medfall

commit e519c8953eed9f3ad4ac31f4c446650e3ea15c83
parent 0f522205317e5a7d8e27e1ea45238c851db8c7ab
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Fri Dec  9 20:41:13 +0200

Make heightmap_build_quadtree fill in a user provided array

Diffstat:
heightmap.cc
 | 
11
+++++++----
heightmap.h
 | 
5
+++--
mod_btt.cc
 | 
5
++++-
3 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/heightmap.cc b/heightmap.cc
@@ -245,17 +245,20 @@ static void heightmap_build_quadtree_node( HeightmapQuadTree * qt, size_t node_i
 	qt->nodes[ node_idx ].max_z = hi;
 }
 
-HeightmapQuadTree heightmap_build_quadtree( const Heightmap * hm ) {
+size_t heightmap_quadtree_max_nodes( const Heightmap * hm ) {
 	// with a power of 2 + 1 sized quadtree it should be exactly 4/3 (1 +
 	// 1/4 + 1/16 + ...) but with other sizes it gets funny. 1.34 seems to
 	// work with minimal wasted space
-	size_t num_nodes = 1.34 * ( hm->width - 1 ) * ( hm->width - 1 );
+	return 1.34 * ( hm->width - 1 ) * ( hm->width - 1 );
+}
+
+HeightmapQuadTree heightmap_build_quadtree( const Heightmap * hm, array< HeightmapQuadTreeNode > & nodes ) {
+	ASSERT( nodes.n >= heightmap_quadtree_max_nodes( hm ) );
 
 	HeightmapQuadTree qt;
 	qt.hm = hm;
 	qt.dim = hm->width - 1;
-	qt.nodes_memory = ( HeightmapQuadTreeNode * ) malloc( num_nodes * sizeof( HeightmapQuadTreeNode ) );
-	qt.nodes = array< HeightmapQuadTreeNode >( qt.nodes_memory, num_nodes );
+	qt.nodes = nodes;
 	memset( qt.nodes.ptr(), 0, qt.nodes.num_bytes() );
 
 	AABBu32 aabb( v3u32( 0, 0, 0 ), v3u32( qt.dim, qt.dim, 255 ) );
diff --git a/heightmap.h b/heightmap.h
@@ -2,7 +2,7 @@
 #define _HEIGHTMAP_H_
 
 #include "intrinsics.h"
-#include "memory_arena.h"
+#include "array.h"
 #include "linear_algebra.h"
 
 class Heightmap {
@@ -35,7 +35,8 @@ struct HeightmapQuadTree {
 	const Heightmap * hm;
 };
 
-HeightmapQuadTree heightmap_build_quadtree( const Heightmap * hm );
+size_t heightmap_quadtree_max_nodes( const Heightmap * hm );
+HeightmapQuadTree heightmap_build_quadtree( const Heightmap * hm, array< HeightmapQuadTreeNode > & nodes );
 
 // TODO: these are all pretty general
 // struct Intersection {
diff --git a/mod_btt.cc b/mod_btt.cc
@@ -170,7 +170,10 @@ extern "C" GAME_INIT( game_init ) {
 	int w, h;
 	u8 * pixels = stbi_load( "terrains/" TERRAIN_NAME, &w, &h, NULL, 1 );
 	heightmap_init( &game->hm, pixels, w, h );
-	qt = heightmap_build_quadtree( &game->hm );
+
+	size_t num_nodes = heightmap_quadtree_max_nodes( &game->hm );
+	array< HeightmapQuadTreeNode > nodes = memarena_push_array( &mem->persistent_arena, HeightmapQuadTreeNode, num_nodes );
+	qt = heightmap_build_quadtree( &game->hm, nodes );
 
 	size_t horizons_size = ( w + 1 ) * ( h + 1 ) * sizeof( float );
 	horizons = ( float * ) malloc( horizons_size );