Text 3d render using rlgl raylib. zig.

sample_plane_text02.zig

// working

const rl = @import("raylib");
// https://github.com/raylib-zig/raylib-zig
const rlgl = rl.gl; // raylib rlgl

pub fn main() anyerror!void {
    // Initialization
    const screen_width = 800;
    const screen_height = 450;
    rl.initWindow(screen_width, screen_height, "raylib-zig - 2D Text on 3D Plane");
    defer rl.closeWindow();

    rl.disableCursor(); // Keeps the mouse locked to the window center

    // 1. Create a Render Texture to hold our text "canvas"
    const tex_width = 256;
    const tex_height = 64;
    const target = try rl.loadRenderTexture(tex_width, tex_height);
    defer rl.unloadRenderTexture(target);

    // 2. Set up a basic 3D Camera
    var camera = rl.Camera3D{
        .position = rl.Vector3{ .x = 0.0, .y = 2.0, .z = 5.0 },
        .target = rl.Vector3{ .x = 0.0, .y = 0.0, .z = 0.0 },
        .up = rl.Vector3{ .x = 0.0, .y = 1.0, .z = 0.0 },
        .fovy = 45.0,
        .projection = .perspective,
    };

    rl.setTargetFPS(60);

    // Main game loop
    while (!rl.windowShouldClose()) {
        // Update Camera (allows you to orbit around to see the 3D effect)
        // rl.updateCamera(&camera, .orbital);
        rl.updateCamera(&camera, .first_person);

        // 3. Render the 2D text onto our Render Texture
        rl.beginTextureMode(target);
        rl.clearBackground(.blank); // Transparent background
        rl.drawText("Hello 3D Plane!", 10, 20, 24, .blue);
        rl.endTextureMode();

        // 4. Draw the 3D Scene
        rl.beginDrawing();
        rl.clearBackground(.ray_white);

        rl.beginMode3D(camera);

        // Draw a grid for spatial reference
        rl.drawGrid(10, 1.0);

        // --- Draw Flat Static 3D Text Quad ---
        // 1. Bind our text texture ID directly to the GPU shader context
        rlgl.rlSetTexture(target.texture.id);

        // 1. Save current matrix state
        rlgl.rlPushMatrix();
        // 2. Position the text plane in your 3D world (X, Y, Z)
        rlgl.rlTranslatef(0.0, 1.0, 0.0);
        // 3. Rotate 90 degrees around the X-axis to stand the text upright
        rlgl.rlRotatef(90.0, 1.0, 0.0, 0.0);

        // 2. Start drawing a Quad. Zig enums map this to .quads
        // rlgl.rlBegin(rlgl.quads);
        rlgl.rlBegin(rlgl.rl_quads);
        rlgl.rlColor4ub(255, 255, 255, 255); // Keep original texture colors

        // Corner 1: Top-Left (Texture mappings use f32 ranges from 0.0 to 1.0)
        rlgl.rlTexCoord2f(0.0, 1.0);
        rlgl.rlVertex3f(-1.5, 0.01, -0.5);

        // Corner 2: Bottom-Left
        rlgl.rlTexCoord2f(0.0, 0.0);
        rlgl.rlVertex3f(-1.5, 0.01, 0.5);

        // Corner 3: Bottom-Right
        rlgl.rlTexCoord2f(1.0, 0.0);
        rlgl.rlVertex3f(1.5, 0.01, 0.5);

        // Corner 4: Top-Right
        rlgl.rlTexCoord2f(1.0, 1.0);
        rlgl.rlVertex3f(1.5, 0.01, -0.5);

        // 3. Finalize drawing geometry
        rlgl.rlEnd();

        // 4. Reset texture state back to 0 so other 3D items draw correctly
        rlgl.rlSetTexture(0);
        rlgl.rlPopMatrix();
        // -------------------------------------

        rl.endMode3D();

        // Optional: Draw instructions on the 2D UI screen layer
        rl.drawText("Hold right-click & drag mouse to rotate camera", 10, 10, 10, .dark_gray);

        rl.endDrawing();
    }
}