twn_draw.c: add draw_quad()

src/rendering/twn_draw.c

@@ -179,6 +179,31 @@ void draw_nine_slice(const char *texture, Vec2 corners, Rect rect, float border_
 }
 
 
+TWN_API void draw_quad(char const *texture,
+                       Vec3        v0,          /* upper-left */
+                       Vec3        v1,          /* bottom-left */
+                       Vec3        v2,          /* bottom-right */
+                       Vec3        v3,          /* upper-right */
+                       Rect        texture_region,
+                       Color       color)
+{
+    Vec2 const uv0 = { texture_region.x,                    texture_region.y };
+    Vec2 const uv1 = { texture_region.x,                    texture_region.y + texture_region.h };
+    Vec2 const uv2 = { texture_region.x + texture_region.w, texture_region.y + texture_region.h };
+    Vec2 const uv3 = { texture_region.x + texture_region.w, texture_region.y };
+
+    draw_triangle(texture,
+                  v0, v1, v3,
+                  uv0, uv1, uv3,
+                  color, color, color);
+
+    draw_triangle(texture,
+                  v3, v1, v2,
+                  uv3, uv1, uv2,
+                  color, color, color);
+}
+
+
 static void render_2d(void) {
     use_2d_pipeline();