feat: major engine overhaul - scene demo with lighting, sphere, ground

- Scene Demo: cube + sphere + ground plane with proper lighting
- Audio: XAudio2 dynamic loading + WAV playback
- Physics: expanded collision system
- Renderer: improved pipeline with materials
- UI: extended widget system
- VisualScript: enhanced serializer + block interactions
- ASM: optimized math/memory/profiling routines
- Window: mouse input + scroll support

Engine/Rendering/renderer.c

@@ -1,5 +1,18 @@
 #include "renderer.h"
 #include <stdlib.h>
+#include <string.h>
+
+static void fill_constant_buffer(float* cb, const Mat4* world, const Mat4* wvp,
+                                 Vec3 light_dir, Vec4 light_color, Vec4 ambient_color,
+                                 int use_texture, Vec4 diffuse_color) {
+    memcpy(cb + 0,  world->m, sizeof(float) * 16);
+    memcpy(cb + 16, wvp->m,    sizeof(float) * 16);
+    cb[32] = light_dir.x; cb[33] = light_dir.y; cb[34] = light_dir.z; cb[35] = 0.0f;
+    cb[36] = light_color.x; cb[37] = light_color.y; cb[38] = light_color.z; cb[39] = light_color.w;
+    cb[40] = ambient_color.x; cb[41] = ambient_color.y; cb[42] = ambient_color.z; cb[43] = ambient_color.w;
+    cb[44] = use_texture ? 1.0f : 0.0f; cb[45] = 0.0f; cb[46] = 0.0f; cb[47] = 0.0f;
+    cb[48] = diffuse_color.x; cb[49] = diffuse_color.y; cb[50] = diffuse_color.z; cb[51] = diffuse_color.w;
+}
 
 Renderer* renderer_create(GraphicsDevice* device) {
     Renderer* r = (Renderer*)calloc(1, sizeof(Renderer));
@@ -15,7 +28,14 @@ Renderer* renderer_create(GraphicsDevice* device) {
 void renderer_destroy(Renderer* r) { free(r); }
 
 void renderer_begin_frame(Renderer* r) {
+    ID3D11DeviceContext* ctx = r->device->context;
     graphics_device_clear(r->device, 0.1f, 0.1f, 0.15f, 1.0f);
+    D3D11_VIEWPORT vp = {0};
+    vp.Width = (float)r->device->width;
+    vp.Height = (float)r->device->height;
+    vp.MaxDepth = 1.0f;
+    ctx->lpVtbl->RSSetViewports(ctx, 1, &vp);
+    ctx->lpVtbl->IASetPrimitiveTopology(ctx, D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
 }
 
 void renderer_end_frame(Renderer* r) {
@@ -37,9 +57,41 @@ void renderer_draw_mesh(Renderer* r, Mesh* m) {
 }
 
 void renderer_draw_mesh_with_shader(Renderer* r, Mesh* m, Shader* s, const Mat4* world, Texture* t) {
-    if (!m || !s) return;
+    if (!m || !s || !r) return;
     ID3D11DeviceContext* ctx = r->device->context;
     shader_bind(s, ctx);
+
+    Mat4 wvp;
+    mat4_multiply(world, &r->view, &wvp);
+    mat4_multiply(&wvp, &r->projection, &wvp);
+
+    float cb[64];
+    memset(cb, 0, sizeof(cb));
+    fill_constant_buffer(cb, world, &wvp, r->light_dir, r->light_color, r->ambient_color, t ? 1 : 0, (Vec4){1,1,1,1});
+
+    shader_set_matrix(s, ctx, cb);
+    if (t) texture_bind(t, ctx, 0);
+
+    renderer_draw_mesh(r, m);
+}
+
+void renderer_draw_mesh_with_material(Renderer* r, Mesh* m, Material* mat, const Mat4* world) {
+    if (!m || !mat || !mat->shader || !r) return;
+    ID3D11DeviceContext* ctx = r->device->context;
+    shader_bind(mat->shader, ctx);
+
+    Mat4 wvp;
+    mat4_multiply(world, &r->view, &wvp);
+    mat4_multiply(&wvp, &r->projection, &wvp);
+
+    float cb[64];
+    memset(cb, 0, sizeof(cb));
+    fill_constant_buffer(cb, world, &wvp, r->light_dir, r->light_color, r->ambient_color,
+                         mat->use_texture, mat->color);
+
+    shader_set_matrix(mat->shader, ctx, cb);
+    if (mat->use_texture && mat->texture) texture_bind(mat->texture, ctx, 0);
+
     renderer_draw_mesh(r, m);
 }