When I swap from rasterized translucency to ray traced translucency, transparent objects lose their color.
Rasterized translucency
Ray traced translucency
Notice how the fourth sphere is red when using rasterized translucency, and clear when using ray traced translucency. Is this a limitation of Lumen, or should I adjust my material?
If it's a Lumen limitation, are there are recommended ways to get around this?
Related
I'm using the EMGU CV .NET library. I noticed that when I take pictures of anything with color, the colors usually get "washed out" if the background is dark(ish). General rule of thumb I've found is that, the darker the background is, the more washed out the colors are.
Here is how I'm retrieving the image from the camera with EMGU.
Dim imgFeed As Bitmap = mCamera.RetrieveBgrFrame.ToBitmap
In the images below (cropped out some of the background on both), the left image is on dry white cement and the right image is on wet white cement. You can see the "washed out" color especially on the first tag, which is bright orange duct tape.
Here is another image, taken on black pavement in the sun, which in reality is much darker than the white cement, but appears similar in color to the background in the wet cement image above.
Is there some sort of auto-balancing that's occurring in the EMGU library? If so, can I stop this from happening? I need to see the colors more clearly than the background. I've read about _EqualizeHist() and I implemented it, but that did not help me see the colors any more clearly; adding contrast to the image didn't really help because the colors were already close to white.
Update
After reading Spark's answer, I found the SetCaptureProperty() method. I see that you can disable the auto exposure property by setting the value to 0 as shown below.
mCamera.SetCaptureProperty(CvEnum.CAP_PROP.CV_CAP_PROP_AUTO_EXPOSURE, 0.0)
Sadly though, with the particular camera I'm using, it looks like the driver does not support changing this property.
This is nothing to do with the algorithm. It is the behavior of Auto Exposure (AEC) algorithm running inside camera chip. Try disabling auto exposure control of camera and reduce the manual exposure level.
Little theory: Most of the AEC algorithm works with full frame weighted method. So in the sample which you showed for white washed case, the black background occupies more portion of the image, which make AEC algorithm to assume that the image is too dark and hence increase exposure level internally.
I'm a novice in OpenGL ES 1.1(for IOS) texturing and I have a problem with making the effect of motion blur. During googling, I found that I should render my scene in different time moments to several textures and then draw all these textures on the screen with different alpha values. But the problem is that I don't know how to implement all this!So,my questions are:
How to draw a 2D texture on the screen? Should I make a square and put my texture on it?Or may be, there is a way to draw a texture on the screen directly?
How to draw several textures(one upon another) on the screen with different alpha values?
I've already come up with some ideas, but I'm not sure if they are correct or not.
Thanks in advance!
Well, of course the first advice is, understand the basics before trying to do advanced stuff. Other than that:
Yes indeed, to draw a full-screen texture you just draw a textured screen-sized quad. An orthographic projection would be a good idea in this case, making the screen-alignment of the quad and its proper sizing easier. For getting the textures in the first place (by rendering into them), FBOs might be of help, but I'm not sure they are supported on ES 1 devices, otherwise the good old glCopyTexSubImage2D will do, too, albeit requiring a copy operation.
Well, you just draw multiple textured quads (see 1) one over the other. You might configure the texture environment to scale the texture's color with the quad's base color (glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE)) and give your quads a color of (1, 1, 1, alpha) (of course lighting should be disabled). Additionally you have to enable alpha blending (glEnable(GL_BLEND)) and use an appropriate blending function (glBlendFunc(GL_SRC_ALPHA, GL_ONE) should do).
But if all these terms don't tell you anything, you should rather first learn the basics using a good learning resource before delving into more advanced effects.
I have a CCSprite that was created from a png with transparent background.
I want to be able to apply colors to this sprite in a way that I`m free to define which color it is, without the actual color of the sprite affecting the amount of each color I have to add.
I`ve tried this:
mySprite.color = ccc3(200,200,255);
In an attempt to add a little blue-ish feel to my sprite, but as it works by setting the amount of tint that's gonna be displayed based on existant color of the sprite, and my sprite has virtually no blue in any of it (most of it is yellow) the resulting effect is pretty sketchy, everything gets really dark, and there is one slight blue-ish coloring, but not as I wanted.
The ideal effect for me on this case would be to ADD a light blue mask to it with very low alpha.
Is there an easy way to do that without composing sprites?
I've tried using CCTexture2D, but had no luck, as there is no built in method for working with colors, and most tutorials only teach you how to build textures out of image files.
This is deceptively hard to do in code with the original sprite. Another option would be:
create a new sprite, which is just a white outline version of your original sprite
the color property of this white sprite will now respond exactly to the RGB values you pass in
so pass in your light blue value to the white sprite and set the opacity correctly
then overlay it on your original sprite
Any good?
The only way you can achieve this is by overlaying (masking) the sprite with the proper OpenGL blend functions. When you say "add a light blue mask" then that's what you need to do. You may find this visual blendfunc tool helpful, if only to understand how blending with mask sprites works and what you can achieve with it. There's no built-in support for this by Cocos2D however, so you'll have to revert to pure OpenGL inside a cocos2d node's -(void) draw {} method.
Tinting (changing the color property) will only modify the RGB channels of the entire image by changing the vertex colors of all 4 vertices.
I am a coder but not a graphic maker. I can decently produce graphics that meet the quality standards visually although I cannot produce graphics that will technically "work." This is what I mean:
I am using CGRectIntersectsRect for colliding images. My image has SOME extra space which I have made completely transparent using Adobe PhotoShop but even if this extra transparent space is not visible, when the two images collide, it will look like you will be hitting nothing as this extra invisible transparent space is PART of the image and when CGRectIntersectsRect is called it detects touch between two images. So if the other image touches the transparent space, CGRectIntersectsRect is called and my code is executed. I only want my code to be executed if it hits the actual COLOR space of the image. Here is two things that could help me through that, they follow through with questions.
Learn how to make NO EXTRA SPACE on an image in photoshop. How could I do this, tutorials?
CGRectIntersectsRect only called when touching a color part of an image. A way to do this?
Thank you guys!
Regarding your question #1, it depends. All images are rectangular, all. So, if your sprite is rectangular, you can crop it in Photoshop to just the rectangular area. But if you want to handle, say, a circle ball, then you can't do such thing as "remove extra space". Your circle ball will always be stored in a rectangular image, with transparent space on the corners.
Learn how to make NO EXTRA SPACE on an image in photoshop. How could I do this, tutorials?
You can manually select an area using the Rectangular Marquee Tool and Image > Crop or automatically trim the image based on an edge pixel color using Image > Trim.
CGRectIntersectsRect only called when touching a color part of an image. A way to do this?
You can use pixel-perfect collisions or create better bounding shapes for your game objects. For example, instead of using pixel-perfect collision for a spaceship like this one, you could use a triangle for the wings, a rectangle for the body, and a triangle for the head.
Pixel-perfect collision
One way you could implement it would be to
Have an blank image in memory.
Draw visible pixels from one image in blue (#0000ff).
Draw visible pixels from the other image in red (#ff0000).
If there's any purple pixels in the image (#ff00ff), then there's an intersection.
Alternative collision detection solution
If your game is physics-based, then you can use a physics engine like Box2D. You can use circles, rectangles, and polygons to represent all of your game objects and it'll give you accurate results without unnecessary overhead.
For collision detection for non-rectangular shapes, you should look into one of the many game and/or physics libraries available for iOS. Cocos2d coupled with Box2d or chipmunk are popular choices.
If you want to do it yourself, you'll need to start with something like a custom CGPath tracing the actual shape of each object, then use a function like CGPathContainsPoint (that's from memory, it may be wrong). But it is not a simple job. Angry birds uses box2d, AFAIK.
Hello I am having a hard time making this UI element look the way I want (see screenshot). Notice the image on the right--how the line width and darkness looks inconsistent compared to the image on the left (which happens to be a screen grab from safari) where the border width is more consistent. How does apple make their lines so perfect?
I'm using a CALayer and the Core Graphics API to draw the image on the right. Is it possible to draw such perfect lines with the standard apis?
The problem with drawing a 1-pixel path is that Quartz draws paths on an exact point grid, starting from {0,0}. This means that if you stroke a vertical path starting at {10,10} with a 1-point width, half of that line will render in the pixel to the left of the coordinate and half in the pixel to the right, causing a blurring effect.
You should therefore shift your drawing by {0.5,0.5} if you want lines to draw on exact pixels.
You can definitely draw what you want with Quartz.
Apple uses images for the tab elements.