/// Specify a 2d position in the range from 0,0 to
// w,h with w,h being the camera visible area size
// as from @{blitwizard.graphics.camera:getDimensions|
// getDimensions} with consider_zoom set to <b>false</b>.
//
// (So the position you specify is the coordinates a
// @{blitwizard.object:pinToCamera|pinned object} would have on screen
// or the coordinates you get from @{blitwizard.onMouseMove})
//
// The position can also be smaller than 0,0 or larger than the
// actual camera dimensions, in which case you'll get an out-of-screen
// world position as a result.
// @function screenPosTo2dWorldPos
// @tparam number pos_x the X coordinate of the screen position
// @tparam number pos_y the Y coordinate of the screen position
// @tparam number parallax (optional) if you want, specify the @{blitwizard.object:setParallax|parallax} effect strength to get the world position displaced accordingly for an object with that parallax effect strength
// @treturn number X coordinate of the resulting world position
// @treturn number Y coordinate of the resulting world position
int luafuncs_camera_screenPosTo2dWorldPos(lua_State* l) {
struct luacameralistentry* e = toluacameralistentry(
l, 1, 0, "blitwizard.graphics.camera:screenPosTo2dWorldPos");
if (lua_type(l, 2) != LUA_TNUMBER) {
return haveluaerror(l, badargument1, 1,
"blitwizard.graphics.camera:screenPosTo2dWorldPos", "number", lua_strtype(l, 2));
}
if (lua_type(l, 3) != LUA_TNUMBER) {
return haveluaerror(l, badargument1, 2,
"blitwizard.graphics.camera:screenPosTo2dWorldPos", "number", lua_strtype(l, 3));
}
double parallax = 1;
if (lua_gettop(l) >= 4 && lua_type(l, 4) != LUA_TNIL) {
if (lua_type(l, 4) != LUA_TNUMBER) {
return haveluaerror(l, badargument1, 3,
"blitwizard.graphics.camera:screenPosTo2dWorldPos", "number", lua_strtype(l, 4));
}
if (lua_tonumber(l, 4) <= 0) {
return haveluaerror(l, badargument2, 3,
"blitwizard.graphics.camera:screenPosTo2dWorldPos",
"parallax effect strength needs to be greater than zero");
}
parallax = lua_tonumber(l, 4);
}
double x = lua_tonumber(l, 2);
double y = lua_tonumber(l, 3);
// calculate camera top left world position:
double tx = graphics_getCamera2DCenterX(e->cameraslot);
double ty = graphics_getCamera2DCenterY(e->cameraslot);
double zoomscale =
(UNIT_TO_PIXELS * graphics_getCamera2DZoom(e->cameraslot))
/ (double)UNIT_TO_PIXELS_DEFAULT;
double cameraWidth = graphics_getCameraWidth(e->cameraslot)
/ (double)UNIT_TO_PIXELS;
double cameraHeight = graphics_getCameraHeight(e->cameraslot)
/ (double)UNIT_TO_PIXELS;
tx -= (cameraWidth / zoomscale) * 0.5f;
ty -= (cameraHeight / zoomscale) * 0.5f;
// apply parallax effect as desired with screen center as parallax center:
x -= cameraWidth / 2;
y -= cameraHeight / 2;
x /= parallax;
y /= parallax;
x += cameraWidth / 2;
y += cameraHeight / 2;
// the onscreen coordinates need to be translated into "zoomed" space:
x /= graphics_getCamera2DZoom(e->cameraslot);
y /= graphics_getCamera2DZoom(e->cameraslot);
lua_pushnumber(l, tx + x);
lua_pushnumber(l, ty + y);
return 2;
}
void graphicsrender_draw(void) {
graphicssdlrender_startFrame();
graphics2dsprites_lockListOrTreeAccess();
// render world sprites:
double w = graphics_getCameraWidth(0);
double h = graphics_getCameraHeight(0);
double z = graphics_getCamera2DZoom(0);
double cwidth = (w/UNIT_TO_PIXELS) * z;
double cheight = (w/UNIT_TO_PIXELS) * z;
double ctopleftx = graphics_getCamera2DCenterX(0) - cwidth/2;
double ctoplefty = graphics_getCamera2DCenterY(0) - cheight/2;
graphics2dspritestree_doForAllSpritesSortedBottomToTop(
ctopleftx, ctoplefty, cwidth, cheight,
&graphicssdlrender_spriteCallback, NULL);
// render camera-pinned sprites:
graphics2dspriteslist_doForAllSpritesBottomToTop(
&graphicssdlrender_spriteCallback, NULL);
graphics2dsprites_releaseListOrTreeAccess();
graphicssdlrender_completeFrame();
}