SDL3CPlusPlus/scripts/gui_demo.lua

local Gui = require('gui')
local math3d = require('math3d')

local ctx = Gui.newContext()
local input = Gui.newInputState()

local function log_trace(fmt, ...)
    if not lua_debug or not fmt then
        return
    end
    print(string.format(fmt, ...))
end

local buttonStates = {
    button1 = false,
    button2 = false,
    button3 = false,
    button4 = false
}

local statusMessage = 'Ready'
local viewProjectionLogged = false
local fpsMode = false
local fpsToggleWasDown = false
local fpsToggleKey = "F1"
if type(config) == "table" then
    local bindings = config.input_bindings
    if type(bindings) == "table" then
        local key = bindings.fps_toggle or bindings.fps_toggle_key
        if type(key) == "string" or type(key) == "number" then
            fpsToggleKey = key
        end
    end
end

local function setFpsMode(enabled)
    fpsMode = enabled
    if window_set_relative_mouse_mode then
        window_set_relative_mouse_mode(enabled)
    end
    if window_set_mouse_grabbed then
        window_set_mouse_grabbed(enabled)
    end
    if window_set_cursor_visible then
        window_set_cursor_visible(not enabled)
    end
    statusMessage = enabled and "FPS mode enabled" or "FPS mode disabled"
    log_trace("FPS mode toggled: %s", enabled and "on" or "off")
end

local function updateFpsModeToggle()
    if not input_is_key_down then
        return
    end
    if fpsToggleKey == nil or fpsToggleKey == "" then
        return
    end
    local down = input_is_key_down(fpsToggleKey)
    if down and not fpsToggleWasDown then
        setFpsMode(not fpsMode)
    end
    fpsToggleWasDown = down
    if fpsMode and window_get_mouse_grabbed and not window_get_mouse_grabbed() then
        fpsMode = false
        statusMessage = "FPS mode disabled"
    end
end

local shader_variants = {
    default = {
        vertex = "shaders/gui_2d.vert",
        fragment = "shaders/gui_2d.frag",
    },
}

local function drawTestButtons()
    -- Background panel
    ctx:pushRect({x = 50, y = 50, width = 400, height = 400}, {
        color = {0.1, 0.1, 0.1, 0.9},
        borderColor = {0.5, 0.5, 0.5, 1.0},
    })

    -- Title
    Gui.text(ctx, {x = 70, y = 70, width = 360, height = 40}, "2D Test Buttons", {
        fontSize = 28,
        alignX = "center",
        color = {1.0, 1.0, 1.0, 1.0},
    })

    -- Button 1
    if Gui.button(ctx, "btn1", {x = 100, y = 130, width = 150, height = 50}, "Button 1") then
        buttonStates.button1 = not buttonStates.button1
        statusMessage = "Button 1 " .. (buttonStates.button1 and "pressed" or "released")
        log_trace("Button 1 clicked: %s", statusMessage)
    end

    -- Button 2
    if Gui.button(ctx, "btn2", {x = 270, y = 130, width = 150, height = 50}, "Button 2") then
        buttonStates.button2 = not buttonStates.button2
        statusMessage = "Button 2 " .. (buttonStates.button2 and "pressed" or "released")
        log_trace("Button 2 clicked: %s", statusMessage)
    end

    -- Button 3
    if Gui.button(ctx, "btn3", {x = 100, y = 200, width = 150, height = 50}, "Button 3") then
        buttonStates.button3 = not buttonStates.button3
        statusMessage = "Button 3 " .. (buttonStates.button3 and "pressed" or "released")
        log_trace("Button 3 clicked: %s", statusMessage)
    end

    -- Button 4
    if Gui.button(ctx, "btn4", {x = 270, y = 200, width = 150, height = 50}, "Button 4") then
        buttonStates.button4 = not buttonStates.button4
        statusMessage = "Button 4 " .. (buttonStates.button4 and "pressed" or "released")
        log_trace("Button 4 clicked: %s", statusMessage)
    end

    -- Status display
    Gui.text(ctx, {x = 70, y = 280, width = 360, height = 30}, "Status: " .. statusMessage, {
        fontSize = 18,
        alignX = "center",
        color = {0.8, 0.8, 1.0, 1.0},
    })

    -- Button states display
    local statesText = string.format("States: 1:%s 2:%s 3:%s 4:%s",
        buttonStates.button1 and "ON" or "OFF",
        buttonStates.button2 and "ON" or "OFF",
        buttonStates.button3 and "ON" or "OFF",
        buttonStates.button4 and "ON" or "OFF")
    Gui.text(ctx, {x = 70, y = 315, width = 360, height = 22}, statesText, {
        fontSize = 16,
        alignX = "center",
        color = {1.0, 0.8, 0.8, 1.0},
    })

    local deltaX = input.mouseDeltaX or 0
    local deltaY = input.mouseDeltaY or 0
    Gui.text(ctx, {x = 70, y = 340, width = 360, height = 20},
        string.format("Mouse d: %.1f, %.1f", deltaX, deltaY), {
            fontSize = 14,
            alignX = "center",
            color = {0.85, 0.9, 0.85, 1.0},
        })

    local grabState = window_get_mouse_grabbed and window_get_mouse_grabbed() or false
    local fpsLabel = fpsMode and "ON" or "OFF"
    local fpsToggleLabel = tostring(fpsToggleKey or "F1")
    Gui.text(ctx, {x = 70, y = 362, width = 360, height = 20},
        string.format("FPS Mode: %s (grab=%s, %s toggle)", fpsLabel, grabState and "on" or "off", fpsToggleLabel), {
            fontSize = 14,
            alignX = "center",
            color = {0.85, 0.85, 0.95, 1.0},
        })

    if Gui.button(ctx, "fps_toggle", {x = 155, y = 385, width = 140, height = 28},
                  fpsMode and "FPS: ON" or "FPS: OFF") then
        setFpsMode(not fpsMode)
    end

    -- Reset button
    if Gui.button(ctx, "reset", {x = 175, y = 418, width = 100, height = 28}, "Reset") then
        buttonStates.button1 = false
        buttonStates.button2 = false
        buttonStates.button3 = false
        buttonStates.button4 = false
        statusMessage = "All buttons reset"
        log_trace("Reset button clicked")
    end
end

gui_context = ctx
gui_input = input

function get_scene_objects()
    return {}  -- No 3D objects
end

function get_shader_paths()
    log_trace("GUI demo shader variants: default vertex=%s fragment=%s",
        shader_variants.default.vertex,
        shader_variants.default.fragment)
    return shader_variants
end

function get_view_projection(aspect)
    if not viewProjectionLogged then
        log_trace("GUI demo view projection: identity (aspect=%.2f)", aspect)
        viewProjectionLogged = true
    end
    return math3d.identity()
end

function get_gui_commands()
    updateFpsModeToggle()
    ctx:beginFrame(input)
    drawTestButtons()
    if fpsMode then
        local width, height = 1024, 768
        if window_get_size then
            local w, h = window_get_size()
            if type(w) == "number" and type(h) == "number" then
                width, height = w, h
            end
        end
        Gui.cursor(ctx, {mouseX = width * 0.5, mouseY = height * 0.5, mouseDown = input.mouseDown}, {
            size = 18,
            thickness = 2,
            color = {0.9, 0.95, 1.0, 1.0},
            activeColor = {1.0, 0.4, 0.2, 1.0},
        })
    else
        Gui.cursor(ctx, input, {
            size = 16,
            thickness = 2,
            color = {1.0, 0.9, 0.2, 1.0},
            activeColor = {1.0, 0.35, 0.15, 1.0},
        })
    end
    ctx:endFrame()
    return ctx:getCommands()
end