model shader

★★☆☆by Ramon Santamaria (@raysan5)

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ZigC (original)

//! raylib [shaders] example - model shader
//!
//! Zig-API translation of examples/shaders/shaders_model_shader.c (raylib 6.2).
//! Example licensed under an unmodified zlib/libpng license.
//! Copyright (c) 2014-2025 Ramon Santamaria (@raysan5)
//!
//! NOTE: Shaders used in this example are #version 330 (OpenGL 3.3).

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

const glsl_version = 330;

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

    rl.setConfigFlags(.{ .msaa_4x_hint = true }); // Enable Multi Sampling Anti Aliasing 4x (if available)

    rl.initWindow(screen_width, screen_height, "raylib [shaders] example - model shader");
    defer rl.closeWindow(); // Close window and OpenGL context

    // Define the camera to look into our 3d world
    var camera: rl.Camera = .{
        .position = .{ .x = 4.0, .y = 4.0, .z = 4.0 }, // Camera position
        .target = .{ .x = 0.0, .y = 1.0, .z = -1.0 }, // 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
    };

    const model = try rl.loadModel("resources/models/watermill.obj"); // Load OBJ model
    defer rl.unloadModel(model);
    const texture = try rl.loadTexture("resources/models/watermill_diffuse.png"); // Load model texture
    defer rl.unloadTexture(texture);

    // Load shader for model
    // NOTE: Defining null for vertex shader forces usage of internal default vertex shader
    const shader = try rl.loadShader(null, std.fmt.comptimePrint("resources/shaders/glsl{d}/grayscale.fs", .{glsl_version}));
    defer rl.unloadShader(shader);

    const material = &model.materials.?[0];
    material.shader = shader; // Set shader effect to 3d model
    material.map(.diffuse).texture = texture; // Bind texture to model

    const position: rl.Vector3 = .{ .x = 0.0, .y = 0.0, .z = 0.0 }; // Set model position

    rl.disableCursor(); // Limit cursor to relative movement inside the window
    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, .free);

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

        rl.clearBackground(.ray_white);

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

            rl.drawModel(model, position, 0.2, .white); // Draw 3d model with texture
            rl.drawGrid(10, 1.0); // Draw a grid
        }

        rl.drawText("(c) Watermill 3D model by Alberto Cano", screen_width - 210, screen_height - 20, 10, .gray);
        rl.drawFPS(10, 10);
    }
}

/*******************************************************************************************
*
*   raylib [shaders] example - model shader
*
*   Example complexity rating: [★★☆☆] 2/4
*
*   NOTE: This example requires raylib OpenGL 3.3 or ES2 versions for shaders support,
*         OpenGL 1.1 does not support shaders, recompile raylib to OpenGL 3.3 version
*
*   NOTE: Shaders used in this example are #version 330 (OpenGL 3.3), to test this example
*         on OpenGL ES 2.0 platforms (Android, Raspberry Pi, HTML5), use #version 100 shaders
*         raylib comes with shaders ready for both versions, check raylib/shaders install folder
*
*   Example originally created with raylib 1.3, last time updated with raylib 3.7
*
*   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) 2014-2025 Ramon Santamaria (@raysan5)
*
********************************************************************************************/

#include "raylib.h"

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

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

    SetConfigFlags(FLAG_MSAA_4X_HINT);      // Enable Multi Sampling Anti Aliasing 4x (if available)

    InitWindow(screenWidth, screenHeight, "raylib [shaders] example - model shader");

    // Define the camera to look into our 3d world
    Camera camera = { 0 };
    camera.position = (Vector3){ 4.0f, 4.0f, 4.0f };    // Camera position
    camera.target = (Vector3){ 0.0f, 1.0f, -1.0f };     // 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

    Model model = LoadModel("resources/models/watermill.obj");                   // Load OBJ model
    Texture2D texture = LoadTexture("resources/models/watermill_diffuse.png");   // Load model texture

    // Load shader for model
    // NOTE: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
    Shader shader = LoadShader(0, TextFormat("resources/shaders/glsl%i/grayscale.fs", GLSL_VERSION));

    model.materials[0].shader = shader;                 // Set shader effect to 3d model
    model.materials[0].maps[MATERIAL_MAP_DIFFUSE].texture = texture; // Bind texture to model

    Vector3 position = { 0.0f, 0.0f, 0.0f };    // Set model position

    DisableCursor();                    // Limit cursor to relative movement inside the window
    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_FREE);
        //----------------------------------------------------------------------------------

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

            ClearBackground(RAYWHITE);

            BeginMode3D(camera);

                DrawModel(model, position, 0.2f, WHITE);   // Draw 3d model with texture

                DrawGrid(10, 1.0f);     // Draw a grid

            EndMode3D();

            DrawText("(c) Watermill 3D model by Alberto Cano", screenWidth - 210, screenHeight - 20, 10, GRAY);

            DrawFPS(10, 10);

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

    // De-Initialization
    //--------------------------------------------------------------------------------------
    UnloadShader(shader);       // Unload shader
    UnloadTexture(texture);     // Unload texture
    UnloadModel(model);         // Unload model

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

    return 0;
}

From raylib 6.2. The original on GitHub.