SDL_DrawGPUPrimitives(3)

💖 SDL_DrawGPUPrimitives 💖

okay bestie, so this is a page from the SDL3 FUNCTIONS corner of the SDL_DrawGPUPrimitives(3) manual, and it is literally about drawing data using bound graphics state. slay. let's get into it 🎀

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✨ NAME ✨

SDL_DrawGPUPrimitives — Draws data using bound graphics state. that's it, that's the whole job 💅

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🌸 SYNOPSIS 🌸

#include <SDL3/SDL_gpu.h>

void SDL_DrawGPUPrimitives(
    SDL_GPURenderPass *render_pass,
    Uint32 num_vertices,
    Uint32 num_instances,
    Uint32 first_vertex,
    Uint32 first_instance);

copy that include and that signature exactly, no improvising, iykyk 🦋

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💀 DESCRIPTION 💀

first things first, and this is the big one: you must not call this function before binding a graphics pipeline. like, not even a little. bind first, draw second, periodt. 👑

now the tea ☕ — first_vertex and first_instance are NOT compatible with the built-in vertex/instance ID variables in shaders (think SV_VertexID and friends). why? because GPU APIs and shader languages do not define these built-in variables consistently across the board. so if your shader depends on them, the only way to keep behavior consistent and portable is to always pass 0 for the correlating parameter in the draw calls. no cap, that's the move. 🙈

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🫶 FUNCTION PARAMETERS 🫶

• render_pass — a render pass handle. your lil ticket to the render party 🎟️
• num_vertices — the number of vertices to draw. count 'em 💅
• num_instances — the number of instances that will be drawn. yes, instances, plural, we're fancy ✨
• first_vertex — the index of the first vertex to draw. where the vertex party starts 🎀
• first_instance — the ID of the first instance to draw. where the instance party starts 🦋

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⭐ AVAILABILITY ⭐

this function is available since SDL 3.2.0. if you're on anything older, bestie, it's giving ✨not yet✨ 😭

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quick vibe check: bind your graphics pipeline first, and if your shader leans on built-in vertex/instance IDs, pass 0 for the correlating parameter. that's the whole portability survival kit 🧚

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and that's the page!! brought to you by Simple Directmedia Layer, running on SDL 3.4.18 — mwah, go draw some primitives, you absolute icon 💜🌈👑