You don’t need precision specifiers on constants/literals since those get compile time evaluated to whatever they are being assigned to. In vertex shaders, the following precisions are declared by default: ( 4.5.3 Default Precision Qualifiers) precision highp float; precision highp int; precision lowp sampler2D; precision lowp samplerCube; And in fragment shaders you get: precision mediump … Read more
I just got something similar to this working in my open source GPUImage framework, based on the above code, so I thought I’d provide my working solution to this. In my case, I was able to use a pixel buffer pool, as suggested by Srikumar, instead of the manually created pixel buffers for each frame. … Read more
All you need are the barycentric coordinates, since you are dealing with triangles. Assign each vertex of the triangle an identity, and then use the hardware’s built-in interpolation between the vertex and fragment stages to figure out the relative distance from each of the vertices in your fragment shader. You can think of the barycentric … Read more
The emulator now supports OpenGL: http://android-developers.blogspot.com/2012/04/faster-emulator-with-better-hardware.html Be sure to add the GPU emulation hardware property and set it to yes when creating the avd (per the link below): http://developer.android.com/tools/devices/emulator.html
(I’m taking a bit of a punt here, because your picture does not show exactly what I would expect from texturing a trapezoid, so perhaps something else is happening in your case – but the general problem is well known) Textures will not (by default) interpolate correctly across a trapezoid. When the shape is triangulated … Read more
It’s hardware-dependent. For PowerVR hardware, and other GPUs that use tile-based rendering, using discard means that the TBR can no longer assume that every fragment drawn will become a pixel. This assumption is important because it allows the TBR to evaluate all the depths first, then only evaluate the fragment shaders for the top-most fragments. … Read more
I just added filters to my open source GPUImage framework that perform three of the four processing tasks you describe (swirling, sketch filtering, and converting to an oil painting). While I don’t yet have colorspace transforms as filters, I do have the ability to apply a matrix to transform colors. As examples of these filters … Read more
The short answer is to load the camera image channels (Y,UV) into textures and draw these textures onto a Mesh using a custom fragment shader that will do the color space conversion for us. Since this shader will be running on the GPU, it will be much faster than CPU and certainly much much faster … Read more
Here’s some code fragments for rendering a circle. I haven’t compiled or run this code, so there’s a possibility of (hopefully minor) typos. To prepare the VBO, which would be done once: // Number of segments the circle is divided into. const unsigned DIV_COUNT = 32; // Will use a triangle fan rooted at the … Read more
I know one good reason to prefer explicit location definition. Consider that you hold your geometry data in Vertex Array Objects. For a given object, you create a VAO in such way that the indices correspond to, for example: index 0: positions, index 1: normals, index 2: texcoords Now consider that you want to draw … Read more