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basic pbr

★★★★by Afan OLOVCIC (@_DevDad)

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Is it the same as C?

//! raylib [shaders] example - basic pbr
//!
//! Zig-API translation of examples/shaders/shaders_basic_pbr.c (raylib 6.2).
//! Example contributed by Afan OLOVCIC (@_DevDad) and reviewed by Ramon Santamaria (@raysan5)
//! Example licensed under an unmodified zlib/libpng license.
//! Copyright (c) 2023-2025 Afan OLOVCIC (@_DevDad)
//!
//! Model: "Old Rusty Car" (https://skfb.ly/LxRy) by Renafox,
//! licensed under Creative Commons Attribution-NonCommercial
//! (http://creativecommons.org/licenses/by-nc/4.0/)

const std = @import("std");
const rl = @import("raylib");

const glsl_version = 330;

const max_lights = 4; // Max dynamic lights supported by shader

/// Light type
const LightType = enum(i32) {
    directional = 0,
    point,
    spot,
};

/// Light data
const Light = struct {
    type: LightType,
    enabled: bool,
    position: rl.Vector3,
    target: rl.Vector3,
    color: rl.Vector4, // Normalized color
    intensity: f32,

    // Shader light parameters locations
    type_loc: i32,
    enabled_loc: i32,
    position_loc: i32,
    target_loc: i32,
    color_loc: i32,
    intensity_loc: i32,

    /// Create light `index` (of the shader's `lights[max_lights]` array) and get its shader locations
    fn init(index: usize, light_type: LightType, position: rl.Vector3, target: rl.Vector3, color: rl.Color, intensity: f32, shader: rl.Shader) Light {
        const light: Light = .{
            .enabled = true,
            .type = light_type,
            .position = position,
            .target = target,
            .color = rl.colorNormalize(color),
            .intensity = intensity,

            // NOTE: Shader parameters names for lights must match the requested ones
            .enabled_loc = rl.getShaderLocation(shader, rl.textFormat("lights[{d}].enabled", .{index})),
            .type_loc = rl.getShaderLocation(shader, rl.textFormat("lights[{d}].type", .{index})),
            .position_loc = rl.getShaderLocation(shader, rl.textFormat("lights[{d}].position", .{index})),
            .target_loc = rl.getShaderLocation(shader, rl.textFormat("lights[{d}].target", .{index})),
            .color_loc = rl.getShaderLocation(shader, rl.textFormat("lights[{d}].color", .{index})),
            .intensity_loc = rl.getShaderLocation(shader, rl.textFormat("lights[{d}].intensity", .{index})),
        };
        light.update(shader);
        return light;
    }

    /// Send light properties to shader
    /// NOTE: Light shader locations should be available
    fn update(light: Light, shader: rl.Shader) void {
        const enabled: i32 = @intFromBool(light.enabled);
        const light_type: i32 = @backingInt(light.type);
        rl.setShaderValue(shader, light.enabled_loc, enabled);
        rl.setShaderValue(shader, light.type_loc, light_type);

        // Send to shader light position and target position values
        rl.setShaderValue(shader, light.position_loc, light.position);
        rl.setShaderValue(shader, light.target_loc, light.target);
        rl.setShaderValue(shader, light.color_loc, light.color);
        rl.setShaderValue(shader, light.intensity_loc, light.intensity);
    }

    /// The light's color, back in 8-bit channels
    fn rgba(light: Light) rl.Color {
        return .{
            .r = @intFromFloat(light.color.x * 255),
            .g = @intFromFloat(light.color.y * 255),
            .b = @intFromFloat(light.color.z * 255),
            .a = @intFromFloat(light.color.w * 255),
        };
    }
};

/// Unbind (disconnect) the shared shader from the model's material, so
/// unloadMaterial() does not unload it, then unload the model
fn unloadPbrModel(model: rl.Model) void {
    const material = &model.materials.?[0];
    material.shader = .{ .id = 0, .locs = null };
    rl.unloadMaterial(material.*);
    material.maps = null;
    rl.unloadModel(model);
}

pub fn main() !void {
    // Initialization
    const screen_width = 800;
    const screen_height = 450;

    rl.setConfigFlags(.{ .msaa_4x_hint = true });
    rl.initWindow(screen_width, screen_height, "raylib [shaders] example - basic pbr");
    defer rl.closeWindow(); // Close window and OpenGL context

    // Define the camera to look into our 3d world
    var camera: rl.Camera = .{
        .position = .{ .x = 2.0, .y = 2.0, .z = 6.0 }, // Camera position
        .target = .{ .x = 0.0, .y = 0.5, .z = 0.0 }, // Camera looking at point
        .up = .{ .x = 0.0, .y = 1.0, .z = 0.0 }, // Camera up vector (rotation towards target)
        .fovy = 45.0, // Camera field-of-view Y
        .projection = .perspective, // Camera projection type
    };

    // Load PBR shader and setup all required locations
    const shader = try rl.loadShader(
        std.fmt.comptimePrint("resources/shaders/glsl{d}/pbr.vs", .{glsl_version}),
        std.fmt.comptimePrint("resources/shaders/glsl{d}/pbr.fs", .{glsl_version}),
    );
    defer rl.unloadShader(shader);

    shader.loc(.map_albedo).* = rl.getShaderLocation(shader, "albedoMap");
    // WARNING: Metalness, roughness, and ambient occlusion are all packed into a MRA texture
    // They are passed as to the SHADER_LOC_MAP_METALNESS location for convenience,
    // shader already takes care of it accordingly
    shader.loc(.map_metalness).* = rl.getShaderLocation(shader, "mraMap");
    shader.loc(.map_normal).* = rl.getShaderLocation(shader, "normalMap");
    // WARNING: Similar to the MRA map, the emissive map packs different information
    // into a single texture: it stores height and emission data
    // It is binded to SHADER_LOC_MAP_EMISSION location an properly processed on shader
    shader.loc(.map_emission).* = rl.getShaderLocation(shader, "emissiveMap");
    shader.loc(.color_diffuse).* = rl.getShaderLocation(shader, "albedoColor");

    // Setup additional required shader locations, including lights data
    shader.loc(.vector_view).* = rl.getShaderLocation(shader, "viewPos");
    const light_count_loc = rl.getShaderLocation(shader, "numOfLights");
    const max_light_count: i32 = max_lights;
    rl.setShaderValue(shader, light_count_loc, max_light_count);

    // Setup ambient color and intensity parameters
    const ambient_intensity: f32 = 0.02;
    const ambient_color: rl.Color = .{ .r = 26, .g = 32, .b = 135, .a = 255 };
    const ambient_color_normalized: rl.Vector3 = .{
        .x = @as(f32, @floatFromInt(ambient_color.r)) / 255.0,
        .y = @as(f32, @floatFromInt(ambient_color.g)) / 255.0,
        .z = @as(f32, @floatFromInt(ambient_color.b)) / 255.0,
    };
    rl.setShaderValue(shader, rl.getShaderLocation(shader, "ambientColor"), ambient_color_normalized);
    rl.setShaderValue(shader, rl.getShaderLocation(shader, "ambient"), ambient_intensity);

    // Get location for shader parameters that can be modified in real time
    const metallic_value_loc = rl.getShaderLocation(shader, "metallicValue");
    const roughness_value_loc = rl.getShaderLocation(shader, "roughnessValue");
    const emissive_intensity_loc = rl.getShaderLocation(shader, "emissivePower");
    const emissive_color_loc = rl.getShaderLocation(shader, "emissiveColor");
    const texture_tiling_loc = rl.getShaderLocation(shader, "tiling");

    // Load old car model using PBR maps and shader
    // WARNING: We know this model consists of a single model.meshes[0] and
    // that model.materials[0] is by default assigned to that mesh
    // There could be more complex models consisting of multiple meshes and
    // multiple materials defined for those meshes... but always 1 mesh = 1 material
    const car = try rl.loadModel("resources/models/old_car_new.glb");
    defer unloadPbrModel(car);
    const car_material = &car.materials.?[0];

    // Assign already setup PBR shader to model.materials[0], used by models.meshes[0]
    car_material.shader = shader;

    // Setup materials[0].maps default parameters
    car_material.map(.albedo).color = .white;
    car_material.map(.metalness).value = 1.0;
    car_material.map(.roughness).value = 0.0;
    car_material.map(.occlusion).value = 1.0;
    car_material.map(.emission).color = .{ .r = 255, .g = 162, .b = 0, .a = 255 };

    // Setup materials[0].maps default textures
    car_material.map(.albedo).texture = try rl.loadTexture("resources/old_car_d.png");
    car_material.map(.metalness).texture = try rl.loadTexture("resources/old_car_mra.png");
    car_material.map(.normal).texture = try rl.loadTexture("resources/old_car_n.png");
    car_material.map(.emission).texture = try rl.loadTexture("resources/old_car_e.png");

    // Load floor model mesh and assign material parameters
    // NOTE: A basic plane shape can be generated instead of being loaded from a model file
    const floor = try rl.loadModel("resources/models/plane.glb");
    defer unloadPbrModel(floor);
    const floor_material = &floor.materials.?[0];
    //const floor_mesh = rl.genMeshPlane(10, 10, 10, 10);
    //rl.genMeshTangents(&floor_mesh); // TODO: Review tangents generation
    //const floor = try rl.loadModelFromMesh(floor_mesh);

    // Assign material shader for our floor model, same PBR shader
    floor_material.shader = shader;

    floor_material.map(.albedo).color = .white;
    floor_material.map(.metalness).value = 0.8;
    floor_material.map(.roughness).value = 0.1;
    floor_material.map(.occlusion).value = 1.0;
    floor_material.map(.emission).color = .black;

    floor_material.map(.albedo).texture = try rl.loadTexture("resources/road_a.png");
    floor_material.map(.metalness).texture = try rl.loadTexture("resources/road_mra.png");
    floor_material.map(.normal).texture = try rl.loadTexture("resources/road_n.png");

    // Models texture tiling parameter can be stored in the Material struct if required (CURRENTLY NOT USED)
    // NOTE: Material.params[4] are available for generic parameters storage (float)
    const car_texture_tiling: rl.Vector2 = .{ .x = 0.5, .y = 0.5 };
    const floor_texture_tiling: rl.Vector2 = .{ .x = 0.5, .y = 0.5 };

    // Create some lights
    const origin: rl.Vector3 = .{ .x = 0.0, .y = 0.0, .z = 0.0 };
    var lights = [max_lights]Light{
        .init(0, .point, .{ .x = -1.0, .y = 1.0, .z = -2.0 }, origin, .yellow, 4.0, shader),
        .init(1, .point, .{ .x = 2.0, .y = 1.0, .z = 1.0 }, origin, .green, 3.3, shader),
        .init(2, .point, .{ .x = -2.0, .y = 1.0, .z = 1.0 }, origin, .red, 8.3, shader),
        .init(3, .point, .{ .x = 1.0, .y = 1.0, .z = -2.0 }, origin, .blue, 2.0, shader),
    };

    // Setup material texture maps usage in shader
    // NOTE: By default, the texture maps are always used
    const usage: i32 = 1;
    rl.setShaderValue(shader, rl.getShaderLocation(shader, "useTexAlbedo"), usage);
    rl.setShaderValue(shader, rl.getShaderLocation(shader, "useTexNormal"), usage);
    rl.setShaderValue(shader, rl.getShaderLocation(shader, "useTexMRA"), usage);
    rl.setShaderValue(shader, rl.getShaderLocation(shader, "useTexEmissive"), usage);

    rl.setTargetFPS(60); // Set our game to run at 60 frames-per-second

    // Main game loop
    while (!rl.windowShouldClose()) { // Detect window close button or ESC key
        // Update
        rl.updateCamera(&camera, .orbital);

        // Update the shader with the camera view vector (points towards { 0.0f, 0.0f, 0.0f })
        rl.setShaderValue(shader, shader.loc(.vector_view).*, camera.position);

        // Check key inputs to enable/disable lights
        if (rl.isKeyPressed(.one)) lights[2].enabled = !lights[2].enabled;
        if (rl.isKeyPressed(.two)) lights[1].enabled = !lights[1].enabled;
        if (rl.isKeyPressed(.three)) lights[3].enabled = !lights[3].enabled;
        if (rl.isKeyPressed(.four)) lights[0].enabled = !lights[0].enabled;

        // Update light values on shader (actually, only enable/disable them)
        for (lights) |light| light.update(shader);

        // Draw
        rl.beginDrawing();
        defer rl.endDrawing();

        rl.clearBackground(.black);

        {
            rl.beginMode3D(camera);
            defer rl.endMode3D();

            // Set floor model texture tiling and emissive color parameters on shader
            rl.setShaderValue(shader, texture_tiling_loc, floor_texture_tiling);
            const floor_emissive_color = rl.colorNormalize(floor_material.map(.emission).color);
            rl.setShaderValue(shader, emissive_color_loc, floor_emissive_color);

            // Set floor metallic and roughness values
            rl.setShaderValue(shader, metallic_value_loc, floor_material.map(.metalness).value);
            rl.setShaderValue(shader, roughness_value_loc, floor_material.map(.roughness).value);

            rl.drawModel(floor, .{ .x = 0.0, .y = 0.0, .z = 0.0 }, 5.0, .white); // Draw floor model

            // Set old car model texture tiling, emissive color and emissive intensity parameters on shader
            rl.setShaderValue(shader, texture_tiling_loc, car_texture_tiling);
            const car_emissive_color = rl.colorNormalize(car_material.map(.emission).color);
            rl.setShaderValue(shader, emissive_color_loc, car_emissive_color);
            const emissive_intensity: f32 = 0.01;
            rl.setShaderValue(shader, emissive_intensity_loc, emissive_intensity);

            // Set old car metallic and roughness values
            rl.setShaderValue(shader, metallic_value_loc, car_material.map(.metalness).value);
            rl.setShaderValue(shader, roughness_value_loc, car_material.map(.roughness).value);

            rl.drawModel(car, .{ .x = 0.0, .y = 0.0, .z = 0.0 }, 0.25, .white); // Draw car model

            // Draw spheres to show the lights positions
            for (lights) |light| {
                const light_color = light.rgba();

                if (light.enabled) {
                    rl.drawSphereEx(light.position, 0.2, 8, 8, light_color);
                } else {
                    rl.drawSphereWires(light.position, 0.2, 8, 8, rl.colorAlpha(light_color, 0.3));
                }
            }
        }

        rl.drawText("Toggle lights: [1][2][3][4]", 10, 40, 20, .light_gray);

        rl.drawText("(c) Old Rusty Car model by Renafox (https://skfb.ly/LxRy)", screen_width - 320, screen_height - 20, 10, .light_gray);

        rl.drawFPS(10, 10);
    }
}
/*******************************************************************************************
*
*   raylib [shaders] example - basic pbr
*
*   Example complexity rating: [★★★★] 4/4
*
*   Example originally created with raylib 5.0, last time updated with raylib 5.5
*
*   Example contributed by Afan OLOVCIC (@_DevDad) and reviewed by Ramon Santamaria (@raysan5)
*
*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
*   BSD-like license that allows static linking with closed source software
*
*   Copyright (c) 2023-2025 Afan OLOVCIC (@_DevDad)
*
*   Model: "Old Rusty Car" (https://skfb.ly/LxRy) by Renafox,
*   licensed under Creative Commons Attribution-NonCommercial
*   (http://creativecommons.org/licenses/by-nc/4.0/)
*
********************************************************************************************/

#include "raylib.h"

#if defined(PLATFORM_DESKTOP)
    #define GLSL_VERSION            330
#else   // PLATFORM_ANDROID, PLATFORM_WEB
    #define GLSL_VERSION            100
#endif

#include <stdlib.h>             // Required for: NULL

#define MAX_LIGHTS  4           // Max dynamic lights supported by shader

//----------------------------------------------------------------------------------
// Types and Structures Definition
//----------------------------------------------------------------------------------
// Light type
typedef enum {
    LIGHT_DIRECTIONAL = 0,
    LIGHT_POINT,
    LIGHT_SPOT
} LightType;

// Light data
typedef struct {
    int type;
    int enabled;
    Vector3 position;
    Vector3 target;
    float color[4];
    float intensity;

    // Shader light parameters locations
    int typeLoc;
    int enabledLoc;
    int positionLoc;
    int targetLoc;
    int colorLoc;
    int intensityLoc;
} Light;

//----------------------------------------------------------------------------------
// Global Variables Definition
//----------------------------------------------------------------------------------
static int lightCount = 0;     // Current number of dynamic lights that have been created

//----------------------------------------------------------------------------------
// Module Functions Declaration
//----------------------------------------------------------------------------------
// Create a light and get shader locations
static Light CreateLight(int type, Vector3 position, Vector3 target, Color color, float intensity, Shader shader);

// Update light properties on shader
// NOTE: Light shader locations should be available
static void UpdateLight(Shader shader, Light light);

//----------------------------------------------------------------------------------
// Program main entry point
//----------------------------------------------------------------------------------
int main(void)
{
    // Initialization
    //--------------------------------------------------------------------------------------
    const int screenWidth = 800;
    const int screenHeight = 450;

    SetConfigFlags(FLAG_MSAA_4X_HINT);
    InitWindow(screenWidth, screenHeight, "raylib [shaders] example - basic pbr");

    // Define the camera to look into our 3d world
    Camera camera = { 0 };
    camera.position = (Vector3){ 2.0f, 2.0f, 6.0f };    // Camera position
    camera.target = (Vector3){ 0.0f, 0.5f, 0.0f };      // Camera looking at point
    camera.up = (Vector3){ 0.0f, 1.0f, 0.0f };          // Camera up vector (rotation towards target)
    camera.fovy = 45.0f;                                // Camera field-of-view Y
    camera.projection = CAMERA_PERSPECTIVE;             // Camera projection type

    // Load PBR shader and setup all required locations
    Shader shader = LoadShader(TextFormat("resources/shaders/glsl%i/pbr.vs", GLSL_VERSION),
                               TextFormat("resources/shaders/glsl%i/pbr.fs", GLSL_VERSION));
    shader.locs[SHADER_LOC_MAP_ALBEDO] = GetShaderLocation(shader, "albedoMap");
    // WARNING: Metalness, roughness, and ambient occlusion are all packed into a MRA texture
    // They are passed as to the SHADER_LOC_MAP_METALNESS location for convenience,
    // shader already takes care of it accordingly
    shader.locs[SHADER_LOC_MAP_METALNESS] = GetShaderLocation(shader, "mraMap");
    shader.locs[SHADER_LOC_MAP_NORMAL] = GetShaderLocation(shader, "normalMap");
    // WARNING: Similar to the MRA map, the emissive map packs different information
    // into a single texture: it stores height and emission data
    // It is binded to SHADER_LOC_MAP_EMISSION location an properly processed on shader
    shader.locs[SHADER_LOC_MAP_EMISSION] = GetShaderLocation(shader, "emissiveMap");
    shader.locs[SHADER_LOC_COLOR_DIFFUSE] = GetShaderLocation(shader, "albedoColor");

    // Setup additional required shader locations, including lights data
    shader.locs[SHADER_LOC_VECTOR_VIEW] = GetShaderLocation(shader, "viewPos");
    int lightCountLoc = GetShaderLocation(shader, "numOfLights");
    int maxLightCount = MAX_LIGHTS;
    SetShaderValue(shader, lightCountLoc, &maxLightCount, SHADER_UNIFORM_INT);

    // Setup ambient color and intensity parameters
    float ambientIntensity = 0.02f;
    Color ambientColor = (Color){ 26, 32, 135, 255 };
    Vector3 ambientColorNormalized = (Vector3){ ambientColor.r/255.0f, ambientColor.g/255.0f, ambientColor.b/255.0f };
    SetShaderValue(shader, GetShaderLocation(shader, "ambientColor"), &ambientColorNormalized, SHADER_UNIFORM_VEC3);
    SetShaderValue(shader, GetShaderLocation(shader, "ambient"), &ambientIntensity, SHADER_UNIFORM_FLOAT);

    // Get location for shader parameters that can be modified in real time
    int metallicValueLoc = GetShaderLocation(shader, "metallicValue");
    int roughnessValueLoc = GetShaderLocation(shader, "roughnessValue");
    int emissiveIntensityLoc = GetShaderLocation(shader, "emissivePower");
    int emissiveColorLoc = GetShaderLocation(shader, "emissiveColor");
    int textureTilingLoc = GetShaderLocation(shader, "tiling");

    // Load old car model using PBR maps and shader
    // WARNING: We know this model consists of a single model.meshes[0] and
    // that model.materials[0] is by default assigned to that mesh
    // There could be more complex models consisting of multiple meshes and
    // multiple materials defined for those meshes... but always 1 mesh = 1 material
    Model car = LoadModel("resources/models/old_car_new.glb");

    // Assign already setup PBR shader to model.materials[0], used by models.meshes[0]
    car.materials[0].shader = shader;

    // Setup materials[0].maps default parameters
    car.materials[0].maps[MATERIAL_MAP_ALBEDO].color = WHITE;
    car.materials[0].maps[MATERIAL_MAP_METALNESS].value = 1.0f;
    car.materials[0].maps[MATERIAL_MAP_ROUGHNESS].value = 0.0f;
    car.materials[0].maps[MATERIAL_MAP_OCCLUSION].value = 1.0f;
    car.materials[0].maps[MATERIAL_MAP_EMISSION].color = (Color){ 255, 162, 0, 255 };

    // Setup materials[0].maps default textures
    car.materials[0].maps[MATERIAL_MAP_ALBEDO].texture = LoadTexture("resources/old_car_d.png");
    car.materials[0].maps[MATERIAL_MAP_METALNESS].texture = LoadTexture("resources/old_car_mra.png");
    car.materials[0].maps[MATERIAL_MAP_NORMAL].texture = LoadTexture("resources/old_car_n.png");
    car.materials[0].maps[MATERIAL_MAP_EMISSION].texture = LoadTexture("resources/old_car_e.png");

    // Load floor model mesh and assign material parameters
    // NOTE: A basic plane shape can be generated instead of being loaded from a model file
    Model floor = LoadModel("resources/models/plane.glb");
    //Mesh floorMesh = GenMeshPlane(10, 10, 10, 10);
    //GenMeshTangents(&floorMesh);      // TODO: Review tangents generation
    //Model floor = LoadModelFromMesh(floorMesh);

    // Assign material shader for our floor model, same PBR shader
    floor.materials[0].shader = shader;

    floor.materials[0].maps[MATERIAL_MAP_ALBEDO].color = WHITE;
    floor.materials[0].maps[MATERIAL_MAP_METALNESS].value = 0.8f;
    floor.materials[0].maps[MATERIAL_MAP_ROUGHNESS].value = 0.1f;
    floor.materials[0].maps[MATERIAL_MAP_OCCLUSION].value = 1.0f;
    floor.materials[0].maps[MATERIAL_MAP_EMISSION].color = BLACK;

    floor.materials[0].maps[MATERIAL_MAP_ALBEDO].texture = LoadTexture("resources/road_a.png");
    floor.materials[0].maps[MATERIAL_MAP_METALNESS].texture = LoadTexture("resources/road_mra.png");
    floor.materials[0].maps[MATERIAL_MAP_NORMAL].texture = LoadTexture("resources/road_n.png");

    // Models texture tiling parameter can be stored in the Material struct if required (CURRENTLY NOT USED)
    // NOTE: Material.params[4] are available for generic parameters storage (float)
    Vector2 carTextureTiling = (Vector2){ 0.5f, 0.5f };
    Vector2 floorTextureTiling = (Vector2){ 0.5f, 0.5f };

    // Create some lights
    Light lights[MAX_LIGHTS] = { 0 };
    lights[0] = CreateLight(LIGHT_POINT, (Vector3){ -1.0f, 1.0f, -2.0f }, (Vector3){ 0.0f, 0.0f, 0.0f }, YELLOW, 4.0f, shader);
    lights[1] = CreateLight(LIGHT_POINT, (Vector3){ 2.0f, 1.0f, 1.0f }, (Vector3){ 0.0f, 0.0f, 0.0f }, GREEN, 3.3f, shader);
    lights[2] = CreateLight(LIGHT_POINT, (Vector3){ -2.0f, 1.0f, 1.0f }, (Vector3){ 0.0f, 0.0f, 0.0f }, RED, 8.3f, shader);
    lights[3] = CreateLight(LIGHT_POINT, (Vector3){ 1.0f, 1.0f, -2.0f }, (Vector3){ 0.0f, 0.0f, 0.0f }, BLUE, 2.0f, shader);

    // Setup material texture maps usage in shader
    // NOTE: By default, the texture maps are always used
    int usage = 1;
    SetShaderValue(shader, GetShaderLocation(shader, "useTexAlbedo"), &usage, SHADER_UNIFORM_INT);
    SetShaderValue(shader, GetShaderLocation(shader, "useTexNormal"), &usage, SHADER_UNIFORM_INT);
    SetShaderValue(shader, GetShaderLocation(shader, "useTexMRA"), &usage, SHADER_UNIFORM_INT);
    SetShaderValue(shader, GetShaderLocation(shader, "useTexEmissive"), &usage, SHADER_UNIFORM_INT);

    SetTargetFPS(60);                   // Set our game to run at 60 frames-per-second
    //---------------------------------------------------------------------------------------

    // Main game loop
    while (!WindowShouldClose())    // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        UpdateCamera(&camera, CAMERA_ORBITAL);

        // Update the shader with the camera view vector (points towards { 0.0f, 0.0f, 0.0f })
        float cameraPos[3] = {camera.position.x, camera.position.y, camera.position.z};
        SetShaderValue(shader, shader.locs[SHADER_LOC_VECTOR_VIEW], cameraPos, SHADER_UNIFORM_VEC3);

        // Check key inputs to enable/disable lights
        if (IsKeyPressed(KEY_ONE)) { lights[2].enabled = !lights[2].enabled; }
        if (IsKeyPressed(KEY_TWO)) { lights[1].enabled = !lights[1].enabled; }
        if (IsKeyPressed(KEY_THREE)) { lights[3].enabled = !lights[3].enabled; }
        if (IsKeyPressed(KEY_FOUR)) { lights[0].enabled = !lights[0].enabled; }

        // Update light values on shader (actually, only enable/disable them)
        for (int i = 0; i < MAX_LIGHTS; i++) UpdateLight(shader, lights[i]);
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();

            ClearBackground(BLACK);

            BeginMode3D(camera);

                // Set floor model texture tiling and emissive color parameters on shader
                SetShaderValue(shader, textureTilingLoc, &floorTextureTiling, SHADER_UNIFORM_VEC2);
                Vector4 floorEmissiveColor = ColorNormalize(floor.materials[0].maps[MATERIAL_MAP_EMISSION].color);
                SetShaderValue(shader, emissiveColorLoc, &floorEmissiveColor, SHADER_UNIFORM_VEC4);

                // Set floor metallic and roughness values
                SetShaderValue(shader, metallicValueLoc, &floor.materials[0].maps[MATERIAL_MAP_METALNESS].value, SHADER_UNIFORM_FLOAT);
                SetShaderValue(shader, roughnessValueLoc, &floor.materials[0].maps[MATERIAL_MAP_ROUGHNESS].value, SHADER_UNIFORM_FLOAT);

                DrawModel(floor, (Vector3){ 0.0f, 0.0f, 0.0f }, 5.0f, WHITE);   // Draw floor model

                // Set old car model texture tiling, emissive color and emissive intensity parameters on shader
                SetShaderValue(shader, textureTilingLoc, &carTextureTiling, SHADER_UNIFORM_VEC2);
                Vector4 carEmissiveColor = ColorNormalize(car.materials[0].maps[MATERIAL_MAP_EMISSION].color);
                SetShaderValue(shader, emissiveColorLoc, &carEmissiveColor, SHADER_UNIFORM_VEC4);
                float emissiveIntensity = 0.01f;
                SetShaderValue(shader, emissiveIntensityLoc, &emissiveIntensity, SHADER_UNIFORM_FLOAT);

                // Set old car metallic and roughness values
                SetShaderValue(shader, metallicValueLoc, &car.materials[0].maps[MATERIAL_MAP_METALNESS].value, SHADER_UNIFORM_FLOAT);
                SetShaderValue(shader, roughnessValueLoc, &car.materials[0].maps[MATERIAL_MAP_ROUGHNESS].value, SHADER_UNIFORM_FLOAT);

                DrawModel(car, (Vector3){ 0.0f, 0.0f, 0.0f }, 0.25f, WHITE);   // Draw car model

                // Draw spheres to show the lights positions
                for (int i = 0; i < MAX_LIGHTS; i++)
                {
                    Color lightColor = (Color){
                        (unsigned char)(lights[i].color[0]*255),
                        (unsigned char)(lights[i].color[1]*255),
                        (unsigned char)(lights[i].color[2]*255),
                        (unsigned char)(lights[i].color[3]*255) };

                    if (lights[i].enabled) DrawSphereEx(lights[i].position, 0.2f, 8, 8, lightColor);
                    else DrawSphereWires(lights[i].position, 0.2f, 8, 8, ColorAlpha(lightColor, 0.3f));
                }

            EndMode3D();

            DrawText("Toggle lights: [1][2][3][4]", 10, 40, 20, LIGHTGRAY);

            DrawText("(c) Old Rusty Car model by Renafox (https://skfb.ly/LxRy)", screenWidth - 320, screenHeight - 20, 10, LIGHTGRAY);

            DrawFPS(10, 10);

        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    // Unbind (disconnect) shader from car.material[0]
    // to avoid UnloadMaterial() trying to unload it automatically
    car.materials[0].shader = (Shader){ 0 };
    UnloadMaterial(car.materials[0]);
    car.materials[0].maps = NULL;
    UnloadModel(car);

    floor.materials[0].shader = (Shader){ 0 };
    UnloadMaterial(floor.materials[0]);
    floor.materials[0].maps = NULL;
    UnloadModel(floor);

    UnloadShader(shader);       // Unload Shader

    CloseWindow();              // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;
}

//----------------------------------------------------------------------------------
// Module Functions Definition
//----------------------------------------------------------------------------------
// Create light with provided data
// NOTE: It updated the global lightCount and it's limited to MAX_LIGHTS
static Light CreateLight(int type, Vector3 position, Vector3 target, Color color, float intensity, Shader shader)
{
    Light light = { 0 };

    if (lightCount < MAX_LIGHTS)
    {
        light.enabled = 1;
        light.type = type;
        light.position = position;
        light.target = target;
        light.color[0] = (float)color.r/255.0f;
        light.color[1] = (float)color.g/255.0f;
        light.color[2] = (float)color.b/255.0f;
        light.color[3] = (float)color.a/255.0f;
        light.intensity = intensity;

        // NOTE: Shader parameters names for lights must match the requested ones
        light.enabledLoc = GetShaderLocation(shader, TextFormat("lights[%i].enabled", lightCount));
        light.typeLoc = GetShaderLocation(shader, TextFormat("lights[%i].type", lightCount));
        light.positionLoc = GetShaderLocation(shader, TextFormat("lights[%i].position", lightCount));
        light.targetLoc = GetShaderLocation(shader, TextFormat("lights[%i].target", lightCount));
        light.colorLoc = GetShaderLocation(shader, TextFormat("lights[%i].color", lightCount));
        light.intensityLoc = GetShaderLocation(shader, TextFormat("lights[%i].intensity", lightCount));

        UpdateLight(shader, light);

        lightCount++;
    }

    return light;
}

// Send light properties to shader
// NOTE: Light shader locations should be available
static void UpdateLight(Shader shader, Light light)
{
    SetShaderValue(shader, light.enabledLoc, &light.enabled, SHADER_UNIFORM_INT);
    SetShaderValue(shader, light.typeLoc, &light.type, SHADER_UNIFORM_INT);

    // Send to shader light position values
    float position[3] = { light.position.x, light.position.y, light.position.z };
    SetShaderValue(shader, light.positionLoc, position, SHADER_UNIFORM_VEC3);

    // Send to shader light target position values
    float target[3] = { light.target.x, light.target.y, light.target.z };
    SetShaderValue(shader, light.targetLoc, target, SHADER_UNIFORM_VEC3);
    SetShaderValue(shader, light.colorLoc, light.color, SHADER_UNIFORM_VEC4);
    SetShaderValue(shader, light.intensityLoc, &light.intensity, SHADER_UNIFORM_FLOAT);
}

From raylib 6.2. The original on GitHub.