Garry's Mod GTA4 HUD

--[[
        DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.
]]

local clip = {}

do
    local render = render

    local STENCILOPERATION_REPLACE = STENCILOPERATION_REPLACE
    local STENCILOPERATION_ZERO = STENCILOPERATION_ZERO
    local STENCILCOMPARISONFUNCTION_EQUAL = STENCILCOMPARISONFUNCTION_EQUAL
    local STENCILCOMPARISONFUNCTION_NEVER = STENCILCOMPARISONFUNCTION_NEVER
    local STENCILCOMPARISONFUNCTION_NOTEQUAL = STENCILCOMPARISONFUNCTION_NOTEQUAL

    function clip.Start()
        render.SetStencilEnable(true)
        render.SetStencilWriteMask(1)
        render.SetStencilTestMask(1)
        render.SetStencilReferenceValue(1)
    end

    function clip.End()
        render.ClearStencil()
        render.SetStencilEnable(false)
    end

    function clip.Render(call1, call2, clipOuter)
        render.ClearStencil()

        render.SetStencilFailOperation(STENCILOPERATION_REPLACE)
        render.SetStencilPassOperation(STENCILOPERATION_ZERO)
        render.SetStencilZFailOperation(STENCILOPERATION_ZERO)
        render.SetStencilCompareFunction(STENCILCOMPARISONFUNCTION_NEVER)

        call1()

        render.SetStencilFailOperation(STENCILOPERATION_ZERO)
        render.SetStencilPassOperation(STENCILOPERATION_REPLACE)
        render.SetStencilZFailOperation(STENCILOPERATION_ZERO)

        if clipOuter then
            render.SetStencilCompareFunction(STENCILCOMPARISONFUNCTION_EQUAL)
        else
            render.SetStencilCompareFunction(STENCILCOMPARISONFUNCTION_NOTEQUAL)
        end

        call2()
    end
end

local GenerateCircleVertices = nil

do
    local cos, rad, sin = math.cos, math.rad, math.sin

    function GenerateCircleVertices(centreX, centreY, radius, angStart, angSize)
        local vertices = {}
        local passes = 64 -- Seems to look pretty enough

        vertices[1] = { -- Ensure vertices resemble sector and not a chord
            x = centreX,
            y = centreY
        }

        for i = 0, passes do
            local sectorVertexAng = rad(-90 + angStart + angSize * (i / passes))

            vertices[i + 2] = {
                x = centreX + cos(sectorVertexAng) * radius,
                y = centreY + sin(sectorVertexAng) * radius
            }
        end

        return vertices
    end
end

local miniMapMat = Material("roleplay/minimap.png")
local miniMapRT = GetRenderTarget("MiniMapRT", 512, 512, true)
local miniMapRTMat = CreateMaterial("MiniMapRTMat", "UnlitGeneric", {["$basetexture"] = "MiniMapRT"})

local radius = math.Clamp(math.floor(ScrH() / 8.5), 80, 256)
local x, y = 32 + radius, 32 + radius
local barSize = radius / 9
local outlineSize = 3

local innerBarVertices = GenerateCircleVertices(x, y, radius - barSize, 0, 360)
local healthBarVertices = GenerateCircleVertices(x, y, radius, 0, 0)
local armorBarVertices = GenerateCircleVertices(x, y, radius, 0, 0)

local innerBackgroundVertices = innerBarVertices
local backgroundVertices = GenerateCircleVertices(x, y, radius, 0, 360)

local innerOutlineVertices = backgroundVertices
local innerInlineVertices = GenerateCircleVertices(x, y, radius - barSize - outlineSize, 0, 360)
local outlineVertices = GenerateCircleVertices(x, y, radius + outlineSize, 0, 360)
local inlineVertices = GenerateCircleVertices(x, y, radius - barSize, 0, 360)

local lastHealth = nil
local lastArmor = nil

hook.Add("Think", "rp_radar", function()
    if not IsValid(LocalPlayer()) then return end

    local ply = LocalPlayer()

    if ply:Health() ~= lastHealth or ply:Armor() ~= lastArmor then
        local hp = Lerp(0.25, lastHealth or 100, ply:Health())
        local armor = Lerp(0.25, lastArmor or 100, ply:Armor())
        local healthFrac = hp / 100
        local armorFrac = armor / 100

        local healthAngSize = 180 * healthFrac
        local armorAngSize = 180 * armorFrac

        local healthAngStart = 180 + (180 - healthAngSize)
        local armorAngStart = healthAngStart - armorAngSize

        healthBarVertices = GenerateCircleVertices(x, y, radius, healthAngStart, healthAngSize)
        armorBarVertices = GenerateCircleVertices(x, y, radius, armorAngStart, armorAngSize)

        lastHealth = hp
        lastArmor = armor
    end
end)

local color_white = color_white
local color_black = color_black
local color_health = Color(92, 131, 86)
local color_lowhealth = Color(148, 76, 67)
local color_armor = Color(74, 148, 160)
local color_innerbackground = Color(0, 0, 0, 210)
local texWhite = surface.GetTextureID("vgui/white")

local rendering_minimap = false

hook.Add("PreDrawViewModel", "Radar", function()
    if rendering_minimap then
        return true
    end
end)

hook.Add("ShouldDrawLocalPlayer", "Radar", function()
    if rendering_minimap then
        return true
    end
end)

hook.Add("HUDPaint", "Radar", function()
    if not IsValid(LocalPlayer()) then return end

    local ply = LocalPlayer()
    surface.SetDrawColor(color_white)
    surface.SetTexture(texWhite)

    do
        local oldRT = render.GetRenderTarget()
        local oldW, oldH = ScrW(), ScrH()

        render.SetRenderTarget(miniMapRT)
            render.SetViewPort(0, 0, 512, 512)
                render.Clear(40, 40, 40, 255)

                cam.Start2D()
                    local ang = EyeAngles()
                    local pos = EyePos()

                    render.SuppressEngineLighting(true)

                        rendering_minimap = true

                        render.RenderView({
                            angles = Angle(90, ang.y, 0),
                            origin = Vector(pos.x, pos.y, 2400),
                            x = 0,
                            y = 0,
                            w = 512,
                            h = 512,
                            fov = 40,
                            dopostprocess = false
                        })

                        rendering_minimap = false

                    render.SuppressEngineLighting(false)

                cam.End2D()
            render.SetViewPort(0, 0, oldW, oldH)
        render.SetRenderTarget(oldRT)
    end

    clip.Start()

        clip.Render(
            function()
                surface.DrawPoly(innerInlineVertices)
            end,
            function()
                surface.SetMaterial(miniMapRTMat)
                surface.DrawTexturedRect(x - 256, y - 256, 512, 512)
                surface.SetTexture(texWhite)
            end,
            true
        )


        clip.Render(
            function()
                surface.DrawPoly(innerOutlineVertices)
            end,
            function()
                surface.SetDrawColor(color_black)
                surface.DrawPoly(outlineVertices)
            end
        )

        clip.Render(
            function()
                surface.DrawPoly(innerInlineVertices)
            end,
            function()
                surface.SetDrawColor(color_black)
                surface.DrawPoly(inlineVertices)
            end

        )

        clip.Render(
            function()
                surface.DrawPoly(innerBackgroundVertices)
            end,
            function()
                surface.SetDrawColor(color_innerbackground)
                surface.DrawPoly(backgroundVertices)
            end
        )

        clip.Render(
            function()
                surface.DrawPoly(innerBarVertices)
            end,
            function()
                if ply:Health() > 10 or math.ceil(RealTime()) % 2 == 0 then
                    surface.SetDrawColor(color_health)
                else
                    surface.SetDrawColor(color_lowhealth)
                end

                surface.DrawPoly(healthBarVertices)
            end
        )

        clip.Render(
            function()
                surface.DrawPoly(innerBarVertices)
            end,
            function()
                surface.SetDrawColor(color_armor)
                surface.DrawPoly(armorBarVertices)
            end
        )

    clip.End()
end)