I render all my surfaces to a buffer, then at the end of the frame I flip the buffer.
However, when a certain event is happening in the game, I wanted to shake the buffer around to add intensity. Rather than blitting each surface at the offset individually, I thought I would just offset the entire buffer at the end of the frame, since I wanted everything of the buffer to shake.
Is there a way that I can render to buffer at on offset, or do I need to then blit the buffer to a second buffer and flip that?
You can make a function and put it right before your render.
It should get a random direction (up, down, left or right), and add the same small transformation for all textures being rendered at that frame (all textures should be moved a little bit down in that frame, for example).
In the next frame you get again a random direction, avoiding the last one picked.
The function should also have a timer (use SDL_GetTicks() ), so you can set how long is the shaking going to last.
I don't know if I was clear but, good luck anyway. :)
Related
I have an infinite terrain generator and wanted to make a water sprite (moving water) to add some detail to the map. Terrain is devided into chunks and when I load new water chunks, the water sprite is not synced with old chunks.
So, my question is: How can I make sure all my water sprites are synced (same frame and same time of changing to a new frame), even when I load the new ones?
You can change them all yourself by adding an enterFrame listener to the Runtime. Each frame the listener function is called, you can use the sprite setFrame() to update the appearance of each sprite. This approach should not necessary be more costly than Corona's convenience methods for playing sequences of frames.
It is important that all those water sprites use the same image sheet for their frames to save space in texture memory. Also, I understand that your map is huge/infinite, you really only need to update the frame in ** on screen** sprites. As the player moves around the map and different grid squares need to move into view, you set the frame on those sprites to whatever it needs to be to fit with whatever was already on screen at the end of the previous frame.
I'm currently working on a XNA project where I need to create a Picture in picture Overlay to displaying a 3D scene from multiple angles. currently I'm trying to use 2 viewports to do this. The main one fills whole screen and is working as desired. The second is placed in one of the corners of the first (overlapping that corner) and is less than a 5th of the size as the first. apart from the size and placement of the viewports the only thing really difference between the 2 is the placement of their cameras with-in the scene.
As long as the second viewport is drawn second and there are no objects close to the camera of the first viewport in the overlapping corner this actually works greate. However if there is an object close to the camera and in the corner of the first viewport objects seem to experience occlusion culling as a result of the first viewport's object. The occluding object of the first viewport is not shown in the second viewports space though.
My question is how would one prevent the "cross viewport culling" from happening? I've searched all over and the closes threads I could find suggest drawing the second viewport to a RenderTarget2D and using a SpriteBatch to display the resulting texture. Though doing so does fix the occlusion issue it does mayhem on the z ordering, CCW culling, and my water effects all of which I've never had issue with using the default render target.
This issue, at least in my case, Seems to have been resolved by simply clearing the depth buffer between drawing the 2 Viewports. I did this by adding the following line between the function calls that draws the individual Viewports
GraphicsDevice.Clear(ClearOptions.DepthBuffer, Color.Black, 1, 0);
I ran in to this solution while trying to use the Stencil buffer to prevent the Main viewport from drawing under the second, but everything I did before this discovery did not really have a noticeable effect. After I removed all the Stencil code and it looks like I'm getting the desired effect. Sorry but I can't really explain how or why this works without messing up the first Viewport cause I have no clue myself.
Question is in the title:
[ActionScript3.0] How to get color (uint) of pixel at coordinates? (Stage3D, Flare3D)
I am using Flare3D library to render 3D scene on an iPad2. I need to get color values at 768 different coordinates every time screen is redrawn. Previously, on simple stage (2D), I could just draw it on 1x1 bitmaps translated to specified coordinates, now it does not work on stage3D. Plus, I am a bit worried weather it will kill the performance since I really need to do it as often as possible - actually every time screen is drawn.
It would be really nice if that currently displayed screen was like a bitmap somewhere, so I could access it like simple array...but yeah, I am not holding my breath:)
Since Stage3D renders to back-buffer and one can't directly access it, you also need to render to BitmapData using Context3D.drawToBitmapData() method. Rendering to a bitmap is very slow, especially if the viewport is large. As you only need to access those 768 pixels, you could use Context3D.setScissorRectangle to render scene 768 times with the size of scissor rectangle set to 1x1 along with needed coordinates. I haven't tested that myself so I don't know if rendering scene 700 times won`t be slower than rendering it once, but you may want to try that. :)
I'm trying to move a sprite around a CCTMXMap in a smooth fashion. I've figured out how (using CCActions) to move from tile to tile, but I get gaps in my animation (it pauses for a frame while it reevaluates which direction to walk). I've tried moving the character in a scheduled update: method, but that gets messy when you try and restrict the sprite to only moving from tile to tile. Any suggestions on how to get the clean, consistent animation without messy manual animation using update?
Yes, don't use actions. You'll always have the 1-frame delay problem when using CCActions.
Moving the sprite in update is really pretty simple. Especially if you restrict movement to a speed (points per frame) that is clearly divisible by the tile size. For example if your tiles are 40x30, then horizontal speeds of 1,2,4,8,10 would work fine. Vertically 1,2,3,5,6,10 would work.
Update the position by this number, cast it down to int, compare it with the destination location:
if ((int)currentPos.x == (int)targetPos.x && (int)currentPos.y == (int)targetPos.y)
{
NSLog(#"I'm there!");
}
The reason for casting to int is to avoid rounding errors in floating point values.
Another solution would be - especially if your character can only move in one direction at a time - to figure out the number of frames it will take him to get there. If the character has to move 40 points to the right, and he moves at 4 points per frame, it'll take him 10 frames. Then just count the number of frames (how many times the update method ran) and if it reaches 10 (or 0 if you count down) then you know that the character has arrived without needing to check his position.
I am trying to cut a mesh in half or at least be able to delete faces from it in real-time.
How to go about doing this i wonder?
Lock the vertex buffers, memset the selected face or vertex to 0, does not work for me.
has anyone a solution or a tutorial on this i really want this feature in my program!
Cheers
Oh - that one is easy. There is no need to modify the mesh. D3D can already do this for you!
Set the clip-plane via IDirect3DDevice9::SetClipPlane, then enable the plane via the D3DRS_CLIPPLANEENABLE renderstate. You can even set multiple clip-planes at the same time if you want to..
Here is a link to the msdn-entry: http://doc.51windows.net/Directx9_SDK/?url=/directx9_sdk/graphics/reference/d3d/interfaces/idirect3ddevice9/setclipplane.htm
And if you do a google search on "D3D SetClipPlane" you will find lots of discussions and example codes how to use it.
If you need to dynamically delete triangles from a mesh the best/fastest way is to use indexed triangles. When you create the index buffer, use the 'D3DUSAGE_DYNAMIC' flag. When you want to delete triangles, lock it with the 'D3DLOCK_DISCARD' flag. Write the entire new list of indices into the buffer, leaving out the triangles you want to delete.
The index buffer will be much smaller than the vertex buffer, so re-uploading only indices won't be as much of a drag on the system as the vertex buffer would be. But if it would be a big problem for you to convert to indexed triangle lists, then doing these stame operations using the vertex buffer instead is probably your next best option.
You say that setting the vertex to 0 doesn't work. In what way doesn't it work?
If you set the position of all the verticies of a triangle to (0.0, 0.0, 0.0) then the resulting triangle will be of zero size and shouldn't be drawn. Just to be sure you could set it to an offscreen position instead of zero.