r3d/examples/instanced.c

#include "./common.h"

/* === Constants === */

#define INSTANCE_COUNT 1000

/* === Resources === */

static Camera3D camera = { 0 };

static R3D_Mesh mesh = { 0 };
static R3D_Material material = { 0 };
static Matrix transforms[INSTANCE_COUNT] = { 0 };
static Color colors[INSTANCE_COUNT] = { 0 };

/* === Example === */

const char* Init(void)
{
    /* --- Initialize R3D with its internal resolution --- */

    R3D_Init(GetScreenWidth(), GetScreenHeight(), 0);
    SetTargetFPS(60);

    /* --- Generates a cube mesh and a default material to render it --- */

    mesh = R3D_GenMeshCube(1, 1, 1);
    material = R3D_GetDefaultMaterial();

    /* --- Randomly generate the transformation and color of each cube instance --- */

    for (int i = 0; i < INSTANCE_COUNT; i++) {
        Matrix translate = MatrixTranslate(
            (float)GetRandomValue(-50000, 50000) / 1000,
            (float)GetRandomValue(-50000, 50000) / 1000,
            (float)GetRandomValue(-50000, 50000) / 1000
        );
        Matrix rotate = MatrixRotateXYZ((Vector3) {
            (float)GetRandomValue(-314000, 314000) / 100000,
            (float)GetRandomValue(-314000, 314000) / 100000,
            (float)GetRandomValue(-314000, 314000) / 100000
        });
        Matrix scale = MatrixScale(
            (float)GetRandomValue(100, 2000) / 1000,
            (float)GetRandomValue(100, 2000) / 1000,
            (float)GetRandomValue(100, 2000) / 1000
        );
        transforms[i] = MatrixMultiply(MatrixMultiply(scale, rotate), translate);
        colors[i] = ColorFromHSV((float)GetRandomValue(0, 360000) / 1000, 1.0f, 1.0f);
    }

    /* --- Setup the scene lighting --- */

    R3D_Light light = R3D_CreateLight(R3D_LIGHT_DIR);
    {
        R3D_SetLightDirection(light, (Vector3) { 0, -1, 0 });
        R3D_SetLightActive(light, true);
    }

    /* --- Setup the camera --- */

    camera = (Camera3D){
        .position = (Vector3) { 0, 2, 2 },
        .target = (Vector3) { 0, 0, 0 },
        .up = (Vector3) { 0, 1, 0 },
        .fovy = 60,
    };

    /* --- Capture the mouse and ready to go! --- */

    DisableCursor();

    return "[r3d] - Instanced rendering example";
}

void Update(float delta)
{
    UpdateCamera(&camera, CAMERA_FREE);
}

void Draw(void)
{
    R3D_Begin(camera);
        R3D_DrawMeshInstancedEx(&mesh, &material, transforms, colors, INSTANCE_COUNT);
    R3D_End();

    DrawFPS(10, 10);
}

void Close(void)
{
    R3D_UnloadMaterial(&material);
    R3D_UnloadMesh(&mesh);
    R3D_Close();
}