How can I efficently interpolate per-pixel two textures A and B by a dynamic texture C and draw them on a simple quad? Multi-pass algorithms accepted. I've had moderate success calculating the C texture per-frame on the CPU and uploading it with glTexImage2D into an alpha-only texture. While this worked, performance was lacking and I h...
I have been having trouble finding straightforward code to render a scene to a texture in OpenGL ES (specifically for the iPhone, if that matters). I am interested in knowing the following: How do you render a scene to a texture in OpenGL ES? What parameters must you use to create a texture that is capable of being a render target in ...
When I render to texture, and then draw the same image, it seems to make everything darker. To get this image: I'm rendering the upper-left square with color (1, 1, 1, .8) to a texture, then rendering that texture, plus the middle square (same color) to another texture, then finally that texture plus the lower-right square (same color...
This is related to my last question. To get this image: I draw a white background (color = (1, 1, 1, 1)). I render-to-texture the two upper-left squares with color = (1, 0, 0, .8) and blend function (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA), and then draw the texture with color = (1, 1, 1, 1) and blend function (GL_ONE, GL_ONE_MINUS_SRC...
This should be really simple, but it's consumed multi-hours of my time, and I have no clue what's going on. I'm rendering a flat-colored full-screen quad to a texture, then reading back the result with glGetTexImage. It's GPGPU related, so I want the alpha value to behave as if it's any of the other three. I'm using an FBO, texture form...
I was wondering, if I render a scene using a shader to which I pass in a texture that also happens to be the render target for that scene will it cause any unwanted behaviour? So basically: texture t; shader->SetTexture("texture",t); device->SetRenderTarget( 0, t->surface ); shader->Begin("effect") // do some more shader stuff devi...
I'm trying to render to a texture, then draw that texture to the screen using OpenGL ES on the iPhone. I'm using this question as a starting point, and doing the drawing in a subclass of Apple's demo EAGLView. Instance variables: GLuint textureFrameBuffer; Texture2D * texture; To initialize the frame buffer and texture, I'm doing th...
Hey! I write graphics apps for the iPhone and I'm looking to port my most recent app, 'Layers,' to the Android platform. Layers is painting app that allows users to draw on the screen and create multi-layered paintings with different brushes, colors, etc... and export to PSD. It's got desktop sync, a smudge tool, lots of good stuff... ht...
I'm writing some code which is intended to: 1. Render into an OpenGL texture using an FBO. 2. Draw from the FBO texture to a GLXPixmap, which is attached to an X Pixmap. 3. Draw the X Pixmap to a window on the screen. Step 3 works great, and step 2 works fine if I replace the FBO texture with normal OpenGL drawing. But if I do what's a...
Hello, I am rendering to a texture through a framebuffer object, and when I draw transparent primitives, the primitives are blended properly with other primitives drawn in that single draw step, but they are not blended properly with the previous contents of the framebuffer. Is there a way to properly blend the contents of the texture w...
I'm in the process of writing a wrapper for some OpenGL functions. The goal is to wrap the context used by the game Neverwinter Nights, in order to apply post-processing shader effects. After learning OpenGL (this is my first attempt to use it) and much playing with DLLs and redirection, I have a somewhat working system. However, when ...
I've googled around everywhere, but cannot find much for rendering strings to textures and then displaying that texture on a quad on the screen. Can someone provide a run-down on the process or provide good resources that describe how? Is rendering strings to textures even the best method for displaying text in an Android OpenGL ES app? ...
Okay, so I am trying to render a scene to a small 32x32 texture and ran into problems. I get an "invalid framebuffer operation" error when I try to actually draw anything to the texture. I have simplified the code below so that it simply tries to render a quad to a texture and then bind that quad as a texture for another quad that is ren...
I have a problem with rendering to texture and offscreen framebuffer with OpenGL ES on iPhone. First image shows mahjong tiles rendered to CAEAGLLayer directly and this is correct. Second one shows tiles rendered to offscreen framebuffer, copied to texture using glCopyTexImage2D and the texture rendered to CAEAGLLayer. Both use white ...
Hello, pros and gurus! Here is another question about rendering to texture. The whole stuff is all about saving texture between passing image into different filters. Maybe all iPhone developers knows about Apple's sample code with OpenGL processing where they used GL filters(functions), but pass into them the same source image. I need ...
UPDATE: Danvil solved it in a comment below. My texture format was GL_RGB not GL_RGBA which of course means that the alpha values aren't kept. Don't know why I didn't realize... Thanks Danvil. I am rendering to a texture using a GLSL shader and then sending that texture as input to a second shader. For the first texture I am using RGB c...
I know to use glGet to get various parameters. I need to know how to get the current GL_FRAMEBUFFER_OES and get the GLuint type framebuffer id. I need to use renderToTexture. This will make one of the classes code easier when switching back to normal framebuffer. ...
I'm doing heavy computation using the GPU, which involves a lot of render-to-texture operations. It's an iterative computation, so there's a lot of rendering to a texture, then rendering that texture to another texture, then rendering the second texture back to the first texture and so on, passing the texture through a shader each time. ...
Hello guys, Let me shortly describe the "battlefield" of my task: Multi-room audio/video chat with more than 1M users; Custom Direct3D renderer; What I need to implement is TextOverVideo feature. The Text itself goes via network and is to be rendered on the recipient side with Direct3D renderer. AFAIK, it is commonly used in game de...
Hello! In my iPhone game I use separate thread to load resources. I use multiple EAGLContext's. Sometimes I need to render to texture in this background thread. But all I get is the black 1024*1024 texture. How do I render to texture in one thread while other thread is performing screen rendering? ...