Add basic 3D functionality

run

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 set -e
 ./lua_translate
-gcc src/main.c -g -lSDL2 -llua5.3 -o engine -O3 -Werror -Wall
+gcc src/main.c -g -lSDL2 -llua5.3 -lm -o engine -O3 -Werror -Wall
 exec ./engine

src/3d.c

@@ -0,0 +1,49 @@
+#include <math.h>
+
+void engine_3d_find_rotation(struct ENGINE_VECTOR_3D * rot,float x, float y, float z) {
+	float distance = sqrtf(x * x + y * y);
+	rot->x = atan2f(y,x) * (180.0/M_PI);
+	rot->y = atan2f(z,distance) * (180.0/M_PI);
+	rot->z = 0.0;
+}
+
+void engine_3d_rotate_position(struct ENGINE_VECTOR_3D * pos,float x, float y, float z, float rx, float ry, float rz) {
+	rx = rx * (M_PI/180.0);
+	ry = ry * (M_PI/180.0);
+	rz = rz * (M_PI/180.0);
+	float sinX = sinf(rx);
+	float cosX = cosf(rx);
+	float sinY = sinf(ry);
+	float cosY = cosf(ry);
+	float sinZ = sinf(rz);
+	float cosZ = cosf(rz);
+	pos->x = x * (cosY * cosZ) + y * (sinX * sinY * cosZ - cosX * sinZ) + z * (cosX * sinY * cosZ + sinX * sinZ);
+	pos->y = x * (cosY * sinZ) + y * (sinX * sinY * sinZ + cosX * cosZ) + z * (cosX * sinY * sinZ - sinX * cosZ);
+	pos->z = x * (-sinY) + y * (sinX * cosY) + z * (cosX * cosY);
+}
+
+void engine_3d_project(struct ENGINE_VECTOR_2D * screen,float x, float y, float z, float rx, float ry, float rz, float fov) {
+	struct ENGINE_VECTOR_3D pos;
+	pos.x = x;
+	pos.y = y;
+	pos.z = z;
+	
+	engine_3d_rotate_position(&pos,pos.x,pos.y,pos.z,0.0,ry,0.0);
+	engine_3d_rotate_position(&pos,pos.x,pos.y,pos.z,0.0,0.0,rx);
+	pos.x = -pos.x; pos.y = -pos.y; pos.z = -pos.z;
+	struct ENGINE_VECTOR_3D rot;
+	engine_3d_find_rotation(&rot,pos.x,pos.y,pos.z);
+	
+	// rot.y (screen X)
+	while (rot.y >  180.0) { rot.y -= 360.0; }
+	while (rot.y < -180.0) { rot.y += 360.0; }
+	rot.y = rot.y / (fov * 0.5);
+	
+	// rot.x (screen Y)
+	while (rot.x >  180.0) { rot.x -= 360.0; }
+	while (rot.x < -180.0) { rot.x += 360.0; }
+	rot.x = rot.x / (fov * 0.5);
+	
+	screen->x = rot.y;
+	screen->y = rot.x;
+}

src/lua_manual.c

@@ -36,6 +36,50 @@ int engine_luaf_window_texture_get(lua_State *L) {
 	return 1;
 }
 
+int engine_luaf_3d_find_rotation(lua_State *L) {
+	float x = luaL_checknumber(L,1);
+	float y = luaL_checknumber(L,2);
+	float z = luaL_checknumber(L,3);
+	
+	struct ENGINE_VECTOR_3D rot;
+	engine_3d_find_rotation(&rot,x,y,z);
+	lua_pushnumber(L,rot.x);
+	lua_pushnumber(L,rot.y);
+	lua_pushnumber(L,rot.z);
+	return 3;
+}
+
+int engine_luaf_3d_rotate_position(lua_State *L) {
+	float x = luaL_checknumber(L,1);
+	float y = luaL_checknumber(L,2);
+	float z = luaL_checknumber(L,3);
+	float rx = luaL_checknumber(L,4);
+	float ry = luaL_checknumber(L,5);
+	float rz = luaL_checknumber(L,6);
+	
+	struct ENGINE_VECTOR_3D pos;
+	engine_3d_rotate_position(&pos,x,y,z,rx,ry,rz);
+	lua_pushnumber(L,pos.x);
+	lua_pushnumber(L,pos.y);
+	lua_pushnumber(L,pos.z);
+	return 3;
+}
+
+int engine_luaf_3d_project(lua_State *L) {
+	float x = luaL_checknumber(L,1);
+	float y = luaL_checknumber(L,2);
+	float z = luaL_checknumber(L,3);
+	float rx = luaL_checknumber(L,4);
+	float ry = luaL_checknumber(L,5);
+	float rz = luaL_checknumber(L,6);
+	float fov = luaL_checknumber(L,7);
+	struct ENGINE_VECTOR_2D pos;
+	engine_3d_project(&pos,x,y,z,rx,ry,rz,fov);
+	lua_pushnumber(L,pos.x);
+	lua_pushnumber(L,pos.y);
+	return 2;
+}
+
 void engine_lua_init_manual() {
 	lua_pushcfunction(engine_lua_state,engine_luaf_lua_event_get_data);
 	lua_setglobal    (engine_lua_state,"engine_lua_event_get_data");
@@ -43,4 +87,10 @@ void engine_lua_init_manual() {
 	lua_setglobal    (engine_lua_state,"engine_texture_color_get");
 	lua_pushcfunction(engine_lua_state,engine_luaf_window_texture_get);
 	lua_setglobal    (engine_lua_state,"engine_window_texture_get");
+	lua_pushcfunction(engine_lua_state,engine_luaf_3d_find_rotation);
+	lua_setglobal    (engine_lua_state,"engine_3d_find_rotation");
+	lua_pushcfunction(engine_lua_state,engine_luaf_3d_rotate_position);
+	lua_setglobal    (engine_lua_state,"engine_3d_rotate_position");
+	lua_pushcfunction(engine_lua_state,engine_luaf_3d_project);
+	lua_setglobal    (engine_lua_state,"engine_3d_project");
 }

src/main.c

@@ -3,6 +3,7 @@
 #include "frontend/sdl/structs.c"
 //#include "frontend/sdl/structs.c"
 #include "engine.c"
+#include "3d.c"
 #include "frontend/sdl/main.c"
 #include "helpers.c"
 //#include "frontend/sdl/main.c"

src/values/functions.toml

@@ -120,3 +120,25 @@ type = "void"
 arguments =   ["struct ENGINE_WINDOW *"]
 argNames =    ["window"]
 description = "Destroy a window."
+
+# 3D
+[engine_3d_find_rotation]
+type = "void"
+arguments =   ["struct ENGINE_VECTOR_3D *","float","float","float"]
+argNames =    ["rot",                      "x",    "y",    "z"]
+description = "Find the rotation required to get from 0,0,0 to the coordinates (look at). Output is put into rot pointer. Pointer not required in Lua."
+lua = "manual"
+
+[engine_3d_rotate_position]
+type = "void"
+arguments =   ["struct ENGINE_VECTOR_3D *","float","float","float","float","float","float"]
+argNames =    ["pos",                      "x",    "y",    "z",    "rx",   "ry",   "rz"]
+description = "Rotate a point around 0,0,0 using rotation vectors. Output is put into pos pointer. Pointer not required in Lua."
+lua = "manual"
+
+[engine_3d_project]
+type = "void"
+arguments =   ["struct ENGINE_VECTOR_2D *","float","float","float","float","float","float","float"]
+argNames =    ["screen",                   "x",    "y",    "z",    "rx",   "ry",   "rz",   "fov"]
+description = "Project a 3D point onto a 2D surface. -1. = Top/Left, 1. = Bottom/Right. Output is put into screen pointer. Pointer not required in Lua."
+lua = "manual"