medfall

commit 93e95d2192c17cb01df62bf8d3ba7e6893569803
parent daedcbe98bcbb6ac210d089a5b7aa3cdb1973beb
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Tue Sep 15 22:57:15 +0100

Push BTTs to the GPU. Don't do anything with them yet

Diffstat:
Makefile
 | 
2
+-
btt.cc
 | 
3
+++
game.h
 | 
2
++
gpubtt.cc
 | 
85
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
gpubtt.h
 | 
23
+++++++++++++++++++++++
heightmap.h
 | 
5
+++++
6 files changed, 119 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
@@ -32,7 +32,7 @@ bsp.so: $(BSPOBJS)
 pp: $(PPOBJS)
 	$(CXX) $^ $(LDFLAGS) -o $@
 
-btt.so: btt.o heightmap.o memory_arena.o work_queue.o stb_image.o immediate.o
+btt.so: btt.o heightmap.o memory_arena.o work_queue.o stb_image.o immediate.o gpubtt.o
 	$(CXX) $^ $(LDFLAGS) -o $@ -shared
 
 clean:
diff --git a/btt.cc b/btt.cc
@@ -230,6 +230,9 @@ extern "C" GAME_INIT( game_init ) {
 		state->test_at_normal, state->test_at_lit );
 	state->btt = btt_from_heightmap( &state->hm, &mem->persistent_arena );
 
+	const OffsetHeightmap ohm = { state->hm, 0, 0 };
+	gpubtt_init( &mem->persistent_arena, &state->gpubtt, &ohm, state->btt, state->test_at_position );
+
 	glClearColor( 0, 0.5, 0.7, 1 );
 }
 
diff --git a/game.h b/game.h
@@ -67,6 +67,7 @@
 #include "assets.h"
 #include "terrain_manager.h"
 #include "btt.h"
+#include "gpubtt.h"
 #include "heightmap.h"
 #include "bsp.h"
 #include "bsp_renderer.h"
@@ -107,6 +108,7 @@ struct GameState {
 	GLint test_outline_un_vp;
 
 	BTTs btt;
+	GPUBTT gpubtt;
 	Heightmap hm;
 
 	ImmediateContext test_immediate;
diff --git a/gpubtt.cc b/gpubtt.cc
@@ -0,0 +1,85 @@
+#include "platform_opengl.h"
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.hpp>
+
+#include "intrinsics.h"
+#include "memory_arena.h"
+#include "btt.h"
+#include "heightmap.h"
+#include "gpubtt.h"
+
+static u32 btt_count_leaves( const BTT * const btt ) {
+	if( btt->left ) {
+		return btt_count_leaves( btt->left ) + btt_count_leaves( btt->right );
+	}
+
+	return 1;
+}
+
+static void gpubtt_build(
+	glm::vec3 * const verts, u32 * i,
+	const OffsetHeightmap * ohm, const BTT * btt,
+	const glm::ivec2 iv0, const glm::ivec2 iv1, const glm::ivec2 iv2
+) {
+	const glm::vec3 offset( ohm->x_offset, ohm->y_offset, 0.0f );
+
+	const glm::vec3 v0( ohm->hm.point( v0.x, v0.y ) + offset );
+	const glm::vec3 v1( ohm->hm.point( v1.x, v1.y ) + offset );
+	const glm::vec3 v2( ohm->hm.point( v2.x, v2.y ) + offset );
+
+	if( btt->left ) {
+		const glm::ivec2 mid = ( iv0 + iv2 ) / 2;
+
+		gpubtt_build( verts, i, ohm, btt->left, iv1, mid, iv0 );
+		gpubtt_build( verts, i, ohm, btt->right, iv2, mid, iv1 );
+	}
+	else {
+		verts[ *i++ ] = v0;
+		verts[ *i++ ] = v1;
+		verts[ *i++ ] = v2;
+	}
+}
+
+void gpubtt_init(
+	MemoryArena * const mem, GPUBTT * const gpubtt,
+	const OffsetHeightmap * const ohm, const BTTs btts,
+	const GLuint at_position
+) {
+	MemoryArenaCheckpoint cp = memarena_checkpoint( mem );
+
+	const u32 num_leaves = btt_count_leaves( btts.left_root )
+		+ btt_count_leaves( btts.right_root );
+
+	glm::vec3 * const verts = memarena_push_many( mem, glm::vec3, num_leaves * 3 );
+	u32 i = 0;
+
+	gpubtt_build( verts, &i, ohm, btts.left_root, glm::ivec2( 0, 0 ), glm::ivec2( 0, ohm->hm.h - 1 ), glm::ivec2( ohm->hm.w - 1, ohm->hm.h - 1 ) );
+	gpubtt_build( verts, &i, ohm, btts.right_root, glm::ivec2( ohm->hm.w - 1, ohm->hm.h - 1 ), glm::ivec2( ohm->hm.w - 1, 0 ), glm::ivec2( 0, 0 ) );
+
+	glGenVertexArrays( 1, &gpubtt->vao );
+	glBindVertexArray( gpubtt->vao );
+
+	glGenBuffers( 1, &gpubtt->vbo_verts );
+	glBindBuffer( GL_ARRAY_BUFFER, gpubtt->vbo_verts );
+	glBufferData( GL_ARRAY_BUFFER, num_leaves * sizeof( GLfloat ) * 3, verts, GL_STATIC_DRAW );
+	glEnableVertexAttribArray( at_position );
+	glVertexAttribPointer( at_position, 3, GL_FLOAT, GL_FALSE, 0, 0 );
+
+	glBindVertexArray( 0 );
+
+	gpubtt->num_verts = i;
+
+	memarena_restore( mem, &cp );
+}
+
+void gpubtt_destroy( GPUBTT * const gpubtt ) {
+	glDeleteBuffers( 1, &gpubtt->vbo_verts );
+	glDeleteVertexArrays( 1, &gpubtt->vao );
+}
+
+void gpubtt_render( const GPUBTT * const gpubtt ) {
+	glBindVertexArray( gpubtt->vao );
+	glDrawElements( GL_TRIANGLES, gpubtt->num_verts, GL_UNSIGNED_INT, 0 );
+	glBindVertexArray( 0 );
+}
diff --git a/gpubtt.h b/gpubtt.h
@@ -0,0 +1,23 @@
+#ifndef _GPUBTT_H_
+#define _GPUBTT_H_
+
+#include "platform_opengl.h"
+
+#include "heightmap.h"
+#include "btt.h"
+
+struct GPUBTT {
+	GLuint vao;
+	GLuint vbo_verts;
+	u32 num_verts;
+};
+
+void gpubtt_init( MemoryArena * const mem, GPUBTT * const gpubtt,
+	const OffsetHeightmap * const ohm, const BTTs btts,
+	const GLuint at_position );
+
+void gpubtt_destroy( GPUBTT * const gpubtt );
+
+void gpubtt_render( const GPUBTT * const gpubtt );
+
+#endif // _GPUBTT_H_
diff --git a/heightmap.h b/heightmap.h
@@ -31,4 +31,9 @@ public:
 	void render() const;
 };
 
+struct OffsetHeightmap {
+	Heightmap hm;
+	float x_offset, y_offset;
+};
+
 #endif // _HEIGHTMAP_H_