Point sprites are indeed well suited for particle systems. But they don’t have anything to do with VBOs and GLSL, meaning they are a completely orthogonal feature. No matter if you use point sprites or not, you always have to use VBOs for uploading the geometry, be they just points, pre-made sprites or whatever, and … Read more
Most modern engines I know have a “shader cache” and use the second option, because apparently it’s faster. Also you can take a look at the ARB_shader_subroutine which allows dynamic linkage. But I think it’s only available on DX11 class hardware.
The Eclipse Shaders plugin mentioned by Gilbert Le Blanc works for me with Eclipse Juno. Place the contents of the “plugins” folder in your Eclipse plugins folder, and place the contents of the “features” folder in your Eclipse features folder. Then restart Eclipse. You might need to name your shaders with the extension “.glsl”, or … Read more
Attributes: Your mesh has a number of data streams. For each stream you can keep the following info: (name, type, data). Upon linking, you can query the GLSL program for active attributes and form an attribute dictionary for this program. Each element here is just (name, type). When you draw a mesh with a specified … Read more
The fragment shader receives gl_Color and gl_SecondaryColor as vertex attributes. It also gets four varying variables: gl_FrontColor, gl_FrontSecondaryColor, gl_BackColor, and gl_BackSecondaryColor that it can write values to. If you want to pass the original colors straight through, you’d do something like: gl_FrontColor = gl_Color; gl_FrontSecondaryColor = gl_SecondaryColor; gl_BackColor = gl_Color; gl_BackSecondaryColor = gl_SecondaryColor; Fixed functionality … Read more
Yup, a local server’s really the only way to go if you want to use XHR. I’ve written a bunch of WebGL lessons, and have often considered moving away from embedding the shaders in the HTML, but have been scared off by amount of explanation about web security I’d need to write… Fortunately it’s super … Read more
I think the confusion comes from the idea of normalizing “a value” as opposed to “a vector”; if you just think of a single number as a value, normalization doesn’t make any sense. Normalization is only useful when applied to a vector. A vector is a sequence of numbers; in 3D graphics it is usually … Read more
One option is to pass information via uniform variables. After glUseProgram(myShaderProgram); you can use GLint myUniformLocation = glGetUniformLocation(myShaderProgram, “myUniform”); and for example glUniform1f(myUniformLocation, /* some floating point value here */); In your vertex or fragment shader, you need to add the following declaration: uniform float myUniform; That’s it, in your shader you can now access … Read more
It is very simple, really. All you need is to bind the sampler to some texture unit with glUniform1i. So for your code sample, assuming the two uniform samplers: uniform sampler2D DecalTex; // The texture (we’ll bind to texture unit 0) uniform sampler2D BumpTex; // The bump-map (we’ll bind to texture unit 1) In your … Read more
Let’s look at #1: Considering every object might have its own material, it involves a lot of glUseProgram calls. This isn’t that big of a deal, really. Swapping programs is hard, but you’d be swapping textures too, so it’s not like you’re not already changing important state. Implies the creation of a lot of shaderprogram … Read more