begin, babes ⭐
• vertex_offset — a value added to the vertex index before indexing into the vertex buffer. a little nudge, a little offset, we love her for it.
• first_instance — the ID of the first instance to draw.

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🦋 AVAILABILITY 🦋

this function is available since SDL 3.2.0 ✨ so if you're on 3.2.0 or later, you're good, you're golden, you're glowing 🌟

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and that's the whole page, bestie!! no SEE ALSO section on this one, she's short and sweet and she knows it 💜

kisses, and remember: pipeline bound first, 0 for the correlating param, and always, always slay 🎀

Simple Directmedia Layer · SDL 3.4.18 · SDL_DrawGPUIndexedPrimitives(3) — mwah, bye!! 💅🌸🫶